View Full Version : Spit/109 sea level speed comparisons in 1.08 beta patch
NZtyphoon
09-19-2012, 10:27 PM
I got the weights from several flight test but did not have a ladeplan. The weight I used leaves out the pilot.
I fixed it and it narrows the gap but does not eliminate it.
The RAE chart uses CLmax neither airplane can attain in clean configuration by any calculation or measurement, including the RAE's. Read the report you claim I have not!
In fact, the CLmax comes very close to matching full flaps for both aircraft.
So while Crumpp is prepared to say that maths has all the answers compromises, such as leaving out the pilot and reducing the weight of an aircraft is okay - especially if it favours one type in particular over another. "I fixed it and it narrows the gap" but no explanation as to how this was done. Instead we are told to have faith in Crumpp's genius because he knows better than everyone else, as per usual.
bongodriver
09-19-2012, 10:48 PM
So while Crumpp is prepared to say that maths has all the answers compromises, such as leaving out the pilot and reducing the weight of an aircraft is okay - especially if it favours one type in particular over another. "I fixed it and it narrows the gap" but no explanation as to how this was done. Instead we are told to have faith in Crumpp's genius because he knows better than everyone else, as per usual.
Yep, one of the main flaws of Crumpps beloved maths, put garbage in and get more garbage back.
IvanK
09-19-2012, 10:51 PM
The RAE shows better turn radius in this chart. The Spitfire always has a better turn radius than the Bf-109.
Radius being just one parameter of turn performance and not the most important either.
Not specifically. It appears to be RAM power because the chart list's power in flight.
Exactly, once the parameters are input, the math does it's magic.
http://i40.photobucket.com/albums/e215/zulu64/susturn2934_zps42dd3e5b.jpg
Er the chart above also shows Sustained G for any given IAS....at pretty much any IAS the Spitfire can sustain somewhere around 0.5G more than the BF109 ..... (not hard to determine turn rate here either)
The Blue RAE chart (from the same document) also shows sustained G, Turn times for 360 and also provides a means to determine Ps for bleeding turns ..... So we have turn radius, turn rate, sustained G (Ps=0) and a means to determine -Ve Ps values for energy bleed .... what more is there to turn performance ...... give us a break !
So far you have admitted to a weight error in your calculation. We know you made an error on the Spitfire power as well using 950/990BHP whilst RAE used 1050Hp at 12,500ft .... and we also know that a Merlin II power rating at Combat power was 1030hp at 16,500ft as detailed in the 2 seperate Inspection and test certificates.... shown earlier. And in Post 209 with respect Spitfire BHP you said "I suspect it was for an improved high altitude version".... when we know it wasn't and that RAE used standard Combat Power ratings.
pstyle
09-19-2012, 11:00 PM
They are not at the same speed or angle of bank!
Are you saying that, because we don;t know the AoB, we cannot therefore assume that their rotational velocity is equivalent - because the air passing over the indicator would not be equally displaced with respect to each aircraft's flight path?
If so, then yes, you're right I suppose.
Rotational velocity is dependant on more that simply airspeed and turn radius.. it needs "ground speed", essentially - which is the "real" speed around the spatial unit that is the turn.
Can we make any assumptions about likely AoB? The graph indicates that the turn is level (horizontally in each case). Do we know what the AoB differential is likely to be for each aircraft in each case? (then we can work out the proportion of airspeed that is in the horizontal plane).
IvanK
09-20-2012, 02:53 AM
Now lets look at this Clmax discussion which Crumpp claims the RAE cocked up. Lets look at some other peoples estimates for Spitfire Clmax values.
How about we start with NACA ... we will use that very same report Crumpp that you are so smitten with that you used in setting up the "Spitfire Dangerous Stability thread". Here is NACA's estimate on Clmax
http://i40.photobucket.com/albums/e215/zulu64/NACA_Clmax_zps0dfde387.jpg
So at Cruise power (3.75lbs boost 2650RPM) in clean configuration they come up with 1.68 (Recalling that the RAE plot is based on +6.25Lbs/3000RPM)
Then lets look at the RAE document they wrote in response to the NACA report:
http://i40.photobucket.com/albums/e215/zulu64/rae_Clmax_zpsa488cccd.jpg
Interestingly the RAE methodolgy is slightly different to NACA's (Trailing versus Pole with swivel head) the RAE came up with Clmax on the glide (power off) of 1.36 and at max power of 1.89. The RAE Blue Turn plot uses a Clmax value under full power of 1.87
Of course we know the NACA report was based on a Spitfire MKVA so there will be some variance to the numbers of a Spitfire MKI but it does give some validation of the RAE determined Clmax under power values.
The NACA Spitfire MKVA document was good enough for you Crumpp in the stability argument regarding the MKI so I assume its an acceptable reference in this discussion ?
Crumpp
09-20-2012, 03:44 AM
Pstyle says:
Are you saying that, because we don;t know the AoB, we cannot therefore assume that their rotational velocity is equivalent
That is correct.
IvanK says:
Now lets look at this Clmax discussion which Crumpp claims the RAE cocked up.
Why don't you do the math IvanK? You have a better idea of how to interpret aircraft data. That is not being patronizing, it is just a fact. You can set emotion aside and let numbers fall where they may....
If you do the math, you will find the values for CLmax align with the NACA's!!
Spitfire Mk I:
Speeds Dynamic pressure CL
66 14.76610169 1.693067034
http://imageshack.us/a/img716/1508/nacaclmaxzps0dfde387.jpg (http://imageshack.us/photo/my-images/716/nacaclmaxzps0dfde387.jpg/)
Once more, the RAE admits that operating a trailing static head is difficult as best. Do you know what you have to do? When installed, you have a tangle of tubes in the cockpit that the pilot must pinch off with an airtight seal on the correct lines at the right time. It is hard enough in cruise flight and would be extremely difficult to do accurately in a high performance fighter at the stall point.
That is why they labeled the values as "assumed values of CLmax".
http://imageshack.us/a/img571/9113/raeclmaxzpsa488cccd.jpg (http://imageshack.us/photo/my-images/571/raeclmaxzpsa488cccd.jpg/)
Crumpp
09-20-2012, 04:01 AM
IvanK says:
RAE methodolgy is slightly different to NACA's
Because of the difficulty in obtaining accurate measurements under certain conditions of flight.....
See above.
Glad you brought up all these points. You read my mind. .
You can use the NACA's values for some things on the Spitfire Mk V. The airfoil is the same. Airfoil selection is what determines Coefficient of lift.
If I would have posted it, some people would have just attacked it was from a different variant without understanding what is comparible and what is not.
ATAG_Dutch
09-20-2012, 04:01 AM
Let me guess here.
The 'math' (or 'maths' as it's referred to over here) according to Crummp, shows something adverse to the documented real life performance of the Supermarine Spitfire relative to the performance of the Bf109.
There is a distinct pattern developing here.
I find it surprising that a man who purports to concern himself with the performance of 'real aircraft', does not spend his time debating these issues on a more appropriate forum involving comparisons between 'real world' aircraft.
Why would such an expert in his field waste his time on a forum geared to the analysis of a Battle of Britain based computer game? With most of his efforts geared toward the discrediting of the Supermarine Spitfire relative to the Messerschmidt Bf109?
It's a mystery to me, but maybe a psychologist could write a thesis.
Crumpp
09-20-2012, 04:05 AM
shows something adverse to the documented real life performance
:rolleyes:
It is not documented real life performance.....
It is calculated from a single data point with assumed values for CLmax.
That single data point was measured from a trailing static head.
What do you think the spreadsheet is??? Try the same the exact thing...calculated performance from data.
I just have the advantage of being able to use Mtt data, Supermarine, and NACA data that did not exist in 1940.
Kurfürst
09-20-2012, 07:03 AM
So while Crumpp is prepared to say that maths has all the answers compromises, such as leaving out the pilot and reducing the weight of an aircraft is okay - especially if it favours one type in particular over another.
Uhm, the weight Crumpp used for the Spitfire I doesn't include the weight of armor either. So how this - marginal - weight difference favours one type over the other, Sherlock?
"I fixed it and it narrows the gap" but no explanation as to how this was done. Instead we are told to have faith in Crumpp's genius because he knows better than everyone else, as per usual.
I see. Crumpp understands the formulae behind calculating turn radii and time, you do not, and somehow he is to be blamed for your ignorance? Or maybe it is his fault that after your never ceasing personal attacks, he is not particularly inclined to bother to explain it to you? :D
Glider
09-20-2012, 07:25 AM
Crumpp
You are reading something into the paper which isn't there and as a result are making an incorrect assumption.
Once more, the RAE admits that operating a trailing static head is difficult as best. Do you know what you have to do? When installed, you have a tangle of tubes in the cockpit that the pilot must pinch off with an airtight seal on the correct lines at the right time. It is hard enough in cruise flight and would be extremely difficult to do accurately in a high performance fighter at the stall point.
That is why they labeled the values as "assumed values of CLmax".
You are right in some of what you say but have ignored other parts of the quote. The paragraph can be summerised as follows
a) An accurate calculation of the turn performance is dependent on an accurate measure of the CL max in level flight
b) The only way that the CLmax can be accurately measured is the use of the trailing static head.
c) It is difficult to do (this is the part which you highlight)
d) Despite it being difficult it has been successfully done on both the Spitfire and Me109
e) That the method used by the NACA is not as reliable and gave a misleading result
By ignoring the other relevent parts your assumption that the RAE had to calculate the results because they couldn't measure the CL max is fundamentally flawed.
Its because they were able to get an accurate measure of the CL max in a glide and max throttle that an accurate calculation of turn performance was possible
I should add that the RAE did exactly the same with the Me109 so these are by far the best calculations around.
Kurfürst
09-20-2012, 08:28 AM
Crumpp
You are reading something into the paper which isn't there and as a result are making an incorrect assumption.
You are right in some of what you say but have ignored other parts of the quote. The paragraph can be summerised as follows
a) An accurate calculation of the turn performance is dependent on an accurate measure of the CL max in level flight
b) The only way that the CLmax can be accurately measured is the use of the trailing static head.
c) It is difficult to do (this is the part which you highlight)
d) Despite it being difficult it has been successfully done on both the Spitfire and Me109 Nope it was not done on the 109
e) That the method used by the NACA is not as reliable and gave a misleading result According to RAE...
By ignoring the other relevent parts your assumption that the RAE had to calculate the results because they couldn't measure the CL max is fundamentally flawed.
No, it's correct, RAE admits that it has estimated Bf 109 Clmax values from earlier Spitfire flights, and did not measure them.
The " stall boundary " depends on an estimate of CL max at full throttle. In the case of the Spitfire this has been measured in flight, while the Me.109 figures were based on the Spitfire results; tables of the assumed values of CL max are given in Fig. 17. CL max falls off as g is increased, because the stalling speed increases as g gets larger, thus lessening the slipstream effect.
In contrast, RAE only measured Clmax in throttled back conditions:
Only one flight was made, as operating a suspended static head from a single-seater aircraft with a rather cramped cockpit is difficult.[b] Stalling speeds with engine throttled right back were measured/b] with flaps and undercarriage up and down, and the speed at which the slots opened were also noted ; in every case both slots opened almost simultaneously.
http://kurfurst.org/Tactical_trials/109E_UKtrials/Morgan.html
Its because they were able to get an accurate measure of the CL max in a glide and max throttle that an accurate calculation of turn performance was possible. I should add that the RAE did exactly the same with the Me109 so these are by far the best calculations around.
Nope. What RAE did can be best described as a reasonably close estimate based on guessworked Clmax, with wrong weight, and with wrong power. REA did not measure full throttle Clmax on the 109, they have estimated that from results with the Spitfire... so who's quoting out of context now, David?
The most accurate calculations for the Me 109 turn capability are those done by Messerschmitt A.G., for obvious reasons.
Glider
09-20-2012, 09:12 AM
No, it's correct, RAE admits that it has estimated Bf 109 Clmax values from earlier Spitfire flights, and did not measure them.
This paper clearly states that these measurements had been successfully done on the Me109. and it is clear that they had been measured on the Spitfire, Me109, Buffalo and Whirlwind.
Only one flight was made, as operating a suspended static head from a single-seater aircraft with a rather cramped cockpit is difficult.[b]
So you agree that they were measured
Stalling speeds with engine throttled right back were measured/b] with flaps and undercarriage up and down, and the speed at which the slots opened were also noted ; in every case both slots opened almost simultaneously.
http://kurfurst.org/Tactical_trials/109E_UKtrials/Morgan.html
And you agree that they were measured in landing configuration (flaps and gear down), plus gliding config (with flaps and gear up).
It should be noted that this section in the paper is titled
Stalling Tests 4.4 4.41 determination of CL max
Would you really expect them to comment on the CL max at full throttle during stalling tests?
However, you are corect when you say that the CL max at full throttle was based on the SPit figures but the RAE did have the accurate figs on the Stall and Gliding configs which is half the battle so would be a good estimate
Nope. What RAE did can be best described as a reasonably close estimate based on guessworked Clmax, with wrong weight, and with wrong power.
Let me reword this for you
What RAE did can be best described as a close estimate of CL max at full throttle based on known Clmax for Gliding config.
so who's quoting out of context now, David?
I would say both of us missed something. However Crumpp when commenting on the RAE reply on the NACA tests missed a heck of a lot.
One obvious point which no one including me has mentioned, is that the RAE did have the 109. If their calculations said that one was better than the other at something, they had the aircraft to test the results. A luxury that we would love to have
PS - By the way, I have no problem you using my real name but can I ask what yours is?
Crumpp
09-20-2012, 12:47 PM
they had the aircraft to test the results.
And we have 70 years of data including classified documents from the people who built, designed, and flew the airplane in service.
Sorry, but we have the information advantage.
Glider
09-20-2012, 02:28 PM
And we have 70 years of data including classified documents from the people who built, designed, and flew the airplane in service.
Sorry, but we have the information advantage.
Are you saying that having the real aircraft, most up to date test facilities at the time, the only trained test pilots in the world (at the time) is not an advantage when testing theory.
There is a reason why the premier Aviation University in the UK is at Cranfield (not Cambridge who do not teach Aeronautical engineering or theory) its because they have their own test flight of aircraft often passed down from the RAF research establishments.
You should tell them they don't need the aircraft, it would save them a ton of money
Crumpp
09-20-2012, 02:37 PM
the only trained test pilots in the world
That is a good point. We are talking about the test pilots who felt the Bf-109 was "embarrassed" by the slats opening in the turn.
I would not be surprised if the pilots did not operate the propeller at its most efficient point at the single data point the RAE used. That would throw off all of Gates assumption for the entire envelope.
In order to reproduce the RAE results, I have to drop the propeller efficiency to below average and assume VDM could not properly design a propeller.
Crumpp
09-20-2012, 02:42 PM
classified documents from Vickers-Supermarine
:rolleyes:
It is the ones from Mtt that the RAE did not have access too. Germany was at war with England at the time so they were not exactly sharing information.
Instead, a pilot with little experience with a selectable pitch propeller had to go up and operate it to record data using a very difficult method of gathering airspeed data.
My Spitfire analysis is in agreement with the RAE's analysis.
The relative performance is not in agreement, but that has to do with Bf-109 performance and not the Spitfire's.
SlipBall
09-20-2012, 03:01 PM
:rolleyes:
It is the ones from Mtt that the RAE did not have access too. Germany was at war with England at the time so they were not exactly sharing information.
Instead, a pilot with little experience with a selectable pitch propeller had to go up and operate it to record data using a very difficult method of gathering airspeed data.
My Spitfire analysis is in agreement with the RAE's analysis.
The relative performance is not in agreement, but that has to do with Bf-109 performance and not the Spitfire's.
It's great that some of the information survived all these years, I've often wondered. Here in the States much of our early mechanical history, can be found in the library of Congress.
Crumpp
09-20-2012, 03:42 PM
Here in the States much of our early mechanical history, can be found in the library of Congress.
You can find all the patent information and applications in the National Archives. The Smithsonian has a bunch too.
Even foreign patents, I got all of BMW and Focke Wulfs on one of my visits.
bongodriver
09-20-2012, 03:45 PM
So we can all look forward to you sharing this data so we can all draw our own conclusions? or are we just going to get your assurance you've seen it and done the maths and we can take your word for it?
Glider
09-20-2012, 06:08 PM
That is a good point. We are talking about the test pilots who felt the Bf-109 was "embarrassed" by the slats opening in the turn.
I would not be surprised if the pilots did not operate the propeller at its most efficient point at the single data point the RAE used. That would throw off all of Gates assumption for the entire envelope.
In order to reproduce the RAE results, I have to drop the propeller efficiency to below average and assume VDM could not properly design a propeller.
As it happens yes they are. The UK had the first and at that time only test pilot training school in the world. As for being embarrased yes the Me109E was embarased by the way the slots opened, which no doubt was why they were redesigned for the Me109F. Unless you have a better reason for the redesign.
As for you having to drop the propeller efficiency to get the same results, working on the basis that you are not a trained test pilot then I can only assume that your model is wrong. I know you believe that the test pilots are not important but if I had to pick between their hard earned experience and training, backed up be the science of the day and access to the real aircraft, against your maths and how you read documents, I would go for the experts.
5./JG27.Farber
09-21-2012, 03:12 PM
The title of the thread is:
Spit/109 sea level speed comparisons in 1.08 beta patch
So, we know that all aircraft are two slow, surely we just need a general consensus of which top speeds are correct given the fact that:
109 speed tests are not full throttle, 1.3 Ata is the maximum recorded/logged
Aircraft have a gate system for more power
speeds are slightly different on multiple tests
Specific engines
So from this can we just agree on some numbers to submitted? :confused:
Talisman
09-21-2012, 04:02 PM
Crumpp,
You said:
"That is a good point. We are talking about the test pilots who felt the Bf-109 was "embarrassed" by the slats opening in the turn.
I would not be surprised if the pilots did not operate the propeller at its most efficient point at the single data point the RAE used. That would throw off all of Gates assumption for the entire envelope.
In order to reproduce the RAE results, I have to drop the propeller efficiency to below average and assume VDM could not properly design a propeller".
Given what Rall said below, would you not say that the "embarassed" remark was fair comment? If an event and effect designed for taking off and landing happens in the middle of fast air combat with no warning, when you do not intend it to happen, it is not a good thing is it? Esp if the slats do not function in an even way as per the design function. I would have thought that this effect should be part of the CloD FM. Thoughts?
Talisman
Me 109 E:
"And there I discovered the first thing you have to consider in a 109. The 109 had slots. The slot had a purpose to increase the lift during takeoff and landing. In the air automatically it's pressed to the main wing. And if you turn very roughly you got a chance, it's just by power, the wing, the forewing, comes out a little bit, and you snap. This happened to me. I released the stick immediately and it was ok then. "
- Major Gunther Rall in April 1943. German fighter ace, NATO general, Commander of the German Air Force. 275 victories. Source: Lecture by general Rall.
Me 109 E/F/G: - The plane had these wing slats and you mentioned they pop open uneven?
"Two meter slots on fore wings. The reason was to increase the lift during low speed take off and landing. To reduce the length of runway you need. In the air, if you make rough turns, just by gravity, the outer slot might get out. You can correct it immediately by release of stick, you know? Only little bit, psssssssht, its in, then its gone. You have to know that. And if you know it, you prevent it."
- Major Gunther Rall. German fighter ace, NATO general, Commander of the German Air Force. 275 victories. Source: Lecture by general Rall.
Glider
09-21-2012, 05:34 PM
Its only fair to point out that problems with automatic leading edge slots that opened suddenly, were not unique to the Me109 at this time . The Westland Whirlwind also had the same issue but the squadrons decided in most (maybe all) cases to lock them so they wouldn't come out and live with the extra landing speed.
The Luftwaffe with the greater emphasis on these devices changed the design on the Me109F so they opened gradually. Kurfurst knows more than me about this but I think thats the basic situation.
TomcatViP
09-21-2012, 07:03 PM
This is not correct. They hve always open gradully. The diff in pressure makes them open as a function of it. It's a suction effect. The more, the wider ( humm.... stay focused.. )
The prob with the wider LE was IMOHO with the prop wash that in certain situation (yaw) prevented one slat to fully open. Having yaw angle is fairly comune during a DF unless you stay focused on your slip angle.
~S!
bongodriver
09-21-2012, 08:21 PM
This is not correct. They hve always open gradully. The diff in pressure makes them open as a function of it. It's a suction effect. The more, the wider ( humm.... stay focused.. )
The prob with the wider LE was IMOHO with the prop wash that in certain situation (yaw) prevented one slat to fully open. Having yaw angle is fairly comune during a DF unless you stay focused on your slip angle.
~S!
This is not correct, when the aircraft is pulling tight turns the g load on the slats makes them snap open, they are designed only to open gently at slow speeds for landing and take off.
The leading edge slats of the 109 work through air pressure distribution and this is depending on the angle of attack. The slats deploy gradually over a small range of the angle of attack, making it possible for them to snap open in abrupt manoeuvres, but they can also be made deploy gradually when increasing angle of attack gently.
The leading edge slats were reworked with the F series in that their span was reduced and the mechanism simplified. I don't think the deployment was changed a lot.
Glider
09-21-2012, 09:39 PM
In my mind Kurfurst is the person for this, but what isn't in question is that they were redesigned for the 109F
Crumpp
09-21-2012, 09:42 PM
Given what Rall said below, would you not say that the "embarassed" remark was fair comment?
No.
Here is handley page automatic slats in operation on my old airplane:
http://www.youtube.com/watch?v=-vbqgfjyW2Q
Unless they are new to you, the slats are nothing of note as far as piloting goes.
What do for the airplane is outstanding. You can pull some insane body angles with them.
Here is another video I made on the way to work. It was beautiful day to fly.
http://www.youtube.com/watch?v=UdgohV4gpXE
SlipBall
09-21-2012, 09:48 PM
Pilot notes to a whole new level
NZtyphoon
09-21-2012, 09:58 PM
Its only fair to point out that problems with automatic leading edge slots that opened suddenly, were not unique to the Me109 at this time . The Westland Whirlwind also had the same issue but the squadrons decided in most (maybe all) cases to lock them so they wouldn't come out and live with the extra landing speed.
The Luftwaffe with the greater emphasis on these devices changed the design on the Me109F so they opened gradually. Kurfurst knows more than me about this but I think thats the basic situation.
