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FM/DM threads Everything about FM/DM in CoD

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  #1  
Old 09-19-2012, 02:08 PM
IvanK IvanK is offline
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I guess RAE were clueless ... and you have superior knowledge Crumpp... trouble is your graph reflects the opposite of pretty much every known record,chart,computation or actual flight test or pilots account of the facts !



One more from the RAE clearly showing better turn performance of the Spitfire in all regimes.
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Old 09-19-2012, 03:23 PM
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Originally Posted by IvanK View Post
I guess RAE were clueless ... and you have superior knowledge Crumpp... trouble is your graph reflects the opposite of pretty much every known record,chart,computation or actual flight test or pilots account of the facts !



One more from the RAE clearly showing better turn performance of the Spitfire in all regimes.
The RAE shows better turn radius in this chart. The Spitfire always has a better turn radius than the Bf-109.

Radius being just one parameter of turn performance and not the most important either.

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Pstyle says:
Crummp, when the RAE refer to "normal bhp", do you know what the term "normal" refers to.
Not specifically. It appears to be RAM power because the chart list's power in flight.

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Pstyle says:
At least then we are all able to work to the same assumptions and review each others work. It's be good to see how the manipulation of one or more of the variables influences tge overall outputs.
Exactly, once the parameters are input, the math does it's magic.
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Old 09-19-2012, 04:03 PM
Kurfürst Kurfürst is offline
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Originally Posted by Crumpp View Post
The RAE shows better turn radius in this chart. The Spitfire always has a better turn radius than the Bf-109.
Flaps...
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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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Old 09-19-2012, 04:17 PM
pstyle pstyle is offline
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Quote:
Originally Posted by Crumpp View Post
The RAE shows better turn radius in this chart. The Spitfire always has a better turn radius than the Bf-109.

Radius being just one parameter of turn performance and not the most important either.
True, if the aircraft are BOTH at the same speed (according to that chart) , the spitfire will have less distance to travel, and thus will turn faster, in every case.

I think I can convert the figures to turn rate fairly easily... Then we can see, using that very ddata, the combinations of speeds at which the two have varying turn speeds right?
See here, http://s13.postimage.org/4fo4e806f/turns_comparison.jpg

According to that, Provided the sptfire remains between 200kph and 370kph TAS, the 109 can never out turn it.

Last edited by pstyle; 09-19-2012 at 04:56 PM.
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Old 09-19-2012, 09:23 PM
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Wow....maths really is magic........it made Crumpp dissapear.
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Old 09-19-2012, 09:32 PM
TomcatViP TomcatViP is offline
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"Normal" shld stand for standard atmospheric value. The HP being a function of the air density, the Power have to be converted to the reference to be absolutely rigorous.

Note that standards varies (and still does) from one country to another.

ISO being 0°C and 1013mbar - CFM around 15°C etc..

Note also that if this is the case, there might be some error in the the conversion.

Last edited by TomcatViP; 09-19-2012 at 09:40 PM.
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Old 09-19-2012, 10:52 PM
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True, if the aircraft are BOTH at the same speed (according to that chart) , the spitfire will have less distance to travel, and thus will turn faster, in every case.
They are not at the same speed or angle of bank!

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I'm not Ivan but they are obviously power on clmax.
They don't match CLmax power on for either type. In otherwords, a bad assumption.

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Only one flight was made, as operating a suspended static head from a single-seater aircraft with a rather cramped cockpit is difficult.
http://kurfurst.org/Tactical_trials/...ls/Morgan.html
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Old 09-19-2012, 10:53 PM
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"Normal" shld stand for standard atmospheric value. The HP being a function of the air density, the Power have to be converted to the reference to be absolutely rigorous.
I think you are right.
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Old 09-19-2012, 11:19 PM
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Quote:
Originally Posted by Crumpp View Post
They are not at the same speed or angle of bank!
Doesn't matter if they are not at the same angle of bank, it's almost entirely the point that the spitfire was able to maintain level and sustained turns at a higher angle of bank than the 109.....kinda the key to a tighter turn don't you think? and in any case the Spit is achieving the tighter turn at higher speed than the 109 too.


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Originally Posted by Crumpp View Post
They don't match CLmax power on for either type. In otherwords, a bad assumption.
I'd still rather accept the professionals theory on it opposed to yours....no offence.


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Quote: Only one flight was made, as operating a suspended static head from a single-seater aircraft with a rather cramped cockpit is difficult.
Only one flight was made, as operating a suspended static head from a single-seater aircraft with a rather cramped cockpit is difficult.

http://kurfurst.org/Tactical_trials/...ls/Morgan.html
Not sure why you quoted a snippet from a 'stalling' Cl max trial.
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  #10  
Old 09-20-2012, 12:00 AM
pstyle pstyle is offline
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Quote:
Originally Posted by Crumpp View Post
They are not at the same speed or angle of bank!
Are you saying that, because we don;t know the AoB, we cannot therefore assume that their rotational velocity is equivalent - because the air passing over the indicator would not be equally displaced with respect to each aircraft's flight path?

If so, then yes, you're right I suppose.
Rotational velocity is dependant on more that simply airspeed and turn radius.. it needs "ground speed", essentially - which is the "real" speed around the spatial unit that is the turn.
Can we make any assumptions about likely AoB? The graph indicates that the turn is level (horizontally in each case). Do we know what the AoB differential is likely to be for each aircraft in each case? (then we can work out the proportion of airspeed that is in the horizontal plane).

Last edited by pstyle; 09-20-2012 at 12:03 AM.
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