Spit IIa [Archive] - Official Fulqrum Publishing forum

Whiski

10-10-2011, 04:30 PM

So, I have read quite a few posts regarding this a/c.

One question. Why do most people think its over modeled/over powered?

After flying it offline to test some (not all) of the speeds at various alts it seems to conform to most if not all the websites I have visited regarding its real life spec's. Some websites being:

http://www.spitfireperformance.com/spittest.html
http://www.zenoswarbirdvideos.com/Images/spit/Spit2Manual.pdf
http://acepilots.com/planes/specs.html.

All spec's from various sites are rather close. I did not find anything to be "Over powered/Over modeled" when comparing in game to these websites.

I only tested the speeds at various alts and nothing else. Using combat and normal operating procedures (by that I mean using it so not to blow an engine) I found it within the stated specs from the websites I visited.

So am I missing something here, have I not found the end all be all of spitfire specs website?

I know there are 2 sides to this debate: "the 109 is superior and should not be out performed by a spit" and the other side "The spit was far superior and could out perform the 109". Both planes had advantages in different areas of combat and normal flight. So, can anyone provide irrefutable proof that the Spit IIa is not modeled properly in game (conforming to real life specifications).

I am neither saying it is or it isn't. I am just trying to get your facts (not an opinion) to either prove it is or it isn't over modeled.

Cheers

Whiskey

Sven

10-10-2011, 04:46 PM

http://forum.1cpublishing.eu/showthread.php?t=23994

&

http://forum.1cpublishing.eu/showthread.php?t=25956

Have a good read, the search function is your friend too.

310_cibule

10-10-2011, 05:05 PM

Not most of the people but most of those who fly for the blue side primarily ;)

Ze-Jamz

10-10-2011, 05:19 PM

Not most of the people but most of those who fly for the blue side primarily ;)

Lol, Well that would be the most obvious statement of the year then ;) what you mean the side that doesn't fly it?

:rolleyes:

Sven

10-10-2011, 05:22 PM

Not most of the people but most of those who fly for the blue side primarily ;)

Could either mean the 'those' who fly red are not honest or that the Spit II is indeed correct.

I don't really care at this point, we like to fly more historical minded missions and the Spit II doesn't show up in those all that much, if not at all.

JG52Krupi

10-10-2011, 05:23 PM

Simple its not over modelled the other aircraft are under modelled..

310_cibule

10-10-2011, 05:26 PM

(Blue) guys: Don't take it (yourself) so seriously ;)

Whiski

10-10-2011, 05:27 PM

http://forum.1cpublishing.eu/showthread.php?t=23994

&

http://forum.1cpublishing.eu/showthread.php?t=25956

Have a good read, the search function is your friend too.

Read my post again, fact is what I am looking for, various websites giving specs to compare in game performance to either prove or disprove its current modeled state. But thanks for your input.

Whiskey

Jaws2002

10-10-2011, 05:29 PM

It's mostly those that fly German ONLY and always outbalance the teams. :rolleyes:

MkII Spit is a bit later version and it's slightly better than the available German planes. So this guys that are used to easilly get away from the earlier versions of the spit, without any kind of effort, get their panties in a bunch when they have to actually work hard for a kill, or even for survival.:rolleyes:

"Grass is allways greener on the other side of the fence" type of atitude.

jojovtx

10-10-2011, 05:30 PM

Read my post again, fact is what I am looking for, various websites giving specs to compare in game performance to either prove or disprove its current modeled state. But thanks for your input.

Whiskey

Simple its not over modelled the other aircraft are under modelled..

There is your answer. Move on to new ground, this horse has suffered enough.

Whiski

10-10-2011, 05:43 PM

There is your answer. Move on to new ground, this horse has suffered enough.

May have been beaten to death but still not proven to be over modeled. Nor have the 109's been proven to be under modeled. Have they been tested using specs gained from a well known sources with results to back either claim?

Whiskey

310_cibule

10-10-2011, 05:46 PM

Blue guys, I am just teasing you ;) Of course the Spit IIA is overmodelled by all means (überflugzeug) 'cause we would had no chance else. And Bf-109 is undermodelled (thanks God, well done luthier).

But it is a challenge for you, isn't it? You can beat reds flying much worse planes any time (or shall we switch to gladiators)? ;)

310_cibule

10-10-2011, 05:48 PM

May have been beaten to death but still not proven to be over modeled. Nor have the 109's been proven to be under modeled. Have they been tested using specs gained from a well known sources with results to back either claim?
Whiskey

It was. By the Blues ;)

Hellbender

10-10-2011, 05:54 PM

Question that arises in that context for me: Did the historical Spit IIa had a better climbing rate than the 109 E-4 ? Can´t find any proper info on that in wiki. It just says that the IIa had a better climb rate than the Mk I but was it better in the end than the 109 concernign climbing rate ??

Redroach

10-10-2011, 06:03 PM

Quite simple: Many, too many people in these forums think of themselves as a unique snowflake and are completely convinced that they have something to contribute or to prove that the rest of the world seems to conspire on to keep it secret. Thus, non-existent issues will be taken up and defended, and promoted, even if contradicted repeatedly - (objective) truth is of no concern to those people.
Its something like an OCD, really.

see also
http://en.wikipedia.org/wiki/Dunning%E2%80%93Kruger_effect

310_cibule

10-10-2011, 06:10 PM

jf1981

10-10-2011, 06:38 PM

Not sure which engine the Mark IIa in the available servers are fitted with but there's no sign of 4 kft/min in the website, but in the game you can get to such vertical speed.
I was expecting about 3 kft/min, not sure which is the realistic one for this Mark.
It climbs very fast at 170 mph.

41Sqn_Stormcrow

10-10-2011, 06:48 PM

Yesterday on Atag server I had a hurri on my tail which pursued me over the whole channel flying low (so not a hurri with energy advantage). I could not loose it in my 109 even though I was at its ingame max speed of something between 450-460 kph (at least my extensive offline tests yielded this as the implemented max speed for the 109 whatever type). Sorry, but this is definitely not historic right now.

But to my knowledge they will anyhow overhaul the FM completely so we simply have to wait with what they come up with in the future and then see again.

I just want historic performance. Old IL2 was not that bad - at least it got the overall tendencies right.

Hellbender

10-10-2011, 07:02 PM

Ze-Jamz

10-10-2011, 07:08 PM

I think the Hurri and 109 situation makes the problem more noticeable in the FM's wether it be the 109 to slow or the rotol to fast

MD_Titus

10-10-2011, 08:58 PM

ReconNZ

10-10-2011, 10:21 PM

Yeah, I realized that too that the Hurricane Rotol ahs almost the same climbing rate, dive speed and max speed at sea level as the 109. Also I accelerates as fast as the 109 from my observations in the Rotol. However, the turning rate is only slightly better than the 109 meaning that the King of turning is still the spitfire.

Sorry lads this is not accurate at all. The 109's (E4 Especially) have a much better climb rate than the rotol in this game, and they are faster at sealevel.

All you Blue drivers didnt evolve the dive and run strategy that you are all so fond of because it didnt work. Oh and lets not forget your cannons.

I fly hurries all the time and the 109 is slightly faster at sea level - just enough so that while you might not loose us completely, you can quite easily draw away out of gun range. It also climbs much better - in a boom and zoom situation the 109 will be able to hold energy and EASILY out climb a hurri everytime.

That may well be historically accurate, so its fine, but it is a little rich when the 109 drivers who are so used to having the advantage and the ability to always run away, then moan like little girls when they come up against a correctly modelled SpitII - which is supposed to be a better aircraft than the 109.

Plus as you would expect a hurri with E can outpace a 109 of course for as long as the E advantage is relevant.

The one good thing though, the current advantage to Blue is forcing us red pilots to evolve better tactics and improve our skill levels. When the devs finally come out and clear up this debate once and for all by stating that the planes are correctly modelled, we will be well placed to make the most our our better aircraft.

CWMV

10-10-2011, 11:06 PM

Ya, Oleg also said that the FM's for the IL2 aircraft were correct-didn't make it true. It took the mod community to create FM's that were even close to achieving the tested performance of the modeled aircraft.

And I'm sure the same is true here. Sorry, but a 109E topping out at 440-450 kph at sea level is about 50kph to slow.
See here: performance at 1.3ata demonstrated to be 498kph at sea level and 572 at 4800 meters.
And this was done with an E-1 prototype which did not have the later style, more efficient air intake and thus the performance of production E series types would probably be higher.
http://kurfurst.org/Performance_tests/109E_V15a/Geschw_109V15a.html
Even better, here:
http://kurfurst.org/Performance_tests/109E_Baubeschreibung/109E3_Baubeschreibung.html
Quite a bit more than we get currently.
So complain all you want but the hard data backs that the 109E is substantially under modeled, as are just about all aircraft in game, with the obvious exception of the Spit IIa.

Valec

10-10-2011, 11:18 PM

See here: performance at 1.3ata demonstrated to be 498kph at sea level and 572 at 4800 meters.
498 kph :):):):)

Bf E3 0m=467 max speed 4440m=552

ReconNZ

10-10-2011, 11:21 PM

Valec

10-10-2011, 11:30 PM

ReconNZ N.1 :)

41Sqn_Stormcrow

10-10-2011, 11:38 PM

Woahhh hang on a minute CWMV.. Since when do hard facts and historical data have any place in this arguement?? That's no fair! :-P

Seems I might have to rethink my postion on the whole 109's are modelled correctly stance...

I still think 109's are way better than Hurries and all Blue drivers who run away are little girls. :cool:

So you're after little girls? :o

VO101_Tom

10-11-2011, 12:48 AM

So, I have read quite a few posts regarding this a/c.
One question. Why do most people think its over modeled/over powered?
...

Hi. What is relatively accurately be measured, is the speed at sea level. (mph) (RL datas from Spitperformance):

Hurri D-5-20. In the game 240 instead of 262. -8,4%
Hurri Rotol. In the game 260 instead of 265. -1,8%
Spit I. In the game 240 instead of 283. -15,9%
Spit Ia. In the game 240 instead of 283*. -15,9%
Spit IIa. In the game 300 instead of 290. +3,4%

Fiat G.50. In the game 223 instead of 248. -9,9%
Messer E-1. In the game 273 instead of 302**. -9,4%
Messer E-3, E-4. In the game 273 instead of 290***. -5,7%

* If I am wrong in this, then I apologize. I do not know well the Spit subtypes.
** (edit) The measurement of this ratio does not matter, but it's good to know: this is not the 109's top speed, is only 1.35 ata boost pressure, instead of 1.45 (this is called the "start und notleistung"). That would be 200 PS power (http://iaro.3dmax.hu/images/2011/11/29/chart01.jpg) (~ 20%), which increases the speed only 10 kph (~ 2%) in the game.
*** Performance tests in RL are possible margin of error of ±5%. Maybe this is why measure at slower than the E-1, despite the fact that the E-3 is more powerful engines were built. Or the E-1 graph is bad. Who knows?)

Jugdriver

10-11-2011, 01:00 AM

That is the most concise description of what is going on with the FM’s with regards to sea level speeds yet. Nice Tom.

JD
AKA_MattE

CWMV

10-11-2011, 01:16 AM

Al Schlageter

10-11-2011, 01:42 AM

And I'm sure the same is true here. Sorry, but a 109E topping out at 440-450 kph at sea level is about 50kph to slow.

L.Dv.556/3 for the E-1, -3

Max speed @

0km - 460kph
1km - 480kph
2km - 500kph
3km - 520kph
4km - 540kph
5km - 555kph
6km - 555kph
7km - 550kph

Now what were you saying about 50kph to slow?

Hellbender

10-11-2011, 02:33 AM

Wow, when I see these numbers and compare it to the ingame perfomance of all the planes, I ask myself why the developers haven´t implemented that kind of data to the planes of the game ?

CWMV

10-11-2011, 05:24 AM

L.Dv.556/3 for the E-1, -3

Max speed @

0km - 460kph
1km - 480kph
2km - 500kph
3km - 520kph
4km - 540kph
5km - 555kph
6km - 555kph
7km - 550kph

Now what were you saying about 50kph to slow?

That its 50kph too slow.
Ive already posted it, but here goes again...
http://www.kurfurst.org/Performance_tests/109E_Baubeschreibung/109E3_Baubeschreibung.html

Valec

10-11-2011, 05:37 AM

That its 50kph too slow.
Ive already posted it, but here goes again...
http://www.kurfurst.org/Performance_tests/109E_Baubeschreibung/109E3_Baubeschreibung.htmlLOOK

http://www.airpages.ru/eng/lw/bf109e1.shtml http://www.aviation-history.com/messerschmitt/bf109.html

IvanK

10-11-2011, 05:38 AM

CWM Yes but see if you can find another source for E models getting 500Kmh at sea level, that is imo an exceptional event. Just about every ref I have seen is in the 460Kmh or so sea level area.

Even here the Swiss tests show 460-470 at sea level:

http://kurfurst.org/Performance_tests/109E_SwissJ347/109E_J347.html

And the French tests only get 500Kmh (clapped out E I can here some saying :) at around 3000m, though the other numbers compare quiet well with the L.Dv.556/3 for the E-1, -3 stuff quoted in this thread.

http://img560.imageshack.us/img560/8659/61187376.jpg

http://img214.imageshack.us/img214/6868/92145029.jpg

This all becomes a circular tail chase depending on the references you choose and or trust. The majority are in the L.Dv.556/3 type performance area.

JG53Frankyboy

10-11-2011, 06:04 AM

perhaps we have to know if these speedtests were made with DB601A-1 or DB601Aa...and wich engines drives the CoD 109s :D

IvanK

10-11-2011, 06:22 AM

You cant have enough Graphs :)

http://img843.imageshack.us/img843/5341/109espeed.jpg

The chart below I have no idea on its origin/provenance but post for further info.
http://img195.imageshack.us/img195/9846/speedclimbmap109e.jpg

CWMV

10-11-2011, 06:26 AM

Indeed.
My only problem with the french numbers is that they had to run the low altitude tests with rads open due to cooling issues from not using the correct fluids. Especially when you look at the 5000M+ (Where the rads were closed) numbers that are well within 5% of the German numbers I posted.
Do I think that the rads being full open could take 40kph off the top end-you bet!

British tests with the same aircraft mirror those of the French, off the top of my head 16000ft was 355mph=571kph.

So weve got an aircraft that performs the same as German tests when you close the rads, and then is slower when you open them..seems logical to me lol.

And the Swiss tests were of an aircraft that had already gone through a third of its operational lifespan (if I recall 111 hours at test, retired at 350ish). In addition to this Kurfurst has summed up my thoughts on J-347 fairly well:

"Comparison of the speed results with Bf 109E prototype V15a's test report show remarkable similarity in the top speed achieved at altitude with the original VDM propeller 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 altitude). However 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 achieved with the Höhenlader in operation, and the appropriate Bodenlader (low-altitude supercharger speeds, or 'M.S. gear' in British terms) was not used to record the results, therefore full performance of the aircraft was not reached below ca. 3500 meter altitude."

Regardless, the numbers call for a +/- 5%, so really Id be happy with anything from 470-500.
Ideally, to me anyway, 490 would be taken as a base, and a random power fluctuation within 5% would be applied to every 109, but I'm not sure the sim is there yet...

And yes, we all have our favored sources, but at least in this thread they were posted, and we can argue about the numbers rather than what we think the aircraft should do.

I suppose that's better...lol.

JG53Frankyboy

10-11-2011, 06:30 AM

wondering about these supercharger comments having the DB601's automatic variable supercharger system in mind ?!

IvanK

10-11-2011, 06:35 AM

Some more data we must include the TSAGI stuff for balance :) ... though I think its a bit skewed to the slow side ... differrent time and place... got to make the local product look good perhaps :)

http://img5.imageshack.us/img5/7933/tsagivol2page038image00.jpg

And another that looks good with all sorts of detail but no idea on its provenance so caution on its use. Looks like some engineers calculations and extrapolations rather than actual test data ... just another of the countless snippets on my HD :)

http://img850.imageshack.us/img850/1253/61178879.jpg

David198502

10-11-2011, 06:49 AM

this thread is quite interesting and provides a lot of source for the arguments taken.
but i have a question,...did luthier ever post a statement about their FMs?...whether they think they should rework them, or if they are happy with the current state?
can we expect them to be finetuned?

IvanK

10-11-2011, 07:04 AM

You can expect them to be fine tuned ... that I know for a fact .

JG52Krupi

10-11-2011, 07:32 AM

Yes somewhere he states that they want to get the game basics working right (performance etc) before dealing with FM issues. Annoying yes, but it makes sense.