When the Whirlwind's slats were tested at the A&AEE, it was found that when the slats were locked shut the take-off and landing characteristics remained the same, while the aircraft was more pleasant to fly at speeds during which the slats were normally open:
http://i91.photobucket.com/albums/k304/Major_Sharpe/Whirlwind2-002_zpsbaca5f5f.jpg
http://i91.photobucket.com/albums/k304/Major_Sharpe/Whirlwind1-002_zps6824eb2e.jpg
TomcatViP
09-21-2012, 10:20 PM
Crumpp, you need to take some drawings lessons :rolleyes:
SlipBall
09-21-2012, 10:28 PM
It was cool to fly over that pretty countryside though...Crumpp what engine, a Lycoming?
NZtyphoon
09-21-2012, 10:45 PM
I prefer this one, showing the glorious NZ countryside ;)
http://www.youtube.com/watch?v=yEWKC6cX2o8
bongodriver
09-21-2012, 10:52 PM
http://www.youtube.com/watch?v=UdgohV4gpXE
You went through all that trouble instead of just showing me a scan of a pilot's license? the aircraft in the first video is not pulling high G so no wonder the slats are quite gentle.
Since you asked, yes intro flights are probably much more expensive in the UK than in the US, if you want to fly with me in a Stearman it will cost about £360 per hour, I don't remember what we charge for the 152's or warriors but it's around £150 per hour.
Heres the vid of me and fruitbat in a Stearman taken from that GoPro camera on my head in my avatar pic, check 14:30 for the 'hello Crumpp' and 17:30 for some basic aero's.
http://www.youtube.com/watch?v=oq4RoEP4dSo&feature=g-upl
Heres a vid of me flying the Learjet, 2008 fresh back from Dallas and doing my 6 cirquits to finish the type rating.
http://www.youtube.com/watch?v=Ud2Rb6tuR_A&feature=g-upl
ATAG_Snapper
09-21-2012, 11:27 PM
You went through all that trouble instead of just showing me a scan of a pilot's license? the aircraft in the first video is not pulling high G so no wonder the slats are quite gentle.
Since you asked, yes intro flights are probably much more expensive in the UK than in the US, if you want to fly with me in a Stearman it will cost about £360 per hour, I don't remember what we charge for the 152's or warriors but it's around £150 per hour.
Heres the vid of me and fruitbat in a Stearman taken from that GoPro camera on my head in my avatar pic, check 14:30 for the 'hello Crumpp' and 17:30 for some basic aero's.
http://www.youtube.com/watch?v=oq4RoEP4dSo&feature=g-upl
Heres a vid of me flying the Learjet, 2008 fresh back from Dallas and doing my 6 cirquits to finish the type rating.
http://www.youtube.com/watch?v=Ud2Rb6tuR_A&feature=g-upl
Very cool. Here's me and Riley squished in a Spit cockpit.....
http://www.youtube.com/watch?v=IZUZrruIAB8&sns=em
ATAG_Dutch
09-21-2012, 11:31 PM
Sigh........sayin' nuffin.
Glider
09-21-2012, 11:32 PM
When the Whirlwind's slats were tested at the A&AEE, it was found that when the slats were locked shut the take-off and landing characteristics remained the same, while the aircraft was more pleasant to fly at speeds during which the slats were normally open:
http://i91.photobucket.com/albums/k304/Major_Sharpe/Whirlwind2-002_zpsbaca5f5f.jpg
http://i91.photobucket.com/albums/k304/Major_Sharpe/Whirlwind1-002_zps6824eb2e.jpg
Thanks for this
NZtyphoon
09-21-2012, 11:34 PM
Thanks for this
You're welcome - That comes from Victor Bingham's book on the Whirlwind
http://www.amazon.com/Whirlwind-Westland-Victor-F-Bingham/dp/1853100048
Crumpp
09-21-2012, 11:49 PM
Crumpp, you need to take some drawings lessons
There is a reason why I am not a commercial artist, LOL.
Here is picture of my hanger, these are my planes....sole ownership....
Means you are alone on the bills too! ;)
http://imageshack.us/a/img198/2444/thehanger.jpg (http://imageshack.us/photo/my-images/198/thehanger.jpg/)
Both are fully aerobatic but the Thorp is not a good platform for it. It is too slick and you really have to pay attention to your speeds when you point the nose down.
The Thorp is a good cheap, fast, and fun to fly cross country machine. It has a Lycoming O-360 with a Hartzell CSP. It is IFR, four place, and a traveling machine.
The Extra 300 is my sky cutter. It has a Lycoming IO-540 with an MT propeller.
Back to the thread....
Looking at all the data and trying to pick averages staying away from either extreme using both Supermarines and Mtt data......
This is the relative turn performance of these two aircraft taking as much data from the Operating Notes and Flugzeug Handbuch.
http://imageshack.us/a/img62/1949/spitfiremkivsbf109e3sus.jpg (http://imageshack.us/photo/my-images/62/spitfiremkivsbf109e3sus.jpg/)
Here is a Rate of Turn comparison. Rate of turn is the most important aspect of turn performance as it represents how fast the aircraft can swing its guns thru the compass to bear on a target.
http://imageshack.us/a/img402/8112/rateofturn.jpg (http://imageshack.us/photo/my-images/402/rateofturn.jpg/)
Hope it helps!
NZtyphoon
09-22-2012, 12:57 AM
There's some info on the 109 slats here http://109lair.hobbyvista.com/index1024.htm apparently the Fs still used the swing arm assembly of the E to actuate the slats, while the G series used a simplified roller track.
Crumpp
09-22-2012, 02:38 AM
Just further weight to the fact handley page style slats open with force under load.
If you pull hard they will open with a loud bang but you don't even feel it on the stick.
You feel it most when you slowly change angle of attack.
Dami55an
09-22-2012, 03:26 AM
The graphs having different scales makes it very hard to compare
http://www.gqth.info/0.jpghttp://www.gqth.info/7.jpghttp://www.gqth.info/8.jpghttp://www.gqth.info/9.jpghttp://www.ymeu.info/test5.jpg
Crumpp
09-22-2012, 04:57 AM
Which Graphs?
What is the input data for your calculation?
- clmax (or stall speeds used + source)
- cdo (or power output, boost, rpm and speed + source)
- weight (source)
- assumed wing efficiency
- assumed prop efficiency
I would think the relation is about OK, but both planes are turning too fast and I also think that the high speed relation is a bit off.
SlipBall
09-22-2012, 07:49 AM
Crumpp..Nice barn! but too small:-P
Crumpp
09-22-2012, 01:13 PM
Slipball says
Crumpp..Nice barn! but too small
LOL, Yes it is and now I need a bigger one!
NzTyphoon says:
they have everything to do with WW2 military aviation
I don't have everything to do with WWII Aviation Nztyphoon.
Never claimed too but I do sit on the Board of Directors for a warbird restoration company.
Try spending a month looking for a waffengeber for a month and see if you don't learn something.
JtD says:
both planes are turning too fast and I also think that the high speed relation is a bit off.
The airplanes are at sea level. Of course they are turning too fast....
Density effects will increase velocity, widen the radius, and increase the rate of turn. The engine power will also change with supercharger characteristics.
As for the high speed relation, anytime the aircraft has more excess thrust it will have a better turn rate as it can sustain more angle of bank at velocity.
The relationship is correct.
SlipBall
09-22-2012, 02:20 PM
LOL, Yes it is and now I need a bigger one!
Considering the shape of the building and the powers of Google earth, it's for the best that you removed it.
The airplanes are at sea level. Of course they are turning too fast....Planes at sea level still turn as physics determine, not "of course too fast". If you posted your input data as requested, I could easily check if there's anything I'd disagree with.As for the high speed relation, anytime the aircraft has more excess thrust it will have a better turn rate as it can sustain more angle of bank at velocity.
The relationship is correct.I could easily see that if you posted requested input data. The way it looks from here, you chose 285 mph for the Spitfire and 500 km/h for the 109 - which leaves me to wonder: Do you know of a lower sea level top speed for the Spitfire and do you know of a higher sea level top speed for the 109? Just asking, because I don't.
Crumpp
09-22-2012, 03:21 PM
Planes at sea level still turn as physics determine
Yes they do and the formula's are all standard BGS for calculating aircraft performance.
They are same ones found in Perkins & Hage, Aerodynamics for Naval Aviators, Flight Mechanics, and Flight Theory and Aerodynamics.
You can argue with the authors of these books....
http://www.amazon.com/Mechanics-Flight-Warren-F-Phillips/dp/0470539755
http://www.amazon.com/Flight-Theory-Aerodynamics-Practical-Operational/dp/0471370061/ref=sr_1_1?s=books&ie=UTF8&qid=1348327097&sr=1-1&keywords=flight+theory+and+aerodynamics
http://www.amazon.com/Airplane-Performance-Stability-Control-Courtland/dp/047168046X/ref=sr_1_1?s=books&ie=UTF8&qid=1348327130&sr=1-1&keywords=Perkins+and+Hage+Aircraft+stability+and+c ontrol
http://www.amazon.com/Aerodynamics-Naval-Aviators-Publisher-Academics/dp/B004TBYVPQ/ref=sr_1_2?s=books&ie=UTF8&qid=1348327168&sr=1-2&keywords=aerodynamics+for+naval+aviators
The formulas are correct and the performance agrees with generic turn performance charts used in aircraft flight planning.
Input the correct parameters for wing area, power, aspect ratio, CLmax, and the formulas produce the results.
It is that simple.
Crumpp
09-22-2012, 03:25 PM
"of course too fast"
They don't turn too fast. The performance aligns perfectly with a standard turn performance chart.
I'd like to know what data you used, a request couldn't be more straightforward and simple. I didn't ask for adverts, standard turn performance charts or other rubbish.
Crumpp
09-22-2012, 09:29 PM
other rubbish
Hold on a second. You attacked the effort and claimed it did not conform to physics.
When I explain it is all standard formulation commonly found in aerodynamic text using the BGS system and present a General Turn Performance table the results agree with perfectly, you claim it is all rubbish.
So what is not "rubbish" to you??
Before I present you with the data, should we agree on what we are looking at???
Glider
09-22-2012, 10:32 PM
I admit that my problem is a simple basic one. I believe a huge amount of time and effort is going into trying to hide one clear and obvious truth. That all the pilots and all the test pilots of all the test establishments, in all the nations that compared the 109 and the Spitfire, all agreed that the SPit turned better than the 109.
None of the above mentioned said that there was any difference when in a turning climb and the RAE clearly documented the advantage to the Spitfire. No advice was given to German pilots to go into a climbing turn to escape attack and as far as I am aware, no pilot of the time has said that they used this tactic in combat.
I frankly don't care what a theoretical calculation shows when compared to the tests that were done at the time. Why, because anything done today is just that, a theory unable to be tested in real life, a pricless advantage which occurred in the war years.
Its also worth remembering that the calculations being done today are being done without that 12lb thrust which increased performance of the engine by approx 30%
I invite those who believe that the 109 had the advantage to find any test from any establishment of any nation to support their view.
It shouldn't be difficult if the results are so clear and obvious mathmatically.
Crumpp
09-22-2012, 10:46 PM
all agreed that the SPit turned better than the 109.
It does turn better. Look at the calculations I posted.
It just does not do it under all conditions or speeds. That is important, Glider.
If the two airplanes were to have a turning battle to the stall point, the Bf-109E-3 would loose.
Here is the acceleration rates of the two aircraft. The Bf-109E-3 out accelerates the Spitfire Mk I due to its being lighter with more excess thrust.
http://imageshack.us/a/img338/6370/spitfirevsbf109eacelera.jpg (http://imageshack.us/photo/my-images/338/spitfirevsbf109eacelera.jpg/)
Of course, the Spitfire can fly at a slower speed were the Bf-109E3 cannot fly at all.
If the Bf-109E3 maintains his trim speed of 400 kph, he is tough customer for a Spitfire to deal with. At that speed, the Bf-109 can sustain better performance and accelerates better. The Spitfire needs to take the fight to the low speed realm where it has all the advantages.
Hold on a second. You attacked the effort and claimed it did not conform to physics. Man, whatever goes on in your world. I asked you to share your input data. Three times, won't ask a fourth, so forget about it.
Crumpp
09-22-2012, 11:19 PM
Typo on the chart axis....
Acceleration is in fps^2
Crumpp
09-22-2012, 11:22 PM
I asked you to share your input data
The data has been posted for each evaluation.
I would be glad to share the input data for this one but what would be the point when you are saying the whole effort does not conform to standard physics.
It does conform. Aerodynamics is nothing more than applied physics and all the formulation is straight out of my college text. It is the same stuff we did in the classroom!
If you agree it conforms, I will be glad to continue the discussion and share the data.
I plan on sharing the spreadsheet too.
5./JG27.Farber
09-22-2012, 11:52 PM
Crump - you know if you click the "multi off" button it says "mutli on", then when you click "reply" it will contain these quotes and you can make one post? ;)
NZtyphoon
09-23-2012, 12:03 AM
The data is listed in the thread.
Here it is too, right off the spreadsheet:
Spitfire Mk I
Aircraft Data
weight 6050lbs
Power 990bhp
Level speed 247KEAS
Propeller efficiency 0.8
Wing area 242 sqft
wing efficiency 0.85
Dynamic pressure 206.8101695psf
Aspect Ratio 5.6
Mass 187.8881988 ft/s^2
Where did you assume the propeller efficiency was 0.8?
De H 55409 B 0.930
Rotol RA 611 0.924
Rotol RA 621 0.920
Rotol RA 600 0.911
Rotol RA 640 0.940
Take your pick, which propeller did you claim had an efficiency of 0.8?
http://www.spitfireperformance.com/spit2prop-b.jpg
Crumpp
09-23-2012, 12:34 AM
Take your pick, which propeller did you claim had an efficiency of 0.8?
That is a standard assumption in aircraft performance for power producers. It assumes a good propeller design.
The data listed below is peak efficiency which is a small part of the advance ratio curve. When you average out the entire curve, it comes out to ~.8 for a well designed propeller.
Rotol RA 611 0.924
Rotol RA 621 0.920
Rotol RA 600 0.911
Rotol RA 640 0.940
IvanK
09-23-2012, 01:14 AM
Crumpp your Spitfire V 109 acceleration chart is I presume 1G flight ?
Crumpp
09-23-2012, 02:07 AM
Yes
Crumpp
09-23-2012, 02:09 AM
Crump - you know if you click the "multi off" button it says "mutli on", then when you click "reply" it will contain these quotes and you can make one post?
Thanks!
IvanK
09-23-2012, 02:16 AM
Ok then its straight line running not sustained turn performance. So wrt your comment :
"If the Bf-109E3 maintains his trim speed of 400 kph, he is tough customer for a Spitfire to deal with." I respectfully disagree. Obviously I prefer to accept the RAE's views rather than yours.
WRT the sustained turn performance based on RAE computation at 12000ft, 400Kmh/248mph (TAS). The Spitfire can sustain 2.95G giving an approximate sustained turn rate of around 14.0 deg sec. The 109 on the other hand can sustain only 2.3G giving an approximate turn rate of 10.5deg sec.
So according to the RAE The Spit at 12,000ft/400Kmh TAS has 0.65G sustained G advantage over the 109 and 3.5 deg sec sustained turn rate advantage. Thats a nose position advantage of just on 119degrees in a single 360 degree turn. Sustained turn radius wise the Spitfire is around 526ft smaller to boot. So based on RAE calculations the 109 is not so "tough a customer at 400Kmh" in any turn fight.
A 109 Pilot in this engagement is just going to watch the Spitfire translate aft in his canopy until he ends up nose in lead with guns firing. Best option for the 109 (imo) is as soon as he sees the aft translation back through his 3/9 line to ease off on the G (maybe holding the bank on for deception) extend (using his superior 1G Ps) then transition into a climb, get the separation he needs and come back into the fight at a later point..... and that sort of thing is exactly what the good On line 109 drivers do.
Ties in with the Historical record and what we see On line every day.
MiG-3U
09-23-2012, 05:44 AM
Well IvanK, had RAE chosen the lowest available speed and max lift coefficient values for the Spitfire and the highest available speed and max lift coefficient values for the 109, at the altitude which is most favorable for the 109, their results would have agreed with Crumpp's :)
Ironic mode off: Why waste time with obviously deeply biased stuff? Just google with keywords: Crumpp Spitfire calculation. You will get thousands of hits from the several sim forums over the past few years, I think he has produced enough text and calculations for several books.
Kurfürst
09-23-2012, 07:15 AM
Where did you assume the propeller efficiency was 0.8?
De H 55409 B 0.930
Rotol RA 611 0.924
Rotol RA 621 0.920
Rotol RA 600 0.911
Rotol RA 640 0.940
Take your pick, which propeller did you claim had an efficiency of 0.8?
http://www.spitfireperformance.com/spit2prop-b.jpg
Apparantly, you can't even read your own tables..
Column 12, "Airscrew effiency" from flight results, at 18 000 feet:
Rotol RA 611 0.924 = 0,800
Rotol RA 621 0.920 = 0,805
Rotol RA 600 0.911 = 0,785
Rotol RA 640 0.940 = 0,800
... besides the fact that NZTypoon has reading comprehension problems, there's also the fact that the above values are only true for 18 000 feet altitude and max. speed level flight of about 365 mph.
Well IvanK, had RAE chosen the lowest available speed and max lift coefficient values for the Spitfire and the highest available speed and max lift coefficient values for the 109, at the altitude which is most favorable for the 109, their results would have agreed with Crumpp's :)
Instead, RAE has picked the lowest available speed and max lift coefficient values for the 109 and the highest available speed and max lift coefficient values for the Spitfire, and so they have arrived at the results they did.
What all people seem to forget that the results in all these calculations are deeply rooted in the source base data, and since there is a great deal incertainity in those, the results tend to diverge quite a bit.
I just recalled I still have my near three year old turn performance estimate spreadsheet. I attached it, so anyone interested can produce charts to their likings. I've added some 109 E and Spitfire I data, feel free to use your own data sets. If you have any questions, just ask.
Kurfürst
09-23-2012, 07:39 AM
I just recalled I still have my near three year old turn performance estimate spreadsheet. I attached it, so anyone interested can produce charts to their likings. I've added some 109 E and Spitfire I data, feel free to use your own data sets. If you have any questions, just ask.
Thanks, this is very usuful.
I fooled around with the specs a bit, with best/worst case data in bost cases, but interestingly the tables keep showing that the 109E is evening things out in turn and then having an advantage at and above around 400 km/h.
Math is just too impartial I guess.
The only way to change that would be using 100 octane performance for the Spitfire I, giving it a level speed similar to the 109. Or go to high altitude, were Spitfire and 109 are always fairly close in terms of speed. Other than that, 30ish extra km/h is quite a bit.
NZtyphoon
09-23-2012, 09:36 AM
Well IvanK, had RAE chosen the lowest available speed and max lift coefficient values for the Spitfire and the highest available speed and max lift coefficient values for the 109, at the altitude which is most favorable for the 109, their results would have agreed with Crumpp's :)
Ironic mode off: Why waste time with obviously deeply biased stuff? Just google with keywords: Crumpp Spitfire calculation. You will get thousands of hits from the several sim forums over the past few years, I think he has produced enough text and calculations for several books.
So noted: screeds of data all showing the terrible inferiority of the Spitfire, and all stemming from one or two reports.
Kurfürst
09-23-2012, 11:38 AM
The only way to change that would be using 100 octane performance for the Spitfire I, giving it a level speed similar to the 109. Or go to high altitude, were Spitfire and 109 are always fairly close in terms of speed. Other than that, 30ish extra km/h is quite a bit.
Agreed! 100 octane is giving a Spit roughly equal speed at low level, even greater speed at low-medium altitudes, which governs most of the high speed turning stuff. Apart from that, without 100 octane the Spit is a bit of trouble against the 109E at higher speeds, since the latter is faster at low altitudes, and in the end its speed that govers most of the high speed turning stuff (since parasitic drag is much more dominant there). Its simply how the turning formulae works, something that some of spit fanatics simply do not want to accept.
Higher altitudes would be interesting btw. The Spit has a more power there (save for the 109E/N) and the two aircraft about the same speed. The Spit has less wingloading, the 109 has higher AR - thus the main factors governing turning are going both ways.. my guess would be a slight Spit advantage there though (save again for the 109E/N).
Bottomline, it doesn't matter how good the plane can turn, if the pilot can't fly it right through the edge. 1-2 seconds can be generally made up by good piloting skills, both ways. ;)
Crumpp
09-23-2012, 01:52 PM
Kurfurst says
but interestingly the tables keep showing that the 109E is evening things out in turn and then having an advantage at and above around 400 km/h.
When you calculate out the performance, it is easy to see why Mtt defaulted the trim to 400kph.
That is a very good speed to dogfight the airplane.
http://imageshack.us/a/img542/1949/spitfiremkivsbf109e3sus.jpg (http://imageshack.us/photo/my-images/542/spitfiremkivsbf109e3sus.jpg/)
http://imageshack.us/a/img840/8112/rateofturn.jpg (http://imageshack.us/photo/my-images/840/rateofturn.jpg/)
Crumpp
09-23-2012, 01:57 PM
Crumpp Spitfire calculation
LOL, you do know I was on the FM team for Warbirds at the time. The first FM done was the Spitfire Mk I and Bf-109E series.
When you combined the performance with the flying qualities, these two airplanes are the most evenly matched close quarter dogfighter that existed, IMHO.
Robo.
09-23-2012, 02:58 PM
When you calculate out the performance, it is easy to see why Mtt defaulted the trim to 400kph.
That is a very good speed to dogfight the airplane.
Doghfight at 400kph in 1940. Very good :grin:
How exactly would you outturn a Spitfire in a combat again?
Crumpp
09-23-2012, 03:08 PM
Doghfight at 400kph in 1940
Why do you think it would be so difficult to dogfight at 400 kph in an airplane?
Have you flown many airplanes?
Do you know how easy it is to hold a design speed?
Crumpp
09-23-2012, 03:53 PM
First of all, 400kph is within the power stable region of the Bf-109's curves.
What does that mean? It requires ~350 hp to go from the stall point of 82 Knots to 215 Knots (400kph). That is a change of 133 Knots.
We are in a region that small power changes make for large changes in speed.
Compare that with the power required to go from 400 kph to Vmax in the Bf-109E3 is another ~545 hp to increase speed ~54 Knots.
http://imageshack.us/a/img545/7629/powerstableregionbf109e.jpg (http://imageshack.us/photo/my-images/545/powerstableregionbf109e.jpg/)
How long will this take?
That too is easy to find out with some applied physics.
Acceleration = (Change in Velocity) divided by (Change in Time)
The average acceleration of the Bf-109E3 from 82 KEAS to 215 KEAS is ~9.6 fps^2.
We have to use the same units so our KEAS is converted to feet per second.
