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  #121  
Old 09-13-2012, 02:45 PM
Kurfürst Kurfürst is offline
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There is no doubt that there is some sort of demonstrating our superiority ooze about these turn radii graphs... but regardless the figures seem to be about right.

It is entirely another question why this so called superiority is given so much importance. Even the graph shows that the turn radii difference between the Hurri and the 109 was about 200 feet, or about 60 meters. Even the span of these aircraft was 11-12 meters, and actually that's about the distance a 109 wingman kept from his leader... or even less. So what's all the fuss about it?

BTW the figures are rather similiar to what Morgan and Morris came up with in 1940 (for 12k feet - both figures are more of an educated estimate, not trials): http://kurfurst.org/Tactical_trials/...ls/Morgan.html

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Il-2Bugtracker: Feature #200: Missing 100 octane subtypes of Bf 109E and Bf 110C http://www.il2bugtracker.com/issues/200
Il-2Bugtracker: Bug #415: Spitfire Mk I, Ia, and Mk II: Stability and Control http://www.il2bugtracker.com/issues/415

Kurfürst - Your resource site on Bf 109 performance! http://kurfurst.org
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  #122  
Old 09-13-2012, 02:46 PM
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Crumpp Crumpp is offline
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Quote:
No my statement is 100% correct, the graph is turn radius at sea level
Your statement the graph is at sea level is correct and not the issue.

The issue is you imply that speed is not part of the equation and therefore it is wrong to say it is Equivilent Airspeed.

You do know we cannot have rotational motion without velocity, right?

An airplane that is not in motion has no turn radius.

It is not the fact the performance is graphed at sea level.

In fact, that is WHY it is Equivilent Airspeed!

Quote:
Bongodriver says:
My interpretation of the graph is that that bot the left and bottom figures are radius (note how the lines intersect exactly the same figures on both) and the note on the left just means 'sea level', no EAS or IAS involved, admittedly it is a very badly designed illustration.......what's the big deal?
It is the claim that you knew what EAS is used for and do not recognize that is questionable.

Does that mean EAS is just a term that you heard someplace or do you know its uses? It is ok to admit you don't know everything. I certainly don't, just ask my wife!

I did not call you a liar at all either. I said either you did not know or you are lying. You claimed to know about Equivilent Airspeed in your second reply but you made the statement EAS or IAS is not a part of the math used to derive the graph published in the book. It is probably NOT done in IAS. While it is valid to do a turn performance analysis in IAS, it is not valid for performance comparision because of the PEC. It is also valid to do it in Calibrated Airspeed but CAS = EAS = TAS at sea level.

The fact is your only point is get the conversation shut down at this point so that we do not get to see any analysis that might not fit a small and very vocal agenda. Don't do that. What will follow is unbiased math that anyone can reproduce given the knowledge of aerodynamics. I will even keep it to the college algebra level so it is easy to see.

I am hoping it will quiet down the critism of developers on their FM's. I think they are close in the big picture and the Spitfire's issue is the heat effects. We can prove that.

Bottom line, I did not call you a liar. I said you made the claim to know something and either you did not fully understand it or not forthcoming about the level of understanding you posses. I have no idea what you do or do not know outside of what you write on these forums. The impetus is on you.
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Last edited by Crumpp; 09-13-2012 at 02:56 PM. Reason: clarity
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  #123  
Old 09-13-2012, 02:53 PM
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bongodriver bongodriver is offline
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Quote:
The issue is you imply that speed is not part of the equation and therefore it is wrong to say it is Equivilent Airspeed.
merely a case of you making the wrong assumption, I made no reference to equations or any such thing, you were obviously a little over eager to jump all over a grammatical error, I should really have said 'no EAS or IAS refered to'......there.....does that help your blood pressure any?