VO101_Tom

10-11-2011, 07:45 AM

Agreed, but I'm interested in where you get your data on the 109's? All the original docs Ive read indicate the E-1 was +/- 310 at sea level, and subsequent tests indicated that there was no appreciable difference between wing cannon armed aircraft and those without.
Links please? Always interested in new data.

If you ask me, all data is from the Spitperformance.com (http://www.spitfireperformance.com/spit1vrs109e.html):
Here is the E-1 Chart: http://www.wwiiaircraftperformance.org/me109/me109e-1774chart.jpg

IvanK

10-11-2011, 09:32 AM

BF109V15 in that chart I think being V15 means its a pre production prototype ?

VO101_Tom

10-11-2011, 09:55 AM

BF109V15 in that chart I think being V15 means its a pre production prototype ?

Yes
109 versions (http://www.klueser.eu/Me109.php)

(Edit. It was a test-aircraft in Rechlin)

JG53Frankyboy

10-11-2011, 10:03 AM

the V15a was the second pre production 'prototype' of the 109E series, yes.
And as you see in the chart. the DB601 engine lacked power - around 200PS were 'missing' (hence the graph 'Geschwindigktn. bei garantierter Motorleistung')
Daimler Benz pointed different reasons for it - different test were made to overcome the proplems. Unfortunatly 'Radinger & Schick' 109 Book does not know the results of these tests and the choosen solution to solve the proplem.

David198502

10-11-2011, 10:14 AM

You can expect them to be fine tuned ... that I know for a fact .

good to know....the FMs definitely need to be tuned.
i think that there is a major consensus that all of the planes are undermodeled except the spitII.at least the majority of the community seems to be of that opinion, including myself.

one interesting situation i had today on atag server....i flew one sortie which lasted over more than one hour with the E1.it was really immersive...i took of with max fuel and flew pretty careful, knowing that im pretty heavy with that load.at the time when i left France and headed to England, i spottet a Wellington.it was a single plane and the gunners didnt shoot at me when i began a shallow dive on it...so i assumed it to be flown by a human.at the right distance i gave a 2 to 3seconds burst on the right wing and the engine caught fire.it also took a few hits on the rudder and finally it spiraled down from 2k straight into the channel in front of the french shoreline

....then i continued my flight to england.over the airfield west of dover i saw a spit approaching slightly above my alt directly towards me(so its heading was exact the opposite of mine)...i decided not to climb immediately, with the result that my oponent didnt see me.i stayed a little longer in level flight until we passed each other. i watched the spit, and it stayed on its course, so i proceeded a really slow immelmann, to gain as much altitude as possible while changing direction....i climbed until a stall, which was recovered quickly.then the hunt began.
the first burst hit its wings and didnt really damage it.i was expecting to see a really hard turn so i zoomed away, but realised that my oponent didnt really want to survive and only pulled turns, which i was sure that i could follow.so i dived again, and this time stayed on his six.looking at his behaviour, i gained confidence to win the fight, so my hand remained calm while i shot really well-aimed bursts at his engine and cockpit, until he went down in flames....i almost smelled the other spit which gained vicinity on me...i knew i was down low and lost speed as well due to the turns i made, so i hit the Notleistung, closed the rads as much as possible without overheating and focused on my rpms only adjusting with the pp...the spit couldnt follow my slight climb at 400kph, but it managed to damage my left aileron.when i realised that i was out of immediate danger, i took a short look at the left and right, to see if i was loosing any liquid.i was happy that my crate seemed to be leakproof and the gauges showed its normal values...so i turned slightly to the right, to gain sight on my pursuer, staying in a shallow climb.when i considered myself to be in the better energie condition, i began a really steep climb and turned right, pulling my nose slowly towards the hunter....but at that point the tables were already turned, and the hunter was suddenly the prey.this spit turned hard so i boomed and zoomed and finally i had my revenge when he bailed out....
at this time i decided to fly home, considering that my aileron was damaged and that i shot the wingpositioned mgs empty at my second fight of the sortie.so i crossed the channel at 3k.when i was half way home, i saw a black silhouette heading from france to england, certainly 500meters above me.it was far away and i couldnt identify the UFO, so i zoomed in....it was a hurri.
first i thought it didnt spot me, so i banked right and began to climb, when i suddenly saw that it began to loop,followed by half a roll.it did spot me, and now it had the advantage.i immediately pushed the stick as hard as possible to dive,but that wasnt enough.he gained on me although i already had 700kph and feared to loose my wings(i heard that with this beta beta patch it is indeed possible to loose wings, but didnt encounter it myself yet), so i slowly pulled the stick and hit the Notleistung while listening to the scary noises my plane made at this state(love the new sounds!) when i leveled out, i could see that the hurri was at a greater distance again but still at higher alt, and after a few seconds it came closer and took a few hits at my rads...he really wanted me to go down.and everytime i tried to gain only a little altitude,he came closer.so it was a row of slight climbs and dives and really wide turns trying to escape his rounds.this pursuit lastet certainly 10 minutes, and i feared that my engine could stop every second until i finally managed to be at the same height and same speed.i then pulled the stick until i climbed vertically and focused on my rpms, to get the most out of it(seems to be a successful manouver against british fighters except the spitII) until the nose tilted towards the ground again.now i had the advantage again, but i had to make a decision...going home safely or hunt that bastard and letting him know that i wasnt easy meat.

i looked again at my rads, and they stopped leaking(do the tanks and other systems which carry liquid have the ability of self-sealing?) and also the gauges still showed an healthy engine, so i decided to earn another kill marking.meanwhile we both have drifted to the far west of the map near the english coast.when he realised that he lost his advantage, he headed back east to the airfield near Dover in a shallow dive.i was expecting to catch him, but that didnt happen.slowly but continuously he became harder to spot....he outdived me,... i have to confess slowly, but nevertheless he managed to do so.
he finally crashlanded on the airfield, because he approached too fast and lost his landing gear....normally i dont do that, but in this situation i decided to give him a short burst, just to let him know that he didnt win that fight.so i hit his fuselage with a few bullets and then finally went home to france.

after i landed safely, i thought that this sortie was certainly the best flightsim expirience i have ever had.really immersive, full of tension,fear and relief.
i lighted a cigarette and thanked my oponent for that really hard fight.unfortunately he didnt answer, propably because he doesnt have the chatbar opened.after the sortie it would have been really cool to be able to have a look at my plane from an outside view.

what im trying to say with this really long post, is that the FMs really need to be reworked.while i had no problem to outrun the spits, the hurri was as fast as me.in real level flight, without loosing any alt,and without WEP i can get the E1 and E3 to 460kph(since the latest beta beta patch i dont use the E4 anymore because of its bugged pp)
i dont claim to be an ace, but im confident with the handling of the bfs.i know how to get the most out of them, and manage to slowly outrun most of my comrades up in the air due to correct rpm,oil and water rads and pp settings.
it doesnt happen often, but this sortie was the second time, that a hurri gained on me while i tried to escape.
it is definitely possible that a good hurri pilot can get as fast as one in a bf.

VO101_Tom

10-11-2011, 10:42 AM

good to know....the FMs definitely need to be tuned.
i think that there is a major consensus that all of the planes are undermodeled except the spitII.at least the majority of the community seems to be of that opinion, including myself....

Nice details, but... broken off on the right wing. I flew home and landed (http://iaro.3dmax.hu/images/2011/10/08/shot_20111008_205848_986.jpg). :rolleyes:

David198502

10-11-2011, 10:48 AM

Nice details, but... broken off on the right wing. I flew home and landed (http://iaro.3dmax.hu/images/2011/10/08/shot_20111008_205848_986.jpg). :rolleyes:

i dont know on what you are exactly refering to, but if its a gramar mistake, i have to apologize.
english isnt my mothertongue and i expect mistakes in this long post of mine.

Whiski

10-11-2011, 11:56 AM

Indeed some really good info here. If I am correct in my interpretation, it would seem the Spit IIa conforms within the +/- 5% with regard to speed at alt. The 109 seems to be out of range regarding speed and falls short of its proper maximum limits at various altitudes.

Would that be a correct analogy? If so, I agree that having a correctly modeled a/c flying against ones that are currently not modeled correctly, inappropriate and unnecessary. Unnecessary because there are great virtual pilots among us who can fight extremely well with what planes they have available, be it at a disadvantage or not, and still come out with victory, or in a defeat, a hard fought battle that both victor and vanquished can say "good fight mate, white knuckle all the way".

I am looking forward to having the a/c fine tuned for performance. In the mean time, flying the 109, Spit variants and the Hurricane with a great bunch of people, I am still having fun and learning quite a bit about each a/c's pro's and con's.

Keep the info coming gents, I love reading and learning about these era fighters and the men who flew them.

Cheers

Whiskey

Al Schlageter

10-11-2011, 12:13 PM

That its 50kph too slow.
Ive already posted it, but here goes again...
http://www.kurfurst.org/Performance_tests/109E_Baubeschreibung/109E3_Baubeschreibung.html

Auszüge aus Flugzeugdatenblatt Bf 109 E-1, E-3 nach L.Dv.556/3
http://www.rolfwolf.de/daten/E4/Emil.html

Official documentation for production 109Es is trash. Right, got you.

1.) V0 = 467 km/h
2.) V0 = 467 km/h Werte graphisch
3.) V0 = 467 km/h auf 0 m bezogen!
4.) V0 = 466 km/h

http://www.kurfurst.org/Performance_tests/109E_MP_E3_1792/WNr1792_E3_MP16feb39.html

Strange that you would ignore other data on Barbi's site.

Ze-Jamz

10-11-2011, 12:16 PM

David198502

10-11-2011, 12:36 PM

fruitbat

10-11-2011, 12:41 PM

i just made another test with the E1.
i really focused that i stay in real level flight without loosing or gaining alt.
first test was at 3k:i stayed for ten minutes at 3k as close as i could get, only variying about +/-5meters in height.
the E1 reached its max speed at 440-445kph without WEP.

second test at 500m:again for ten minutes as close as possible in level flight.
max speed at 450-455kph

so that the E1 is faster at low alt which shouldnt be the case.

IAS to TAS.

top speeds are measured in TAS, are you going by the instruments in the cockpit, if so, you've got IAS

at SL IAS and TAS are roughly equal depending in atmospheric pressure, at 3K TAS will be higher than IAS.

PS, i love how all the Blues are going on about how the 109 is nerfed, don't see much mention of the spit1 and 1a from the same folks, despite them being even more nerfed, lol. Give the spit1a is proper prop, its a bob sim not battle of france.

See june 25 entry.

http://i7.photobucket.com/albums/y290/thefruitbat1/92propconversion.gif

Whiski

10-11-2011, 12:43 PM

Here we go again...done and done and done to death

Please OP use the search function m8 your find all the info you need because as you can see this thread will now turn into a flame war on whos right and whos wrong

I am the original poster, and if you had read this thread carefully, you would have noticed I asked for factual, documented information regarding this issue for comparison, the search function did not provide such information (as stated before as well) just opinions and virtual simulation experiences. Now, this thread contains some great documentation to back up performance issues for all a/c within the game (from various sources).

I did not ask for a flame war, fact only backed up with information. A flame war would be beyond my control and request.

Whiskey

robtek

10-11-2011, 12:48 PM

David198502

10-11-2011, 12:49 PM

IAS to TAS.

top speeds are measured in TAS, are you going by the instruments in the cockpit, if so, you've got IAS

at SL IAS and TAS are roughly equal depending in atmospheric pressure, at 3K TAS will be higher than IAS.

PS, i love how all the Blues are going on about how the 109 is nerfed, don't see much mention of the spit1 and 1a from the same folks, despite them being even more nerfed, lol.

yes i measure by the instruments, cause i dont know another way in this game.
well i only fly "blue" planes in this game, so i dont really know how to fly a spit or the hurri correctly, therefore the outcome wouldnt reflect the reality of the game.but why dont you do it by yourself and let us know the result.

btw i never stated that the other planes are modeled correctly.if you read my post on the last page, you would know that im of the opinion that all planes except the spitII are undermodeled.

fruitbat

10-11-2011, 12:52 PM

yes i measure by the instruments, cause i dont know another way in this game.

btw i never stated that the other planes are modeled correctly.if you read my post on the last page, you would know that im of the opinion that all planes except the spitII are undermodeled.

i wasn't talking about you mate.

Don't know if its the same as in il2, cause i've never flown with cockpit off in Clod, but in the old il2 flying wonderwomen use to give you a TAS readout.

for the record i fly both sides evenly, cause i don't see the point in depriving myself half the game. never understood that mentality, but thats me.

David198502

10-11-2011, 12:54 PM

dont know either because of the same reason.
Edit:
well i tried both sides in 1946, and began flying with spits.
i played with the spitIX 25lbs and became successful pretty fast...until someone said that this plane is a "noobplane" which is extremely overmodeled and a kill therefore is nothing to be proud of.
so i decided to try the "dark" side.i realised really fast that it was almost impossible to fight that plane in a g2, but although i got killed many many times, when i actually killed someone in this spit, the kill was really rewarding...so i stayed in the g2 whenever it was available and tried to learn the ropes of it.
i began to love this plane and the way you have to fight with it.

as cliffs of dover was released i expected accurate flightmodels and therefore really hard fights with those different planes of both sides, but supposedly pretty equally dangerous.so i decided to stay on the dark side and learn all the tactics which lead to success against the beautiful british planes.
unfortunately all the planes are undermodeled...except the spitII
and they arent undermodeled equally....the spitI is slower than the hurri which is really strange.

fruitbat

10-11-2011, 01:34 PM

pah, i love the 109 up to and including the f4 (my fav ride in il2), then its Fw190 all the way for the dark side, lol!

although that siad, i do have a soft spot for the G10.

anyway re Clod, I agree that all of the fighters to some degree are undermodelled except the SpitII, and would like to see this rectified.

at the moment its the Spit MkI thats the most undermodelled imo, save for Dunkirk the 2 stage pitch is just plain wrong, and then there's the boost/fuel.....

Anyway, i guess we should all wait to see what 1c do, as has been pointed out that they are aware of the situation.

I want them to all be modelled correctly (both sides), and it should then be a really close match for either side where the pilot will determine the result, not pure plane advantage.

Trouble is, some will never be quite satisfied, because there are reports for both sides that are slightly out of the ordinary that people will cherry pick to push there own agenda.

Ze-Jamz

10-11-2011, 01:40 PM

MD_Titus

10-11-2011, 01:52 PM

Ze-Jamz

10-11-2011, 01:58 PM

Spoilsport

:popcorn:

http://dl.dropbox.com/u/17713394/chomp.gif

VO101_Tom

10-11-2011, 04:54 PM

i dont know on what you are exactly refering to, but if its a gramar mistake, i have to apologize.
english isnt my mothertongue and i expect mistakes in this long post of mine.

Oh, nothing wrong with what you wrote, i agree with it. The FMs really need to be reworked. I just wrote, because the cooling water is interesting, but until a broken wing is not a fatal damage, what can we expect at all the other damage :rolleyes:? Maybe not a big deal, but I was stunned :(

MD_Titus

10-11-2011, 05:00 PM

looking a few pages back at the figures posted for in game speeds and percentage they are off from r/l, is this something that is reproduced by a wide number of competent pilots, as in what's the sample size? anyone got figures/speeds outside those ranges posted?

Redroach

10-11-2011, 09:05 PM

no, it's surely not, considering I made just a quick test a few months ago in a Spit Ia and it behaved exactly as advertised in a real performance graph. That was at a time where those people here had a major rant about why they couldn't reproduce the plane's max speed (as in absolute max) at sea level resp. "at about 1000 feet". Well, they've got that figured out as of now but I wouldn't exactly think of them as test pilots...

Ataros

10-11-2011, 09:29 PM

109s must be banned on all the servers as they outturn even Hurri. Proved now.
(the gunsight is a track recording bug and I am not the driver)

What is the historical 109 turnrate?

http://www.youtube.com/watch?v=9G5BepZ_J-4&feature=player_embedded

/trolling mode off :)

Yes, track recording works online now.

Ataros

10-11-2011, 09:32 PM

IvanK

10-11-2011, 10:42 PM

VO101_Tom

10-11-2011, 10:54 PM

109s must be banned on all the servers as they outturn even Hurri. Proved now.
(the gunsight is a track recording bug and I am not the driver)
What is the historical 109 turnrate?
/trolling mode off :)
Yes, track recording works online now.