Rearranging our formula to solve for time:
Change in Time = Change in Velocity / Acceleration
delta t = (363fps - 138.4fps) / 9.6 fps^2
Feet cancel out as well as one of the second leaving us with the unit of seconds....
Change in Time = 23.3 seconds
Twenty three seconds from the stall point to the 215 Knots for the Bf-109E3.
Same conditions for the Spitfire:
Going from 82KEAS to 215KEAS, the Spitfire has an average acceleration of 8.4 fps.
delta t = (363fps - 138.4fps) / 8.4 fps^2
Change in time = 27 seconds
Now going from the stall point of 67 KEAS in the Spitfire, we see an average acceleration rate of 9.96 fps. This is because the Spitfire has more excess thrust at low velocity.
Considering that it would be a very stupid Bf-109E3 pilot to be slow flight in the vicinity of a Spitfire, the Bf-109E3 can maneuver quite well and dogfight the Spitfire.
The Bf-109 is pretty safe it if stays in its envelope and does not try to fly were it cannot.
Glider
09-23-2012, 05:01 PM
It does turn better. Look at the calculations I posted.
It just does not do it under all conditions or speeds. That is important, Glider.
If the two airplanes were to have a turning battle to the stall point, the Bf-109E-3 would loose.
Here is the acceleration rates of the two aircraft. The Bf-109E-3 out accelerates the Spitfire Mk I due to its being lighter with more excess thrust.
http://imageshack.us/a/img338/6370/spitfirevsbf109eacelera.jpg (http://imageshack.us/photo/my-images/338/spitfirevsbf109eacelera.jpg/)
I am sorry but this is rubbish.
a) You are using the wrong power settings for a Spit
b) The 109 controls lock at higher speeds far more so than the spit
c) The German test establishments let alone the pilots in combat would have identified that the 109 turned better at high speed and would have given instructions to their pilots similar to those given to Typhoon, Tempest and USAAF fighters. These essentially went 'Dont enter a slow turning fight with an Me109, keep your energy up and you will have him' Substitute Spitfire for 109 and you would have the german instructions. These were never given.
[QUOTE]
If the Bf-109E3 maintains his trim speed of 400 kph, he is tough customer for a Spitfire to deal with. At that speed, the Bf-109 can sustain better performance and accelerates better. The Spitfire needs to take the fight to the low speed realm where it has all the advantages.
At 12 lb thrust the Spit produces 1300 hp which puts the power to weight ratio firmly in favour of the Spitfire from which a lot of performance calcs are decided. Without this calculation the charts you posted are of little value.
400 Km is about 250 mph which is not fast.
The Me109E is a tough customer no question and in the overall view there is nothing between them
Crumpp
09-23-2012, 05:17 PM
I am sorry but this is rubbish.
LOL...
According to the Merlin III power curve, I actually being generous. RAM power for the Merlin III is only about 850 bhp.
weight 6050 lbs
Power 990 bhp
Level speed 247
Propeller efficiency 0.85
Wing area 242
wing efficiency 0.85
Dynamic pressure 206.8101695
Aspect Ratio 5.6
Mass 187.8881988
http://imageshack.us/a/img542/1949/spitfiremkivsbf109e3sus.th.jpg (http://imageshack.us/photo/my-images/542/spitfiremkivsbf109e3sus.jpg/)
Crumpp
09-23-2012, 05:18 PM
The German test establishments let alone the pilots in combat would have identified that the 109 turned better at high speed and would have given instructions to their pilots similar to those given to Typhoon, Tempest and USAAF fighters
Why do you think the trim on the Bf-109 is set to 400 kph IAS???
You do understand they can trim the aircraft for whatever speed they desired?? Having a fixed trim condition is a great way to set the combat speed for your airforce.
Crumpp
09-23-2012, 05:27 PM
Without this calculation the charts you posted are of little value
Problem is we don't have any good data on the 100 Octane.
The only data we have does not match our engine curves. Find some good data and I will be happy to do the calculations.
http://www.spitfireperformance.com/spitfire-I-rae-12lbs.jpg
Takes but a second to change the values.
Crumpp
09-23-2012, 05:32 PM
It just does not do it under all conditions or speeds. That is important, Glider.
That is how airplanes work, Glider.
It is not going to outperform the Bf-109 without changing the physics. The Spitfire has to be faster and have more excess thrust.
It is going to be very tough for the heavier Spitfire to overcome the weight differences when the Bf-109 maintains power parity.
It is that simple.
NZtyphoon
09-23-2012, 10:23 PM
Why do you think the trim on the Bf-109 is set to 400 kph IAS???
You do understand they can trim the aircraft for whatever speed they desired?? Having a fixed trim condition is a great way to set the combat speed for your airforce.
This is priceless - doesn't Crumpp know that apart from the variable incidence tailplane of the 109 the trim for all control surfaces had to be set on the ground, whereas the Spitfire could be trimmed in flight by the pilot using tabs on the elevators and rudder? For example, the speeds for aerobatics posted in the Spitfire II PNs:
http://i91.photobucket.com/albums/k304/Major_Sharpe/SpitfireIIaerobatics-001_zps09887768.jpg
The optimum trim for a 109 was set for 400 kph (248 mph)? No wonder the controls got so heavy at higher speeds.
Glider
09-23-2012, 11:16 PM
Problem is we don't have any good data on the 100 Octane.
The only data we have does not match our engine curves. Find some good data and I will be happy to do the calculations.
http://www.spitfireperformance.com/spitfire-I-rae-12lbs.jpg
Takes but a second to change the values.
What exactly would be your definition of good data?
Christop55her
09-24-2012, 12:47 AM
I don't care if the failure rate is 100% at 6 minutes it's just highly unrealistic to have guaranteed failure at 5:01.
http://www.gqth.info/0.jpghttp://www.gqth.info/7.jpghttp://www.gqth.info/8.jpghttp://www.gqth.info/9.jpghttp://www.ymeu.info/test5.jpg
Crumpp
09-24-2012, 01:26 AM
What exactly would be your definition of good data?
Data that matches the characteristics of the engine and makes sense.
If our engine has a RAM FTH of say 12,000 feet and our data shows a FTH of 8,000 feet....
It is not the same engine in the airplane. If we use the power data from the wrong engine with the wrong speed....our result's will be just as incorrect!
Crumpp
09-24-2012, 01:28 AM
NzTiffoon says:
109 the trim for all control surfaces had to be set on the ground
Crumpp says:
fixed trim
Grab a dictionary and look it up....
Also, go to the local airport and ask a mechanic about the number of airplanes that just have longitudinal trim controls. It is pretty common for a well designed control system. Most modern SE airplanes have fixed trim for everything but the elevator.
Al Schlageter
09-24-2012, 02:13 AM
It is pretty common for a well designed control system. Most modern SE airplanes have fixed trim for everything but the elevator.
So you are saying that the Americans did a bad job in designing the control system of their fighters as the had to put trim on the elevator, rudder and ailerons?
How many modern s/e a/c have a speed range of a WW2 fighter?
How many modern s/e a/c have a disposable load that a WW2 fighter has?
How many modern s/e a/c swing a 10' plus prop turned by 1500hp plus engine?
NZtyphoon
09-24-2012, 05:57 AM
Grab a dictionary and look it up....
Also, go to the local airport and ask a mechanic about the number of airplanes that just have longitudinal trim controls. It is pretty common for a well designed control system. Most modern SE airplanes have fixed trim for everything but the elevator.
So what? As per ususl Crumpp conflates modern civilian practices for sports aircraft and says this should have been the same on high speed fighters during WW2 How many high speed WW2 fighters has Crumpp flown?
Why do you think the trim on the Bf-109 is set to 400 kph IAS???
Having a fixed trim condition is a great way to set the combat speed for your airforce.
Utter balony, it's a great way to ensure that once in flight pilots do not have the ability to trim the aircraft to suit the circumstances - the 109E rudder became increasingly heavy, to the point where it was almost impossible to use - it's interesting that later "tall tailed" 109 variants had a trim tab to help overcome this problem. Setting the "combat speed" to a uniform and abitrary 248 mph? What's the point of that?
Any WW2 fighter that used trim controls rather than fixed trim was, by Crumpp's definition, badly designed and therefore inferior to uber Luftwaffe aircraft.
Robo.
09-24-2012, 07:38 AM
Utter balony, it's a great way to ensure that once in flight pilots do not have the ability to trim the aircraft to suit the circumstances - the 109E rudder became increasingly heavy, to the point where it was almost impossible to use - it's interesting that later "tall tailed" 109 variants had a trim tab to help overcome this problem. Setting the "combat speed" to a uniform and abitrary 248 mph? What's the point of that?
Any WW2 fighter that used trim controls rather than fixed trim was, by Crumpp's definition, badly designed and therefore inferior to uber Luftwaffe aircraft.
It's not a question of which airforce had 'better' trim system.
It was just a different approach in USAAF and LW. LW fighters had no variable rudder trim and a/c was trimmed for certain cruise speed, so at most typical cruise speed pilot would not have to kick the rudder to compensate for sideslip. Allied fighter pilot would twist the rudder trim and climb or fly with feet off. No biggie imho, just more comfortable.
What Crumpp is saying that Emil was trimmed for 400kph because that was best combat speed. That is obviously wrong, 400kph was typical cruise speed (achieved at some 1.15ata and 2200 U/min). This worked in game btw, but then the devs changed the fixed trim value for 300kph for some reason, which is too low and now LW pilots complain because the Emil is very unstable during combat phase:
See bugtracker issue No. 387: http://www.il2bugtracker.com/issues/387
There is nothing wrong with 109E turning well at 400kph, it's actually pretty obvious to any virtual pilot in here, e.g. fast Emil will outturn slow Spitfire with no problem for long enough to score some hits. But as for sustained turn advantage in typical horizontal turnfight and as for 400kph turn used in TnB combat for long enough to be called sustained turn, that's all nonsense. :-P 109 will win if the pilot keeps the speed up, but not via sustained turn performance advantage. At co-E situation, Spitfire would outturn and hit a 109 turning at 400kph flat with no problem. Just for long enough to score hits.
I'd say Crumpp is not entirely wrong here but his statements are irellevant to what is actually important in TnB combat (re: sustained turn argument). I don't blame him for he has no experience with combat sims.
He's wrong in his statement that 109E was trimmed for 400kph purely for combat purposes. Fixed trims are usually set for cruise speed even for fighter aircraft.
Crumpp
09-24-2012, 02:19 PM
That is obviously wrong
Do the math....
The 12lb boost calculation done by the RAE is an absolutely reasonable extrapolation.
Kurfürst
09-25-2012, 06:16 AM
The 12lb boost calculation done by the RAE is an absolutely reasonable extrapolation.
I have my doubts about it having been made by RAE. It's an obvious farce.
Crumpp
09-25-2012, 12:24 PM
The 12lb boost calculation done by the RAE is an absolutely reasonable extrapolation.
Well, then walk us through the explaination of how the engine data aligns with the graph. I would love to hear it.
Performance graph showing FTH of 11,000 ft:
http://www.spitfireperformance.com/spitfire-I-rae-12lbs.jpg
Engine data with RAM effect at max level speed showing FTH of 8,500 feet:
http://www.spitfireperformance.com/merlin3curve.jpg
41Sqn_Banks
09-25-2012, 12:59 PM
Well, then walk us through the explaination of how the engine data aligns with the graph. I would love to hear it.
Performance graph showing FTH of 11,000 ft:
http://www.spitfireperformance.com/spitfire-I-rae-12lbs.jpg
Engine data with RAM effect at max level speed showing FTH of 8,500 feet:
http://www.spitfireperformance.com/merlin3curve.jpg
Let's have a look at +6.25 boost ...
FTH at 17,000 ft (http://www.spitfireperformance.com/merlin3curve.jpg)
Max level speed at 19,000 ft (http://www.spitfireperformance.com/spitfire-I-rae-12lbs.jpg)
Looks like max level speed is achieved 2,000 feet above the FTH. Pretty much in line with the difference for +12 boost.
Edit: I want to make clear that this 2,000 ft difference between FTH and max speed must not be present in reality, it's more a systematical difference between the two charts that must be considered when they are compared.
Crumpp
09-25-2012, 01:35 PM
That chart was not used because it does not align. The engine chart you linked already includes RAM effect at Vmax.
That means the FTH should match. Not be close or have the same margin of error, but match if that is the correct engine data.
I used the power figures as listed in the flight reports NOT a seperate engine curve that does not match the performance data.
Crumpp
09-25-2012, 01:38 PM
http://imageshack.us/a/img19/1355/merlin3curve1.jpg (http://imageshack.us/photo/my-images/19/merlin3curve1.jpg/)
41Sqn_Banks
09-25-2012, 02:26 PM
I know that, I can read. You asked how the engine data align with the speed graph. They align with an consistent altitude difference of about of 2,000 ft.
The altitude difference between the FTH in the charts can be explained by a different level flight speed. E.g.
Hurricane I has a FTH of 17,750 ft at 316 mph.
Spitfire I has a FTH of 18,600 ft at 364 mph.
As we see the 50 mph speed difference results in a drop of 1000 ft for the FTH.
There is nothing contradicting in the charts ...
Crumpp
09-25-2012, 02:54 PM
I know that, I can read.
Then what is the issue with the data not aligning?
The altitude difference between the FTH in the charts can be explained by a different level flight speed. E.g.
It will align. If you looked at other aircraft and not just confined yourself to one specific type, you would see this the case.
A speed difference is not going to account for a 2000 ft increase in FTH.
How do you explain the fact this chart comes from an investigation of performance with an experimental high altitude engine.
The chart exactly matches the one found in:
Messerschmitt Me. 109
Handling and Manoeuvrability Tests
BY
M. B. MORGAN, M.A. and D. E. MORRIS, B.SC.
COMMUNICATED BY THE PRINCIPAL DIRECTOR OF SCIENTIFIC RESEARC (AIR)
MINISTRY OF SUPPLY
__________________________________
Reports and Memoranda No. 2361
September 1940*
http://kurfurst.org/Tactical_trials/109E_UKtrials/Morgan.html
Crumpp
09-25-2012, 03:15 PM
I know that, I can read. You asked how the engine data align with the speed graph. They align with an consistent altitude difference of about of 2,000 ft.
The altitude difference between the FTH in the charts can be explained by a different level flight speed. E.g.
Hurricane I has a FTH of 17,750 ft at 316 mph.
Spitfire I has a FTH of 18,600 ft at 364 mph.
As we see the 50 mph speed difference results in a drop of 1000 ft for the FTH.
There is nothing contradicting in the charts ...
The data matches the same fan plot in another report on a Spitfire equipped with a Merlin XX engine.
AFAIK, the Spitfire Mk I was equipped with the Merlin III engine.
Seadog
09-25-2012, 03:40 PM
http://imageshack.us/a/img19/1355/merlin3curve1.jpg (http://imageshack.us/photo/my-images/19/merlin3curve1.jpg/)
Merlin II/III could hold 12lb boost to over 10,000ft in a Hurricane and higher in a Spitfire:
http://www.wwiiaircraftperformance.org/hurricane/hurricane-l1717-cal.jpg
Crumpp
09-25-2012, 03:54 PM
Wow, the data does not match. It is that simple.
It does not mean there is not good data out there, it just means these charts presented are not it.
The fan plot for the Spitfire is for a Merlin XX engine.
I have my doubts about it having been made by RAE. It's an obvious farce.I agree it looks simplistic, but technically it is sound and I see no reason it not being an original document. No reason for it being one either, but I will accept it on face value as I see no reason to mistrust Mr.Williams on this issue. If you have more than a gut feeling, I'm willing to re-evaluate my opinion.
Engine data with RAM effect at max level speed showing FTH of 8,500 feet:It's not with ram effect. That's painfully obvious from all the engine and plane data on 6.25lbs around. The power level generated by the engine on this chart has the designation "all out level" and that's all there is to it. Assuming otherwise is like assuming "combat" power is only available when the aircraft is in actual combat.
Robo.
09-25-2012, 05:10 PM
The fan plot for the Spitfire is for a Merlin XX engine.
And which Spitfire version would that be? ;)
Do the math....
I shall do the math to prove that 400kph was the cruise speed and that in turn was the reason to set the fixed trims to that speed - not your graph? :eek:
41Sqn_Banks
09-25-2012, 05:42 PM
It's not with ram effect. That's painfully obvious from all the engine and plane data on 6.25lbs around. The power level generated by the engine on this chart has the designation "all out level" and that's all there is to it. Assuming otherwise is like assuming "combat" power is only available when the aircraft is in actual combat.
You are right, e.g. AP 1590B states 890 bhp at sea level and 1030 bhp at 16,250 ft for +6.25 and 3,000 rpm. The chart is obviously without RAM effect.
Glider
09-25-2012, 10:31 PM
I have put in a request to the Rolls Royce Heritage Trust part of Rolls Royce to see what they say. The NA don't seem to have anything that would satisfy everybodies requirements. I wouldn't hold your breath as it might take forever but should at least deliver a definitive reply.
Crumpp
09-25-2012, 11:52 PM
I shall do the math to prove that 400kph was the cruise speed
Do you know where cruise speeds are located on the Power and thrust curves?
Need me to show you.....????
Crumpp
09-25-2012, 11:57 PM
Spitfire III, AFAIK only the prototype was built.
http://imageshack.us/a/img17/1140/summary1k.jpg (http://imageshack.us/photo/my-images/17/summary1k.jpg/)
http://imageshack.us/a/img109/7506/fanclnsml.jpg (http://imageshack.us/photo/my-images/109/fanclnsml.jpg/)
Seadog
09-26-2012, 01:23 AM
Spitfire III, AFAIK only the prototype was built.
The 2nd (lower) page is not a Spitfire III. Spitfire III had a wingspan of 30 ft 6 in (9.3 m) and wing area of 220 square feet and for 6000lb that gives a wing loading of 27.3lb.
Jam66es
09-26-2012, 01:55 AM
I sense that Red pilots not knowing/ignoring this limitation may be at the culprit.
http://www.qmku.info/0.jpghttp://www.qmku.info/7.jpghttp://www.qmku.info/8.jpghttp://www.qmku.info/9.jpghttp://www.ymeu.info/test5.jpg
Robo.
09-26-2012, 06:37 AM
Spitfire III, AFAIK only the prototype was built.
Yes, I know, only few built. My point was that the original data linked by Banks were of Merlin III powered Spitfire.
Even your image is not an Mk.III, just the 1st page.
Robo.
09-26-2012, 06:47 AM
Do you know where cruise speeds are located on the Power and thrust curves?
Need me to show you.....????
No need, thank you.
All I said was that you were wrong in your statement that 400kph fixed trim setting was due to the 'good speed for dogfight' reason
http://forum.1cpublishing.eu/showpost.php?p=463187&postcount=323
When you calculate out the performance, it is easy to see why Mtt defaulted the trim to 400kph.
That is a very good speed to dogfight the airplane.
It is a very good speed to dogfight the airplane, but that has nothing to do with the sustained turn debate (in practical reality of an actual air combat). I explained that earlier. It is also not the reason for default trim settings, that reason was actually cruise speed at 1.15ata @ 2200U/min.
Here again:
Why do you think the trim on the Bf-109 is set to 400 kph IAS???
You do understand they can trim the aircraft for whatever speed they desired?? Having a fixed trim condition is a great way to set the combat speed for your airforce.
Please don't mix up facts as they suit you to prove your bizzare theories.
Osprey
09-26-2012, 07:09 AM
Spitfire III, AFAIK only the prototype was built.
That was built for the Griffon engine but they had a ton of problems and dropped it. The Merlin XX wasn't used in the Spitfire, that's why Robo is rightly taking the mick out of you.
NZtyphoon
09-26-2012, 09:04 AM
That was built for the Griffon engine but they had a ton of problems and dropped it. The Merlin XX wasn't used in the Spitfire, that's why Robo is rightly taking the mick out of you.
In this case Crumpp is right, just for once - the Spitfire III prototype was built with the Merlin XX, which had a single-stage two speed supercharger - it also had clipped wings, a revised undercarriage which was raked forward by 2 inches, and a revised windscreen with two straight side pieces and flat windscreen with internal glass (the undercarriage and windscreen were later used on the Spitfire VC) . When it was decided to reserve the XX for Hurricane IIs the Mk III was adapted to take the first Merlin 60 series engine, becoming a Mk IX prototype. The Mk IV was very similar to the Mk III but had the Griffon engine.
Osprey
09-26-2012, 09:39 AM
OK so I may be a version out here lol Either way it's another case of running with it because there's a war on, not exactly the engineers style planning he expects in theory. Of course it's theory that engineers plan because where I work, which is a very successful global engineering firm, the engineers have virtually zero planning, all prototyping and wing their projects (plastering it with documentation on the fly). It's in software, my dept, which has far more planning than the engineers.
Robo.
09-26-2012, 10:24 AM
In this case Crumpp is right, just for once - the Spitfire III prototype was built with the Merlin XX, which had a single-stage two speed supercharger - it also had clipped wings, a revised undercarriage which was raked forward by 2 inches, and a revised windscreen with two straight side pieces and flat windscreen with internal glass (the undercarriage and windscreen were later used on the Spitfire VC) . When it was decided to reserve the XX for Hurricane IIs the Mk III was adapted to take the first Merlin 60 series engine, becoming a Mk IX prototype. The Mk IV was very similar to the Mk III but had the Griffon engine.
Very true, thanks for the details NZtyphoon. The key is the different (clipped) wings and therefore different wing load than the one we see at the top right corner of the above sheet.
Crumpp came up with the Merlin XX theory only to prove that the fan plot posted was for different engine with 2 stage supercharger. That is wrong just as was wrong his assumption that the chart posted previously by Banks (post 345) already included RAM effect.
No matter how I look at it, the post 345 makes perfect sense. ;)
Crumpp
09-26-2012, 11:00 AM
All I said was that you were wrong in your statement that 400kph fixed trim setting was due to the 'good speed for dogfight' reason
Again, robo...
I asked you if you know how to determine the cruise speeds for an airplane. These are not random figures, pulled from a hat.
They are specific points on the power required and thrust required curves. The cruise speeds points of the thrust required and power required curves are fixed by the design and completely independent of engine settings.
Do you need me to talk you through how to determine them?
It is very easy to proved I am not wrong if you understand how the physics works.
Robo.
09-26-2012, 11:41 AM
Again, robo...
I asked you if you know how to determine the cruise speeds for an airplane. These are not random figures, pulled from a hat.
They are specific points on the power required and thrust required curves. The cruise speeds points of the thrust required and power required curves are fixed by the design and completely independent of engine settings.
Do you need me to talk you through how to determine them?
It is very easy to proved I am not wrong if you understand how the physics works.
