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FM/DM threads Everything about FM/DM in CoD

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  #1  
Old 09-22-2012, 09:29 PM
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Quote:
other rubbish
Hold on a second. You attacked the effort and claimed it did not conform to physics.

When I explain it is all standard formulation commonly found in aerodynamic text using the BGS system and present a General Turn Performance table the results agree with perfectly, you claim it is all rubbish.

So what is not "rubbish" to you??

Before I present you with the data, should we agree on what we are looking at???
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Old 09-22-2012, 10:32 PM
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I admit that my problem is a simple basic one. I believe a huge amount of time and effort is going into trying to hide one clear and obvious truth. That all the pilots and all the test pilots of all the test establishments, in all the nations that compared the 109 and the Spitfire, all agreed that the SPit turned better than the 109.

None of the above mentioned said that there was any difference when in a turning climb and the RAE clearly documented the advantage to the Spitfire. No advice was given to German pilots to go into a climbing turn to escape attack and as far as I am aware, no pilot of the time has said that they used this tactic in combat.

I frankly don't care what a theoretical calculation shows when compared to the tests that were done at the time. Why, because anything done today is just that, a theory unable to be tested in real life, a pricless advantage which occurred in the war years.

Its also worth remembering that the calculations being done today are being done without that 12lb thrust which increased performance of the engine by approx 30%

I invite those who believe that the 109 had the advantage to find any test from any establishment of any nation to support their view.
It shouldn't be difficult if the results are so clear and obvious mathmatically.
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Old 09-22-2012, 10:46 PM
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all agreed that the SPit turned better than the 109.
It does turn better. Look at the calculations I posted.

It just does not do it under all conditions or speeds. That is important, Glider.

If the two airplanes were to have a turning battle to the stall point, the Bf-109E-3 would loose.

Here is the acceleration rates of the two aircraft. The Bf-109E-3 out accelerates the Spitfire Mk I due to its being lighter with more excess thrust.




Of course, the Spitfire can fly at a slower speed were the Bf-109E3 cannot fly at all.

If the Bf-109E3 maintains his trim speed of 400 kph, he is tough customer for a Spitfire to deal with. At that speed, the Bf-109 can sustain better performance and accelerates better. The Spitfire needs to take the fight to the low speed realm where it has all the advantages.
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Old 09-22-2012, 11:19 PM
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Typo on the chart axis....

Acceleration is in fps^2
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Old 09-22-2012, 11:22 PM
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I asked you to share your input data

The data has been posted for each evaluation.

I would be glad to share the input data for this one but what would be the point when you are saying the whole effort does not conform to standard physics.

It does conform. Aerodynamics is nothing more than applied physics and all the formulation is straight out of my college text. It is the same stuff we did in the classroom!

If you agree it conforms, I will be glad to continue the discussion and share the data.

I plan on sharing the spreadsheet too.
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Old 09-22-2012, 11:52 PM
5./JG27.Farber 5./JG27.Farber is offline
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Crump - you know if you click the "multi off" button it says "mutli on", then when you click "reply" it will contain these quotes and you can make one post?
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Old 09-23-2012, 05:01 PM
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[QUOTE=Crumpp;463075]It does turn better. Look at the calculations I posted.

It just does not do it under all conditions or speeds. That is important, Glider.

If the two airplanes were to have a turning battle to the stall point, the Bf-109E-3 would loose.

Here is the acceleration rates of the two aircraft. The Bf-109E-3 out accelerates the Spitfire Mk I due to its being lighter with more excess thrust.



I am sorry but this is rubbish.
a) You are using the wrong power settings for a Spit
b) The 109 controls lock at higher speeds far more so than the spit
c) The German test establishments let alone the pilots in combat would have identified that the 109 turned better at high speed and would have given instructions to their pilots similar to those given to Typhoon, Tempest and USAAF fighters. These essentially went 'Dont enter a slow turning fight with an Me109, keep your energy up and you will have him' Substitute Spitfire for 109 and you would have the german instructions. These were never given.

Quote:
If the Bf-109E3 maintains his trim speed of 400 kph, he is tough customer for a Spitfire to deal with. At that speed, the Bf-109 can sustain better performance and accelerates better. The Spitfire needs to take the fight to the low speed realm where it has all the advantages.
At 12 lb thrust the Spit produces 1300 hp which puts the power to weight ratio firmly in favour of the Spitfire from which a lot of performance calcs are decided. Without this calculation the charts you posted are of little value.
400 Km is about 250 mph which is not fast.

The Me109E is a tough customer no question and in the overall view there is nothing between them
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Old 09-23-2012, 05:17 PM
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I am sorry but this is rubbish.
LOL...

According to the Merlin III power curve, I actually being generous. RAM power for the Merlin III is only about 850 bhp.

weight 6050 lbs
Power 990 bhp
Level speed 247
Propeller efficiency 0.85
Wing area 242
wing efficiency 0.85
Dynamic pressure 206.8101695
Aspect Ratio 5.6
Mass 187.8881988

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Old 09-23-2012, 05:18 PM
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The German test establishments let alone the pilots in combat would have identified that the 109 turned better at high speed and would have given instructions to their pilots similar to those given to Typhoon, Tempest and USAAF fighters


Why do you think the trim on the Bf-109 is set to 400 kph IAS???

You do understand they can trim the aircraft for whatever speed they desired?? Having a fixed trim condition is a great way to set the combat speed for your airforce.
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Old 09-23-2012, 05:27 PM
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Quote:
Without this calculation the charts you posted are of little value

Problem is we don't have any good data on the 100 Octane.

The only data we have does not match our engine curves. Find some good data and I will be happy to do the calculations.

http://www.spitfireperformance.com/s...-rae-12lbs.jpg

Takes but a second to change the values.
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