Hi. Who was the pilot of a Hurricane? He said what? Which systems is damaged, when he got the first hit? After that the speed at which he could turn to? He was able to keep the corner speed? Does it make sense to compare after that?

When we practicing on own server, the Hurricane does not seem a bad aircraft. It would be nice, if these "proofs" repeated under controlled conditions, for example on a 1v1 map...? It is possible...? :rolleyes:

41Sqn_Stormcrow

10-11-2011, 11:07 PM

That is an interesting chart, IvanK, but a bit difficult to read as the time scale is logarithmic.

The tendency is that in terms of turn rates full circle both planes were quite close with perhaps a very small advantage for the spit (perhaps 2s as absolut max generously estimated optically. Would have to print it out and measure it to be more precise) at medium velocities. The spit will rule at slow speeds. For high velocities theres a minor advantage for the 109 in terms of turn rate.

CWMV

10-12-2011, 12:40 AM

Auszüge aus Flugzeugdatenblatt Bf 109 E-1, E-3 nach L.Dv.556/3
http://www.rolfwolf.de/daten/E4/Emil.html

Official documentation for production 109Es is trash. Right, got you.

1.) V0 = 467 km/h
2.) V0 = 467 km/h Werte graphisch
3.) V0 = 467 km/h auf 0 m bezogen!
4.) V0 = 466 km/h

http://www.kurfurst.org/Performance_tests/109E_MP_E3_1792/WNr1792_E3_MP16feb39.html

Strange that you would ignore other data on Barbi's site.

Far from ignored, just not relevant. That info does nothing more than prove that the difference between cannon and mg wing guns is negligible, and that the max speed at 1.3 ata is around 470kph.
So what is it at 1.35, or even better the MAX speed using the 1.42 emergency setting...Ill bet its closer to 490, unless you believe that the max speed wouldn't change with more power.
We are talking about MAX speed, right?

But I find your attitude even stranger.
See, this is the part of this site that I thought we were going to avoid in this thread. You act like you've got a dog in this fight, when were doing nothing more than comparing notes.
IvanK got on here and posted the same info, and more of it, but wasn't a snide little troll when he did it. In that way he came off as a professional and someone worth listening to.
You, not so much. I'm sorry to see that civil discussion is something you have not mastered.

And hypocritical to boot, you would chide me for ignoring information that you (erroneously) believe supports your point, while dismissing what I bring to the fore.

Now, perhaps we can continue this discussion in less derisive manner?

Id also like to add that I am amazed that with this exception the discussion here has been as informative and civil as it has been, lets hope it catches on around here! :grin:

CWMV

10-12-2011, 12:45 AM

i wasn't talking about you mate.

Don't know if its the same as in il2, cause i've never flown with cockpit off in Clod, but in the old il2 flying wonderwomen use to give you a TAS readout.

for the record i fly both sides evenly, cause i don't see the point in depriving myself half the game. never understood that mentality, but thats me.

Truely Id like to see them all modeled correctly. No point in a sim if they aren't!

Have you got a good IAS to TAS converter link? On the phone now, cant search...

Kudos to you on flying both sides, I'm simply not interested in any British aircraft prior to the tempest.

David198502

10-12-2011, 07:28 AM

Oh, nothing wrong with what you wrote, i agree with it. The FMs really need to be reworked. I just wrote, because the cooling water is interesting, but until a broken wing is not a fatal damage, what can we expect at all the other damage :rolleyes:? Maybe not a big deal, but I was stunned :(

well when my left aileron was hit, it lost maybe about a third of its surface(only of the aileron), and i immediately could feel the decreased rollrate,so that is modeled correctly i think....regarding the damaged rads....im not really sure what was hit,...but i lost liquid for a short period.it didnt last long until my plane seemed to be leakproof again.

David198502

10-12-2011, 07:46 AM

regarding the turn rate of the bf...i know that is no evidence and im not an expert on these matters, but i recently watched an interesting docu on history channel where a former german fighter pilot states that the early bfs were really agile planes which could follow a turn of the spits in certain conditions for a certain time.he also stated that the spits were overall better turners, but that expierenced pilots knew how and when they were able to follow a turn and shoot the enemy.i found it interesting that he also said that he was dissapointed by the late g models cause they became too heavy to be used as turn fighters.

VO101_Tom

10-12-2011, 10:19 AM

So what is it at 1.35, or even better the MAX speed using the 1.42 emergency setting...Ill bet its closer to 490, unless you believe that the max speed wouldn't change with more power.
We are talking about MAX speed, right?

Exactly. The notleistung 20% extra power would not cause any acceleration (only up to 10 km/h)? Nonsense.

http://www.enginehistory.org/German/DB/Chart01.jpg
source: www.enginehistory.com (http://www.enginehistory.org/German/daimler-benz.shtml)

TomcatViP

10-12-2011, 12:56 PM

"What is the historical 109 turnrate?" .... same problem as always it depends whose data you believe !. It also depends on how the turn is being flown in each aircraft. You after Sustained or instantaneous ?

These charts are reasonable for sustained turn performance:

http://www.spitfireperformance.com/spit109turn.gif

Spit V 109 Turn times.

Those curves are contestable regarding how the both planes shld hve performed:
- first: on the ground of the knowledge of both nation at the time of the test/calculation (1940)
- Secondly : on the base of the contradictions that a modern analysis would tell us

First pt : If British engineer in 1940 had let an elliptical winged (EW) fighter be the most advanced defense they had allowed to be put on the frontline, for sure they were not aware of the advance Germans had made in that grounds. Remind that EW are the panacea only when dealing with inviscid flows etc... etc... Look at max Cl of both plane, max Pow and wing loading.

I know that I can be annoying but those value and the fact that the wing thickness of the spit is lower tell us that there SHLD be an inversion in turn radius as the speed decrease. in other terms the spit shld turn tighter at high speed but hve a greater radius of turn when the speed is low.

In other words they couldn't hve found any other value as their assumptions were made on false grounds.

Skoshi Tiger

10-12-2011, 02:43 PM

in other terms the spit shld turn tighter at high speed but hve a greater radius of turn when the speed is low.

What do you mean by the term 'tighter'? Degrees per second or radius?

Sounds counter intuitive to me.

TomcatViP

10-12-2011, 03:42 PM

It's a rather long reply needed here indeed.

I think I did alrdy give an answer.

To make it short here :
1st we are talking of turn radius as we are dealing with cte speed turn
2nd it's almost certain that at much of the speed range the SPit had an instant turn speed greater than the 109 as here Wing area rules (at comparable wingspan, nose authority etc.. etc... )
3rd at cte speed, the drag generated by the wing in a turn attitude (AoA) and power to weight ratio are the keys. Simple calculation give you a result dependent only of Wing surface and Power to weight ratio as they are based on simpler theory that does not apply to high speed fighter and high G ( high AoA) turns.

In their calculation they are in effect minoring the drag of the Spit wing.

41Sqn_Stormcrow

10-12-2011, 05:55 PM

TomcatViP

10-12-2011, 06:42 PM

How to read the chart :

Choose a speed for a plane -> then select your G level / bank angle - > read the time to 360° *-> then compare to the other plane

*You can also read the nearest dotted line that give you the nearest computed radius but as the speed V=d/t if you hve V (cte) and t then d is alrdy in your hands

Alternatively you can follow a firm line that stand for a level turn (cte height) -> you can then see how much G/ bank angle is needed at a given speed for a given plane and what wld be the radius of turn.

IvanK

10-12-2011, 08:44 PM

Those curves are contestable regarding how the both planes shld hve performed:
- first: on the ground of the knowledge of both nation at the time of the test/calculation (1940)
- Secondly : on the base of the contradictions that a modern analysis would tell us

First pt : If British engineer in 1940 had let an elliptical winged (EW) fighter be the most advanced defense they had allowed to be put on the frontline, for sure they were not aware of the advance Germans had made in that grounds. Remind that EW are the panacea only when dealing with inviscid flows etc... etc... Look at max Cl of both plane, max Pow and wing loading.

I know that I can be annoying but those value and the fact that the wing thickness of the spit is lower tell us that there SHLD be an inversion in turn radius as the speed decrease. in other terms the spit shld turn tighter at high speed but hve a greater radius of turn when the speed is low.

In other words they couldn't hve found any other value as their assumptions were made on false grounds.

The chart is one of the earliest plan Fan plots (or "Dog house plot" in US terms) that I have seen. As such its straight Energy Manoeuvrability theory that is Excess Power (ps) applied to the turning problem. As such it takes into account the total Airframe engine combination so Wing loading,planform,wing section etc is part and parcel of plot. The actual RAE derivation of these charts is discussed in great detail in AVIA 6/2366 RAE report "Notes on the dogfight" A more detailed version of the Spit fan plot chart from this report is shown below. In this case the study also takes into account various extrapolated wing areas and therefore wing loading etc.

http://img4.imageshack.us/img4/2973/turnsmall.jpg

I dont agree that their assumptions were made on false grounds. Everything I have read in these reports indicates to me that the boffins doing this work were really on top of their game. Here is some of the data they were using in this report obtained from a physical specimen BF109E3:

http://img404.imageshack.us/img404/7426/nf109aerdydata.jpg

http://img703.imageshack.us/img703/2551/spit109aileron.jpg

The USN also produced a comprehensive study on turn performance on the F2B (Buffalo) that is equally involved and again is based on straight out EM theory applied to the turn problem and again chock full of fan plots.

Here is another chart from the same source source document as the original Fan plot came from (AVIA 5/2394 "Messerschmitt Me.109 Handling and Manoeuvrability Tests" which is a pretty exhaustive 63 page document. This chart provides similar data to the fan plot but perhaps in a more easily digestible format as both Spitfire and 109 plots are overlayed on the same chart.

http://img444.imageshack.us/img444/4445/turn2y.jpg

fruitbat

10-12-2011, 09:49 PM

Thanks for posting IvanK, really interesting stuff.:grin:

41Sqn_Stormcrow

10-12-2011, 09:53 PM

Resumee:

The Spit has a turn radius of 700 ft (about 215m) and the 109 slightly below 900 ft (275 m). The turn rate is at medium and high speed similar (slight advantage for spit at medium speed, tendency vice-versa for high speed). Good advantage for spit at low speed. Altitude loss higher for 109 during full circle (nearly 0 for spit at medium speed, 5° for 109 at medium speed)

Does not feel that way in game ...

GF_Mastiff

10-13-2011, 12:50 AM

CWMV

10-13-2011, 01:51 AM

no it doesnt I fly the spitIa and the 109s keep in a turn at medium speed the spit can not out turn them. or instant climb like the 109s E4s.

In truth you need to realize that you piloting ability, or lack there of, are more likely the reason why you cant conquer the 109's.

You in game experience simply does not hold up to numbers, so if you have some charts post them, please! Otherwise your "The 109's are sooo much better than me" just show your a bad pilot.

SEE

10-13-2011, 02:23 AM

CWMV

10-13-2011, 02:35 AM

How do you know he is a bad pilot? How would you react if you were told that you were a bad pilot because you cannot deal with a Spit Mk2? Pretty sure you would jump on the FM differences and state your case based on evidence but be a tad annoyed that someone simply tells you to fly better.

The current Spit Mk1a is not right in its specification or its FM. If people are discussing these issues then it is more constructive to debate them rather than impy posters are incompetent. It makes posters feel that their opinion is worthless on a baseless assumption.

The Clod Spit Mk1a is very capable at altitude and handles beautifully but the Bfs have had a lot of goodies in previous patches. Spit Mk1 jockeys are still stuck with a 'Boost Cut Out' that does nothing, a top speed of 245mph, a two speed prop and debatable Neg G modelling.

Id respond by posting a graph showing the under-modeled nature of the 109E-4.
Wait a minute...:grin:

And I agree that EVERYTHING in the game needs to have its FM reworked, including the current inaccurate Spits.

I don't know him or his abilities, whats more is that without something to back his opinion its pointless.
I mean how many times have we seen this in the past with IL2?
"Aircraft A is over-modeled because when I'm flying aircraft B it shoots me down every time!"
....:confused:

Really though, what worth is an opinion if you don't have any data to base it off of?

Trying to base the truth of an FM off of "Well it cant be right because I cant shoot them down in game" is ludicrous.
Saying that an aircraft is under-modeled in regard to a certain aspect (say 109E's top speed?) and then posting technical information showing the difference from the accepted in game performance of that aircraft is another thing entirely.

Now I did ask him to post his evidence, or something at all that backs his claim because were after the truth here, right?

And I have to admit I took a short temper with him because of his other "The 109 is SOOOOOOOOOOOOOOOOOOOOOOOOOOO uber!" threads. its just annoying.
Sorry for any offense, none intended.

SEE

10-13-2011, 02:44 AM

It's Ok bud, I get a bit defensive regards the Spit v BF arguments, so apolgies if I over reacted to your post. I am sure you meant well.....

CWMV

10-13-2011, 02:47 AM

I do the same, trust me.
I think both of our favorite aircraft need new FM's!

David198502

10-13-2011, 05:52 AM

...yes as realistic as possible please,...and please do not tweak them in unrealisic manners just to ensure online balance!!
make them as they were, with all their advantages and drawbacks, its supposed to be a SIM!

TomcatViP

10-13-2011, 08:15 AM

Guys are you even reading the charts IvanK hve just posted ? Those are great stuff and real dynamite.

Before complaining abt the lack of boost on the spit pls do start to question yourself about how the Spit is turning (indefinitely level) in game and hold E.

Regarding the neg G cut-out, I think it has been extensively debated to the point that it s rather insulting to read that it has not been modeled in a real (and honest ) manner.

Damn, we even hve a video of a latter model itching the camera while flying upside down: : pump up the volume and L.I.S.T.E.N by yourself !

SEE

10-13-2011, 01:11 PM

Tomcat, I stated the Neg G is 'debatable' which means it may be correct or it may be incorrect - hence the discussion. The other aspects of FM I pointed out with the Mk1 are incorrect for that model/timeperiod and, on many servers,
the only Spit in the Plane set.

You seem to have an issue with the Spit, that's OK, some posters have issues with the BFs but that's not OK?

Read my post....(the Spit Mk1 is very capable at altitude and handles beautifully) I do not feel at a disadvantage against any of the BF's even with its current modelling but that does not mean it is correct either. The Boost data for the Spit Mk1 has been extracted from the FM file....it adds 0.002 Ibs/sq ...are you seriousley telling me that is correct or a signicant figure?

+1 to David198502 last post.

bugmenot

10-13-2011, 02:06 PM

The chart is one of the earliest plan Fan plots (or "Dog house plot" in US terms) that I have seen. As such its straight Energy Manoeuvrability theory that is Excess Power (ps) applied to the turning problem. As such it takes into account the total Airframe engine combination so Wing loading,planform,wing section etc is part and parcel of plot. The actual RAE derivation of these charts is discussed in great detail in AVIA 6/2366 RAE report "Notes on the dogfight" A more detailed version of the Spit fan plot chart from this report is shown below. In this case the study also takes into account various extrapolated wing areas and therefore wing loading etc.

http://img4.imageshack.us/img4/2973/turnsmall.jpg

I dont agree that their assumptions were made on false grounds. Everything I have read in these reports indicates to me that the boffins doing this work were really on top of their game. Here is some of the data they were using in this report obtained from a physical specimen BF109E3:

http://img404.imageshack.us/img404/7426/nf109aerdydata.jpg

http://img703.imageshack.us/img703/2551/spit109aileron.jpg

The USN also produced a comprehensive study on turn performance on the F2B (Buffalo) that is equally involved and again is based on straight out EM theory applied to the turn problem and again chock full of fan plots.

Here is another chart from the same source source document as the original Fan plot came from (AVIA 5/2394 "Messerschmitt Me.109 Handling and Manoeuvrability Tests" which is a pretty exhaustive 63 page document. This chart provides similar data to the fan plot but perhaps in a more easily digestible format as both Spitfire and 109 plots are overlayed on the same chart.

http://img444.imageshack.us/img444/4445/turn2y.jpg

The problem with Me performance numbers

Case: Bf.109E

"Another problem is with the test itself, when compared to a Spitfire. Overall the accuracy of the test suffers from the fact that it was flown with a crash landed plane wirh a worn, several years old engine producing less power than usual. It was then flown against a brand new Spitfire with a 1940 engine. As shown by the test data, the turns were made in the 120mph range which is too slow for the 109 slats to be deployed, which doesn't compare the maximum turning abilities of each aircraft."

http://www.virtualpilots.fi/feature/articles/109myths/#testflights

TomcatViP

10-13-2011, 02:56 PM

You seem to have an issue with the Spit, that's OK, some posters have issues with the BFs but that's not OK?