No, thank you, that is not necessary at all. I already know you're completely wrong with your 'combat speed default trim setting' statement, no matter how hard you now try to prove that you were actually right.
As for the actual question (sorry I thought it was a rhetorical one) I don't know how exactly to calculate cruise speed for an aircraft, and I don't need it in order to see that you wrote 'combat speed' instead of 'cruise speed'. Now you will probably reply with another graph to prove that it's the same thing. Maybe you're even right, but essentially, you wrote nonsense, hence my reply. Consider my knowledge as limited if you wish, but then if I even can see that you're wrong and that you're bending facts to fit your bizarre theories (maintain rpm by changing it constantly, RAM effect, Merlin XX etc...), that says something about your activity here, not mine.
I am not too sure anymore about what are you trying to achieve on this game's forums, perhaps you enjoy the arguing for the sake of arguing, perhaps you enjoy the advantage you think you're having with your theoretical knowledge. I actually enjoy some of your technical posts and I have no problem to understand what you were saying, but when you're wrong you're wrong. And for some reason you never admit it, you just go on and on and every thread ends up to be about Crumpp vs. the 'sane world' rather than about the original topic. I fond that a bit frustrating to be honest.
Let me ask you a question you also omitted before - how exactly would a 400kph sustained turn in a Bf 109E be useful in actual turnfight vs. a Spitfire Mk.I?
Crumpp
09-26-2012, 01:18 PM
I already know you're completely wrong with your 'combat speed default trim setting' statement
In otherwords, forget any facts....
You are going to stick to your immature and emotional reaction.
Well, let's see how it pans out.
You can look in the Bf-109E3 Flugzeug Handbuch and see that the engine out instructions call for the pilot to pitch for 200kph IAS. This is best glide speed and corresponds to L/Dmax.
If our curves are correct, this will be the botton of the thrust required curve and tangent of the power required curve.
First the Thrust and Power Required curves:
http://imageshack.us/a/img193/4543/powerandthrustcurvecrui.jpg (http://imageshack.us/photo/my-images/193/powerandthrustcurvecrui.jpg/)
200kph = 124mph +10 mph PEC = 134mph CAS * .869 = 117KCAS = 117KEAS at sea level.
Yep, best glide aligns perfectly with our curves so we know the curves are correct.
Using the curves, it is easy to find the other cruise speeds.
Maximum endurance will be at the point of minimum power required. Carson's speed is a modern innovation and is the best balance of fuel consumption and speed.
The trim speed of 400kph IAS does not align with any cruise point on the curves. That means the speed was chosen for a different reason.
Now it we look at the rate of turn, or how fast an airplane can bring the guns on target, we see that 206KEAS is a point the Bf-109E3 maintains a healthy rate of turn advantage and can sustain better maneuvering performance.
http://imageshack.us/a/img15/8112/rateofturn.jpg (http://imageshack.us/photo/my-images/15/rateofturn.jpg/)
So, if it was not intentional, it certainly was a very fortunate turn of fate that the Germans choose 400kph to set the trim for the Bf-109E3.
Crumpp
09-26-2012, 01:30 PM
how exactly would a 400kph sustained turn in a Bf 109E be useful in actual turnfight vs. a Spitfire Mk.I?
Robo,
This is the key performance parameter for a fighter. It gives the aircraft which can sustain a higher load factor at a higher velocity the initiative in a dogfight.
This characteristic allows the Bf-109E3 to force the Spitfire to a lower airspeed in order to survive the fight.
The outcome of any dogfight is not predetermined. There are too many "what if's" and pilot skills are the determining factor.
What it tells Spitfire pilots is if you enter a sustained turn fight at high speed, the Bf-109 will win if you don't slow your speed down to the point you have a better sustained turn rate.
What it tells the Bf-109 pilot is you can maneuver against the Spitfire, just don't drop your IAS below 400 kph. If he breaks off and zooms at the point the Spitfire begins to out turn him, the Bf-109 will be above his opponent, out of reach, and able to engage/disengage at will.
400 kph is not a difficult point for the Bf-109 to maintain especially given the stability of the design. It is the trim speed and given the correct amount of power, where the airplane wants to be....
Robo.
09-26-2012, 01:39 PM
In otherwords, forget any facts....
Not at all! The fact is (still) that 400kph was NOT chosen by Mtt because of 'good speed for dogfight' reason, contrary to your statement. No matter how you try to re-pack your words, you were wrong.
Now you will probably reply with another graph
:rolleyes:
I specifically told you that posting the cruise speed calculation and graph is not necessary and irrelevant, but thank you anyway, it was interesting.
Osprey
09-26-2012, 01:43 PM
Did he even read your post Robo? Your point just went whoosh over his head.
http://24.media.tumblr.com/tumblr_lrdx0xtRMJ1qm2g5fo1_500.jpg
Crumpp
09-26-2012, 01:46 PM
400kph was NOT chosen by Mtt because of 'good speed for dogfight' reason
Why did they pick it then, Robo? :confused:
Given the fact cruise speeds are fixed by design? ;)
Crumpp
09-26-2012, 01:54 PM
Did he even read your post Robo? Your point just went whoosh over his head.
Which point would that be? That I am wrong and don't admit it? Certainly I will if I am wrong.
On the otherhand, I did go to college for this stuff, worked hard for my education, and learned a thing or two about the science of flight.
I also have plenty of practical experience working and flying airplanes.
So do you think I am some jerk who can't admit he is wrong or maybe have some knowledge that makes me question conclusions that don't fit the facts or the science??
:rolleyes:
Robo.
09-26-2012, 01:57 PM
Robo,
This is the key performance parameter for a fighter. It gives the aircraft which can sustain a higher load factor at a higher velocity the initiative in a dogfight.
This characteristic allows the Bf-109E3 to force the Spitfire to a lower airspeed in order to survive the fight.
The outcome of any dogfight is not predetermined. There are too many "what if's" and pilot skills are the determining factor.
What it tells Spitfire pilots is if you enter a sustained turn fight at high speed, the Bf-109 will win if you don't slow your speed down to the point you have a better sustained turn rate.
Yes, I agree, you said that already before, and this is very well known to most virtual pilot on this forums. You're not saying anything new here. Yes, the 109 turns better at higher speeds, Spitfire wins at lower speeds. What I was trying to explain before was that in a TnB fight, it's usually lower speeds that matter and decide the fight.
There is absolutely nothing wrong with what you're saying, it just doesn't make sense in regards to actual combat. If you keep the 109 in 400kph sustained turn, the Spitfire will be able to shoot at you for long enough to kill you, even being slower.
What it tells the Bf-109 pilot is you can maneuver against the Spitfire, just don't drop your IAS below 400 kph. If he breaks off and zooms at the point the Spitfire begins to out turn him, the Bf-109 will be above his opponent, out of reach, and able to engage/disengage at will.
If he breaks off and zooms we don't talk about sustained turn competition anymore. Everybody is well aware of 109s BnZ characteristics (if he extends vertically). Again, you're not saying anything new. It's the TnB that matter here. Pure TnB rarely happened because it would be a suicide for the 109 pilot.
400 kph is not a difficult point for the Bf-109 to maintain especially given the stability of the design. It is the trim speed and given the correct amount of power, where the airplane wants to be....
What you're saying with this whole post of yours is basically:
109 can win a turnfight against the Spitfire as long as it won't turn with it
Spitfire has had better sustained turn rate than 109 and it was generally a silly idea to turn with it. This is the case in the sim as well and all other sims.
Crumpp
09-26-2012, 02:12 PM
109 can win a turnfight against the Spitfire
Yes, that is correct.
If he breaks off and zooms we don't talk about sustained turn competition anymore.
Sure we are...
The Spitfire has lost and the Bf-109 has used its sustained turn performance to gain advantage and win the dogfight.
it just doesn't make sense in regards to actual combat.
That is because a computer game is not representing reality in this case.....
There is a very good engineering reason designers have strived for speed as the number one performance parameter for a fighter.
Osprey
09-26-2012, 02:52 PM
I'd have hated to have been in your classes (not that I was ever a chicken feeder) because you'd have constantly put the class off with your maniacal theories.
I loved this bit
There is a very good engineering reason designers have strived for speed as the number one performance parameter for a fighter.
Total misunderstanding of air combat or brilliant trolling?
bongodriver
09-26-2012, 02:58 PM
So do you think I am some jerk who can't admit he is wrong
This!!!.....Ironic that Crumpp would come up with the best description.
or maybe have some knowledge that makes me question conclusions that don't fit the facts or the science??
No, you question the facts and science because you have a little knowlege and a big agenda.
Kurfürst
09-26-2012, 03:00 PM
I agree it looks simplistic, but technically it is sound and I see no reason it not being an original document. No reason for it being one either, but I will accept it on face value as I see no reason to mistrust Mr.Williams on this issue. If you have more than a gut feeling, I'm willing to re-evaluate my opinion.
Its a gut feeling of course - I wasn't there when it was drawn (thank God for that!). To me it just seems that, given that the original was drawn with pen AND was labeled, compared to the rough approximation visibile on the pencil drawn +12 and +16(?!) lines, the latter lines were probably made by some aircraft enthusiast well after the war. The lines/figures look more or less a reasonable guesswork, but I very much doubt it has anything to do with any test establishment.
Yes, I agree, you said that already before, and this is very well known to most virtual pilot on this forums. You're not saying anything new here. Yes, the 109 turns better at higher speeds, Spitfire wins at lower speeds. What I was trying to explain before was that in a TnB fight, it's usually lower speeds that matter and decide the fight.
There is absolutely nothing wrong with what you're saying, it just doesn't make sense in regards to actual combat. If you keep the 109 in 400kph sustained turn, the Spitfire will be able to shoot at you for long enough to kill you, even being slower.
IMHO the real question is how much time to Spit has to shoot at you? Because if the Spit turns at around its peak sustained turn rate - at about 250 kph? 300 max? - its going to be a good deal slower than the 109; maybe slow enough to fall so behind that it will be out of realistic guns range? You cant shoot what is not in range, even if your nose points towards it..
Moreover if say both aircraft start at 400 + kph, the 109 maintains it while the Spit bleeds it off to get a snapshop, all the 109 has to do is to level out with a very significant E advantage, and if the pilot is good at Energy fight, its all cat-and-mouse from there on.
Generally it seems to me a good idea to keep the speed over 400 km/h in a 109. If the Spit tries to follow you in sustained 400 kph turn, or if he slows down to try to get you, he seems to be ... to have gotten into a bad position. Especially in a multi plane enviroment.. you can shoot what is slow, you cant shoot what is fast.
bongodriver
09-26-2012, 03:25 PM
IMHO the real question is how much time to Spit has to shoot at you? Because if the Spit turns at around its peak sustained turn rate - at about 250 kph? 300 max? - its going to be a good deal slower than the 109; maybe slow enough to fall so behind that it will be out of realistic guns range? You cant shoot what is not in range, even if your nose points towards it..
Moreover if say both aircraft start at 400 + kph, the 109 maintains it while the Spit bleeds it off to get a snapshop, all the 109 has to do is to level out with a very significant E advantage, and if the pilot is good at Energy fight, its all cat-and-mouse from there on.
Generally it seems to me a good idea to keep the speed over 400 km/h in a 109. If the Spit tries to follow you in sustained 400 kph turn, or if he slows down to try to get you, he seems to be ... to have gotten into a bad position. Especially in a multi plane enviroment.. you can shoot what is slow, you cant shoot what is fast.
But aren't you missing the point completely......you are not describing a turning engagement, the whole issue here is that if the 109 tried to engage in a 'turning' fight with a Spit it 'will' loose, there has never been any disagreement that the 109 had better speed to maintain an overall tactical advantage, the 109 could choose when to engage but the Spitfire was more than capable of evading, if you felt frustrated by that as a 109 driver and decided to try for a propper knife-fight with a Spit you were likely to lose, the 109's best tactic was to run in quick when an opportunity presents itself and run away quicker once the job is done.
Robo.
09-26-2012, 03:32 PM
IMHO the real question is how much time to Spit has to shoot at you?
Hi Kurfurst,
of course depending on the situation, I say just long enough to score a kill. That is my experience at least, I fly both 109s and Spitfires and pretty much anything in 1946. We're talking strictly horizontal fight as for pure sustained turn performance comparsion.
The question is also, for how long would you keep 400kph IAS in horizontal turn. I see where you're coming from though, you certainly have a point. Let's say the 109 wants to stay out of Spitfires gun range, in that case even 400kph turn would not be sufficient.
Because if the Spit turns at around its peak sustained turn rate - at about 250 kph? 300 max? - its going to be a good deal slower than the 109; maybe slow enough to fall so behind that it will be out of realistic guns range? You cant shoot what is not in range, even if your nose points towards it..
Theoretically, that is absolutely possible. But it is also possible to cut the corner of the 109 and shoot at it alright at lead curve, then ease up the turn and repeat. All depends on the trajectory, the planes will obviously turn on different circles etc. If you make a deal that the 109 won't climb or scissor, just turn, you will win. Because the Spitfire is much better TnB fighter than Emil. Emil is decent turner, too, very maneuvrable and agile, but as for the sustained turn competition in actual dogfight, Spitfire has got better qualities.
Moreover if say both aircraft start at 400 + kph, the 109 maintains it while the Spit bleeds it off to get a snapshop, all the 109 has to do is to level out with a very significant E advantage, and if the pilot is good at Energy fight, its all cat-and-mouse from there on.
Of course, but energy fight is not sustained turn fight.
Generally it seems to me a good idea to keep the speed over 400 km/h in a 109.
Yes of course, that's a great idea in any aircraft ;) But even having 400kph+, I would not enter turnfight with a Spitfire because that bloody thing turns better and would shoot at me. And I don't like that.
Kurfürst
09-26-2012, 03:34 PM
But aren't you missing the point completely......you are not describing a turning engagement, the whole issue here is that if the 109 tried to engage in a 'turning' fight with a Spit it 'will' loose, there has never been any disagreement that the 109 had better speed to maintain an overall tactical advantage, the 109 could choose when to engage but the Spitfire was more than capable of evading, if you felt frustrated by that as a 109 driver and decided to try for a propper knife-fight with a Spit you were likely to lose, the 109's best tactic was to run in quick when an opportunity presents itself and run away quicker once the job is done.
I don't think I have missed anything, but it depends how you define a turn fight. And I am not meaning a 'propper knife-fight' at usually some low speed like 2-300 kph.
What I mean that if
- both the (+6) Spit and the 109E try a sustained turn contest
- near ground level (where the 109 has more power and is faster),
- and both are at or above about 400 kph and try to sustain that,
the Spit WILL loose that turn contest. The Hurricane even more so. As Jtd noted, its simply too hard to overcome some 30(+) km/h speed advantage, and the fact that parasitic drag will be dominant. The general advise is though (apart from don't turn with the Spit at low speeds) is that the faster the 109 turns, the better it is for its pilot.
The other comparisons (one plane flies sustained, the other unsustained, level outs and climbs etc.) I do not adress here. These tactics are essentially combinations of the best peformance envelope against the opponent's worst.
Robo.
09-26-2012, 03:35 PM
Yes, that is correct.
When they unban you, please stop cutting my quotes like that, I do not appreciate that. It seems you have very selective approach and you only choose to take the bits and bobs that suit you. Please stop arguing at least.
Robo.
09-26-2012, 03:42 PM
I don't think I have missed anything, but it depends how you define a turn fight. And I am not meaning a 'propper knife-fight' at usually some low speed like 2-300 kph.
What I mean that if
- both the (+6) Spit and the 109E try a sustained turn contest
- near ground level (where the 109 has more power and is faster),
- and both are at or above about 400 kph and try to sustain that,
the Spit WILL loose that turn contest. The Hurricane even more so. As Jtd noted, its simply too hard to overcome some 30(+) km/h speed advantage, and the fact that parasitic drag will be dominant. The general advise is though (apart from don't turn with the Spit at low speeds) is that the faster the 109 turns, the better it is for its pilot.
The other comparisons (one plane flies sustained, the other unsustained, level outs and climbs etc.) I do not adress here. These tactics are essentially combinations of the best peformance envelope against the opponent's worst.
I agree in general except for the fact (major flow I would say) that the Emil will slow down rather fast in this sustained horizontal turn. Spitfire will win in RL situation described by you, because the pilot would obviously not try to sustain these 400kph, he will try to bear his guns on the 109 and will do so rather soon. No matter what you do in a 109, if you chose to remain horizontal, the only way of evading the Spitfire would be flying straight. And flying straight is not sustained turn. See?
Osprey
09-26-2012, 03:42 PM
there has never been any disagreement that the 109 had better speed to maintain an overall tactical advantage, the 109 could choose when to engage but the Spitfire was more than capable of evading, if you felt frustrated by that as a 109 driver and decided to try for a propper knife-fight with a Spit you were likely to lose, the 109's best tactic was to run in quick when an opportunity presents itself and run away quicker once the job is done.
I assume you are talking about current in game because the Spitfire is not a slower aeroplane, the 109 and Spitfire are very close throughout altitudes.
Whilst I understand Kurfursts point about the Spitfire @+6 the fact of the matter is that it could manage +12 for a significant time. If you are simply setting a scenario where the Spitfire can actually only manage +6 for whatever reason then we could chuck in all sorts, such as the 109 being out of cannon or leaking Glycol, same for the Spitfire. It's either ceteris paribus or a bit pointless to compare imo.
bongodriver
09-26-2012, 04:15 PM
the Spit WILL loose that turn contest.
.
How exactly? the Spit wil still be able to turn at a higher rate of turn but it won't maintain that speed, if it's behind the 109 it will keep it in it's sights and if its ahead the 109 won't get a bead and will just whizz past, you must realize the Spit will have a better 'rate' of turn than the 109 at all speeds.
With a fixed trim at a constant engine power setting, the trim speed of an aircraft is not going to remain constant over altitude. 400 IAS seems to be a pretty high cruising speed at 5 km for a 109E.
MiG-3U
09-26-2012, 05:12 PM
Its a gut feeling of course - I wasn't there when it was drawn (thank God for that!). To me it just seems that, given that the original was drawn with pen AND was labeled, compared to the rough approximation visibile on the pencil drawn +12 and +16(?!) lines, the latter lines were probably made by some aircraft enthusiast well after the war. The lines/figures look more or less a reasonable guesswork, but I very much doubt it has anything to do with any test establishment.
Hm... using the same standars there is no real test data supporting 109E doing 500kmh at sea level. Only a calculation based on a prototype aircraft with a non-standard two speed supercharger and a power value which is higher than normal 601 power.
However, there is several test data sets supporting speeds around 470kmh for 1.3ata and supposedly faster 109F is doing just 495kmh at same power according to kenblat.
Kurfürst
09-26-2012, 05:17 PM
How exactly?
Well let's start with the fact that it turns better already at 400 kph. Everything Spit does, the 109 can do better at these speeds.
the Spit wil still be able to turn at a higher rate of turn but it won't maintain that speed,
That's an unsustained turn. What you forget that in an unsustained turn, the 109 will still loose less speed than the Spit at high speeds, because the basics (=more excess thrust) did not change.
if it's behind the 109 it will keep it in it's sights and if its ahead the 109 won't get a bead and will just whizz past,
If it's behind the 109 and slows down to match the turn the 109 will get out of range quickly and the 109 will be at superior E state.. if the 109 is behind yes the 109 will just wizz past, and at a superior E state. Then cat-and-mouse begins...
you must realize the Spit will have a better 'rate' of turn than the 109 at all speeds.
Simply no. At high speeds it cannot mach the 109 sustained turn, and it will loose more speed in an unsustained turn if the 109 also goes to unsustained turn.
You see the turn rate advantage is only there if the 109 maintains a sustained turn and the Spit goes for an unsustained turn -> superior E for the 109 and you do not want to fight a 109 with
And unfortunately the Spit cannot beat the 109 at high speed in unsustained turns either. The 109 can match an unsustained turn at any time AND loose less speed in the process. If the pilot has his wits about him he will take advantage of this and use the superior E before speed gets really slow where it's Spitfire territory.
The slower Spitfire (at +6) cannot match the faster 109 (any plane) at high speed turns. At least, not for long.
Kurfürst
09-26-2012, 05:20 PM
Hm... using the same standars there is no real test data supporting 109E doing 500kmh at sea level.
Of course there it is.
Only a calculation based on a prototype aircraft with a non-standard two speed supercharger and a power value which is higher than normal 601 power.
I call BS on this. Got any sources for these claims?
However, there is several test data sets supporting speeds around 470kmh for 1.3ata and supposedly faster 109F is doing just 495kmh at same power according to kenblat.
I would like to see them. Hopefully, they are just as detailed as the flight tests and official specs you are dismissing. That includes calibration curves for the pitot, boost and speed measured at various altitudes and known conditions, and proof check of the engine at a bench.
Glider
09-26-2012, 05:25 PM
I agree in general except for the fact (major flow I would say) that the Emil will slow down rather fast in this sustained horizontal turn. Spitfire will win in RL situation described by you, because the pilot would obviously not try to sustain these 400kph, he will try to bear his guns on the 109 and will do so rather soon. No matter what you do in a 109, if you chose to remain horizontal, the only way of evading the Spitfire would be flying straight. And flying straight is not sustained turn. See?
I do find this theory that the 109 will be able to turn better than a SPit at higher speeds a little foolish.
a) There are no, repeat no tests, from any side that support this theory.
b) The 109 locked up faster than a spitfire at higher speeds so the spit will have all the advantages getting into the turn by which time the 109 will be in the smelly stuff
c) You quickly lose speed in a turn which will nulify any theoretical advantages
d) The above description of what will happen shows the folly of this theory
e) The 12 boost throws the theory out anyway as it passes the power to weight ratio advantage to the SPitfire
f) Its worth remembering what the German test establishment said about the turning ability of these aircraft:-
Before turning fights with the Bf 109 E type, it must be noted in every case, that
all three foreign planes have significantly smaller turning circles and turning times.
An attack on the opponent as well as disengagement can only be accomplished on the basis of
existing superiority in performance.
Notice it doesn't say:-
a) The SPitfire is better at slow speeds
b) That the 109 can turn inside the Spitfire at high speeds
c) Ensure you keep your speed up against the Spitfire in a turning fight
It says basically DON'T GET INTO A TURNING FIGHT.
Can someone explain how the German test establishment got it so wrong.
After all they only had the real aircraft, real pilots to fly mock combats who obviously were very up to date on the Me109, amongst the finest engineers and designers in the world, people both well versed in the theory and experienced in this field, plus the resources of a test establishment.
I repeat the question, how did they get it so wrong?
MiG-3U
09-26-2012, 05:37 PM
Of course there it is.
Please post.
I call BS on this. Got any sources for these claims?