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I have no idea what you do or do not know outside of what you write on these forums. The impetus is on you.
Not really, I provided all the evidence of my qualification...what do you need? a picture of me holding a 'hello Crumpp' sign while actually flying an aircraft?....
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  #124  
Old 09-13-2012, 02:55 PM
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Quote:
Originally Posted by bongodriver View Post
what do you need? a picture of me holding a 'hello Crumpp' sign while actually flying an aircraft?....
lol
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Theres a reason for instrumenting a plane for test..
That being a pilots's 'perception' of what is going on can be very different from what is 'actually' going on.
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  #125  
Old 09-13-2012, 02:58 PM
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Quote:
There is no doubt that there is some sort of demonstrating our superiority ooze about these turn radii graphs... but regardless the figures seem to be about right.
Really?....the graphs were sourced from litterature as far as I can see, nobody on this forum produced them in any attempt to ooze superiority, and you can still say that despite providing your own source which verifies the accuracy?.......

Quote:
It is entirely another question why this so called superiority is given so much importance
only because it is further evidence to the argument the Spitfire was a more agile aircraft with better turn performance.....whats all the fuss about?
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  #126  
Old 09-13-2012, 02:58 PM
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Quote:
Originally Posted by ACE-OF-ACES View Post
lol

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  #127  
Old 09-13-2012, 03:01 PM
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ACE-OF-ACES ACE-OF-ACES is offline
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Quote:
Originally Posted by bongodriver View Post
and you can still say that despite providing your own source which verifies the accuracy?.......
That is a good point

Initially I got the impression that is what the graph was trying to do..

But based on the table that Kurfurst just posted, I see now the graph is right, just it's presentation was not all that it could be.

Put another way

As the graph implied.. (at sea level)

And Kurfurst table confirmed.. (at 12kft)

The Spit does turn a lot better than the Bf109

At more than one altitude!
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Theres a reason for instrumenting a plane for test..
That being a pilots's 'perception' of what is going on can be very different from what is 'actually' going on.

Last edited by ACE-OF-ACES; 09-13-2012 at 03:03 PM.
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  #128  
Old 09-13-2012, 04:46 PM
JtD JtD is offline
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Turn radius is for turns at sea level. Estimated best sustained turn. Corresponding turn times from same calculation:
Hurricane I: 17.6s
Spitfire I: 18.2s
Bf 109E-3: 20.5s
Bf 110C-4: 20.5s (was also calculated, with radius of 840ft)

Last edited by JtD; 09-13-2012 at 04:58 PM. Reason: comma
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  #129  
Old 09-17-2012, 03:09 PM
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Quote:
Turn radius is for turns at sea level. Estimated best sustained turn. Corresponding turn times from same calculation:
Hurricane I: 17.6s
Spitfire I: 18.2s
Bf 109E-3: 20.5s
Bf 110C-4: 20.5s (was also calculated, with radius of 840ft)
While absolutely correct for relative performance, just examining a single point of best performance does not give one the best picture of the relative dogfighting capability.

Looking at one single point in the envelope tells us the Bf-109E3 is hopelessly outclassed IF it tries to match the Spitfire at the Spitfires best performance velocity.

Fortunately, all airplanes have their own unique best performance speeds and the Bf-109E3 is no different.

Here we can see the entire sustainable load factor envelope for both aircraft.



What is shows us is that in order for the Spitfire to realize it's turn performance advantage, it must go slower than the Bf-109E3 by some 30Kph or 18 mph.

That means the Bf-109E3 gains the initiative in the fight if the Spitfire tries to use its sustained turn advantage.

Once more, the Bf-109E3 pilot can take his aircraft all the way to its best sustained turn performance point without fear of losing the initiative.

Factor in the stability characteristics and these airplanes are very evenly matched in close quarters dogfighting.
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  #130  
Old 09-17-2012, 03:21 PM
pstyle pstyle is offline
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That means the Bf-109E3 gains the initiative in the fight if the Spitfire tries to use its sustained turn advantage.

Can you reword this so it does not come accross as a bizarre contradiction?
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