I HVE NO ISSUE WITH THE SPIT. Pls bear that in mind. I want that sim to be real and not an ego contest with Ninja planes. Think about you hvn't eared me criticizing the hurri.

I am not trying to impose my view. I think that talking abt the subject is interesting and in no way do I feel perso implicated in "one side or another".

I wld be pleased to fly the Spit as soon its FM won't look likes anymore that of a flying carpet.

The Boost data for the Spit Mk1 has been extracted from the FM file....it adds 0.002 Ibs/sq ...are you seriousley telling me that is correct or a signicant figure?

I am only stating that as the drag is contestable (the E retention) pointing the way it turn in the sim, the Boost can't be accurate or this plane will zoom or accelerate like an F16.

In other words : let them fix the FM and then I guess that the boost restraint will be lifted.

If you fly the hurri you'd see that the boost is already a joke (infinite time, extra cooling...). But as the hurri drag and E seems to be correctly modeled, it does not give it surrealistic perfs (just optimistic ones).

I guess you can't do that on the spit as it is for now

Last but not least, it has been shown that the 12lb boost can't be what it is seen by some here (we shld speak here more abt a "WunderBoost")

SEE

10-13-2011, 03:10 PM

Points taken Tomcat...no arguments with your last post.

It does seem odd that the devs state in the patch notes ' for Spits, 'boost cut out' can now be enabled/disabled' - what they don't say is that it does sweet FA!.....:grin:

IvanK

10-13-2011, 10:08 PM

""Another problem is with the test itself, when compared to a Spitfire. Overall the accuracy of the test suffers from the fact that it was flown with a crash landed plane wirh a worn, several years old engine producing less power than usual. It was then flown against a brand new Spitfire with a 1940 engine. As shown by the test data, the turns were made in the 120mph range which is too slow for the 109 slats to be deployed, which doesn't compare the maximum turning abilities of each aircraft."

Of course the old clapped out engine theory will be presented. The data is the best available and is presented as is. I am not sure about the clapped out bit either. that is a readers assumption, and is not reflected in the report which is very thorough.

as to the slat comment ... The original author shows a fundamental lack of basic aerodynamic knowledge. Slat deployment is a function of AOA. The Slats deploy at a specific AOA every time not at an IAS. The AOA remains the same and IAS at which the slats deploy will vary as a function of G .... BUT ALWAYS AT THE SAME AOA. But the corker is the bit " the turns were made in the 120mph range which is too slow for the 109 slats to be deployed" ... you are not serious surely ! Think about it Slats are High AOA slow speed regime devices they are more likely to deploy at the slower speed (i.e. higher AOA).

For the record here are the 1G slat deployment speeds as found by the RAE in AVIA 6/2394 Messerschmitt Me.109 Handling and Manoeuvrability Tests. Its worth noting a 9Mph diff between the ASI reading and the trailing static source.

http://img265.imageshack.us/img265/7641/slats.jpg

Kurfürst

10-13-2011, 10:29 PM

Hmm, Werknummer 1034s engine problems (seems lubrication related) are documented in both French trial reports and RR reports. Its noteworthy that already in French trials the plane was loosing boost at altitude for some reason - I suspect French lubricants did not go well with the DB engines hydraulic supercharger clutch. But that's besides the point, because the British did not measure turn times for the 109E in flight tests, nor they did measure times for the Spitfire either.

The doghouse charts you presented are inidrectly based on stall speed measurements of the Spitfire. Now, those long enough to remember Ubi there were a number of threads discussing the difficulties of defining and measuring stall speeds, so there is a degree of potential inaccuracy with this base data already. From the established stall speeds of the Spitifre, they estimated its lift coefficient; they used this estimate to guesstimate the 109's lift coefficient. These guesstimates were used to calculate the doghouse charts you presented, using known power curves.

In short, they are calculated estimates with a bit shaky base data.

As to Bf 109E turn times, these are known from German/Mtt calculations, and are given as 18.92 secs for a sustained turn at 0m altitude using 990 PS or 1.3ata output of the DB 601A. (note British guesstimate is for 12k feet so the figures are not directly comparable).

As to Bf 109E(-1, -3, -4) performane in the sim, I note that in the early versions of COD the 109E just can't go past around 460 using 1.35ata, whereas the actual specifications for the type gives top speed as 500 kph at SL and 570 kph at critical altitude, with plus/minus 5% tolerance on production aircraft (so actual production aircraft fell between ca. 545 - 595 kph). Can it now reach its specs in the new beta patch?

The aileron up/down travel angle for the 109E is very interesting though - it seems the F-K increased the travel angle a lot (and changed to Frise type ailerons), though I wonder why. Better control response times, even though the E was already noted as brisk for aileron control response?

Anyway for a reality check with a new patch I always use to try if I can break the Spitty in two by madly pulling back the stick, something that would be suicidal in the real one with a stick force of a mere 4 lbs / G. It isn't possible in the sim. In fact, I did nto manage to break any aircraft in the sim, no wonder what stupid maneuvers I tried.

41Sqn_Stormcrow

10-13-2011, 10:37 PM

The increased aileron travel for the F to K series might be at least partially to counter the increased roll inertia and roll drag with the curved wingtips (hence longer wingspan).

But interesting post, Kurfurst.

I dunno about the doghouse chart and how they produced it but don't you think that they at least verified their method by test flying the Spit?

Has anyone made a test about turn times as implemented in game?

Crumpp

10-15-2011, 02:39 AM

I can break the Spitty in two by madly pulling back the stick, something that would be suicidal in the real one with a stick force of a mere 4 lbs / G.

If the unacceptable stability and control characteristics of the Spitfire are not modeled, then you will never have a simulation of the relative dog-fighting capabilities of these airplanes.

Aerodynamically the Spitfire could easily out-turn a Bf-109E series. A pilot dealing with the real world stability and control issues would leave the contest much closer than the aerodynamic analysis on paper.

The stability and control characteristics of the BF-109 were acceptable and actually conformed to a set standard based on Robert R. Gilruth's findings on flying qualities. Germany was ahead of most of the world in adopting such as standard. Japan was also on an acceptable control standard. None of this was known to the Allies until after the war.

It is interesting to note that the NACA adopted a unified stability and control in 1942 but it was not until 1945 that the USAAF (R-1815-A)and USN (SR 119A) printed their own standards using the NACA findings. The first fighter the NACA tested was a Spitfire Mk V. The aircraft failed miserably and was replaced in USAAF service as soon as possible.

IvanK

10-15-2011, 04:24 AM

If the unacceptable stability and control characteristics of the Spitfire are not modeled, then you will never have a simulation of the relative dog-fighting capabilities of these airplanes.

Unacceptable to Who ? A NACA methodology formalised 4 or so years after the aircraft first flew. Didnt a number of US units actually switch from from MKV's to MK VIII's.

As to NACA's evaulation of the MKV the RAE in Technical note No.Aero 1106 made a bit of a rebuttal on the NACA findings. This includes some criticisms in the way NACA carried out its tests. I guess both reports should be read to draw a balanced view. The RAE document refers to NACA reports ARC 6423 and ARC 6422.

Here is the Summary or conclusions of the Langley evaluation of the Spitfire MKVA "Measurements of the Flying Qualties of A Supermarine Spitfire VA Airplane" ... not all exactly bad :)
http://img825.imageshack.us/img825/6267/langlyva.jpg

Here are the conclusions from the second Langley report "Stalling charcteristics of the Supermarine Spitfire VA Airplane again not all bad:

http://img513.imageshack.us/img513/158/langelyva2.jpg

Crumpp

10-15-2011, 04:47 AM

Unacceptable to Who ?

Any stability and control engineer in existence. Remember there was no such person when the Spitfire was designed.

There is a reason why the RAE added bob-weights to correct the stick force gradient. This fixed the control force issue but did not correct the instability itself.

As to NACA's evaulation of the MKV the RAE in Technical note No.Aero 1106 made a bit of a rebuttal on the NACA findings. This includes some criticisms in the way NACA carried out its tests. I guess both reports should be read to draw a balanced view. The RAE document refers to NACA reports ARC 6423 and ARC 6422.

I am aware of the RAE rebuttal. Keep in mind the British were one of the last to adopt any kind of standard on stability and control.

Of course they thought it was fine, there was no established basis for what was acceptable and what was not. A few fatalities later though, the RAE did something about the Spitfire's longitudinal instability. Again, it made it easier to control but did not eliminate the cause of the instability.

Crumpp

10-15-2011, 12:50 PM

http://img12.imageshack.us/img12/5619/spitfirestability.jpg (http://imageshack.us/photo/my-images/12/spitfirestability.jpg/)

It is right there.

You know what stick fixed stability is right?

41Sqn_Stormcrow

10-15-2011, 03:35 PM

Aerodynamically the Spitfire could easily out-turn a Bf-109E series. A pilot dealing with the real world stability and control issues would leave the contest much closer than the aerodynamic analysis on paper.

I agree that the fighter pilots would have driven their kites closer to the limits than tought at flight school. As you indicate yourself by your phrase, aerodynamic calculations are never as accurate as to predict reproducable stall speeds. But this may go both ways that is that calculations are either pessimistic (stall would occur later than calculated) or also optimistic (stall would occur sooner than calculated). So it may be the way you stated it (the pilots drove their plane closer to the limits than what calculations would have predicted) but it may also be the other way around.

Principally I would guess that stall speeds taught to the cadets were obtained experimentally. And keep in mind that pilots appreciated when they got a feedback from the plane (e.g. buffeting) when they got close to the stall limit.

Kurfürst

10-15-2011, 03:38 PM

I wonder, is there a clear definition of stall at all...?

CaptainDoggles

10-15-2011, 08:44 PM

I wonder, is there a clear definition of stall at all...?

Stall is defined as the point where the airfoil's critical angle of attack is exceeded.

Crumpp

10-15-2011, 11:26 PM

I wonder, is there a clear definition of stall at all...?

Captain Doggles gives a good definition:

Stall is defined as the point where the airfoil's critical angle of attack is exceeded.

The question is not when does the stall occur but rather how much warning the aircraft gives.

That is the conundrum faced by designers. Today stability and control is a well defined science. Aircraft designers have many more tools to take advantage and flying characteristics are a consideration almost from conception. For example, today designers build aircraft with no stall warning at all, these airplanes can be flown at maximum performance right up to CLmax without aerodynamic penalties of a buffet. To warn the pilot he is nearing a stall, an artificial device called a "stick shaker" is used.

To understand that stall warning, one must understand what buffeting is aerodynamically. It is a rapid secession of flow separation and reattachment.

When that boundary layer is not attached to a portion of the wing that portion is stalled, an airplane in turn is no longer turning at maximum rate. If you read the Spitfire Mk I pilots notes it expressly warns the pilot to ensure he experiences no buffeting in a turn. First of all when the airplane is buffeting, the turn rate is reduced even though the airfoil is not at CLmax. Secondly, the Spitfire has an extremely nasty stall that will spin and the aircraft is susceptible to airframe destruction in an aggravated spin.

Skoshi Tiger

10-16-2011, 01:06 AM

If the spitfire's stability was unacceptable why would Werner Molders have written

"It handles well, is light on the controls, faultless in the turn and has a performance approaching that of the BF109."

All very subjective I know, but i can only assume that he would have been comparing it to the 109 he flew.

Just because something doesn't comply to a standard doesn't mean it lacks merit, it just means it doesn't comply to a standard.

It's just like if you get a Porche intended for the German market ands try to licence it in Australia, it would fail to meet the Australian safety standard and you wouldn't be able to legaly drive it on our roads. The same car with minor altertations to meet the Australian standards (and given an appropriate compliance plate) would be fine in Australia but in the process render it non-compliant in Germany.

Cheers!

IvanK

10-16-2011, 01:08 AM

You know what stick fixed stability is right?

Err yes, 36 years professional flying, including one high performance type with neutral stability (and 50+ degrees Alpha and controllable capability) and the ability to fly in both FBW and basic manual modes. So I have a basic understanding of keeping the pointy end forward.

My point is your original comment ... "If the unacceptable stability and control characteristics of the Spitfire...." is imo a sweeping one. The spitfire had issues but then so does every aeroplane. In general its handling was pretty straight forward. In addition, adding Bob weights in the pitch circuit was quite a common practice at the time.

As to your comment on the Spitfires stall :

"the Spitfire has an extremely nasty stall that will spin and the aircraft is susceptible to airframe destruction in an aggravated spin."

I think that is a bit loose as well and needs to be put into the context in which this area of handling is discussed in the pilots notes. The pilots notes (MKI anyway) mention is made in the Accelerated (or high speed) stall that if not quickly corrected could lead to structural damage. To my mind this is simply pointing out that at high speed High G departure (accelerated stall) there is a possibility of structural failure, my presumption exceeding Rolling G limits etc. This description is similar to a Flick roll at high speeds. In 1G flight the Spitfire stall was pretty straight forward. A personal work colleague and friend of mine is fortunate to fly the both Spitfire MKVIII,XVI,P51D and P40F on a regular basis. He absolutely raves about the Spitfires slow speed handling and its abilty to just "keep giving" in the high AOA region. It might not meet all the NACA requirements but it still was a very well behaved aeroplane.

Crumpp

10-16-2011, 06:29 AM

The spitfire had issues but then so does every aeroplane.

Sure, no aircraft is perfect but very few safe designs have unacceptable stability and control. It is a fact that the stability and control of the Spitfire was unacceptable, resulted in fatalities, and bob weights were installed. Those issues should be modeled as they very much effect the relative dog fighting capability of these aircraft.

The major point being made on the stall is the engineering tradeoff for that large amount of stall warning in the form of early and hard buffeting is a reduction in turn rate before Clmax is reached.

The pilots notes (MKI anyway) mention is made in the Accelerated (or high speed) stall that if not quickly corrected could lead to structural damage.

A spin by definition requires an accelerated stall.

Err yes, 36 years professional flying,

How many different kinds of aircraft? Try to think of one that repeats the warnings found in the Spitfire Mk I Operating Notes. Those warnings are all characteristics of unacceptable stick fixed longitudinal stability.

Just because something doesn't comply to a standard doesn't mean it lacks merit, it just means it doesn't comply to a standard.

In this case the standard is a little higher. It is not about comfort but rather what will cause the death of a pilot and what will not.

The longitudinal stick fixed stability of the Spitfire was unacceptable because it could kill the pilot. In fact, it did kill and bob weights were installed on the aircraft in response.

RAF74_Winger

10-16-2011, 07:11 AM

A spin by definition requires an accelerated stall.

No, just a stall.

W.

TomcatViP

10-16-2011, 10:46 AM

Ok guys let's not make this an other "experts" issue.

Both of you are talented with no doubts.

Facts is that raising any suspicion abt the flying qualities of the SPit enclosed you immediately in a defensive posture thx to the grands Spitfire's popes tht cruise there and elsewhere on every WWII's sims forums :(

Reading Crumps I see that he tried only to lift the case on the difficulty to perform well in the spit in slow tight turns. There shld be a far more un-forgiving ctrls pattern for doing such in the sim just like what we have with the hurri (the hurri need cte monitoring of the slip needle).

Remind that there was some extensive washout on that wings to give artificial aileron authority near the stall (what the 109 and the hurri did achieved without any washout). This is a direct layoff of the EW (ellip. wing), the thin airfoil with a max camber point put far frwd).

I think it would be more interesting to discuss the doc IvanK has posted earlier and comments all the data and small info we can gather here.

For example the stick force for the 109 is nearly the same of that of the spit mkV at 400mph !!! That's by itself is a revolution in ll2 world !!! :-)

Bussard_1

10-16-2011, 10:51 AM

Whether the Spit is unacceptably balanced was not the issue, was it?

The discussion WAS; are aircraft in sim over/under powered, which developed into a turning discussion.

And then,..?

IvanK

10-16-2011, 10:54 AM

"A spin by definition requires an accelerated stall. "

So are you saying you cant spin from a 1G stall entry ?

TomcatViP

10-16-2011, 11:01 AM

Whether the Spit is unacceptably balanced was not the issue, was it?

The discussion WAS; are aircraft in sim over/under powered, which developed into a turning discussion.

And then,..?

Bussard the way the SPit pop out in the skies each time it zoom up makes any comments regarding the boost and whatever useless.