V15 chart on your site shows clearly two speed supercharger and text sites höhen and bodenlader, power value in the calculation is 1018ps vs 990ps for Db601A.
All at your site including 109F kenblat.
Robo.
09-26-2012, 05:53 PM
I do find this theory that the 109 will be able to turn better than a SPit at higher speeds a little foolish.
Oh yes, 109 could indeed turn tighter than a Spitfire at speeds around and above 400 kph.
In reality this was not very relevant in pure horizontal turnfight for the reasons you named. It was great advantage at BnZ maneuvring, even turning with a Spitfire that is breaking away from your attack - you can turn long enough to score nice deflection shot on him. But that is not anywhere close to sustained turn, you do a a 1/8 of a turn and away you break. If you stayed at that turn, you would burn your E and you would end up with a very angry Spitfire on your tail very soon.
Kurfürst
09-26-2012, 05:57 PM
Please post.
Here.
Flight test.
http://kurfurst.org/Performance_tests/109E_V15a/files/109v15a_blatt6.jpg
Guranteed specs.
http://kurfurst.org/Performance_tests/109E_Baubeschreibung/109E_Bau_speed.png
I would like to see similiar detailed specs for the Spitfire. At +12 lbs boost. Calibration curves, engine bench test, detailed description of airframe conditions and temperature conditions.
None such exists...
[QUOTE]
V15 chart on your site shows clearly two speed supercharger
Nope.
and text sites höhen and bodenlader,
Yes. And?
power value in the calculation is 1018ps vs 990ps for Db601A.
And have the DB 601Aa (not the DB 601A) in the sim, which had 1045 PS (1175 PS WEP) anyway. So the tested example had to reached 498 kph at 1018 PS. We have an 1045 PS variant. Are you saying that it should be even faster..?
Now, care to tell me, that regardless of the supercharger design, that what is wrong with the test, since the plane has about the same power our plane in the sim has.
All at your site.
Nope.
I also have similiar curves for G-14, G-6, G-1 etc. on my site. It only shows that the DB 60x supercharger could be run at will at fixed speeds as well. It's no witchcraft, all that is needed to override the barometric control of the hydraulic coupling. Which they did often during these tests, see some of the G-6 and G-14 tests:
http://kurfurst.org/Performance_tests/109G14_May44trials/109G14_GLCE-may44_trials.html
Besides the actual supercharger operation is completely irrelevant. We KNOW for a fact that the plane had 951 PS in high speed flight (about 50-60 PS down on power) and reached 493 kph with it (which they calculated to be good for 498 kph at the nominal rating of 996 PS). Any other 109 in similar configuration with the same power should reach the same of course.
Kurfürst
09-26-2012, 05:58 PM
I do find this theory that the 109 will be able to turn better than a SPit at higher speeds a little foolish.
a) There are no, repeat no tests, from any side that support this theory.
b) The 109 locked up faster than a spitfire at higher speeds so the spit will have all the advantages getting into the turn by which time the 109 will be in the smelly stuff
c) You quickly lose speed in a turn which will nulify any theoretical advantages
d) The above description of what will happen shows the folly of this theory
e) The 12 boost throws the theory out anyway as it passes the power to weight ratio advantage to the SPitfire
f) Its worth remembering what the German test establishment said about the turning ability of these aircraft:-
Before turning fights with the Bf 109 E type, it must be noted in every case, that
all three foreign planes have significantly smaller turning circles and turning times.
An attack on the opponent as well as disengagement can only be accomplished on the basis of
existing superiority in performance.
Notice it doesn't say:-
a) The SPitfire is better at slow speeds
b) That the 109 can turn inside the Spitfire at high speeds
c) Ensure you keep your speed up against the Spitfire in a turning fight
It says basically DON'T GET INTO A TURNING FIGHT.
Can someone explain how the German test establishment got it so wrong.
After all they only had the real aircraft, real pilots to fly mock combats who obviously were very up to date on the Me109, amongst the finest engineers and designers in the world, people both well versed in the theory and experienced in this field, plus the resources of a test establishment.
I repeat the question, how did they get it so wrong?
Just explain how a plane with less or no excess thrust can pull a sustained turn better than a plane with more excess thrust, thank you.
How much excess thrust does a Spitfire at SL, running at +6 1/4 boost has at about 280 mph 1g at David?
How much more excess thrust does a Spitfire at SL, running at +6 1/4 boost require in 2g turn at about 280 mph David?
How much excess thrust does a Bf 109E at SL running at 1.35ata bppst has at about 280 mph 1g at David?
Which has a better sustained turn at 400 mph David, a Spitfire IX or a Me 262 (P-80 if you like)?
That's an unsustained turn. What you forget that in an unsustained turn, the 109 will still loose less speed than the Spit at high speeds, because the basics (=more excess thrust) did not change.No, this isn't necessarily an unsustained turn. The same way the 109 has to give up level speed to turn, the Spitfire has, and for each change in turn rate, the speed loss of the 109 is higher, or for each loss of speed, the Spitfires turn rate change is larger. If the 109 settles at a load factor or turn rate, the Spitfire can do the same, at a lower speed.
It really sums up to that the 109's biggest advantage is in flying straight and level, it will remain competitive throughout the high & medium speed range, with the advantage always decreasing. All this, mind you, at sea level against a 6.25lb boosted Spitfire I, which is as good as it gets for the 109.
MiG-3U
09-26-2012, 06:34 PM
Here.
Flight test.
That is a flight test ofa prototype doing 485kmh, non standard engine and 500kmh is a calculation based on non standard power.
Guranteed specs.
Not a test, more like a selling brochure.
But we have multiple tests results around 470kmh.
Yes. And?
That means two speed supercharger, no need for large oil cooler needed for the hydraulic clutch, less drag.
And have the DB 601Aa (not the DB 601A) in the sim, which had 1045 PS (1175 PS WEP) anyway. So the tested example had to reached 498 kph at 1018 PS. We have an 1045 PS variant. Are you saying that it should be even faster...
I can't find a 1C source stating that, please show me.
Besides 601A and Aa power settings are obviously different, 5min power fth is lower for Aa which means higher than 1.3ata.
I also have similiar curves for G-14, G-6, G-1 etc..
Nonsense curves and not relevant for this discussion, the rest is just your speculations.
Kurfürst
09-26-2012, 06:40 PM
That is a flight test ofa prototype doing 485kmh, non standard engine and 500kmh is a calculation based on non standard power.
Wrong on all accounts.
Not a test, more like a selling brochure.
And with the specs laid down within being guaranteed within +/- 5% by the manufacturer of the product.
But we have multiple tests results around 470kmh.
Really. And what power, what supercharger settings, what airframe conditions?
That means two speed supercharger, no need for large oil cooler needed for the hydraulic clutch, less drag.
Speculation.
I can't find a 1C source stating that, please show me.
Look at the source files - or the fact that we a 5-min boost pressure of 1.35 ata...
Nonsense curves and not relevant for this discussion, the rest is just your speculations.
And one more scratch on the tail... ;)
Kurfürst
09-26-2012, 06:44 PM
The same way the 109 has to give up level speed to turn, the Spitfire has, and for each change in turn rate, the speed loss of the 109 is higher
Because?
or for each loss of speed, the Spitfires turn rate change is larger.
Because?
If the 109 settles at a load factor or turn rate, the Spitfire can do the same, at a lower speed.
Yes.
It really sums up to that the 109's biggest advantage is in flying straight and level,
The 109s biggest advantage is its overall smaller drag, more powerful engine, and higher power to weight ratio, good harmony of controls (at least IRL) and superior near-stall handling IMHO.
it will remain competitive throughout the high & medium speed range, with the advantage always decreasing.
Agreed.
All this, mind you, at sea level against a 6.25lb boosted Spitfire I, which is as good as it gets for the 109.
Certainly. But then again, we haven't touched into the realm of 1.45ata WEP or a DB 601N under the hood. Or deploying flaps. ;)
Osprey
09-26-2012, 06:56 PM
How much excess thrust does a Spitfire at SL, running at +12 boost has at about 280 mph 1g at David?
How much more excess thrust does a Spitfire at SL, running at +12 boost require in 2g turn at about 280 mph David?
I edited it to suit reality, otherwise you may as well have put down 1ata or something equally 'not full power'.
MiG-3U
09-26-2012, 07:20 PM
Wrong on all accounts.
These are just facts.
And with the specs laid down within being guaranteed within +/- 5% by the manufacturer of the product.
Manufacturer's quaranteed performance is not a test data and not relevent.
You were asked real test data for 500kmh and none has been posted.
Really. And what power, what supercharger settings, what airframe conditions?
Not specified but these are real tests of the real series planes.
Still, these match well with 109F speed 495kmh for 1.3ata, 500 kmh for 109E at same power or at 1.35ata is unlogical.
Speculation.
Yes in small degree, but much less speculation than assume series engine like you do.
Look at the source files - or the fact that we a 5-min boost pressure of 1.35 ata...
Hm... in game test data is showing 475kmh which is actually slightly faster than swiss tests but acceptable.
Good work 1C, you are able to see behind speculations.
Edit: The point is that if you put doubt on various data on Spitfire at +12lbs, as you did, you should be just as critical in the case of the 109 data. Otherwise a reader gets impression of double standards.
No anykind of polemics, sarcasm, arrogance nor all those little annoyances intended. Leaving this discussion for next 5 days.
Because?It's in the physics. If you look (very closely in well hidden places) at the turn calc spreadsheet I attached the other day, you can see that near each planes top speed, the 109 gains ~1.1 °/s turn rate for every m/s of speed given up, while the Spitfire gains about ~1.5 °/s turn rate for every m/s given up. This means in example, for a 9°/s turn rate the 109 loses ~29 km/h, while the Spitfire loses ~22 km/h and has thus narrowed the gap by ~7 km/h. It's a trend that continues until at low speeds the Spitfire becomes superior.
---
And can we all, now that we have a chance for few days of peace, just once try to get along with each other in a civilised way? No polemics, arrogance, sarcasm and all these little annoyances for say the next 5 days?
Glider
09-26-2012, 10:02 PM
Oh yes, 109 could indeed turn tighter than a Spitfire at speeds around and above 400 kph.
Are you aware of anything apart from a theory that agrees with this?
In reality this was not very relevant in pure horizontal turnfight for the reasons you named. It was great advantage at BnZ maneuvring, even turning with a Spitfire that is breaking away from your attack - you can turn long enough to score nice deflection shot on him.
No you cannot, if a higher speed is such an advantage in a turn then turning when bounced would be an almost suicidal tactic. Yet it was that ability to turn that saved so many pilots. It was the one advantage that Spit V pilots had over the Fw190 and was emphasised at every plot briefing.
But that is not anywhere close to sustained turn, you do a a 1/8 of a turn and away you break. If you stayed at that turn, you would burn your E and you would end up with a very angry Spitfire on your tail very soon.
That would sum up the best tactic for Luftwaffe Pilots fight in the vertical and only do minor, brief turns to get a better shot. Try to turn it into a turning fight and the 109 loses.
Glider
09-26-2012, 10:11 PM
Just explain how a plane with less or no excess thrust can pull a sustained turn better than a plane with more excess thrust, thank you.
How much excess thrust does a Spitfire at SL, running at +6 1/4 boost has at about 280 mph 1g at David?
How much more excess thrust does a Spitfire at SL, running at +6 1/4 boost require in 2g turn at about 280 mph David?
Interesting that you keep talking about the 6 1/4 boost and not the 12 boost.
How much excess thrust does a Bf 109E at SL running at 1.35ata bppst has at about 280 mph 1g at David?
less than a 12 boost Spitfire
Which has a better sustained turn at 400 mph David, a Spitfire IX or a Me 262 (P-80 if you like)? Spit every time.
Show any acual test that says otherwise. Show any 262 pilot who says that he would turn faster than any piston fighter.
No, their advantage was speed and the key was keeping your speed high and making it almost impossible to get a shot at you
I am still trying to work out how the German test authorities got it so wrong. I admit that I cannot find any reason and neither can anyone else, so maybe, just maybe they got it right and the 109 couldn't turn inside the Spitfire, after all thats what their official report says
Igo kyu
09-26-2012, 11:19 PM
The Falcon (one) manual told us some things that some seem to have forgotten, if they ever read them at all.
Two aircraft at the same speed pulling the same 'g' force, turn the same radius circle.
The same 'g' force at higher speed means an increased radius of turn, and a lower rate of turn.
At the same speed, a higher 'g' force causes a reduced turn radius and increased rate of turn.
This is why a fighter at .98 mach pulling 8 'g' can outturn a missile at 3.0 mach pulling 30 'g', the fighter's rate of turn is higher.
ATAG_Snapper
09-27-2012, 01:02 AM
Which explains quite tidily why a Spitfire 1a never fell to a guided air-to-air missile throughout the entire Battle of Britain......
Bounder!
09-27-2012, 01:43 AM
The Falcon (one) manual told us some things that some seem to have forgotten, if they ever read them at all.
Two aircraft at the same speed pulling the same 'g' force, turn the same radius circle.
The same 'g' force at higher speed means an increased radius of turn, and a lower rate of turn.
At the same speed, a higher 'g' force causes a reduced turn radius and increased rate of turn.
This is why a fighter at .98 mach pulling 8 'g' can outturn a missile at 3.0 mach pulling 30 'g', the fighter's rate of turn is higher.
I'm a little out of my depth here but... I read somewhere that if speed and 'g' are equal then the turning circle is proportional to the wing loading and that is one of the reasons the spit out turns the 109.
Igo kyu
09-27-2012, 02:05 AM
I'm a little out of my depth here but... I read somewhere that if speed and 'g' are equal then the turning circle is proportional to the wing loading and that is one of the reasons the spit out turns the 109.
If speed and 'g' are equal, then the circle must be the same size.
If a spit and a 109 are at the same speed, then the spit can pull more 'g' because the wing of the spit is bigger, and thus the loading (aircraft weight/wing area) is lower, and pulling more 'g' makes the circle smaller. This may fail as a rule when you get up to speeds where enough 'g' can be pulled to break the airframe, or to black out the pilot, but as I understand it these aircraft would have to be diving to get fast enough to break their airframes. It also doesn't apply below stalling speed.
<edit>
Wing loading isn't all the story, the Hurricane's wing was more heavily loaded than the Spitfire's, and the Hurricane turned better/pulled more 'g' at a given speed. The greater thickness of the Hurricane's wing I think had something to do with that.
IvanK
09-27-2012, 04:14 AM
Firstly if you think WWII fighter pilots were going to engage in modern energy theory concepts such as sustained optimum energy speed turn fights you are deluding yourselves. Concepts of Energy bleed Ps rates where not really in the the WWII fighter pilots thought process. Zoom and Boom or general turn fighting was. A spitfire pilots mindset was "I can outturn this 109'. The 109 pilots mindset was "I better be careful and not try to turn with this Spit"
The argument about the (debatable) slightly faster level speed of the 109 over the Spitfire means the 109 must have better sustained turn performance at these speeds is bogus imo. If you accept that for a given flight condition the 109 is faster so therefore has superior energy (Ps) than the Spit so therefore can transform this into turn performance advantage think about this. The superior energy (Ps) is only in 1G flight. As soon as you load the airframe up who has the lesser energy rate loss now ? .... i.e. energy bleed ? Ps at 1G and Ps at say 4G are totally different things ... JTD says it quite clearly and even provides some numbers :
"It's in the physics. If you look (very closely in well hidden places) at the turn calc spreadsheet I attached the other day, you can see that near each planes top speed, the 109 gains ~1.1 °/s turn rate for every m/s of speed given up, while the Spitfire gains about ~1.5 °/s turn rate for every m/s given up. This means in example, for a 9°/s turn rate the 109 loses ~29 km/h, while the Spitfire loses ~22 km/h and has thus narrowed the gap by ~7 km/h. It's a trend that continues until at low speeds the Spitfire becomes superior."
So once the G comes on the 109 is losing airspeed faster than the Spit..... and we know where the fight is going now don't we? 1G Ps and Ps under G are not the same thing.
Thats why JTD says (and is correct imo):
"It really sums up to that the 109's biggest advantage is in flying straight and level, it will remain competitive throughout the high & medium speed range, with the advantage always decreasing. All this, mind you, at sea level against a 6.25lb boosted Spitfire I, which is as good as it gets for the 109. "
Then we have this strange concept of the faster 109 being able to turn better than the Spit at say 400Kmh so therefore he can deny a Spit (at less than 400kmh) closing to a Guns shot ! Its an axiom of Defensive BFM that if you just keep turning a slower aircraft can simply arc inside your turn nose in lead and close to guns. Robbo puts it quite eloquently:
"But it is also possible to cut the corner of the 109 and shoot at it alright at lead curve, then ease up the turn and repeat. All depends on the trajectory, the planes will obviously turn on different circles etc. If you make a deal that the 109 won't climb or scissor, just turn, you will win. Because the Spitfire is much better TnB fighter than Emil. Emil is decent turner, too, very maneuvrable and agile, but as for the sustained turn competition in actual dogfight, Spitfire has got better qualities. "
Kurfurst
"Just explain how a plane with less or no excess thrust can pull a sustained turn better than a plane with more excess thrust, thank you"....
I'll have a go or comment at least :) We are talking about 2 aeroplanes one with marginally better 1G Ps at lets say 400kmh. As soon as the 109 starts to turn how much of this Ps superiority does he now have ? If his -Ve Ps under G is less than the Spit then fair enough but is it ? JTD's figure show the 109 -ve Ps under G to be worse than the Spit.
The RAE Fan charts (accepted that a couple of people here contest these) show this quite clearly.
Robo.
09-27-2012, 06:23 AM
Are you aware of anything apart from a theory that agrees with this?
I did not mean I agreed with Crumpps bizarre theory regarding superior sustained turn rate of a 109. :-P I was trying to explain to him the whole time that high speed turn rate of a 109 (or 190) was only usable in unsustained turns in actual dogfight - e.g. you would do 1/4 of turn or less and extend vertically. You would certainly not keep that turn sustained.
I was also saying the same thing to Kurfurst (IvanK and JtD both said it much better using proper terminology) - 400kph sustained turn is practically impossible to use because the 109 will bleed its speed rather fast - certainly faster than the Spitfire. Spitfire would be able to get the guns on the 109 if the 109 pilot maintained the sustained turn anyway.
No you cannot, if a higher speed is such an advantage in a turn then turning when bounced would be an almost suicidal tactic. Yet it was that ability to turn that saved so many pilots. It was the one advantage that Spit V pilots had over the Fw190 and was emphasised at every plot briefing.
I respectfully disagree - higher speed is a great advantage 'especially' when bouncing a slower target. All depends on the situation but in the example you name, the Fw 190 would really be able to outturn a Spitfire at very high speeds for long enough to get guns on him. That is obviously not sustained turn and therefore irrelevant.
That would sum up the best tactic for Luftwaffe Pilots fight in the vertical and only do minor, brief turns to get a better shot. Try to turn it into a turning fight and the 109 loses.
Agreed completely, I guess we ment the same thing. There was also some confusion with what is and what is not sustained turn.
Osprey
09-27-2012, 08:35 AM
No you cannot, if a higher speed is such an advantage in a turn then turning when bounced would be an almost suicidal tactic. Yet it was that ability to turn that saved so many pilots. It was the one advantage that Spit V pilots had over the Fw190 and was emphasised at every plot briefing.
Crossed wires I think. It's entirely situational and depends where and when the Spitfire turns relative to the FW, and their speeds. The common tactic was, and one of Sailor Malan's 10 rules, to always turn into the enemy. This doesn't mean necessarily to do a head on, but to change his angles to one where he cannot get a shot off. A hard break, nose slightly down, from the high 6 is enough simply because in order for him to pull the snap turn (yes, a fast turn if you like) for the lead required, then he will overload and black out. The result is that the attacker usually misses behind or breaks off and gains height for another attack. So, the turn is no problem for the attacker, but only a fool would follow because as he unloads his turn becomes worse (as brilliantly described by other more intelligent posters than myself) and the advantage switches.
What I find confusing though is what I've often read, that a 109 would dive from above and the spitfire, lower and slower, would make a left hand spiral break yet catch the 109 and shoot him down. I guess it's just descriptions, only I can't picture that exactly. Maybe the speeds are similar in the DF the pilot talks about. :confused:
Can people stop referring to the Spitfire as slower when it isn't. Thanks.
NZtyphoon
09-27-2012, 10:55 AM
These are the precautions given to Spitfire pilots facing the Fw 190:
http://i91.photobucket.com/albums/k304/Major_Sharpe/SpitfirevFw190-page-002.jpg
http://i91.photobucket.com/albums/k304/Major_Sharpe/SpitfireprecautionsagainstFw190-page-004.jpg
http://i91.photobucket.com/albums/k304/Major_Sharpe/SpitfireprecautionsagainstFw190-page-005.jpg
Essentially the advice was to cruise as fast as possible, especially in the danger zones where Fw 190s were expected, partly because the Spitfire was slower to accelerate than the 190.
As for claims that the Bf 109E generated less drag than the Spitfire I - there has been no objective data presented to prove this, but here are the figure for the Spitfire I:
http://i91.photobucket.com/albums/k304/Major_Sharpe/SpitfireIdrag-page-002.jpg
Kurfürst
09-27-2012, 12:12 PM
These are just facts.
Nope, this is just your opinion and has nothing to do with any test report's contents.
Manufacturer's quaranteed performance is not a test data and not relevent.
Unfortunately it is test data and it is relevant. Unless you want to dream up specifications.
You were asked real test data for 500kmh and none has been posted.
Oh they were, you just happen to ignore them.
Not specified but these are real tests of the real series planes.
In unknown conditions..
Still, these match well with 109F speed 495kmh for 1.3ata, 500 kmh for 109E at same power or at 1.35ata is unlogical.
Oh but an 500+ kph Spitfire I as fast as the 109F *IS* logical, riiiiight?
Yes in small degree, but much less speculation than assume series engine like you do.
Thank you for admitting that your remark about supposed two speed superchargers was just speculation.
As for my my "assumptions" about the engine, here is what the test report has to say about it:
Motor: DB 601 A, serial number 140.
Quite clear cut is it not?
Hm... in game test data is showing 475kmh which is actually slightly faster than swiss tests but acceptable.
Good work 1C, you are able to see behind speculations.
They did see through speculations, that's why the final patch is going to fix the SL speed of the 109E to its historical 500 kph-ish value.
Edit: The point is that if you put doubt on various data on Spitfire at +12lbs, as you did, you should be just as critical in the case of the 109 data.