Let them fix the drag of the Thing and then we will see what the Merlin has wrong (although as a Hurri pilot I don't see the issue)

TomcatViP

10-16-2011, 11:14 AM

type with neutral stability (and 50+ degrees Alpha and controllable capability) and the ability to fly in both FBW and basic manual modes.

Pffff that's such a commonplace... :rolleyes: [/EnvyMode=OFF]

IvanK

10-16-2011, 11:43 AM

So we are all reading from the same page, here are the relevant bits from both the Spit MK I and Spit MKV pilots notes. (The Spit MKII section is pretty much word for word whats in the MKV manual)

SPIT MKI
http://img10.imageshack.us/img10/6791/spitistall.jpg

SPIT MKI ON FLICK MANOEUVRES
http://img41.imageshack.us/img41/9532/spit1flick.jpg

Warnings on the dangers of high speed flick manoeuvers but no real dramas on Lower speed flick manoeuvres, makes sense as no chance of real overstress or excedence of rolling G etc. As you can see pilots are being encouraged to experiment with these

The section in the Spit MKV manual on Stalling and Spinning.
http://img200.imageshack.us/img200/8251/spitvstallspin.jpg

TomcatViP

10-16-2011, 12:39 PM

intersting to note for the neg G cut-out debate : in the Rolling paragraph of teh Aerobatic section : "The roll being barrelled just enough to keep the engine running throughout"

Def even with an MkV, G as to be kept positive to say the least

OOhh and pls do take attention to the cruise speed ;)

Crumpp

10-16-2011, 01:12 PM

A spin may be defined as an aggravated stall that
results in what is termed “autorotation” wherein the
airplane follows a downward corkscrew path.

http://www.alphatrainer.com/handouts/new%20learning/FAA-H-8083-3A/pg_4-12-2.pdf

A spin is defined as an aggravated stall that results in autorotation with a corkscrew path downward.

http://www.mountainflying.com/Pages/mountain-flying/stalls_revisited.html

A spin may be defined as an aggravated stall that results in what is termed “autorotation” wherein the airplane follows a downward corkscrew path

http://www.pilotoutlook.com/airplane_flying/spin

Can you force an aircraft to spin by control input from a 1G level stalled condition?

Sure!!

What are you doing with your accelerations to the aircraft when you input those controls?

Think about it.

Crumpp

10-16-2011, 07:54 PM

So we are all reading from the same page, here are the relevant bits from both the Spit MK I and Spit MKV pilots notes. (The Spit MKII section is pretty much word for word whats in the MKV manual)

Thanks for posting that.

Can you post the section on maximum turn performance recommendations from the Spitfire Mk I Operating notes so that all can read it?

I think the participants will have a better understanding of what I said earlier:

Crumpp says:
The major point being made on the stall is the engineering tradeoff for that large amount of stall warning in the form of early and hard buffeting is a reduction in turn rate before Clmax is reached.

IvanK

10-16-2011, 09:55 PM

Crump you are mixing terms .... early in this discussion you introduced the term Aggravated and then picked up on Accelerated as others started to use it. Aggravated in terms of aerodynamics is not a common term. The Alpha pdf you refer to is the first time I have seen it used this way. The use of the term Accelerated with respect to stalling refers to to Stall entry at greater than 1G, to do this obviously requires higher IAS to generate the additional G at the same critical AOA. So by definition An Accelerated Stall is a stall at greater than 1G. In our Spitfire discussion where structural damage was being referred to we were describing a Spin entered from a high G accelerated stall departure with subsequent excessive G (notatably rolling G which is usually dramatically lower limit than the usual quoted symmetrical G limit)

Now as to thinking about controls and accelerations at spin entry as you suggest. A standard copybook 1G stall and spin entry has you arriving at the Critical AOA in 1G flight with close to full backstick. As the stall develops (ideally a nanofart before) you smoothly apply and hold full rudder (I guess you could say this is "aggravating" the stall ). The aircraft will then autorotate and (in most cases) if the controls are held it will stabilise in a spin. That is a classic 1G un-accelertaed stall spin entry. At the departure point you are already at max AOA (at or close to full backstick at 1G) so dont have the ability to increase G therefore the stall is un-accelerated.

Is this the section you wanted posted from the Spit I pilots notes ?
http://img577.imageshack.us/img577/7397/spitturn.jpg

Sounds pretty standard to me, Max turn performance in a conventional straight wing aeroplane.

Turning just short of critical AOA is a pretty basic fighter pilot skill. The Stall buffet in many aeroplanes has "depth" and differences in the degree of buffet that can be felt through the stick. As the AOA is eased on the first clues is a low intensity buffet described in some circles as the "Buzz" as the AOA increases the buffet gets harsher (Buzz turns into buffet) eventually you get to critical AOA and the stall ocurrs. Embryo military pilots are taught to feel the subtle differences in the buffet. Max performance turning is done "On the Buzz". A standard exercise is to do this whilst airspeed and G are changing whilst holding the aeroplane on the Buzz throughout without reference to AOA instrumentation etc ... just by feel.

In the more modern types (FBW with active leading and trailing edge flaps etc) high AOA capabilty and aerodynamic configuration has you in a lot of buffet any time you are close to max turn performance ... typically in the 25-30 degree Alpha regime (except in the pussy low AOA limited F16 :). As such AOA cueing via instrumentation or audio is there to help you get the max out of the jet though there still is a certain tactile feel to just how deep into the buffet you really are.

SEE

10-16-2011, 10:20 PM

Every pilot, be they Axis or Allied attested to the Spits flying ability.
Disregarding the BoB, at the end of the Malta aircampaign the attrition rate was 1 allied loss for every 10 LW/Italian confirmed kills. Beurling (Spit Mkv) scored 3 BF109 kills and a Ju88 in one sortie with 29 Kills over the few months he was flying in that campaign - that tells me more than any data sheet!

41Sqn_Stormcrow

10-16-2011, 10:54 PM

RAF74_Winger

10-17-2011, 12:22 AM

Max performance turning is done "On the Buzz". A standard exercise is to do this whilst airspeed and G are changing whilst holding the aeroplane on the Buzz throughout without reference to AOA instrumentation etc ... just by feel.

I was taught to pull to the 'nibble', just a slightly different colloquialism I suspect.

The 'depth' of the buffet is due to washout I suspect, and very indicative of the progressive nature of the stall along the span. With light buffet, a very small inboard section of the wing has actually exceeded alpha max, but the remainder of the wing is at or near CLmax.

W.

Crumpp

10-17-2011, 01:56 AM

Crump you are mixing terms

Nobody is mixing terms.

Aggravated in terms of aerodynamics is not a common term.

Sure it is a common term.

Simone Zuccher∗ and Sergio De Ponte†
Politecnico di Milano, 20158 Milano, Italy.
DOI: 10.2514/1.25389

The spin of an airplane occurs for angles of attack beyond stall, where nonlinear aerodynamics dominates and where complex and unpredictable behaviors might induce to question whether or not such a motion is chaotic. To find an answer to this issue, wind-tunnel tests are carried out on a model of a fighter attached by its center of gravity through an universal joint that allows only the three rotations. These degrees of freedom are analyzed according to modern techniques for the study of “supposedly chaotic data.” It is found that, for increasing Reynolds number, successive bifurcations take place with a consequent more complex structure of the attractor, which reveals some features typical of quasi-periodic systems evolving toward chaos. The model is tested also in other configurations (different nose and/or leading-edge extensions, presence or absence of tail planes) so as to verify the dependence of the motion on some details. It is found that unpredictability and strong dependence on the initial conditions characterize
the basic configuration, whereas a blunt nose and leading-edge extensions make the motion extremely regular. Even though the system might be on its route to chaos, a fully developed chaotic behavior is not observed.

Nomenclature
c = wing mean chord, m
f = frequency, Hz
k = reduced frequency, fc=U1
Re = Reynolds number, U1c=
t = time, s
U = wind-tunnel streamwise velocity, m=s
t = time interval, s
= kinematic viscosity, m2=s
= time delay
’, , = degrees of freedom (roll, pitch, and yaw), deg
Subscript
1 = asymptotic (freestream) conditions

I. Introduction
SPIN is an aggravated stall that results in autorotation [1].

http://profs.sci.univr.it/~zuccher/downloads/ZSDS_JOA2007.pdf

A standard copybook 1G stall and spin entry has you arriving at the Critical AOA in 1G flight with close to full backstick. As the stall develops (ideally a nanofart before) you smoothly apply and hold full rudder (I guess you could say this is "aggravating" the stall ).

Any stall under any acceleration is aggravated. Anytime you have uncoordinated flight, you have lateral acceleration.

http://books.google.com/books?id=nxb7csJ_NooC&pg=PT335&lpg=PT335&dq=lateral+acceleration+uncoordinated+flight&source=bl&ots=Wl2roMIh1v&sig=OMkCWvlvbVCxeL4aXecNF_7w0NM&hl=en&ei=Yo6bTq6tFOLY0QHF7oTpBQ&sa=X&oi=book_result&ct=result&resnum=8&ved=0CEYQ6AEwBw#v=onepage&q=lateral%20acceleration%20uncoordinated%20flight&f=false

The primary cause of an inadvertent spin is exceeding the critical AOA while applying excessive or insufficient rudder and, to a lesser extent, aileron. Insufficient or excessive control inputs to correct for Power Factor (PF), or asymmetric propeller loading, could aggravate the precipitation of a spin. At a high AOA the downward moving blade, which is normally on the right side of the propeller arc, has a higher AOA and therefore higher thrust than the upward moving blade on the left. This results in a tendency for the airplane to yaw around the vertical axis to the left. If insufficient or excessive rudder correction is applied to counteract PF, uncoordinated flight may result.

http://faculty.chicagobooth.edu/john.cochrane/research/Data_and_Programs/CFI/Stall%20Spin%20AC%2061-67C.pdf

Crumpp

10-17-2011, 02:05 AM

Sounds pretty standard to me, Max turn performance in a conventional straight wing aeroplane.

It is and I did not ask you to post it because of some abnormality. I asked you to post it because it specifically warns the pilot NOT to fly in the buffet zone and even to ease off the stick by pushing it forward.

Max performance turning is done "On the Buzz". A standard exercise is to do this whilst airspeed and G are changing whilst holding the aeroplane on the Buzz throughout without reference to AOA instrumentation etc ... just by feel.

Only in modern FBW....

Aerodynamic buffeting will not increase your turn performance, it will degrade it.

In the more modern types (FBW with active leading and trailing edge flaps etc) high AOA capabilty and aerodynamic configuration has you in a lot of buffet any time you are close to max turn performance ..

And that "buffet" has nothing to do with the aerodynamics of the aircraft. It is a programed stick shaker placed there by the engineers to let the pilot know he is nearing stall speed and is "On the Buzz" at the point the stability and control engineers put it.

Crumpp

10-17-2011, 02:28 AM

Watch from 3:50 on to get a better idea what we are discussing. When you see those little pieces of sting stand straight up and then reverse, that portion of the wing is stalled.

That stall progresses if the pilot continues to increase angle of attack to CLmax until the wing can not longer support the weight of the aircraft and is no longer flying.

That flow reversal over a portion of the wing is what causes aerodynamic stall buffeting.

At 4:29 the test pilot begins recording a "light" buffet. Observe the tufts and imagine a "heavy" buffet....

http://www.youtube.com/watch?v=dUj6rmgku10

An airplane does not increase its turn rate if it experiences aerodynamic buffeting. An airplane that buffets will decrease it's turn rate when the buffeting begins.

When artificial means such as stick shaker were not available, the only choice a designer had was to reduce the amount of stall warning he gave the pilot. The less buffet, the closer the pilot can fly to CLmax without degrading his turn performance due to aerodynamic buffeting.

IvanK

10-17-2011, 04:48 AM

Crump you said :

"It is and I did not ask you to post it because of some abnormality. I asked you to post it because it specifically warns the pilot NOT to fly in the buffet zone and even to ease off the stick by pushing it forward."

Guess what you do when you go past the Buzz and get into the buffet ... you ease the back pressure off to get back into the Buzz .... Ideally the very first hint of it. Thats the art of max performance turning.

Then in response to my statement:

"Max performance turning is done "On the Buzz". A standard exercise is to do this whilst airspeed and G are changing whilst holding the aeroplane on the Buzz throughout without reference to AOA instrumentation etc ... just by feel."

You said:
"Only in modern FBW...."

Ok you are really off the plot in this response and thats just wrong.
I learnt to fly on the "Buzz" in a Winjeel and then on MB326H aircraft. Both Cable and or Manual push rod controls no Hydraulics or FBW. I also do it regularly in a YAK52. Whether you like it or not thats the way you practically get max turn performance in conventional straight wing aircraft. You want to get pretty close to Clmax to do achieve that, without an AOA gauge the first onset or the buzz IS the cue that is used. I am not the only one posting here to that effect.... see RAF_Wingers post.

You then said
"Aerodynamic buffeting will not increase your turn performance,it will degrade it."
No argument I didnt say that.... but see above response.....

You then said;
"And that "buffet" has nothing to do with the aerodynamics of the aircraft. It is a programed stick shaker placed there by the engineers to let the pilot know he is nearing stall speed and is "On the Buzz" at the point the stability and control engineers put it."

Sorry mate but with respect thats just total crap, and shows you dont really know what you are talking about. The fighters I have flown operationally the Mirage III and F18 Buffet like hell as soon as you start to get some Alpha on the jet. The Mirage III is even in buffet in the circuit ! ..... nature of the beast..... neither type has a Stick shaker or Stick Pusher system

As to Stick shakers I have flown 2 types that were equipped with these ... both commercial transports that required them certification wise both conventional Hydro mechanical controls.

Now I dont know your background Crummp but if you had some practical experience in realitvely high performance straight wing aerobatic aircraft and had been taught how to get the maximum out of it you wouldnt be saying the things you are.

IvanK

10-17-2011, 06:30 AM

Here is someone elese's view on this. The text is from a civilian Aerobatics manual. The author a qualified Military Test pilot and graduate of ETPS... and even referring to an Aeroplane with a typical WWII type wing.
The last line says it all.

http://img534.imageshack.us/img534/6210/buzzburrble.jpg

Lets put this into a practical example that is a realistic life or death situation that requires your best possible turn performance in this case Min radius.

Lets say you find yourself 90 degrees nose down pointing at the ground. You are unsure if you have sufficient height to pull out you may or may not but you must give it your best shot. How would you fly the recovery ? Any delay makes the problem worse, you need your best Turn RFN. Get it right you live get it wrong you DIE.

RAF74_Winger

10-17-2011, 06:33 AM

I asked you to post it because it specifically warns the pilot NOT to fly in the buffet zone and even to ease off the stick by pushing it forward.

Well, it doesn't actually say that - as given: "Even if the aeroplane does not begin to shudder or otherwise indicate an imminent stall, it may not be turning quite as quickly as it would if the stick is very slightly eased forward."

As has been said before - the buffet region of flight has 'depth' due to washout and the progressive nature of the stall across the wingspan. It's possible for a pilot experienced on type to know how much he can pull through the buffet before a full-blown stall & consequent stall and/or flick will occur.

The 'buzz' or 'nibble' does not necessarily presage an imminent stall, it just indicates that the inner part of the wing has exceeded max AoA, the airflow has separated from that surface and is impinging on the elevator.

Aerodynamic buffeting will not increase your turn performance, it will degrade it.

That's sort of true, but not completely. For a wing with washout, max turn performance might not occur until some portion of the inner part of the wing is stalled and the wing as a whole has reached CLmax.

W.

TomcatViP

10-17-2011, 09:15 AM

For a wing with washout, max turn performance might not occur until some portion of the inner part of the wing is stalled and the wing as a whole has reached CLmax.

W.

only a minor portion

Regarding buffeting it is a highly unstable flight regime by def. Generally a localized buffeting zone is set artificially during the design phase to warn the pilot that is entering the stall flight regime.

The buffeting is caused by a major recirculation of flow above the wing. Thus being unstable by definition. The Lift force ad pitching moment oscillating around a certain value cause the "shaking". Aeroelasticity plays also its role here needing more washout to give a safety margin (and more drag) (see http://www.aerospaceweb.org/question/planes/q0099.shtml)

Winger , I can put my tail plane on top of a 10m pole above the fuselage and will still experience wing buffeting. ;)

Regarding the F18 without going OT, if I wd hve been at Northrop I would hve design the buffeting point before the LERX vortex start to interact with the wings flow. A pilot would know then when he is entering high AoA flight regime. What I mean here is that the buffeting zone might be wider than in a conventional aircraft due to the interaction of conventional wing behavior and LERX.

http://www.aerospaceweb.org/question/planes/q0176.shtml

Regarding the Spitfire, the wider wing chord being rather flat (the max camber line being slightly frwd than conventional design), the pitchng moment is rather stable with AoA. This is good if you want to fit a variety of diverse equipment in a fighter aircraft but nasty when it comes to deal with a stall regime (IvanK that might give you some souvenir of teh Fr delta fighter spin ;) )

In particular once such aircraft is committed in a spin, it is more stable here than an other aircraft with shorter wing chord and more rounded airfoil (there I wld like readers fans of RoF to think abt the barn door wing profiles of British WWI planes).