I see. Your position is, if I got it right, that a completely unreferenced graph, without any details showing 6 1/4 boost performance, on which somebody draw up ex post facto his wishful estimates on +12 and even a fantasy +16 boosted level speed performance with a pencil, for the Mark I. Spitfire has the same credibility as the most detailed test on the 109E, which contains engine bench test data, airframe conditions data, calibration curves, and has been appropriately corrected for German Standard Day conditions.
I respectfully disagree with your assessment.
Otherwise a reader gets impression of double standards.
Indeed they might get this idea. Statements like "Manufacturer's quaranteed performance is not relevent" may lead to such conclusions.
Kurfürst
09-27-2012, 12:29 PM
Originally Posted by Kurfürst
Just explain how a plane with less or no excess thrust can pull a sustained turn better than a plane with more excess thrust, thank you.
How much excess thrust does a Spitfire at SL, running at +6 1/4 boost has at about 280 mph 1g at David?
How much more excess thrust does a Spitfire at SL, running at +6 1/4 boost require in 2g turn at about 280 mph David?
(Glider remains silent on the issue)
Interesting that you keep talking about the 6 1/4 boost and not the 12 boost.
In fact we all do, except for you. The discussion is about trying to explain to you the fact that the 109E has a better sustained turn than the Spitfire using 6 1/4 boost at and above 400 km/h near SL.
Originally Posted by Kurfürst :
How much excess thrust does a Bf 109E at SL running at 1.35ata bppst has at about 280 mph 1g at David?
less than a 12 boost Spitfire
(Glider remains silent on the issue)
... and how much is that David?
Which has a better sustained turn at 400 mph David, a Spitfire IX or a Me 262 (P-80 if you like)?
Spit every time.
And why is that, David? How can a Spitfire sustain a turn without any excess thrust to start with? Does it have anti gravity drives perhaps? Can it just defy the rules of physics?
I am sorry David, but I believe that you did not fully grasp some of the basic elements of the this discussion, such as the difference between sustained and unsustained turns, the effects of parasitic and induced drag depending on airspeed and the importance of thurst and excess thrust. So let me put it down for you in the most simply terms:
Unfurtunately, the Spitfire cannot sustain a turn at 400 mph at all. Depending on altitude, it has either ZERO or NEGATIVE "excess" thrust already at 1 g.
We have been over this already anway, see http://forum.1cpublishing.eu/showpost.php?p=462148&postcount=194
http://forum.1cpublishing.eu/attachment.php?attachmentid=10782&d=1347990667
In short, the 262 (blue line) starts to run circles around the Spitfire IX (red line) above 460 km/h. At 640 kph, the Spitfire is outright hapless...
I am still trying to work out how the German test authorities got it so wrong.
Nope, they got it exactly right. They say:
In summary, it can be said that all three enemy planes types are inferior to the German planes regarding the flying qualities. Especially the Spitfire has bad rudder and elevator stability on the target approach. In addition the wing-mounted weapons have the known shooting-technique disadvantages.
It seems to me that the Germans regarded the flying qualities of the Spitfire overall inferior to their fighters.
Glider
09-27-2012, 12:49 PM
Kurfurst you are full of charts which are calculated by yourself and crumpp, however you never talk about the real tests undertaken by the real pilots and real test establishments.
I know what I know and I acknowledge what I don't.
You talk about the 6 1/4 boost and I talk about the 12 boost. Why, because the RAF fighters in the BOB used 12 boost. You talk about the 6 1/4 boost because that gives the 109 a better chance, not what they faced in combat, a big difference.
The one part of the report that you quote
In summary, it can be said that all three enemy planes types are inferior to the German planes regarding the flying qualities. Especially the Spitfire has bad rudder and elevator stability on the target approach. In addition the wing-mounted weapons have the known shooting-technique disadvantages
You make a big deal on this but forget to mention that the Spit in question didn't have the CSP only the two pitch prop which they rightly make a number of comments about. No one is trying to pretend that the Spit was the greatest gun platform which is part of the equation and they had wing mounted guns, not exactly new.
However you don't quote the bit about turning which is what the conversation is about, interesting. So just to be clear, do you also agree they had it right when they said
Before turning fights with the Bf 109 E type, it must be noted in every case, that
all three foreign planes have significantly smaller turning circles and turning times.
An attack on the opponent as well as disengagement can only be accomplished on the basis of existing superiority in performance.
In which case what are you disagreeing about, or are you only disagreeing with the bits you don't like?
I agree with everything that the report says, will you make the same statement?
As for the 262 I notice another nice chart but nothing re tests or pilot experience so it remains a theory, no more no less.
The chart Kurfürst posted is not a theory, it's a calculation. Physics and maths are just as relevant as tests and pilot experience. There are methods that are standard and accepted. If you use them properly, they can be more accurate than tests and pilot experience and are imho at least as valid.
pstyle
09-27-2012, 01:34 PM
Hi kufurst, any chance you can link me to the records of the 109e maintaining 500kph in level flight at sealevel. Sorry if you've posted this before. Ta.
Edit; sorry I see you never stated sea level. My mistake. Unless SL means sea level, and not STRAIGHT Line?
Osprey
09-27-2012, 01:38 PM
In fact we all do, except for you.
No actually. I have mentioned this twice and you just ignored it.
I have some good news for you though. 1946 HSFX patch 15 just fixed the Hurricane I and Spitfire I FM's to the speeds we talk about here. They are bang on the RAE tests using 12lbs. Fantastic news don't you think? ! I am interested in the link you are referring to for the 109 too because I think the 109E in HSFX may be too slow, but I want a proper flight test, not some calculation which Willie cooked his books in order to win a big fat order from his pal Hitler.
5./JG27.Farber
09-27-2012, 01:41 PM
It seems to me that the Germans regarded the flying qualities of the Spitfire overall inferior to their fighters.
In 1940 I presume, not the enitre war? ;) and when they say "inferior" you mean slightly worse by a small margin? Translation error? German translation can be very direct.
Glider
09-27-2012, 01:55 PM
The chart Kurfürst posted is not a theory, it's a calculation. Physics and maths are just as relevant as tests and pilot experience. There are methods that are standard and accepted. If you use them properly, they can be more accurate than tests and pilot experience and are imho at least as valid.
This is the sort of thing that raises my doubts. I am confident that the Grippen had many thosands of calculations undertaken by some of the finest minds in aviation. Using the latest computers, many hours in a simulator and then this happened. I should add that this was being flown by a test pilot.
http://www.youtube.com/watch?v=k6yVU_yYtEc
Show me any report of any 262 pilots who would go into a turning dogfight against a Mustang, Spit, La 7, whatever take your pick. The theoretical world is one thing, hard combat another.
Look at it another way, Why did the Mig 17 do so well against the F4, F105 and so on. Find any US pilot who would go into a turning combat in any of the above against an old slow Mig 17.
bongodriver
09-27-2012, 02:18 PM
I love the way Kurfurst seems to think the 262 would even be in with a shot at a turning fight, at those speeds it's going to fly circles so big it's circumnavigating the globe :rolleyes:
It's not about turning fights, it's about the ability of a plane to sustain a turn at a given speed. That's what the chart shows. It's something else what you make of it - both here at the forum discussing it, and in the air piloting these planes.
Like with that Gripen, most accidents happen due to pilot error, not erroneous design calculations. It's rather an argument against the reliability of pilot accounts, than an argument against reliability of maths and physics - so I'm not quite sure why you posted the video.
Kurfürst
09-27-2012, 02:59 PM
Hi kufurst, any chance you can link me to the records of the 109e maintaining 500kph in level flight at sealevel. Sorry if you've posted this before. Ta.
Edit; sorry I see you never stated sea level. My mistake. Unless SL means sea level, and not STRAIGHT Line?
I am interested in the link you are referring to for the 109 too because I think the 109E in HSFX may be too slow, but I want a proper flight test,
Here it is. It is as proper as a flight test can get. In fact, its the most detailed performance test I have seen so far. http://kurfurst.org/Performance_tests/109E_V15a/Geschw_109V15a.html
Of particular interest, translated from the paper.
Condition of the airframe :
The surface was painted after the serial production standard. The engine cowling was still rough, exhaust manifolds (DB-type, made at BFW) were lacking top cover. 2 Cowl- and wing-MGs were installed. Antenna wire. Undercarriage retracted, tailwheel out. For air intake, see the reports drawings.
Radiator cooler flaps were 1/4 open. Coolant temperature observed as constant 90 degrees Celsius.
Oil cooler flaps were closed. Oil temperature observed as 62/82 degrees Celsius.'
Speed was measured on the four-way flight track in Haunstetten. Altiude trials were performed near Augsburg airfield.
Measured speed for 0 m was 493 kph at 1,33ata. The engine was measured on test bench, and was found to develop 45 PS less than the guaranteed nominal output at 1,35 ata, so the flight results were corrected (see Blatt 5 for calculations) to the nominal engine ratings and German Standard day : 498 km/h at 0 m (CINA) at 1.35ata..
I have some good news for you though. 1946 HSFX patch 15 just fixed the Hurricane I and Spitfire I FM's to the speeds we talk about here. They are bang on the RAE tests using 12lbs. Fantastic news don't you think? !
It is, actually. Given that the complete lack of + 12 lbs tests, the likely farce but not unreasonable RAE "test" paper is the only source the FM modellers can use.
not some calculation which Willie cooked his books in order to win a big fat order from his pal Hitler.
You see the problem with this kind of thought is that after Willie would have won that big fat order, he would also have to deliver some 4000 aircraft and each will be tested by the German Air Ministry for specs. If they are not capable being withing plus/minus five percent of the figures Willie promised, Willie won't get a single Pfenning, which doesn't sound like a very good deal.
Osprey
09-27-2012, 03:17 PM
I love the way Kurfurst seems to think the 262 would even be in with a shot at a turning fight, at those speeds it's going to fly circles so big it's circumnavigating the globe :rolleyes:
By the time it was allowed to be a fighter those pilots had little intention of being fighters what with the sheer number of escorts to deal with. No, get fast and whip through the formations with those mighty cannon.
Regarding level speed performance of the 109, a question raised by I think MiG-3U puzzled me, maybe you have a good explanation, I'm at a loss for now: How come the 109E is faster than the 109F at less power, if you accept the 498 km/h for the 109E at 990ish hp from the V15 test and the 495 km/h for the 109F at 1065ish hp from the 109F Kennblatt?
bongodriver
09-27-2012, 03:24 PM
It's not about turning fights.
Oh, have I misunderstood something? I just figured since the thread went OT within 7 pages or so and it turned into an argument about which aircraft had the turning advantage it 'was' about turning fights, if I'm not mistaken that is exactly what triggered the whole change of topic was a turning circle diagram and the usual suspects denying that the Spit would win in a turning fight.
Osprey
09-27-2012, 03:26 PM
Here it is. It is as proper as a flight test can get. In fact, its the most detailed performance test I have seen so far. http://kurfurst.org/Performance_tests/109E_V15a/Geschw_109V15a.html
Hmmm, this isn't an original document, it's some html from your website. All of the RAE stuff and other docs are originals (except the 12lbs which is measured in test then calculated/translated/projected onto the graph)
You see the problem with this kind of thought is that after Willie would have won that big fat order, he would also have to deliver some 4000 aircraft and each will be tested by the German Air Ministry for specs. If they are not capable being withing plus/minus five percent of the figures Willie promised, Willie won't get a single Pfenning, which doesn't sound like a very good deal.
Don't be silly Kurfurst. Willy is an old pal of Goering and a few keys of Colombian marching powder and some bonus wraps he'd have been on the hotline to Herr Hitler. We've all seen how Oscar Schindler did it.
Osprey
09-27-2012, 03:28 PM
Regarding level speed performance of the 109, a question raised by I think MiG-3U puzzled me, maybe you have a good explanation, I'm at a loss for now: How come the 109E is faster than the 109F at less power, if you accept the 498 km/h for the 109E at 990ish hp from the V15 test and the 495 km/h for the 109F at 1065ish hp from the 109F Kennblatt?
I could be wrong but I think he was being sarcastic in order to question Kurfursts 498kmph figures. Glider confused me too since he dissected MiG3U's post as if it were in support of Kurfurst, when it wasn't.
Al Schlageter
09-27-2012, 03:32 PM
Doesn't the V in a designation mean a prototype/test a/c?
Bf 109 V15a
Bounder!
09-27-2012, 03:39 PM
Regarding level speed performance of the 109, a question raised by I think MiG-3U puzzled me, maybe you have a good explanation, I'm at a loss for now: How come the 109E is faster than the 109F at less power, if you accept the 498 km/h for the 109E at 990ish hp from the V15 test and the 495 km/h for the 109F at 1065ish hp from the 109F Kennblatt?
Just a stab, Kurfürst is probably the man for this question but looking up the weight of the 109e and 109f and it appears the later is heavier when loaded which might help account for the lack of speed increase over the emil?
Kurfürst
09-27-2012, 03:42 PM
Regarding level speed performance of the 109, a question raised by I think MiG-3U puzzled me, maybe you have a good explanation, I'm at a loss for now: How come the 109E is faster than the 109F at less power, if you accept the 498 km/h for the 109E at 990ish hp from the V15 test and the 495 km/h for the 109F at 1065ish hp from the 109F Kennblatt?
Its difficult to say how much it is on the 109F Kennblatt because the Kennblatt's figures are with the original ratings of the 601N at 495/515 (1.42/1.3, which were reduced to 1.25). In short the 495ish figure is for 1.3ata.
My best guess is that there was a major difference between the Emil and Friedrich propellers (also according to the propeller effiency curves I have seen), the latter was of smaller diameter and almost certainly meant for high altitudes, and probably less efficient in denser air, hence the relative stagnation of speed near SL. The Friedrich would be probably faster with a different prop.
But all of this is not so extraordinary or a surprise since the same can be noted when it comes to the Mark I / Mark V / Mark IX Spitfires's evolution. Hell the Mark I. at +12 is supposedly faster at SL than the Mark IX at +15 boost, how come..?
ACE-OF-ACES
09-27-2012, 03:43 PM
The chart Kurfürst posted is not a theory, it's a calculation.
True..
Physics and maths are just as relevant as tests and pilot experience. There are methods that are standard and accepted. If you use them properly, they can be more accurate than tests and pilot experience and are imho at least as valid.
Agreed.. Just as relevant.. If used properly
As you (and others) know the old saying..
Garbage in Garbage out!
With regards to flight simulation..
You can think of the 6DOF flight simulation model as a black box.. With an input (plane parameters and current state) and an output (results)
The math in the black box can be good to go.. no errors.. But if you input bad values (plane parameters and current state) you will get bogus outputs (results)
With that in said..
I don't know if the 'results' of the Me262 or Spit used in the IL2Comp graph Kurfust posted have ever been validated.. As in have they ever been compared to any real world data, or checked by someone else to ensure the 'inputs' are correct.
In short, in this case the IL2Comp values are suspect until validated.. Sadly I don't know of any real world turn time data of the Me262 that can be used to validate the IL2Comp, which leaves only for someone to doulbe check the input values and 6DOF math.
Kurfürst
09-27-2012, 03:47 PM
Hmmm, this isn't an original document, it's some html from your website. All of the RAE stuff and other docs are originals (except the 12lbs which is measured in test then calculated/translated/projected onto the graph)
You want the original document, Osprey?
Don't be silly Kurfurst. Willy is an old pal of Goering and a few keys of Colombian marching powder and some bonus wraps he'd have been on the hotline to Herr Hitler. We've all seen how Oscar Schindler did it.
Except it just didn't work that way. BAL (the Luftwaffe's QC group) was rejecting Me 262 if they did not do at least 830 kph.. They had a bit of reason and allowed planes even with 825, but no less was accepted.
Again. We are talking 262s. In 1945.
pstyle
09-27-2012, 05:02 PM
Thanks Kurfurst, I’d not seen the V15 trials information before, the test-report is quite nice. Although I’d much rather have all of the pgaes in their originals, not just a few, and not have to rely on transcribed text into your html page.
The above aside, can you help me with a couple of questions:
1) What can we take from the apparent inability of any subsequent tests of the E1s or E3s (that I can find at least) to get anywhere near the “sea-level” (see question 4 below) speed of 493kmh or 498kmh? How do we explain that the prototype was able to record speeds that no subsequent 109 testing seems to have been able to achieve? I see testing data of 109E3 Nr1972, and 109E1s Nr1774 and Nr1791 (all of which are German tests, not British tests), none of which achieve above 485kmh at their lowest altitude of “0” (average is around 470)
2) Can you provide Blatt 3 of the testing documentation, the full-pressure altitude (Volldruckhohen) results – which I cannot find on your page?
3) Your tabulated summary of Blatt 5 indicates that the achieved speed (with the supposedly suboptimal engine pressures) was 493kpm at 0 altitude relative to the ground. Why does Blatt 6 indicate however that only 485 was obtained? is that because Blatt6 projects the speed down to sea level, whereas the tests were carried out at 0 altitude above ground, at a location (Augsburg?) already elevated (~440m) above MSL? If so, according to the test graph, do we get a sea-level speed of 485(490), not 493(498) for the V15?
4) the tests often make corrections for air pressure of a standard (Augsburg?) day "normaltag". Do we know what that pressure was?
Oh, have I misunderstood something?...Some are drawing wrong conclusions from the chart, but that doesn't change the chart. Kurfürst said the 262 can sustain a better turn time than the Spitfire at 400 mph, which is true. This will not win it a sustained turn fight though, as the Spitfire doesn't need to match the 262's speed. It can't do it in straight and level flight, so why bother in turns. Like I said, there's the chart and there's what you make of it.My best guess is that there was a major difference between the Emil and Friedrich propellers...OK, I can see that at altitude the F is at least faster than the E, even if still at more power. Do you have the propeller efficiencies somewhere so I could take a look at them? Regarding the Spits, the IX was quite a bit more dirty than the I, just like a G-6 was more dirty than an F. So I would expect it to need more power for the same speed. But the E-F issue is different.Doesn't the V in a designation mean a prototype/test a/c?Yes, 109E prototype.Just a stab, Kurfürst is probably the man for this question but looking up the weight of the 109e and 109f and it appears the later is heavier when loaded which might help account for the lack of speed increase over the emil?Weight certainly is a factor, but for top speed of high speed fighter aircraft the effect is rather small. It matters much more for climb and turn.
NZtyphoon
09-27-2012, 07:52 PM
But all of this is not so extraordinary or a surprise since the same can be noted when it comes to the Mark I / Mark V / Mark IX Spitfires's evolution. Hell the Mark I. at +12 is supposedly faster at SL than the Mark IX at +15 boost, how come..?
Lack of documentation for this claim noted. Still waiting for data proving the 109E had less drag than the Spitfire I.
Kurfürst
09-27-2012, 08:23 PM
Lack of documentation for this claim noted. Still waiting for data proving the 109E had less drag than the Spitfire I.
http://alexlod.com/wp-content/uploads/2011/02/why-so-serious.jpeg
ACE-OF-ACES
09-27-2012, 08:40 PM
Lack of documentation for this claim noted.
Also noted
Still waiting for data proving the 109E had less drag than the Spitfire I.
Yes that would be something to see!
TomcatViP
09-27-2012, 08:48 PM
By the time it was allowed to be a fighter those pilots had little intention of being fighters what with the sheer number of escorts to deal with. No, get fast and whip through the formations with those mighty cannon.
In fact, I am pretty sure that most of the airplane shot down by the 262 were Spitfire and Mustang. There is some video on the net showing 262 involve in turning fight. Some are really dramatics. You shld take a look into that instead of preaching endlessly that nothing came close to the Spit in term of turn fight.
Turning is all about changing direction. If your plane is stuck at the limit of his performances there is no chance for it to turn corners. That's why fighters pilot enjoyed speed as the most valuable perfs... until reliable short range missile came ;)
The Mig17 Vs F4 is quite a good example. Pass the Mach 0.9 and then the F4 had the advantage. Especially in high G pull up and vertical manoevre. Exvatly what was teach at TopGun (see the the story of R. Cuningham). An F105 could turn with a 17... Above the mach ;)
Keep in Mind that BFM is all about E not turning circle. It's pretty easy to understand that with the late gen fighters. But so much could be said.
Glider
09-27-2012, 09:36 PM
Like with that Gripen, most accidents happen due to pilot error, not erroneous design calculations. It's rather an argument against the reliability of pilot accounts, than an argument against reliability of maths and physics - so I'm not quite sure why you posted the video.
What is more likely to go wrong, A prototype on its sixth flight or a test pilot of many years experience. The problem was traced to issues with the avionics and delayed responses to control input, not pilot error.
These had been calculated and tested in simlators but it was only when they flew that the problem was idnetified.
So the calculations and theory was flawed resulting in a serious accident the pilot was lucky to get away with. People who rely on theory are banking the farm on a theory and thats why I posted the video.
I notice that no one has come up with any examples of an F4, F105 or 262 taking on a slower aircraft in a turning fight. The F4 and F105 people say that they had the advantage in a turning fight at over 0.9. If this is the case then why didn't the US pilots use that advantage?
Its a simple question, in reality they didn't, they used their speed to go vertical or gain a tactical advantage.
This is the core of the difference. In Vietman I can find examples of US pilots going vertical or using speed to gain a tactical advantage. No one has (so far) show that US pilot wanted to go into a turning fight.
I believe from what I have read that the 262 pilots did exactly the same thing.
PS the main target for the 262 were the bombers, not fighters
As far as the game goes, do you want it to reflect what could happen, or did happen.
Going back to the subject. I do get a little frustrated when people pick and choose which part of the offical test reports they agree with.
Can I ask you if you agree with what the German test establishment said about the 109 and Spitfire? I do in its entirety good and bad from all points.
TomcatViP
09-27-2012, 09:55 PM
Its a simple question, in reality they didn't, they used their speed to go vertical or gain a tactical advantage.
This is the core of the difference. In Vietman I can find examples of US pilots going vertical or using speed to gain a tactical advantage. No one has (so far) show that US pilot wanted to go into a turning fight.
I believe from what I have read that the 262 pilots did exactly the same thing.
Tht's what I am saying here, Glider. Changing direction is not about drawing circles like a compass with your plane but to point your nose faster in the intended direction that your opponent.
Again, if your plane fly at the limit of his envelope you have no chance in term of manoeuvrability. A faster plane will fight at a higher speed were he is more efficient in term of E. This what hve ruined Il2 with a Spit that never depleted his E (and again in CoD) turning basic BFM useless (YoYo for example).
pstyle
09-27-2012, 10:19 PM
This what hve ruined Il2 with a Spit that never depleted his E (and again in CoD) .
Are you suggesting that the CLoD spit does not loose energy in the turn?
Al Schlageter
09-27-2012, 11:57 PM
Yes, 109E prototype.