That said, it is mandatory to warm young pilots about the nasty behavior of such an aircraft in the spin. Then they will be more cautious in fight and the "turnability" of a Spitfire will vary greatly with the experience of its pilot.

That's all we said here as I can understand with Crumpp writing and I think this shld be in the sim (I was saying very much the same thing years ago with IL2).

Obviously an experienced fighter pilot will laugh of "the danger of being in a spin". But wait... Germans have shown the world twice that you don't win an air-war with experienced fighters pilots. That's all abt teh Legion Condor and the Hurricane, the experteen and the P51 or the WWI JastaCirkus and SPADs.

Note :
Writing this, I remember a Spit WWII WCO commenting the guncam footage of various pilots that were convinced they have hit their prey and demonstrating to them that they hve missed mostly because their plane were always drifting. This tells us a lot of how they were flying those planes that required much more attention than conventional aircraft when manoeuvring aggressively (of course not more than the early supersonics)

PS: it's a great discussion we hve here :grin:

Crumpp

10-17-2011, 10:56 AM

Here is someone elese's view on this.

WEAK burble.....

Hardly the description of the Spitfire's very hard and pronounced buffet as related by the NACA and its effects on turning performance confirmed in the Spitfire Mk I notes.

winny

10-17-2011, 11:08 AM

I just thought I'd give some historical perspective on this.

I've got lots of BoB RAF pilot's accounts, a recurring theme from the top pilot's is "riding the buffet" Geoff Wellum mentions it in 'First Light' And I've seen it repeated quite often.

Also, when the RAE were conducting the mock dogfights against a 109 they found that in every case where the 109 managed to get behind the Spitfire, it could stay there. when they looked at why, they found that the RAF pilot's were easing off when the buffeting started, when in fact they could have flown it on the edge and even tightened it slightly.

It fits with contemporary accounts from both sides, with plenty of cases of each out-turning the other. As is usually the case, the more familiar the pilot is with his plane the better the chances of survival were. Some flew it on the edge, some flew it as per the handbook.

Crumpp

10-17-2011, 11:16 AM

Ok you are really off the plot in this response and thats just wrong.

I am not wrong and you even agree with what I said.

IvanK says:
you ease the back pressure off to get back into the Buzz .... Ideally the very first hint of it.

Ideally the very first hint of it...... No, Ideally you have none at all and are at the point just before any buffeting occurs. That is also what the Spitfire Mk I notes relate, crazy idea huh!

If you have no other way to determine that point, it works for practical purposes.

Gee, that is exactly what I have said!!

Crumpp says:
Aerodynamic buffeting will not increase your turn performance, it will degrade it.

Now I dont know your background Crummp but if you had some practical experience in realitvely high performance straight wing aerobatic aircraft and had been taught how to get the maximum out of it you wouldnt be saying the things you are.

Degree in aeronautical science....graduate type

Pilot......Aircraft Owner....several of them, they are great way to waste a lot of money! :)

Oh yeah, aerobatics too...

Crumpp

10-17-2011, 05:05 PM

Some flew it on the edge, some flew it as per the handbook.

Umm there is no difference. The handbook tells you how to fly it to the edge...

What do you think the engineers are doing when they tell you those parameters??

Here is a secret....they are telling you how to get the maximum performance out of the aircraft, live to tell about it, and maybe be able to use the airplane on the next mission.

41Sqn_Stormcrow

10-17-2011, 05:15 PM

Mh. I think the pilots were taught to fly their planes after the handbook.

With experience and in battle they started to feel the plane and forgot about the handbook resulting perhaps in situations where they were closer to the edge than written in the handbook. One should remember that air behaviour depends on much more than just velocity and angle of attack. It may well depend on current temperature, roughness of the skin of the plane, winds and gusts, air humidity ...

winny

10-17-2011, 05:57 PM

Umm there is no difference. The handbook tells you how to fly it to the edge...

What do you think the engineers are doing when they tell you those parameters??

Here is a secret....they are telling you how to get the maximum performance out of the aircraft, live to tell about it, and maybe be able to use the airplane on the next mission.

What do you mean, no difference, it's the exact opposite.

You can argue with Geoff Wellum all you want. You said that the pilot's notes say to ease off when buffeting occurrs. Geoff Wellum, for one, didn't do this, and they weren't too concerned with the rule book or the maths of it either, they did what they had to to survive. I've also read of plenty of WEP abuse, bent airframes, bale outs when lost ( i.e. not bothered about using the airplane again)

I think the engineers were conservative in their pilot's notes.

Crumpp

10-17-2011, 07:01 PM

What do you mean, no difference, it's the exact opposite.

Not even close. This is gaming fantasy and not the reality of flying aircraft.

I've also read of plenty of WEP abuse, bent airframes, bale outs when lost ( i.e. not bothered about using the airplane again)

Of course accidents happen and circumstances are not always ideal especially in combat. We get to hear the tails about the lucky ones who survived their experience. Unfortunately we cannot hear from the others who died because of exceeding the published limits.

Let's look at what the reality of operating aircraft has to say about the Pilot Operating Instructions:

The matching of the aerodynamic configuration with the powerplant is accomplished by the manufacturer to provide maximum performance at the specific design condition (e.g., range, endurance, and climb).

MMMM, maximum performance = follow the book

The use of this data in flying operations is
mandatory for safe and efficient operation.

Maximum Performance AND you get to stay alive!!

If you read this primer on Pilot Operating Instructions, you will find that for most maximum performance there is ONLY one point or airspeed that maximum performance can be obtained. That point is linked to the physical design of the aircraft and is given to the pilot by the engineers. There is nothing to be "conservative" about. Additionally, the margins are such there is very little room engineering wise to be "conservative" and still produce a machine that flys.

Read and enjoy!!

http://www.faa.gov/library/manuals/aviation/pilot_handbook/media/PHAK%20-%20Chapter%2010.pdf

winny

10-17-2011, 08:18 PM

Not even close. This is gaming fantasy and not the reality of flying aircraft.

I can't put this any clearer. I'll leave it to someone who was there instead.

Geoff Wellum - " In a Spitfire, just before the stall, the whole aircraft judders, it's a stall warning, if you like. With practice and experience you can hold the plane on this judder in a very tight turn. You never actually stall the aircraft and you don't need to struggle to regain control because you never lose it. A 109 can't stay with you."

Time and time again people push machines past their operational limits, some live some die, that's not the point. The point is that 'riding the buffet' happened, for real. Geoff Wellum did it, as did many many other Battle of Britain pilots.

As for the reality of flying aircraft, what's your experience of flying Spitfires in combat?

I'll take my info from people who know what they are talking about, because they were there, thanks.

MMMM, maximum performance = follow the book

You're sarcasm is palpable.

It's simply not the truth. I'll say it again, The RAE themselves (They conducted the 109 vs Spitfire mock dogfights) found that the reason in initial tests a Spitfire could not shake a 109 of it's tail was because the pilot's were backing off as soon as the buffet set in, when in fact it was possible to fly with the juddering and make a tighter turn. So max turning at least was achieved by not following 'the book'

Maximum Performance AND you get to stay alive!!

No if you follow the book, you can't shake a 109, and you die.

If you read this primer on Pilot Operating Instructions, you will find that for most maximum performance there is ONLY one point or airspeed that maximum performance can be obtained. That point is linked to the physical design of the aircraft and is given to the pilot by the engineers. There is nothing to be "conservative" about. Additionally, the margins are such there is very little room engineering wise to be "conservative" and still produce a machine that flys.

And what exactly has this got to do with combat flying? Irrelevant, they did whatever they could to stay alive.

TomcatViP

10-17-2011, 08:37 PM

Guys we are now entering the irrational. What is not on the book or reported being said by only a few without charts & nbr as a back up is not debatable.

One thing is sure. Some can perform more than other and surely by a slight margin (there is no post stall manoeuvrability in a spit !) some did.

What we care here as a rendering of RL situation would be that very specific node were experienced will get trough with a "slight margin" of G and other that will fear a sudden stall or fail in an accelerated stall aggravated with a wing over with a minor slip angle (that we can all agree - it's documented).

Stick shaking would be not necessary (and hardly done without th erequired hardware compatibility) but head shaking and blur with increasing effect are example of what wld be "easy" to implement. Of course this is speculation. But damn me if any reader here won't prefer TC speculations to both of your tigers pi**ng contest.

On that base it is possible to compute the exact buffeting speed with both wings level and use a charts and RL experience for the resulting bank angle achievable before the stall.

Pls be constructive. I hve the feeling that we could help to build of delectable Spitfire at LEAST !

IvanK

10-17-2011, 08:40 PM

Crumpp you really don't read what other people post. You sprout falsehoods with abandon, surprising for someone with a "Degree in aeronautical science". Your words just don't match that qualification !

Crumpp

10-17-2011, 10:28 PM

Crumpp you really don't read what other people post.

I certainly switched off much of what you said at the constant "your wrong...blah, blah, blah" in your last post over how much lift a wing will produce at flow reversal causing buffeting.

I am sure you understand that aerodynamic buffet is the result of flow reversal of a portion of the wing.

It is especially silly when you flatly state the same thing I am saying and therefore agree in point.

The RAE themselves (They conducted the 109 vs Spitfire mock dogfights)

That is not what I read. The RAE was concerned that pilots were worried about the abrupt stall and subsequent spin entry being afraid to push the airplane. Any sane person would be afraid of that.

Pilots were not finding the limit as IvanK says:

IvanK says:
you ease the back pressure off to get back into the Buzz .... Ideally the very first hint of it.

And I clarified:

Crumpp says:
Ideally the very first hint of it...... No, Ideally you have none at all and are at the point just before any buffeting occurs. That is also what the Spitfire Mk I notes relate

Maximum turn performance will occur at the point just before buffeting begins as the Spitfire POH instructs. That is how the physics works. It does not matter what tricks our mind might play as we shake, rattle, and roll through a turn hunting for that 2D polar CLmax. If you just ease the stick forward to the point the buffeting stops, the airplane will increase in turn rate. With buffet....the entire wing is not working producing maximum lift force in the direction you want it to go....Without buffet...the entire wing is working at your command.

41Sqn_Stormcrow

10-17-2011, 10:46 PM

CWMV

10-17-2011, 11:03 PM

Well...new patch 109 has a little more speed.
Without WEP I can get it up to and maintain 450kph, with WEP 460kph.
Cool with me.

VO101_Tom

10-17-2011, 11:30 PM

I wonder if when being at stall limit in a turn if the speed can be maintained? Usually induced drag increases quite a bit with increased angle of attack. And that's what one does: increasing angle of attack until buffeting. Here draf is highest. Consequence: Loss of speed ==> Closer to stall speed ==> Need to ease up on stick or gain speed by loosing altitude.

Hi. If you turn with stall limit, the turning radius will be very tight, but the aircraft will be very slow (angular velocity is low). If you want to turn to a theoretical maximum angular velocity (constant speed, sustainable energy for a long time), you need the corner speed (http://www.tpub.com/content/aviation2/P-821/P-8210200.htm) (this is a basic, well-known thing. It is taught in military academies).

VO101_Tom

10-17-2011, 11:39 PM

Well...new patch 109 has a little more speed.
Without WEP I can get it up to and maintain 450kph, with WEP 460kph.
Cool with me.

So what changed (http://forum.1cpublishing.eu/showpost.php?p=347529&postcount=29)?
Edit: These speeds are without WEP. The "Notleistung" is 20% plus power (http://www.enginehistory.org/German/DB/Chart01.jpg) that these should be added (of course, the efficiency of the propeller and the air resistance due to the growth rate of less than 20%, but it is certain that more than 10km/h)

CWMV

10-17-2011, 11:45 PM

+10 to 20kph/5 to 12mph
Of course that is with 10% fuel, at less than 10 meters, and no ammunition.
Did you not get an increase? I was always firmly stuck at 440kph before.

VO101_Tom

10-17-2011, 11:57 PM

+10 to 20kph/5 to 12mph
Of course that is with 10% fuel, at less than 10 meters, and no ammunition.
Did you not get an increase? I was always firmly stuck at 440kph before.

I did not tested it today, just my PC performance. But I read that the Spitfire FM is unchanged too.

CWMV

10-18-2011, 12:46 AM

In sustained level flight?
Thats what Im on about, maintained level flight for minutes on end. I was even able to barely touch 470, in level flight, for a few minutes.

Osprey

10-18-2011, 04:44 PM

So what changed (http://forum.1cpublishing.eu/showpost.php?p=347529&postcount=29)?
Edit: These speeds are without WEP. The "Notleistung" is 20% plus power (http://www.enginehistory.org/German/DB/Chart01.jpg) that these should be added (of course, the efficiency of the propeller and the air resistance due to the growth rate of less than 20%, but it is certain that more than 10km/h)

I think you'll have to wait until the next patch where we know that FM's are being worked on before we can evaluate things.

Fenrir

10-18-2011, 11:43 PM

Your efforts Crump are becoming tiresome, and frankly your arguments about the spitfires 'Dangerous Instability' are verging on laughable. Every post that you put up serves only to advertise your bigotry and deepen your alienation of the rest of the forum.

I'll leave on this;

1) A pitch unstable aircraft is not pleasent to fly; it tightens in turns and does not settle automatically from a disturbed path. IT is VERY hard work. EVERY pilot who has flown a Spitfire, particularly those who have flown in combat say time and again the similar thing; words like DELIGHTFUL, EASY and WONDERFUL are repeatedly used to describe the handling and time and again they use the analogy that you didn't get into a Spitfire YOU PUT IT ON. Not to labour the point, but how on earth is there any correlation between these two factors? Cos apparently according to you they co-exist in the same airframe.

In case you missed it the first time, I'll write it again: Spitfires stability was MARGINAL. That does NOT make it UNSTABLE. You, with your self proclaimed expertise on aerodynamics should know this.

2) This bob weight stuff you seem hung up on is a poor argument; I have already related as to how it only affected Mk.V variants - thats Mark Five by the way; introduced many months after the Mk I & II in game - and was a result of increasing amounts of ancilliary equipment that was loaded into these a/c being poorly loaded at squadron level. But yet AGAIN you seem to have missed or ignored someones counter argument when it doesn't fit your model. So, yet AGAIN I'll direct you to Jeffrey Quill's excellent book on the subject. But somehow I get the feeling you won't read it; might not fall into line with some of your 'well founded' opinions.

Crump, your only working to serve your increasing reputation as a stuck up opinionated blowhard. One of these days you're gonna post something ace, a real piece of pukka gen as the old saying goes, and know one round here's gonna give a monkeys cos your credibility is vanishing with every cherry picked argument you present. But please, if you wish to continue shooting yourself in the foot......

Crumpp

10-19-2011, 02:45 AM

spitfires 'Dangerous Instability' are verging on laughable.

http://img268.imageshack.us/img268/5619/spitfirestability.jpg (http://imageshack.us/photo/my-images/268/spitfirestability.jpg/)

Pilots died from it....

http://img706.imageshack.us/img706/4199/mkvdiveaccident.jpg (http://imageshack.us/photo/my-images/706/mkvdiveaccident.jpg/)

A pitch unstable aircraft is not pleasent to fly; it tightens in turns and does not settle automatically from a disturbed path.

Like this??

From the Spitfire Mk II Pilot Operating Notes:

http://img703.imageshack.us/img703/3848/elevatorload.jpg (http://imageshack.us/photo/my-images/703/elevatorload.jpg/)

The same warning is in the Spitfire Mk I which contains even more details.

If you want I will scan the pages from my college text from my stability and control classes. They deal a lot with the Spitfire and the DC-3 as both are famous icons that lack the most basic of stability, longitudinal. Unfortunately, Stability and Control engineering was new science at the time and nobody collected data on just how many accidents could have been prevented had these airplanes had acceptable longitudinal stability.

There is no agenda or bias, bud. You can learn something or not.

Notice, this is not MY opinion.....

http://img43.imageshack.us/img43/681/spitstability.jpg (http://imageshack.us/photo/my-images/43/spitstability.jpg/)

http://img810.imageshack.us/img810/959/spitstability2.jpg (http://imageshack.us/photo/my-images/810/spitstability2.jpg/)

http://img694.imageshack.us/img694/6521/spitstability3.jpg (http://imageshack.us/photo/my-images/694/spitstability3.jpg/)

http://img52.imageshack.us/img52/123/spitstability4.jpg (http://imageshack.us/photo/my-images/52/spitstability4.jpg/)

Here is part of that text book. Read the last myth on a stable aircraft being less maneuverable than an unstable one.

http://books.google.com/books?id=D-ctX2Q-CSIC&pg=PA44&lpg=PA44&dq=John+C+Gibson+Stability+and+control+myths&source=bl&ots=sg5CaDTXAw&sig=gnSywVd43ifk_jMdkp-NRkCkPVU&hl=en&ei=dzyeTouxH-L10gHQwPS-CQ&sa=X&oi=book_result&ct=result&resnum=1&ved=0CB8Q6AEwAA#v=onepage&q=John%20C%20Gibson%20Stability%20and%20control%20 myths&f=false

Fenrir

10-19-2011, 06:46 AM

What kind of verification do you have for these sources Crummp? As far as I know you've written that stuff on an old typewriter and scanned it. Besides, when it says 'failed to meet requirements' - whose?! What requirements? For all I know the Spitfire fails to meet requirements for a heavy lift wide body! Context man, for pitys sake.

Besides, if what you infer is correct we'd have seen spitfires and DC-3s - or more accurately, there constituent parts - scattered all over the landscape because every single one was an inherently dangerous saftey hazard. Take a look how many survive into the modern day and are flown regularly and aerobatted reguularly without incident. Look at the war record of these a/c. Since when on either type is it apparent that they were falling out of the sky in pieces with a methodical regularity?

Do I have to point out that the pictoral example of a structural failure that you provide IS A BLOODY Mk. FIVE again.

Gimme strength!

Besides which where on that photo/drawing does it show that this breakup was caused by excessive g due to instability? Oh that's right, it doesnt. It could have been faulty construction, metal fatigue, flutter, any number of causes. You just assume that it's down to some inherent flaw with Spitfires stability because you've got your axe to grind.

As for your quote on the Mk. II that buffeting can cause large variation in stick travel and g - wow, revelation. Any one who's read into the spitfire knows how sensitive the elevators were. At what what point does it say ANYWHERE in that text that the a/c is longitudinally unstable or prone to taking itself to pieces in that text? It does not. You're extrapolating, badly while your at it, tying it in with other flawed and irrelevant data.

The simple fact is your opinion extrapolated from text book teachings do not correlate with the historical record from a massive amount of disparate sources. And your one textbook evidence - whose validity I suspect - is not only being qouted without context - again WHAT & WHOSE requirements - but upon re-reading them it even agrees with me - NOTE the passage that you underlined 'the small static longitudinal stability',

It says small. It does not say none. It says the stick was very sensitive to movement in pitch.

It does not say Spitfires were falling apart all over the sky.

AT NO POINT DOES IT SAY THAT A SPITFIRE IS DANGEROUSLY AND INHERENTLY UNSTABLE.

Fenrir

10-19-2011, 06:53 AM

Sorry just had to laugh; read the first line of your text, then the last line of the text under the 3rd image.:

Pilots died from it....

http://img706.imageshack.us/img706/4199/mkvdiveaccident.jpg

Er.... But then death and serious injury are the same thing aren't they? Like marginal stability and none, apparently.

VO101_Tom

10-19-2011, 07:58 AM

Sorry just had to laugh; read the first line of your text, then the last line of the text under the 3rd image.:

Why? If he died, he never flew again... ;)

I find it interesting, but I do not think it Crumpp prove that the Spitfire was a bad aircraft, which is obviously not true. But there was not a perfect plane, perhaps, as some would like to believe. The Spitfire is a legend (in a good sense of the word), and not wonder if something like these test results, opinions have never enjoyed great popularity.

TomcatViP

10-19-2011, 10:02 AM

Fenrir comments are way too much aggressive to be relevant.

Nothing that Crumpp has says is a non-sense unless over interpreted by the reader. It fit actually many well known aero principles.

By the way Fenir, the marginal mkV was just the most mass produced Spit variant ever.

Crumpp

10-19-2011, 10:37 AM

Spitfire was a bad aircraft,

Who said the Spitfire was a bad aircraft? DC-3 is not a bad aircraft either.

the marginal mkV

The RAE investigated a series of fatal accidents and concluded that pilots were overloading the airframe on recovery.

The longitudinal instability was not corrected until the Mk V with the installation of bob weights to increase the stick force per G. Bob weights certainly help the pilot to maintain better control of his accelerations but they did not fix the actual problem of insufficient vertical and horizontal stabilizer area. That too was fixed in later marques as stability and control matured greatly as a science during the war. At the time the Spitfire was designed, the United Kingdom did not have a standard and there was no such thing as a stability and control engineer. It just was not that big a deal at the low speeds of open cockpit biplanes common before the war. As speeds and power increased though, it became very important.

Nothing that Crumpp has says is a non-sense unless over interpreted by the reader. It fit actually many well known aero principles.

Yeah folks are very emotionally tied to the Spitfire. I can even remember students in class defending it. That is why it makes such a good example for fledgling stability and control engineers.

Think about what the NACA says on the stick travel. You only have 3/4 of an inch of travel to run the wing from a CL of .3 to CLmax. The minimum standard was 4 inches.

It is no wonder the Operating Notes suggest the pilot brace himself on the cockpit walls to control the aircraft. Imagine trying to land on a gusty day getting tossed around the cockpit with only 3/4 of an inch movement between controlled flight and a stall spin accident.

JtD

10-19-2011, 02:15 PM

...What requirements?...

The Spitfire was at about 5 lb/g, requirements were around 8 lb/g. So it was too light on the elevator.

It would be unstable if it was <=0 lb/g. It wasn't.

P-39 was less stable, with down to 2 lb/g at the most rearward CG allowed.

TomcatViP

10-19-2011, 04:02 PM

It would be unstable if it was <=0 lb/g. It wasn't.

I don't get you ?! Negative mass in a Spit ? Is that in concordance with the black mass theory ? :rolleyes:

Do you mean inverted ctrl ?

Unstable means either that you have a too variable force to pull/push per deg of pitch (ideally it would hve been linear) or that you encounter a zone were the stick forces are reversed (but not negative). For ex the WWI Camel had a degree of reverse ctrl were you needed to push on he stick to raise the nose further up.

Crumpp

10-19-2011, 04:03 PM

The Spitfire was at about 5 lb/g, requirements were around 8 lb/g. So it was too light on the elevator.

It would be unstable if it was <=0 lb/g. It wasn't.

That is not even close to correct. You can easily have a zero static margin for a condition of flight as the NACA determined.

Cable and hinge pressure alone can give you 5lb/G.

Crumpp

10-19-2011, 04:47 PM

Do you mean inverted ctrl ?

He is confused.

He does not understand that classifying control characteristics as Neutral does not mean they are at the Neutral Point with a margin of zero as the engineering definition.

The airplane would be unflyable and that is not what the NACA or anyone else who tested and measured the stability and control of the early Spitfires concluded.

The classification is based on the what control inputs by the pilot, that is why it is termed "flying qualities".

For static that is generally the airplanes reaction to a disturbance. If the airplane returns to last trimmed condition of flight with the stick free, it has positive static stability.

If it does not return but just stays on its disturbed course, it is neutral. That is why the NACA classified the aircraft as poor in rough air. It stays on whatever course the disturbance sets it on for practical purposes.

In this case the low positive static margin is stability is probably eaten up by hinge moments or balances leaving the system neutral for all practical purposes. Certainly it would eventually return to course but the time required is longer than the parameters set for positive stability.

If the disturbance increases, it is divergent or negative.

TomcatViP

10-19-2011, 06:54 PM

He is confused.

I was too :oops:

Poor post than mine. Will delete/correct content

~S

JtD

10-19-2011, 07:21 PM

I don't get you ?! Negative mass in a Spit ? Is that in concordance with the black mass theory ? :rolleyes:

Stick force. Thought that would be clear from the context, but reading again it is not. Sorry.

The Spitfire was tested with around 5 lb stick force per g normal acceleration.

Crumpp

10-20-2011, 12:58 AM

The Spitfire was tested with around 5 lb stick for per g normal acceleration.

Again so everyone is clear. This should read:

The Spitfire exhibited a stick for per g of 5lbs under the tested conditions.

Stick Force per G is not stick force nor is it something that was applied by the tester during the test. It is something that was measured and can be calculated in the design phase for a condition of flight and CG position.

It is the force required to reach 1G increment in acceleration. It represents the slope of the stick force gradient. It is a function of the hinge moments and stability margin. It is also a function of dynamic pressure and varies with altitude and condition.

IIRC, in the case of the NACA test, the stick force at CLmax was ~22lbs. How does that stack up? Sounds like such light controls would be wonderful, huh? Not at all....

To put it in perspective, the FAA dictates minimum control force to reach maximum airframe g limits. Maximum limits is not structural failure. An aerobatic aircraft catagory is rated for a maximum of 6G's for example. A quick formula to ballpark the minimum control force is weight of the aircraft divided by 140.

7500lbs/140 = 53lbs

53lbs would be considered the minimum control force the pilot should experience at a 6G acceleration.

You can begin to see why the NACA classified the Spitfire as unacceptable.

Now let's get a ballpark figure for how long it would take our pilot to stall the aircraft with the Spitfires acceleration gradient. We will fudge it with known NACA measurements that are considerably higher than the Spitfires measured 5lbs per G.

One of things engineers had to do when stability and control became a science was determine what the parameters were for a pilot to move the controls.

According to the NACA, at 33lbs of stick force, the slowest rate of pull they recorded was 33 inches per second and the fastest rate 80 inches per second. With mental distractions, this rate dropped to 22 inches per second for the minimum recorded value.

Time = Distance / Rate

Time = .75 in divided by 22 in/sec

Time = 0.034 seconds to move the stick from cruise CL of .3 to CLmax and stall at the minimum recorded value. The average pilot with the lower Stick Forces of the Spitfire could do it literally in the blink of an eye.

CaptainDoggles

10-20-2011, 01:04 AM

Do you have sources for those numbers?

Crumpp

10-20-2011, 01:37 AM

You can look in the FAR.

http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgFAR.nsf/0/eabb2caab0ffb97585256687006c4ed4!OpenDocument

The stick rates comes from:

NACA RB No. L4E31

ORIGINALLY ISSUED

May 1944 as Restricted Bulletin L4E31

MAXIMUM RATES OF CONTROL
FROM GROUND TESTS

By De E. Beeler

Crumpp

10-20-2011, 01:49 AM

As for the original premise of this discussion, the effect of a hard buffet for stall warning on turn performance:

Aircraft with shallow stick force-per-g gradients
can feel dramatically sensitive if your muscle
memory expects greater forces. Even
experienced aerobatic pilots stepping up to
higher performance aerobatic aircraft usually
find themselves pulling too hard, detaching the
boundary layer, and buffeting the
aircraft—especially in the excitement of
aerobatic competition. This is seen from the
ground as an abrupt flattening in the arc of a
loop, and from the cockpit as a sudden g-break.

http://www.flightlab.net/Flightlab.net/Download_Course_Notes_files/6_%20LongitudinalManeu%232BA152.pdf

In the absence of boundary layer devices, buffeting will increase the radius and decrease the rate of a turn. The harder the buffet and larger the buffet zone, the more dramatic the result.

Stall warning is another engineering trade off. If you produce an airplane with large amount of stall warning, it will not achieve best rate of turn at 2D CLmax. The less buffet with smaller buffet zone and less stall warning, the closer to 2D CLmax the aircraft can achieve best rate of turn.

IvanK

10-20-2011, 01:57 AM

NACA did not classify the Spitfire as Unacceptable what it actually said was .."therefore failed to meet the accepted requirements" (NACA's referenced requirements ... nobody else's) and to a specific item. If you read the various NACA reports in their entirety you don't come away with the impression that the Spitfire was a POS from a handling point of view.

http://img256.imageshack.us/img256/5341/spitunaccep.jpg

They also said with respect to being able to rapidly pull to Clmax without the risk of stalling:

http://img823.imageshack.us/img823/2774/spitstallbehav.jpg

Something most Fighter pilots would consider a highly desirable characteristic.

CRUMPP you said above:

"As for the original premise of this discussion, the effect of a hard buffet for stall warning on turn performance:"

The premise of the discussion was NOT flying in Hard Buffet at all ! but on the very first indication i.e. The "Buzz" or the "Nibble" or the "Burble" ... what ever you want to call it. In a previous post you erroneously said the Buzz and Buffet I described was in fact the stickshaker going off even though in these aeroplanes no stickshaker system was fitted, you also told me that it was only valid technique in FBW aircraft ... even though we were talking about coventional cable/pushrod flight control systems ! You fail to accept that flying on the Buzz was/is a technique practised by Fighter pilots the world over and examples provided in this thread from at my count by 4 independent people/references ... by those that have actually used the technique....including a Spitfire pilot from the Battle Of Britain.

CaptainDoggles

10-20-2011, 02:03 AM

Crumpp

10-20-2011, 02:24 AM

"therefore failed to meet the accepted requirements"

Ok - I admit I shortened "failing to meet acceptable requirements" to just "unacceptable."

Was I wrong? :)

you don't come away with the impression that the Spitfire was a POS from a handling point of view.

Nobody said it was a POS. There are some very good qualities the Longitudinal Instability gave the aircraft from a flying perspective. I love the Spitfire.

It was a two fingered aircraft and one can see how its pilots felt all you had to do was "think about it" and the plane responded. It is an airplane a highly skilled pilot would have love to fight in.

In rough air, Instrument conditions, as a gun platform, precision landing or precision aerobatic platform, the early marques could best be described as skittish. It certainly was not ideal for those missions and a more stable aircraft would not require as high a degree of skill to perform the same maneuvers.

In terms of your game, the excellent stall warning the type possessed means that any computer FM based on 2D Clmax calculated turn performance is optimistic.

They also said with respect to being able to rapidly pull to Clmax without the risk of stalling:

No they don't say CLmax, they say maximum lift coefficient and they list those coefficients achieved in the report. That makes it very easy for somebody who wants to program a computer game, btw.

That is the source of the confusion between the NACA and the RAE. Somebody at the RAE thought it was 2D Clmax too.

Something most Fighter pilots would consider a highly desirable characteristic.

Again, a skilled pilot would love it. He could pull very quickly to the burble and back off to the point just before to achieve that maximum lift coefficient to make his best rate of turn. All within ~3/4 of an inch of stick travel.

NACA's referenced requirements ... nobody else's

The United States had the ONLY stability and control standards during the war on the Allied side.

Only Germany and Japan had stability and control standards at the beginning of the war. The NACA was the first Allied organization to develop any standards. The British never did during the war and it was not until post-war that they came on board to develop any.

Remember, a stable airplane can do any maneuver an unstable aircraft can. The stable airplane can do it just as fast and more precisely requiring a less skilled pilot to do the same thing. It can also do things the unstable one cannot. Such as not destroy itself by overloading the airframe, shoot down other airplanes much faster, land with more control and precision, maneuver better in rough air, and hold a precise altitude/heading in instrument conditions.

Crumpp

10-20-2011, 02:32 AM

It is amusing insight to human perception that some of the pilots were not happy when the RAE did address the Longitudinal Instability of the early marques. Some pilots actually felt the bob weights took away the maneuverability.

All they did was increase the stick force gradient to make the longitudinal control heavier. Bob weights do not effect the dynamic pressure acting on the control surface or even the hinge coefficients.

Bob weight force is simply added to the force gradient already present to achieve a higher stick force per G resulting in the perceived stick forces achieving the minimum standards.

Crumpp

10-20-2011, 02:35 AM

Thanks

You are welcome! :)

Crumpp

10-20-2011, 02:54 AM

The premise of the discussion was NOT flying in Hard Buffet at all ! but on the very first indication i.e. The "Buzz" or the "Nibble" or the "Burble" ... what ever you want to call it.

Why do you think I disagree with you?

Yes the correct technique to achieve maximum rate of turn performance without FBW is to fly to the first indication of flow separation and back off to the point just before that flow detaches.

Tell me this, does CoD model the effects of the stick shaker zone or does maximum rate of turn performance occur at 2D CLmax?