Then why is prototype data being used and not data from a production Bf109E?
ACE-OF-ACES
09-28-2012, 12:52 AM
Then why is prototype data being used and not data from a production Bf109E?
Based on past experience with Kurfürst.. My guess would be the prototype data has better results than the production data.. That is to say Kurfürst tends to go with the best of the best data for 109s and the worst of the worst data for anything allied.. Also known as cherry picking!
NZtyphoon
09-28-2012, 12:52 AM
Then why is prototype data being used and not data from a production Bf109E?
Awww, why so serious? Anyway, Check out http://www.wwiiaircraftperformance.org/me109/me109e.html
What is more likely to go wrong, A prototype on its sixth flight or a test pilot of many years experience. The problem was traced to issues with the avionics and delayed responses to control input, not pilot error.
These had been calculated and tested in simlators but it was only when they flew that the problem was idnetified.
So the calculations and theory was flawed resulting in a serious accident the pilot was lucky to get away with. People who rely on theory are banking the farm on a theory and thats why I posted the video.OK, so they did employ maths and physics improperly. I'm fairly certain that they came up with proper calculations after the accident and managed to simulate the problem. Just like we can calculate turn performance nowadays, the calculation is sound and all you can do wrong is input data.This what hve ruined Il2 with a Spit that never depleted his EYou're wrong, Spits always flew to the same physics that applied to all other planes. The reason it could sustain a 17s turn is because it's one of the aircraft's design features. Just like high speed was a design feature of the Fw 190, which had no problem whatsoever to outrun Spitfires. Take a ton off a 190, give 200 extra hp at altitude and add 20% drag, and you got yourself a Spitfire.
MiG-3U
09-28-2012, 06:02 AM
Nope, this is just your opinion and has nothing to do with any test report's contents.
The facts:
1. Prototype aircraft V15a, tested well before production started
2. Tested speed 493kmh at altitude of 440m, gives 485kmh at 0m
3. The supercharger has two fixed speeds:
- boden- and hohenlader are claimed and the optimal change altitude is determined
- manifold pressure drops above the FTH of the bodenlader, until hohenlader is set on
- the speed test confirms that the supercharger has two fixed speeds
- according to Flugmotoren und Strahltriebwerke by Kyrill von Gersdorff, Kurt Grasmann, Helmut Schubert the first order of the DB601 was the pre-series of 150 motors, A-0 ie Baureihe A (carburator engine with fixed speed supercharger), so based on engine number of 140, the V15a had one of these instead a A-1. The hydralic clutch came later with the Baureihe B along with fuel injection.
Unfortunately it is test data and it is relevant. Unless you want to dream up specifications.
It's not a test, just a piece of paper, no test data nor kenblats of production planes support 500km/h at sealevel. Everything else is around 460-470km/h including swiss planes with the 601Aa.
Oh but an 500+ kph Spitfire I as fast as the 109F *IS* logical, riiiiight?
Calculating the speed of the the Spitfire I at +12lbs the same way as done in the V15A report:
Density at sealevel: 1.225 kg/cubic meter
Power at sealevel at +6.25lbs: 880hp
Power at sealevel at +12lbs: 1180hp
Speed at sealevel at +6.25lbs: 280mph
r = ((1180/880)*(1.225/1.225))^(1/3) = 1.103
V0 = 280mph * 1.103 = 309mph = 497kmh
However, that is a crude, unaccurate and partially wrong way to calculate it.
Thank you for admitting that your remark about supposed two speed superchargers was just speculation.
The only speculative but logically correct part in my post is the size of the oil cooler, and it was there only because you asked it. The rest are facts.
Regarding level speed performance of the 109, a question raised by I think MiG-3U puzzled me, maybe you have a good explanation, I'm at a loss for now: How come the 109E is faster than the 109F at less power, if you accept the 498 km/h for the 109E at 990ish hp from the V15 test and the 495 km/h for the 109F at 1065ish hp from the 109F Kennblatt?
Thanks for correcting the power of the 601N.
We do have several datapoints for production 109E giving 460-470kmh at 1.3ata and 990hp.
Calculating again the speeds of the 109E same crude way using 470kmh as base line:
601Aa 1045hp = 479kmh
601N 1060hp = 481kmh
Then we have the 109F doing 495kmh ie about 15kmh faster than the 109E at same power, that difference is roughly same as found at FTH. These values match very well while 500kmh is clearly an outlier and not supported by any test or kenbalt of the production planes.
Osprey
09-28-2012, 07:21 AM
Would you mind, TomcatVIP, not slandering me by implying that I am some sort of Spitfire fanboy. I don't appreciate it because it's just not true. You constantly insult people with your replies, it's all in the tone you apply, and then you often go on to make ludicrous statements afterward (such as the one about no energy loss for the Spitfire in COD).
If you reply to me again in this manner then I'll report it. The mods here are hot on infractions.
Robo.
09-28-2012, 07:40 AM
It's not a test, just a piece of paper, no test data nor kenblats of production planes support 500km/h at sealevel. Everything else is around 460-470km/h including swiss planes with the 601Aa.
I am completely with you here (although I am a huge Bf 109 fan), the Mtt 500kph +-5% guarantee debate has been here before and I was saying pretty much what you're saying now.
Kurfürst
09-28-2012, 07:54 AM
The facts:
1. Prototype aircraft V15a, tested well before production started
Fact: report says aircraft is identical to production E-1.
2. Tested speed 493kmh at altitude of 440m, gives 485kmh at 0m
Fact: MIG 3U misrepresentats the report, which states:
Erflogene Geschwindigkeit 493 km/h, auf Normaltag und Garantileistung umgerechnete Geschwindigkeit 498 km/h im 0 m.
They have flown 493kmh at altitude of 440m, which was not yet corrected for German Standard Day conditions or the Guaranteed output of the engine. Bench tests confirmed engine was developing 45 PS less than it should have.
3. The supercharger has two fixed speeds:
- boden- and hohenlader are claimed and the optimal change altitude is determined
- manifold pressure drops above the FTH of the bodenlader, until hohenlader is set on
- the speed test confirms that the supercharger has two fixed speeds
Nope.
Fact: Boden and Hohenlader are just generic names for MS and FS speeds, present on all DB 601/605/603.
The supercharger has two . US trials of captured Bf 109E, later Rechlin trials of Bf 109G-6, G-14 also run with fixed supercharger speeds, something which is easily done on the DB 60x series with hydraulic coupling by bypassing the barometric control.
- according to Flugmotoren und Strahltriebwerke by Kyrill von Gersdorff, Kurt Grasmann, Helmut Schubert the first order of the DB601 was the pre-series of 150 motors, A-0 ie Baureihe A (carburator engine with fixed speed supercharger), so based on engine number of 140, the V15a had one of these instead a A-1. The hydralic clutch came later with the Baureihe B along with fuel injection.
Nope.
DB 601A-0.
"Gemischung durch: 1 Bosch PZ 12 HM 100/11 Einspritzpumpe für 12 Zyl."
"Lader: einstufiges Schleudergeblaese mit barometrischer regelung"
http://kurfurst.org/Engine/DB60x/datasheets/601a0.jpg
It's not a test, just a piece of paper, no test data nor kenblats of production planes support 500km/h at sealevel.
Nope. French trials for example with Bf 109E-3 WNr. 1304. (DB 601A-1, so lower power at 1,3ata) show 495 kph at about 500 meter altitude.
http://kurfurst.org/Performance_tests/109E_French_trials/files/vitesse_109EWNR1304.jpg
Everything else is around 460-470km/h including swiss planes with the 601Aa.
All figures match the V15a performance using Höhenlader well, indicating the tests
"Everything else", well.
WNr. 1774. 498 kph, E-1, "DB 601A", 1,35 ata. 1060 PS.
WNr. 1791. 475 kph, E-1, DB 601A-1, 1,3ata 990 PS, ie. 70 PS less power. "figures are not corrected for guaranteed engine output"
WNr. 1792. 467 kph, E-1 DB 601A-1, 1,3ata 990 PS, ie. 70 PS less power. "figures are extrapolated graphically to 0m" and "figures are not corrected for guaranteed engine output"
WNr. 1304, ca. 485 kph, E-3, DB 601A-1, 960 Hgmm (ca. 1,3 ata). 990 PS, ie. 70 PS less power. With estimated position error curves: +/- 15 kph on speed.
WNr. 2404, 464 kph, E-3, DB 601Aa, probably 1,35ata. Conditions unknown. Curves clearly show single speed supercharged performance with no appearant hydraulic curveture. Figures closely match WNr. 1774. Höhenlader performance (extrapolating to about 460 kph at SL)
Calculating the speed of the the Spitfire I at +12lbs the same way as done in the V15A report:
Density at sealevel: 1.225 kg/cubic meter
Power at sealevel at +6.25lbs: 880hp
Power at sealevel at +12lbs: 1180hp
Speed at sealevel at +6.25lbs: 280mph
r = ((1180/880)*(1.225/1.225))^(1/3) = 1.103
V0 = 280mph * 1.103 = 309mph = 497kmh
However, that is a crude, unaccurate and partially wrong way to calculate it.
The only speculative but logically correct part in my post is the size of the oil cooler, and it was there only because you asked it. The rest are facts.
As shown above, they are not facts but misrepresentation of the facts.
Your theory is basically this. Messerschmitt built a prototype for the Bf 109E series, which achieved around 500 kph with the the engine cowling still unpainted, without fuel injection and without a multi speed supercharger, which (then appearantly the Americans got hold somehow of another Bf 109E and oddly tested it the same way as the Germans theirs... :D ) . They have noted in their report that due to time constraints, they could not yet fit the proper exhausts and air intake, so "further increases in performance are possible".
Then they supposedly went on improving it with a oil cooler of the size of an elephant, that chopped down 40 kph (!!! :D :D) from top speed, but strangely enough only at low altitude :D, they added direct fuel injection which probably made the engine even weaker. Happy of good days work, and that they achieved no less than 40 kph speed loss, they decided to put that new version into production. The legal and financial department went nuts too, and decided to give legal guarantees for reaching a performance that according to you, was impossible to achieve. Save for a few odd examples that landed in French, Swiss hands which matched V15a figures finely.
Extremely likely, yes.
Any observations on the "prototype" Bf 109E overlayed with the Swiss trials of WNr 2404?
MiG-3U
09-28-2012, 08:34 AM
Nope.
DB 601A-0.
"Gemischung durch: 1 Bosch PZ 12 HM 100/11 Einspritzpumpe für 12 Zyl."
"Lader: einstufiges Schleudergeblaese mit barometrischer regelung"
http://kurfurst.org/Engine/DB60x/datasheets/601a0.jpg
Well, we have the test data of the V15a showing clearly a supercharger with two fixed speeds instead hydraulic clutch and this is supported by Von Gersdorf et.al. Any source can contain errors or projected things which happened later, this is why any source should be contested. In this case your source, what ever it is, is easily contested because the characters of the hydraulic clutch are not there and Von Gersdorf et.al. can be seen as more credible source (generally the secondary source is seen more credible because it's better contested and refined, like in wikipedia).
Kurfürst
09-28-2012, 08:45 AM
Well, we have the test data of the V15a showing clearly a supercharger with two fixed speeds instead hydraulic clutch
So does this US trial of captured Bf 109E. Does it have "two fixed speeds instead hydraulic clutch"?
http://www.wwiiaircraftperformance.org/me109/Me-109E3-US.jpg
And so does this German trial of captured Bf 109G-6. Does it have "two fixed speeds instead hydraulic clutch"?
http://kurfurst.org/Performance_tests/109G14_May44trials/109G-6_DB605A.jpg
And so does this German trial of captured Bf 109G-14. Does it have "two fixed speeds instead hydraulic clutch"?
http://kurfurst.org/Performance_tests/109G14_May44trials/G14_erflogen_May44_viaGGHopp.jpg
and this is supported by Von Gersdorf et.al.
I don't see "Von Gersdorf et.al." anywhere here. Only your speculations, which happen to be repeating the same as that of a certain figure called Harri Pihl. Who has also kept refusing posting his sources, when cornered. ;)
MiG-3U
09-28-2012, 09:07 AM
Fact: report says aircraft is identical to production E-1.
The E-1 was then still under developement and came out much later.
Erflogene Geschwindigkeit 493 km/h, auf Normaltag und Garantileistung umgerechnete Geschwindigkeit 498 km/h im 0 m.
They have flown 493kmh at altitude of 440m, which was not yet corrected for German Standard Day conditions or the Guaranteed output of the engine. Bench tests confirmed engine was developing 45 PS less than it should have.
No anykind mispresentation there, 485kmh at 0m can be read directly from the chart and calculation is based on density 1.175 kg/cubic meter.
Fact: Boden and Hohenlader are just generic names for MS and FS speeds, present on all DB 601/605/603.
These engines do not have gear change nor pressure drop until FTH. Only a altitude range where the supercharger speed is variable.
Regarding the rest, many organisations have done tests poorly or intrepeted tested data poorly. You just pick the ones which suit to your agenda.
Over and out until something relevant is posted.
Osprey
09-28-2012, 11:12 AM
You want the original document, Osprey?
No need, just making the point. I am happy to liase with pstyle on it though, I would like to just make sure that the 109 is correct in HSFX, of course would seek necessary approval from 109 jockeys who have a similar historically accuracy first agenda to me.
Osprey
09-28-2012, 11:24 AM
So does this US trial of captured Bf 109E. Does it have "two fixed speeds instead hydraulic clutch"?
http://www.wwiiaircraftperformance.org/me109/Me-109E3-US.jpg
Yes, but this one clearly doesn't make 500kmph on the deck (290mph or 464kmph) and has a maximum speed of 340mph (544kmph). That's about 15mph slower than the Spitfire top end and only 6 or so kmph faster than the Spitfire on the deck running at only 6.25lbs of boost. In fact, 290 mph is only slightly faster @ sea level than a Hurricane I @ 12lbs + 3000rpm.
Now, I'm not suggesting that the gap in speed between the Spitfire and 109 is that large, but it's certainly wildly different from your chart. Given that you stated that the prototype you quote is unchanged from the production E-1, how can you account for this discrepancy?
The trouble is, there's this whole 'big lie' about the 109 advantages on the Spitfire (you perpetuate it, that the 109 can out climb, out dive, out speed, out gun and out turn the Spitfire) Some of these are true or course, but not all like you indicate.
Kurfürst
09-28-2012, 11:27 AM
No need, just making the point. I am happy to liase with pstyle on it though, I would like to just make sure that the 109 is correct in HSFX, of course would seek necessary approval from 109 jockeys who have a similar historically accuracy first agenda to me.
I can post the paper for you when I get home, though you have already seen it in full (transcribed) on my site. The Blatt 3 part pstyle was missing is actually there, its the 3rd page that covers the second part of point three and the rest of point four (the typed text part spread through multiple pages), but for reasons of convinience I have ommitted the header for the rest of the pages, which would break the text flow and would say just the same, well, except for "Blatt 3" instead of "Blatt 1" and "Blatt 2" in the right upper corner. ;)
Kurfürst
09-28-2012, 11:37 AM
Yes, but this one clearly doesn't make 500kmph on the deck (290mph or 464kmph) and has a maximum speed of 340mph (544kmph).
Nope, its just another 109 that has it's hydraulic supercharger set up to give fixed gear ratios. All it needs is to disable the second oil pump in the hydraulic clutch to get a fixed low gear, and then to set the second oil pump in the hydraulic clutch to get a fixed high gear (at minimum slip). Looking at the other testing papers, it was commonly done to reduce the margin of error in the measurements.
BTW if you look at the paper carefully you will see that no low level speed measurement was made, the lowest actual data point measured in low gear was 336 mph at 12k feet. Anything below was simply extrapolated (and obviously with a large margin of error, given the very few points available for extrapolation)
That's about 15mph slower than the Spitfire top end and only 6 or so kmph faster than the Spitfire on the deck running at only 6.25lbs of boost. In fact, 290 mph is only slightly faster @ sea level than a Hurricane I @ 12lbs + 3000rpm.
Now, I'm not suggesting that the gap in speed between the Spitfire and 109 is that large, but it's certainly wildly different from your chart. Given that you stated that the prototype you quote is unchanged from the production E-1, how can you account for this discrepancy?
Well for one we have absolutely no idea about the testing conditions. Without these, it's rather pointless to compare different tests. The aircraft does show very different results from the rest, which can mean the testing conditions may have been different, the airframe or engine was subpar and so on. What "109" is this anyway?
The trouble is, there's this whole 'big lie' about the 109 advantages on the Spitfire (you perpetuate it, that the 109 can out climb, out dive, out speed, out gun and out turn the Spitfire) Some of these are true or course, but not all like you indicate.
I don't perpetuate that. Especially, since much of this data, for example climb rates are missing for both aircraft.
pstyle
09-28-2012, 11:50 AM
The Blatt 3 part pstyle was missing is actually there, its the 3rd page that covers the second part of point three and the rest of point four (the typed text part spread through multiple pages), but for reasons of convinience I have ommitted the header for the rest of the pages, which would break the text flow and would say just the same, well, except for "Blatt 3" instead of "Blatt 1" and "Blatt 2" in the right upper corner. ;)
cheers Kurfurst.
Al Schlageter
09-28-2012, 12:29 PM
Can someone tell why these 2 German documents have the Vo as 476-476kph and 466-467kph.
http://www.wwiiaircraftperformance.org/me109/Me-109E1-1791.jpg
http://www.wwiiaircraftperformance.org/me109/me109e3-1792.jpg
Robo.
09-28-2012, 01:07 PM
It says underneath, that although those speeds are re-calculated for normal temperature and correct manifold pressure, they are not corrected for the guaranteed engine perfoamance yet.
Seems to me that no matter how I look at that, the guaranteed performance by Mtt is rather theoretical.
Good point.
Kurfürst
09-28-2012, 01:21 PM
Besides the fact that both of these papers show 109s with the 990 PS DB 601A and not 1045 PS 601Aa....
And, despite the weaker engine operating at an unknown power, the first test (476 kph) still just satisfies the guaranteed specs of Messerschmitt (500 kph +/- 5%, that is: anything between 475 and 525 kph is O.K.).
Al Schlageter
09-28-2012, 01:45 PM
Thanks Robo. The speeds are not within the +/-5% tolerance being in the 7% range.
Another point to discuss.
Someone said the, iirc, that the trim tabs on the Bf109 were set for a speed of 400kph. This would be ~80% of top speed. This would be max continuous speed would it not?
How much time would be spent at max continuous speed? The a/c wouldn't be at this speed when escorting the bombers but at a lower speed for which the a/c would not be trimmed for. I would think that the a/c would be trimmed for a speed the a/c would spend more time at, possibly 300-350kph. At these speeds, it would be much easier on the pilot.
Kurfurst once posted some test data on the Bf109G that was a plot of the top speed of several a/c. There was more a/c below the guaranteed top speed than above the guaranteed top speed. Just something to think about.
NZtyphoon
09-28-2012, 02:04 PM
In other words the Germans took it for granted that there was a possible variation of 50 km/h in guaranteed speed at sea level, which is no form of guarantee at all when life or death in air-to-air combat could rest on very small margins of speed. It also means the top speed of a 109E at FTH could vary by an even wider speed range - anywhere between 532 km/h (330 mph) to 582 km/h (361 mph).
Kurfürst
09-28-2012, 08:35 PM
cheers Kurfurst.
... and here it is. But don't expect anything new...
Al Schlageter
09-29-2012, 12:34 AM
Why do you continually show V15 data and not data for the E-1,3 Kurfurst?
Varrattu
09-29-2012, 08:00 AM
... and here it is. But don't expect anything new...
Referring "Blatt 2" important results concerning speed etc. are reported on "Blatt 6".
Please can you provide "Blatt 6", too?
Regards Varrattu
Kurfürst
09-29-2012, 09:41 AM
Oh, sorry.
http://kurfurst.org/Performance_tests/109E_V15a/files/109v15a_blatt6.jpg
Varrattu
09-29-2012, 10:22 AM
@ Kurfürst
Thank you.
Varrattu
Holtzauge
09-29-2012, 11:32 AM
There are a number of issues with the outlyer 109E 500 km/h sea level top speed:
First of all the Baubeschribung 500/570 Km/h speed curve does not map any known engine power/alt curve: These either have the characteristic bulge associated with the hydralic clutch or the notch type with two speed superchargers where as the curve showing 500 Km/h at SL and 570 Km/h at altitude in the Baubeschribung has a straight line between these points. So which DB601 in a series Me109E had this power/altitude characteristic? None that I have seen published.In addition the date of the the Baubeschribung is stated as "circa 1939"and reference made to the Yugoslavian manual. So this looks more like some early marketing material supporting Messerschmitts export activities which also predictably for marketing material includes a caveat of plus minus 5% which would then place the more realistic speed performance of around 475 Km/h within the guaranteed range.So to conclude, the data supporting 500 Km/h SL speed either references prototype data or refers to some early marketing material. In addition, it looks like estimate for the "guaranteed" engine data coming close to 500 Km/h for the V15 prototype is for 1,35 not 1,3 ata.
Moving then to some more realistic speed estimates based on what could be expected of a series type aircraft at 1.3 ata: Note that the C++ simulation data for the high and low altitude speed of the +6.25 and +12 boost Spitfire is quite consistent with historic data. Using the same principles for calculating the Me109E low level speed the result also yields around 570 Km/ at altitide but at low level the result is around 475 Km/h not 500 Km/h. These curves were calculated using the actual historic series type engine data and consequently show the effects of the hydraulic clutch, something missing from the 500/570 Km/h chart. I'm sure the usual suspects will question the validity of the C++ simulations but as an answer to that we have the Me109E figures posted by HoHun on the All About Warfare forum (www.allaboutwarfare.com) and as can be seen the calculations agree remarkably well. In addition one can conclude that both calculations agree quite well with the actual measured top speed posted earlier by Al Schlageter.
Finaly, it's interesting to note the type of evidence evaluation practiced by some in this forum: There was a mountain of evidence supporting 100 octane that was dismissed as inconclusive and now we are expected to swallow a molehill of evidence for 500 Km/h sea level top speed when most data, calculated and test measurements point to something around 475 Km/h.
Talk about double standards....
Kurfürst
09-29-2012, 11:46 AM
There are a number of issues with the outlyer 109E 500 km/h sea level top speed:
First of all the Baubeschribung 500/570 Km/h speed curve does not map any known engine power/alt curve: These either have the characteristic bulge associated with the hydralic clutch or the notch type with two speed superchargers where as the curve showing 500 Km/h at SL and 570 Km/h at altitude in the Baubeschribung has a straight line between these points.
The Baubeschribung curves are obviously simplified, drawing a straight line between low level and FTH performance. Again, nothing uncommon in that, Rechlin did the same thing for a tested G-1 chart:
http://kurfurst.org/Performance_tests/109G_Rechlinkennblatt/R_G1_kurven.jpg
So which DB601 in a series Me109E had this power/altitude characteristic? None that I have seen published.
All, in fact:
http://i38.photobucket.com/albums/e133/Kurfurst/DB601Abarometricsuperchargercontrolunit.jpg
In addition, it looks like estimate for the "guaranteed" engine data coming close to 500 Km/h for the V15 prototype is for 1,35 not 1,3 ata.
Unsurprising, since both the V15a flight tests results and guaranteed specs in the Baubeschreibung are for 1.35ata.
The sillyness lies in that some people want to compare these 1.35 ata results to 1.3ata, uncorrected figures, and the fact that uncorrected results achieved with the less powerful DB 601A-1 at 1.3ata / 990 PS are irrelevant when modelling our 1.35 ata / 1045 PS Bf 109E equipped with the DB 601Aa.
The rest of your post is irrelevant.
BTW it's worth comparing the V15a (WNr. 1774) results with the speed results with a Swiss export Bf 109E-3a. The reports show remarkable similarity in the top speed achived at altitude with the original VDM propellor of J-347 (572 vs. 564 km/h at rated altitude), especially when taking into account that J-347 already saw considerably use. However the low level speeds diverge greatly (498 vs 464 km/h at 0m altitutude). Note that the low-level performance of V15a with the Höhenlader (high altitude supercharger speed, or 'F.S gear' in British terms) shows good agreement with J-347 at both high- and low altitudes.
This would suggest that J-347`s level speed results were achived with the Höhenlader in operation and agree well with the results of Bf 109E-1 / V15a WNr. 1774.
Also note that the Baubeschreibung agrees well with the V15a results, but the curves are bit more simplified (mean avarage results).
http://i38.photobucket.com/albums/e133/Kurfurst/109E_WNr1774vs2404.jpg
Robo.
09-29-2012, 01:32 PM
Holtzauge, that pretty much sums it up.
Al Schlageter
09-29-2012, 02:18 PM
German speed graph of a Bf109E with a DB601Aa engine.
http://www.allaboutwarfare.com/forums/index.php?act=attach&type=post&id=2042
ACE-OF-ACES
09-29-2012, 03:35 PM
Moving then to some more realistic speed estimates based on what could be expected of a series type aircraft at 1.3 ata: Note that the C++ simulation data for the high and low altitude speed of the +6.25 and +12 boost Spitfire is quite consistent with historic data. Using the same principles for calculating the Me109E low level speed the result also yields around 570 Km/ at altitide but at low level the result is around 475 Km/h not 500 Km/h. These curves were calculated using the actual historic series type engine data and consequently show the effects of the hydraulic clutch, something missing from the 500/570 Km/h chart. I'm sure the usual suspects will question the validity of the C++ simulations but as an answer to that we have the Me109E figures posted by HoHun on the All About Warfare forum (www.allaboutwarfare.com) and as can be seen the calculations agree remarkably well. In addition one can conclude that both calculations agree quite well with the actual measured top speed posted earlier by Al Schlageter.
Very cool! I just joined the All About Warfare.. First thing I noticed was butch2k is there! I was wondering where he had gone! Al, did he ever finish that book he was working on? Or do I have him confused with someone else?
Kurfürst
09-29-2012, 03:46 PM
German speed graph of a Bf109E with a DB601Aa engine.
http://www.allaboutwarfare.com/forums/index.php?act=attach&type=post&id=2042
Swiss.
http://kurfurst.org/Performance_tests/109E_SwissJ347/J-347.jpg
Holtzauge
09-29-2012, 04:55 PM
Holtzauge, that pretty much sums it up.
Yes, I think the case for 500 Km/h SL speed for the Me109E is rather weak.
I don't fly CloD but used to fly IL2 some before, mostly Me109's and Fw190's so I'm not interested in porking them in any way.
What I do want is as realistic performance as possible in any sim which is not something you get if you like some people in this forum consistently take the inside envelope of any allied data and the outside envelope for the Me109 if you get my drift. None mentioned and none forgotten ;-)
Holtzauge
09-29-2012, 04:56 PM
Very cool! I just joined the All About Warfare.. First thing I noticed was butch2k is there! I was wondering where he had gone! Al, did he ever finish that book he was working on? Or do I have him confused with someone else?
I don't know about any book but the site as such contains some nice info and HoHun has posted a lot of interesting speed and climb analysis for a number of aircraft so the site is well worth a visit.
To the best of my knowledge we use different ways to calculate performance but from what I have seen so far we seem to arrive at quite similar conclusions. My C++ simulation also allows incremental integration of data so I can model transient flight conditions like dive and zoom and instantaneous turn etc.
TomcatViP
09-29-2012, 05:03 PM
BTW it's worth comparing the V15a (WNr. 1774) results with the speed results with a Swiss export Bf 109E-3a. The reports show remarkable similarity in the top speed achived at altitude with the original VDM propellor of J-347 (572 vs. 564 km/h at rated altitude), especially when taking into account that J-347 already saw considerably use. However the low level speeds diverge greatly (498 vs 464 km/h at 0m altitutude). Note that the low-level performance of V15a with the Höhenlader (high altitude supercharger speed, or 'F.S gear' in British terms) shows good agreement with J-347 at both high- and low altitudes.
There was some diff btw the 109 exported in Switzerland and the original E. Notably in aerodynamics.
I don't think you can make a comparison without taking this fact into account.
TomcatViP
09-29-2012, 05:15 PM
There are a number of issues with the outlyer 109E 500 km/h sea level top speed:
First of all the Baubeschribung 500/570 Km/h speed curve does not map any known engine power/alt curve: These either have the characteristic bulge associated with the hydralic clutch or the notch type with two speed superchargers where as the curve showing 500 Km/h at SL and 570 Km/h at altitude in the Baubeschribung has a straight line between these points. So which DB601 in a series Me109E had this power/altitude characteristic? None that I have seen published.In addition the date of the the Baubeschribung is stated as "circa 1939"and reference made to the Yugoslavian manual. So this looks more like some early marketing material supporting Messerschmitts export activities which also predictably for marketing material includes a caveat of plus minus 5% which would then place the more realistic speed performance of around 475 Km/h within the guaranteed range.So to conclude, the data supporting 500 Km/h SL speed either references prototype data or refers to some early marketing material. In addition, it looks like estimate for the "guaranteed" engine data coming close to 500 Km/h for the V15 prototype is for 1,35 not 1,3 ata.
Moving then to some more realistic speed estimates based on what could be expected of a series type aircraft at 1.3 ata: Note that the C++ simulation data for the high and low altitude speed of the +6.25 and +12 boost Spitfire is quite consistent with historic data. Using the same principles for calculating the Me109E low level speed the result also yields around 570 Km/ at altitide but at low level the result is around 475 Km/h not 500 Km/h. These curves were calculated using the actual historic series type engine data and consequently show the effects of the hydraulic clutch, something missing from the 500/570 Km/h chart. I'm sure the usual suspects will question the validity of the C++ simulations but as an answer to that we have the Me109E figures posted by HoHun on the All About Warfare forum (www.allaboutwarfare.com) and as can be seen the calculations agree remarkably well. In addition one can conclude that both calculations agree quite well with the actual measured top speed posted earlier by Al Schlageter.
Finaly, it's interesting to note the type of evidence evaluation practiced by some in this forum: There was a mountain of evidence supporting 100 octane that was dismissed as inconclusive and now we are expected to swallow a molehill of evidence for 500 Km/h sea level top speed when most data, calculated and test measurements point to something around 475 Km/h.
Talk about double standards....
I will be delighted to hve a look at your C++ "simulation". Pls show us the core engine instead of hijacking any scientific credits. Let me guess... inviscid, incompressible and lift line theo with linear curve discretisation? lol
Kurfürst
09-29-2012, 05:33 PM
There was some diff btw the 109 exported in Switzerland and the original E. Notably in aerodynamics.
I don't think you can make a comparison without taking this fact into account.
What kind of difference do you have in mind?
Kurfürst
09-29-2012, 05:35 PM
Yes, I think the case for 500 Km/h SL speed for the Me109E is rather weak.
Well of course, since we have your toy excel sheet against thoroughly documented test data! :D :D
TomcatViP
09-29-2012, 05:41 PM
What kind of difference do you have in mind?
I hve in mind the guns (barrel for sure). I think the rad were different. But I need to check this. There is also a good article on the net (in French probably) if you browse around "bf109" and switzerland ("Suisse"). Will try to have a look.
EDIT:
Guns for sure and prop
Holtzauge
09-29-2012, 05:44 PM
I will be delighted to hve a look at your C++ "simulation". Pls show us the core engine instead of hijacking any scientific credits. Let me guess... inviscid, incompressible and lift line theo with linear curve discretisation? lol
Well you guessed wrong! I actually did a post a while back arguing for the introduction of subsonic drag rise which is missing in CloD but modelled in the C++ simulation. Modelled a Spitfire Mk1 and showed that the speed build up in CloD in quicker than it should be because compressibility effects are missing.
Seeing you seem to be such an expert perhaps you would be so kind to point out what is wrong in my Me109E speed/alt chart and how it really should look like?
Kurfürst
09-29-2012, 05:51 PM
I hve in mind the gun barrel for sure. I think the rad were different. But I need to check this. There is also a good article on the net (in French probably) if you browse around "bf109" and switzerland ("Suisse"). Will try to have a look.
Yes I will check that, I had a good (IIRC German language) book about Swiss 109s, which helped me to ID J-347's WNr. and service record.
As for the gun barrels, I am not sure - one of the tests being waved about is explicitely about measuring the speed diff. between guns present/not present, and it's about 1 km/h.. I'd imagine different gun barrels amount to even less. ;)
Rads look interesting though, this might account for something, but again, looking the Swiss test results, the difference is only about 8 kph at VDH, which from my experience, is an extremely good match for a serial production plane compared to the guaranteed specs!
Seeing you seem to be such an expert perhaps you would be so kind to point out what is wrong in my Me109E speed/alt chart and how it really should look like?
Well for one it probably has wrong data.. guessworked drag, guessworked wing effiencies, guessworked propeller effiency, manipulated until it fits one's agenda. :D
As Tagert said, garbage in... garbage out.
BTW, care to tell why you disappeared from allaboutwarafe forums? I am sure it's hell of a story. :D :D :D
TomcatViP
09-29-2012, 06:08 PM
Well you guessed wrong! I actually did a post a while back arguing for the introduction of subsonic drag rise which is missing in CloD but modelled in the C++ simulation. Modelled a Spitfire Mk1 and showed that the speed build up in CloD in quicker than it should be because compressibility effects are missing.
Seeing you seem to be such an expert perhaps you would be so kind to point out what is wrong in my Me109E speed/alt chart and how it really should look like?
The core.. That's not too much to ask.
Holtzauge
09-29-2012, 06:16 PM
Well for one it probably has wrong data.. guessworked drag, guessworked wing effiencies, guessworked propeller effiency, manipulated until it fits one's agenda. :D
As Tagert said, garbage in... garbage out.
BTW, care to tell why you disappeared from allaboutwarafe forums? I am sure it's hell of a story. :D :D :D
I think people are aware by your modus operandi by now: If you don't like the message then discredit the messenger.
Me "disappering" is for no more sinister reason than for working on a book project. Believe me it's much more satisfying than arguing about your doctored data or sparring with your mathematically challenged pal Crumpp!
So if my Me109E data is so totally wrong then I guess this means that HoHun's charts are off the wall as well because we get the same results, i.e. around 475 Km/h on the deck. Garbage in and garbage out in both cases huh?
BTW: Concerning disappering, in your case we know the answer don't we? Permanently banned from a number of forums and as editor in Wikipedia. That sure is one hell of a story! :D :D :D
Holtzauge
09-29-2012, 06:20 PM
The core.. That's not too much to ask.
Actually it is. I'm going to use the C++ results in a book project so I'm not going to sink my own project by posting my code before that :)
Kurfürst
09-29-2012, 06:39 PM
I think people are aware by your modus operandi by now: If you don't like the message then discredit the messenger.
Nobody needs to discredit you.
Me "disappering" is for no more sinister reason than for working on a book project. Believe me it's much more satisfying than arguing about your doctored data or sparring with your mathematically challenged pal Crumpp!
.. but you seem to need to discredit others. :D
So if my Me109E data is so totally wrong
It is. It doesn't match tested results, does it?
Holtzauge
09-29-2012, 06:50 PM
It is. It doesn't match tested results, does it?
I would love too see those test results.
Seems to me like you are confusing the calculated speed of the V15 prototype at 1.35 ata or the caveted Messerschmitt marketing material with actual test results. The only test results I've seen point to 466-475 Km/h.
You still have not answered the question: How do you account for HoHun's estimate of 475 Km/h?
Al Schlageter
09-29-2012, 06:56 PM
I would love too see those test results.
Seems to me like you are confusing the calculated speed of the V15 prototype at 1.35 ata or the caveted Messerschmitt marketing material with actual test results. The only test results I've seen point to 466-475 Km/h.
You still have not answered the question: How do you account for HoHun's estimate of 475 Km/h?
And that is why we only see the V15 prototype data and not data for production Bf109Es.
Kurfürst
09-29-2012, 07:16 PM
I would love too see those test results.
Seems to me like you are confusing the calculated speed of the V15 prototype at 1.35 ata
It takes a great deal of dishonesty and/or confusion to claim the V15a speeds are calculated.
"An Bf 109 V 15 a, der Mustermachine für die E-1-Serie, wurden die Geschwindigkeitsleistungen erflogen."
Can you translate the above please?
or the caveted Messerschmitt marketing material with actual test results.
Trouble is, Messerschmitt's type specification sheet ("marketing material") is the official specification for the aircraft, and was to be met by all similar Bf 109E in the Luftwaffe within +/- 5%.
The only test results I've seen point to 466-475 Km/h.
Well again it takes a great deal of dishonesty and/or confusion to claim not having seen flight test results, when the V15a flight tests have been posted in their full just a couple of pages back.
You still have not answered the question: How do you account for HoHun's estimate of 475 Km/h?
You should ask HoHun, but as you say: it's an estimate. For a different engine.
Curiously though, the French were hitting the exact same speeds at low levels (ca. 493 km/h) with their captured Bf 109E-3 as the Germans did with the E-1 (V15a)
http://kurfurst.org/Performance_tests/109E_French_trials/files/vitesse_109EWNR1304.jpg
It will be amusing when next time, you will claim you have not seen this either.
But, oh boy I forgot, you have your own charts. :D
Now let's see how speed figures claimed by British propaganda measured up to actual speed measurements... ooops, not very well it would seem! I am really looking forward to see a historically accurate Spitfire Mark V. ;)
Holtzauge
09-29-2012, 07:37 PM
I do read German and therefore I know the difference between what was flown and what was projected for the V15 prototype: "Blatt 6" shows about 485 Km/h for the FLOWN 1.3 ata value and the ESTMATED 500 Km/h value for "Geschwindigkeiten bei Garantierter Motorlesitung" 1.35 ata as a dashed line. So who is being dishonest now?
Concerning the French test it looks like very few data points and none at SL as I can tell so your claim that this supports the 500 Km/h seems a stretch.
So HoHuns and my calculations are for "a different engine" and can be discounted as "estimates"?. Quite interesting that this method of calculation works well with the Spitfire and also mirrors 466-475 km/h Rechlin test results for the Me109E SERIES aircraft no?
I see you added some Spitfire data now. I assume it's safe to bet that this is the absolute rock bottom worst data you were able to find on the Spit, right?
Al Schlageter
09-29-2012, 07:59 PM
Here is the document mentioned earlier.
http://www.kurfurst.org/Performance_tests/109G_Erlatrials/Erla109G_13speedrun_scatter_web.jpg
13 a/c
4 below spec -5% > 31%
6 below mean > 46%
3 above mean > 23%
The average for all the a/c is well below the mean.
Applying this to the Bf109E would give an average speed of ~485kph.
Kurfürst
09-29-2012, 08:00 PM
I do read German and therefore I know the difference between what was flown and what was projected for the V15 prototype: "Blatt 6" shows about 485 Km/h for the FLOWN 1.3 ata value and the ESTMATED 500 Km/h value for "Geschwindigkeiten bei Garantierter Motorlesitung" 1.35 ata as a dashed line. So who is being dishonest now?
That's not really a question, it is still you (and you are doing it rather poorly as usual), so continue translating, maybe you are better at that - its funny you have not translated the first part isn't it. :D
2. Stoppflug.
Ergebnis: Erflogene Geschwindigkeit 493 km/h, auf Normaltag und Garantieleistung umgerechnete Geschwindigkeit 498 km/h im 0 m. Umrechnung siehe Blatt 5.
For those who do not wish to bother much with Holtzeuge's incoherent lies, here's the deal (as noted by the report clearly):
The aircraft (V15a), identical in all to series production E-1 flew low altitude speed trials on a four way track. The engine was bench tested as well (actually the ONLY test I am aware was this through), as was found to develop 45 PS less, and developed only 1.31ata in fligth instead of 1.35. Calibration flights were also made.
The 'raw' data collected (493 km/h at 0 m) was then converted for standard conditions: German Standard day atmospheric conditions, and normal engine power. The result was 498 km/h at 0m. The methods are clearly visible at the end of the report.
This is of course entirely normal, almost all Spitfire etc. tests for example do the same thing: correct the figures to normal boost ratings, and adjust for (British) Standard Day conditions. Otherwise, they would be useless for comparison...
Holtzeuge claim is basically because the flight tested data was converted (as usual) to standard conditions it needs to be dismissed because it's an 'estimate.'
Concerning the French test it looks like very few data points and none at SL as I can tell so your claim that this supports the 500 Km/h seems a stretch.
:D :D :D
So HoHuns and my calculations are for "a different engine" and can be discounted as "estimates"?
Well they ARE estimates and they are for a different engine and different boost... :D
Quite interesting that this method of calculation works well with the Spitfire and also mirrors 466-475 km/h Rechlin test results for the Me109E SERIES aircraft no?
Nope, your calculations are not interesting at all. :)
I see you added some Spitfire data now. I assume it's safe to bet that this is the absolute rock bottom worst data you were able to find on the Spit, right?
Oh, not so finnicky about 'marketing brocheres' any longer, are we? :D
ACE-OF-ACES
09-29-2012, 08:07 PM
I don't know about any book but the site as such contains some nice info and HoHun has posted a lot of interesting speed and climb analysis for a number of aircraft so the site is well worth a visit.
Ok, I just remembered butch2k's names from years ago.. He was a very informative and level heading logical guy from what I remember.. There was another guy with a name similar to his.. B something, maybe he was the guy writing the book?
To the best of my knowledge we use different ways to calculate performance but from what I have seen so far we seem to arrive at quite similar conclusions. My C++ simulation also allows incremental integration of data so I can model transient flight conditions like dive and zoom and instantaneous turn etc.
By the way your name rings a bell too.. I seem to recall seeing your C++ stuff a few years back.. Very neat stuff! I have some of Henning Rush's stuff posted at my website.. i.e. www.flightsimtesting.com and would love to post some of yours too! What format is your output files? Simple text I assume? Could I get a copy?
I see you added some Spitfire data now. I assume it's safe to bet that this is the absolute rock bottom worst data you were able to find on the Spit, right?
I see you have 'experience' with Kurfurst too! ;)
TomcatViP
09-29-2012, 08:37 PM
Actually it is. I'm going to use the C++ results in a book project so I'm not going to sink my own project by posting my code before that :)
Well... and naming the eq. that you use is that so much classified that you can't even do it?
MiG-3U
09-30-2012, 05:38 AM
Concerning the French test it looks like very few data points and none at SL as I can tell so your claim that this supports the 500 Km/h seems a stretch.
The French test shows about 494kmh at about 550m and and power chart gives about 1010ps at 550m, these values give 482kmh at sealevel with 990ps.
The outliers, like the sealevel speed in the V15a test, are usually caused by measurement errors. And given the fact that speeds match better with other tests at high altitude, it is probable that something is not right in the V15A measurements (error can be anything; failing device, typing error, calibration problem etc.).
Kurfürst
09-30-2012, 08:45 AM
The facts:
1. Prototype aircraft V15a, tested well before production started
2. Tested speed 493kmh at altitude of 440m, gives 485kmh at 0m
The French test shows about 494kmh at about 550m and and power chart gives about 1010ps at 550m, these values give 482kmh at sealevel with 990ps.
Seems there's then good agreement between the German tests with the E-1 at 1.31ata and the French tests with the E-3 at 1.3 ata then even according to Harri's own estimates.
Of course it should be kept in mind that the final E-1 results were corrected to 1.35ata and Standard Day, and resulting in 498 km/h, and that our E-1/E-3/E-4 models have 1.35 ata.
The outliers, like the sealevel speed in the V15a test, are usually caused by measurement errors.
Good point. Since the two brief trials of 467-475 kph you mentioned fell well out of the official and other measured tests, and they note that some necessary corrections were not made (the first trial mentioning that the SL speeds were simply graphically extrapolated to SL, and both trials noting the figures are not yet corrected to guaranteed engine output) it's likely the scatter is caused by measurment errors.
And given the fact that speeds match better with other tests at high altitude, it is probable that something is not right in the V15A measurements (error can be anything; failing device, typing error, calibration problem etc.).
Which can be entirely ruled out given the fact that the low altitude measurements with the V15a were done on a four way record track, the aircraft having flown in four directions, and the (known) distance covered was timed. This method is by far the most accurate and eliminate all possible instrument errors.
NZtyphoon
09-30-2012, 08:54 AM
On the other hand this thread is about how the Spitfire I and II series performs in CLOD 1.08, which has now been supplemented/superseded by 1.09, not about Kurfurst's interpretation of 109 data which we all know will be skewed in one direction - how about another thread for that?
Fact is neither patch has provided authentic Spitfire performance, with or without +12 lbs, and there are still chronic overheating issues that ATAG_Dutch has helped alleviate.
Kurfürst
09-30-2012, 08:59 AM
On the other hand this thread is about how the Spitfire I and II series performs in CLOD 1.08, which has now been supplemented/superseded by 1.09, not about Kurfurst's interpretation of 109 data which we all know will be skewed in one direction - how about another thread for that?
Thread title says: " Spit/109 sea level speed comparisons in 1.08 beta patch"
Updated paper with French trial results included.
http://i38.photobucket.com/albums/e133/Kurfurst/109E_WNr1774vs2404vs1304_zpsd822ce28.jpg
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