CaptainDoggles

10-20-2011, 03:13 AM

Yes the correct technique to achieve maximum rate of turn performance without FBW is to fly to the first indication of flow separation and back off to the point just before that flow detaches.I imagine this is what the RAF pilots were taught, however I could easily see less-educated pilots or perhaps pilots who didn't grasp (or weren't taught) the physics misinterpreting as "fly in the buffet zone".

Tell me this, does CoD model the effects of the stick shaker zone or does maximum rate of turn performance occur at 2D CLmax? We haven't done a lot of testing yet as our flight models are still somewhat out of whack (see flamefests re: Spit Mk 2) and are due to be changed in the next patch.

If I were to hazard a guess it would be that buffeting does not decrease the turn rate, and is merely a cosmetic effect applied to the player's screen/speakers to warn of impending accelerated stalls.

RAF74_Winger

10-20-2011, 04:03 AM

53lbs would be considered the minimum control force the pilot should experience at a 6G acceleration.

7500lbs/140 = 53lbs

Selective reading, again. The linked document actually states this: (2) For stick controls, W/140 (where W is the maximum weight) or 15 pounds, whichever is greater, except that it need not be greater than 35 pounds.

The spit Mk1 MTOW is 5,844 lb BTW, gives me 42 lbs according to the FAA formula for chimp-proof civil aircraft.

IIRC, in the case of the NACA test, the stick force at CLmax was ~22lbs.

At what speed? What was the resulting acceleration? You're only telling half the story.

W.

RAF74_Winger

10-20-2011, 04:14 AM

no they don't say clmax, they say maximum lift coefficient

?

W.

JtD

10-20-2011, 05:17 AM

Naca Spitfire reports are available here (http://naca.larc.nasa.gov/search.jsp?Ntx=mode%20matchallpartial%20|mode%20ma tchall&Ntk=All|Title&N=0&Ntt=flying%20qualitities%20spitfire|%22Supermarine %20Spitfire%22).

TomcatViP

10-20-2011, 09:42 AM

naca spitfire reports are available here (http://naca.larc.nasa.gov/search.jsp?ntx=mode%20matchallpartial%20|mode%20ma tchall&ntk=all|title&n=0&ntt=flying%20qualitities%20spitfire|%22supermarine %20spitfire%22).

thx !!

Crumpp

10-20-2011, 10:40 AM

Selective reading, again. The linked document actually states this: (2) For stick controls, W/140 (where W is the maximum weight) or 15 pounds, whichever is greater, except that it need not be greater than 35 pounds.

To be airworthy......

That is not the ideal by any means nor did the Spitfire have unacceptable stick force gradients.

It had a low stick force gradient and that served to aggravated the neutral longitudinal stability issue.

Although steepening the stick for per G gradient was the fix used to increase the pilots ability to safely control the aircraft, the stick force gradient was not the issue with the Spitfire.

The issue was the longitudinal stability was neutral and not positive. That makes for a twitchy airplane that is easy to stall, hard to precisely maintain a load factor in a turn, and easy to overstress the airframe.

3/4 of an inch from cruise to stall is not safe and would not be considered acceptable.

FAA formula for chimp-proof civil aircraft.

That is for all aircraft seeking certification in the United States and since most of us are all on the same standard now, much of the world.

Crumpp

10-20-2011, 12:14 PM

Selective reading, again.

Just to clarify. I did read it. You just think my point was the control forces of the Spitfire were bad.

You are mistaken.

They were on the low end of the scale but acceptable. I just illustrated how quickly a pilot could go from cruise to accelerated stall with the neutral stability, tiny stick travel margin, and low stick forces characteristics of the type.

winny

10-20-2011, 02:52 PM

It's an interesting point, and from pilot's accounts it seems true.

Time and time again Spitfire pilots say stuff like "you only had to think about moving the stick and she responded" or "the lightest touch was all that was needed". It's also supported by people who flew both Hurri's and Spits most of who say the Hurricane was more stable. The Spitfire was known to be twitchy if flown heavy handed.

I'm not convinced that it was a problem though, technically maybe, but I've never read anything where Spitfire pilot's were complaining about stability (at least up until some of the bigger ones). Isn't a little bit of unstability good for maneuverability?

I suppose it could cause problems in the 'pit if you're throwing it around simply because it must have been hard to stay relaxed on the stick.

Crumpp

10-20-2011, 04:31 PM

Isn't a little bit of unstability good for maneuverability?

Not at all. In fact that is big myth.

Remember, a stable airplane can do any maneuver an unstable aircraft can. The stable airplane can do it just as fast and more precisely requiring a less skilled pilot to do the same thing. It can also do things the unstable one cannot. Such as not destroy itself by overloading the airframe, shoot down other airplanes much faster, land with more control and precision, maneuver better in rough air, and hold a precise altitude/heading in instrument conditions.

Unstable just means the airplane is skittish and hard to control.

I'm not convinced that it was a problem though

Sure it was....

The RAE even recognized it attempted to fix it. Eventually it was eliminated in the very late marques with an empennage redesign.

winny

10-20-2011, 05:03 PM

Not at all. In fact that is big myth.

Remember, a stable airplane can do any maneuver an unstable aircraft can. The stable airplane can do it just as fast and more precisely requiring a less skilled pilot to do the same thing. It can also do things the unstable one cannot. Such as not destroy itself by overloading the airframe, shoot down other airplanes much faster, land with more control and precision, maneuver better in rough air, and hold a precise altitude/heading in instrument conditions.

Unstable just means the airplane is skittish and hard to control.

Sure it was....

The RAE even recognized it attempted to fix it. Eventually it was eliminated in the very late marques with an empennage redesign.

So, when someone refers to a Modern Aircraft being unstable (I'm thinking of the ones that need a computer to fly them) are they talking about the same 'unstability'? Is it even true? (I'm not arguing here, I'd just like to know)

About the 'problem', how come the vast majority of Spitfire pilots say it was so easy to fly? How did this problem manifest it's self?

Crumpp

10-20-2011, 05:27 PM

Is it even true?

YES!! They are much more maneuverable than if the designer had built a stable aircraft.

They are so twitchy a human being cannot react fast enough to keep them from destroying themselves.

Hence you answered your own question:

I'm thinking of the ones that need a computer to fly them

:-)

IIRC, IL2 players complained quite a bit about the P51 Mustang FM's being twitchy.

That is sort of how an airplane with a small enough stability margin to be considered neutral in longitudinal flying qualities will behave.

CaptainDoggles

10-20-2011, 05:35 PM

In some cases the negative or "relaxed" stability of the aircraft is a consequence of the design, rather than an explicit design goal. I'm thinking here of the F-117 and the B-2, whose fuselages are very unorthodox due to stealth requirements. Aircraft such as these require FBW systems to stay aloft.

In fact I once heard the B-2 described as being "held in the air by sheer computing power" :lol:

Other aircraft such as the F-16 are designed to be intentionally unstable.

People often get mixed up due to the terms stable/unstable having very specific, prescribed meanings.

Crumpp

10-20-2011, 05:37 PM

The problem is people confuse "unstable" with "agile" and "stable" with "sluggish" because the terms stable/unstable have very specific, prescribed meanings that aren't necessarily in line with the common vernacular.

Yes, terminology is very important. Take the "maximum lift coefficient" term. That is often used to define the highest Coefficient of Lift over a given range.

http://www.google.com/search?q=Cruise%20Maximum%20coefficient%20of%20lif t&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a&source=hp&channel=np#pq=%22maximum+coefficient+of+lift%22&hl=en&sugexp=gsih&cp=8&gs_id=et&xhr=t&q=%22cruise+maximum+lift+coefficient%22&pf=p&sclient=psy-ab&client=firefox-a&hs=jQI&rls=org.mozilla:en-US%3Aofficial&channel=np&source=hp&pbx=1&oq=%22cruise+maximum+lift+coefficient%22&aq=f&aqi=&aql=&gs_sm=&gs_upl=&bav=on.2,or.r_gc.r_pw.,cf.osb&fp=a4183349b9a276ea&biw=1920&bih=941

http://enpub.fulton.asu.edu/aero/mae444/sizingchapter.pdf

"Maximum coefficient of lift" is the term for the CLmax a section can produce and defines the Angle of Attack the airfoil stalls.

http://www.google.com/search?q=Cruise%20Maximum%20coefficient%20of%20lif t&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a&source=hp&channel=np#pq=%22cruise+maximum+coefficient+of+lif t%22&hl=en&sugexp=gsih&cp=1&gs_id=9y&xhr=t&q=%22maximum+coefficient+of+lift%22&pf=p&sclient=psy-ab&client=firefox-a&hs=Ajx&rls=org.mozilla:en-US%3Aofficial&channel=np&source=hp&pbx=1&oq=%22maximum+coefficient+of+lift%22&aq=f&aqi=&aql=&gs_sm=&gs_upl=&bav=on.2,or.r_gc.r_pw.,cf.osb&fp=a4183349b9a276ea&biw=1920&bih=941&bs=1

TomcatViP

10-21-2011, 10:22 AM

F117 is unstable due to the interaction of the uncunventional faceted shape and aerodynamics forces. Ben Rich's team added some FBW rules (out of an F16 ;)) to free designer to go much further in the quest for stealth.

The unstability of the B2 is more linked to the clean flying wing shape with no vertical surface.

With the F16 and the Mirage 2000 the world of high perf fighter begin a new aera were the relaxed stability was the norm. What does it means ? Simply that the balancing forces around the CG were modified to allow a more compact design with the CG moving aft with high pitch authority as a direct benefit.

If you look closely at a post 80 design with FBW added you'll see that the jet engines are put at the tip end with no long draggy inner combustion pipe such as in the early jet and mid 60's (draggy because a jet engine blowing in a pipe loose that way its flow momentum due to inner wall friction. Hence a loss in propulsive power). This as freed the designer for a more balanced design improving the overall aero efficiency, lowering the empty weight (hence the direct and OP cost) and increasing the potential modifications in the .

What the FBW do ? It simply act where the pilot can't with only minor correction to correct the induced instability of the aircraft.

This principle was re-used by Airbus to minimize the tail surface of its design (drag lowered) such as the A320 witch was a seemingly logical step forward with the introduction of airfoils with a reflex zone (that cld be discussed today).

SO instability and relaxed stability is not exactly the same thing. In fact you can possibly design an unstable aircraft with relaxed stability ;)
... Or have a stable aircraft with some relaxed stabilty added :rolleyes:
Or hve a stable aircraft that can be turned unstable in pitch if you move the ctrl further bckwrd :cool:

The best way to asses the Spit instability for everyone here and its uncomfortable 3/4 inch (2cm) stick travel would be to reconfigure your joystick to allow only that travel in the pitch zone.

I am sure dozen here will instantly become Spit hatter in a single day !! :rolleyes:

By the way as ths is a Spit mkIIa thread can Devs stop the annoying characteristic of that bird in CoD that have a better P/W ratio than the 109.
Now I see most of the Spit moving in the vertical plan knowing that there is a bug with the FM. :!::-x

JtD

10-21-2011, 03:31 PM

You don't have the real life forces on your joystick. So stick travel doesn't give you the feedback you get in the plane.

CaptainDoggles

10-21-2011, 03:48 PM

robtek

10-21-2011, 04:14 PM

You don't have the real life forces on your joystick. So stick travel doesn't give you the feedback you get in the plane.

As the required forces in the spit are very low, being the "problem", i dont think that matters so much.

There is a spring in your stick, isnt it?

Also there is always ffb a possibility.

JtD

10-21-2011, 09:06 PM

I don't pull 5 lb on my stick, let alone 50, which even with the low stick forces in the Spit were necessary on occasion to bring the plane to the limit.

Stick forces in the Spit were low but OK, not "the problem".

TomcatViP

10-22-2011, 12:28 PM

I'm not certain if you're agreeing or disagreeing with me, or just expounding on the design of the F-117 and B-2

hehe I agree with you. I was just complementing the answer.

Crumpp

10-23-2011, 05:50 PM

The best way to asses the Spit instability for everyone here and its uncomfortable 3/4 inch (2cm) stick travel would be to reconfigure your joystick to allow only that travel in the pitch zone.

Remember, size does matter......

:o

A good simulation of the Spitfire will have the aircraft twitchy or skittish and hard to precisely control in the longitudinal axis. The higher the angle of attack, the more skittish the aircraft; the lower the angle of attack, the more stable the longitudinal axis. It will take skill and constant attention to maintain a set altitude and will require small precise stick inputs to keep it from overloading the airframe on dive recovery or reaching an accelerated stall in a turn. If it does experience an accelerated stall, the stall is extremely harsh and will require immediate application of the correct control inputs ( reduce the angle of attack and increase airspeed) to keep from spinning.

It will take about 2000 feet to stop the spin and then the pilot will have recover the aircraft to flight. The correct inputs are full rudder in the opposite direction until the spin is fully recovered; Stick neutral and then slowly brought forward. The nose will come down and the rotation speed will increase until enough dynamic pressure is built for the control to be effective and stop the rotation. The aircraft will be nose down in a dive which the pilot then recovers from. The book recommends 5,000 to 6,000 foot margin to ensure a recovery from an accidental spin. Deliberate spins are prohibited because the airframe can fail under certain conditions in a spin.

Remember that the Spitfire had poor control force harmony as well. The lateral control forces have a much steeper gradient than the longitudinal. That means the aileron forces increase much faster than the elevator forces. While your elevator is very light in control forces with only a 3/4 inch travel from cruise to stall point, the ailerons require much more force to induce a given roll rate. As the Operating Instructions relate, it would require the pilot to brace his elbow in order to apply the heavy aileron force required to reach maximum deflection while being careful not to induce any elevator input.

TomcatViP

10-25-2011, 10:10 AM

You don't have the real life forces on your joystick. So stick travel doesn't give you the feedback you get in the plane.

No but variable neutral zone can makes you feel as if you had to pull harder

TomcatViP

10-25-2011, 10:16 AM

Remember, size does matter......

:o

A good simulation of the Spitfire will have the aircraft twitchy or skittish and hard to precisely control in the longitudinal axis. The higher the angle of attack, the more skittish the aircraft; the lower the angle of attack, the more stable the longitudinal axis. It will take skill and constant attention to maintain a set altitude and will require small precise stick inputs to keep it from overloading the airframe on dive recovery or reaching an accelerated stall in a turn. If it does experience an accelerated stall, the stall is extremely harsh and will require immediate application of the correct control inputs ( reduce the angle of attack and increase airspeed) to keep from spinning.

It will take about 2000 feet to stop the spin and then the pilot will have recover the aircraft to flight. The correct inputs are full rudder in the opposite direction until the spin is fully recovered; Stick neutral and then slowly brought forward. The nose will come down and the rotation speed will increase until enough dynamic pressure is built for the control to be effective and stop the rotation. The aircraft will be nose down in a dive which the pilot then recovers from. The book recommends 5,000 to 6,000 foot margin to ensure a recovery from an accidental spin. Deliberate spins are prohibited because the airframe can fail under certain conditions in a spin.

Remember that the Spitfire had poor control force harmony as well. The lateral control forces have a much steeper gradient than the longitudinal. That means the aileron forces increase much faster than the elevator forces. While your elevator is very light in control forces with only a 3/4 inch travel from cruise to stall point, the ailerons require much more force to induce a given roll rate. As the Operating Instructions relate, it would require the pilot to brace his elbow in order to apply the heavy aileron force required to reach maximum deflection while being careful not to induce any elevator input.

All is said there.

But the 3/4inch value need to be assessed one more time. We can't only rely on a single NACA report. Even if NACA/NASA docs are among the most reliable sources available on the web.

If we put things back in the contest, at the time of the evaluation the US fighter industry was struggling to produce a viable pony capable to compete with Eu models.

Crumpp

10-25-2011, 11:28 AM

If we put things back in the contest, at the time of the evaluation the US fighter industry was struggling to produce a viable pony capable to compete with Eu models.

Certainly.

Stability and control is one area the United States was ahead of other Allied Nations.

The United States pioneered stability and control research. It was the first to quantify the science.

In fact, both the Germans and the Japanese standards were based on Warner, Norton, and Allen's work at MIT as well as Gilruth's work at the NACA.

In 1942, an RAE engineer named Sydney B Gates made his famous (in stability and control engineering circles only, lol ) "dash around America" comparing NACA research to RAE at the time. It was primarily thru Gates efforts that the RAE eventually did adopt a standard but his efforts did not reach fruition until post war. That standard mirrored the NACA's standard.

Skoshi Tiger

10-25-2011, 02:33 PM