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FM/DM threads Everything about FM/DM in CoD

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  #1  
Old 05-29-2012, 09:04 AM
Kurfürst Kurfürst is offline
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A bit of a clarification, I wasn't suggesting you made your tests badly, dear Ivan! However from what I remember from the SFS files is that the best climb speed of the 109E in the sim is defined as 270 kph instead of 250.
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  #2  
Old 05-29-2012, 11:50 AM
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Crumpp Crumpp is offline
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Quote:
My E4 Climb test flown at 250Kmh IAS 1.35/2350RPM (AUTO)
Did you write down the climb speeds you used as well?

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AFAIK the best speed for climb for the 109E in the sim is 270-280 kph IAS. This would be correct for the 109G, but the E's best climb rate was at 250 kph IAS.
Kurfurst is correct. All aircraft performance occurs at a specific velocity and it fixed by the design.

If the relationships of lift and drag are correct in the model, it will reflect in the best rate of climb speed.

Those airspeeds are listed in the appropriate Operating Handbook for the type.

I would also suggest conducting saw tooth climb schedules to determine the Vy and Vx of the models in the game.
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  #3  
Old 05-29-2012, 12:08 PM
IvanK IvanK is offline
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The speeds used for these tests are those listed in the RAE test schedules so as to replicate the conditions in the test to those of the chart being used to plot the data. These speeds conform with those climb schedules in the relevant Pilots notes.

I am aware of best climb speeds Vx Vy etc and methods used to determine them.
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  #4  
Old 05-29-2012, 01:04 PM
5./JG27.Farber 5./JG27.Farber is offline
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the 250 IAS is for sea level, it drops over altitude.

For example the Bf109T

Alt - 0m's
Speed IAS - 250

Alt - 1000m's
Speed IAS - 243

Alt - 2000m's
Speed IAS - 236

Alt - 3000m's
Speed IAS - 229

Alt - 4000m's
Speed IAS - 222

Alt - 5000m's
Speed IAS - 215

Alt - 6000m's
Speed IAS - 208

Alt - 7000m's
Speed IAS - 200


So merely maintaining 250kmh for a 109 climb test is actually not its best climb. Just a thought.

Last edited by 5./JG27.Farber; 05-29-2012 at 01:13 PM.
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  #5  
Old 05-29-2012, 01:15 PM
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Crumpp Crumpp is offline
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Quote:
the 250 IAS is for sea level, it drops over altitude.
Of course it does. This was another 100 page argument with folks on this forum. It changes with density altitude.

Quote:
the Bf109T
Those are the same as the Bf-109E Flugzeug-Handbuch.
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  #6  
Old 05-29-2012, 06:01 PM
Al Schlageter Al Schlageter is offline
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250mph IAS at 50 ft is not the same as 250mph IAS at 10,000ft?
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  #7  
Old 05-29-2012, 06:31 PM
von Brühl von Brühl is offline
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No, they aren't the same speeds. At 250IAS@50ft, you're pretty close to really going 250, at 10000ft, you're closer to 300mph.
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  #8  
Old 05-30-2012, 05:18 PM
5./JG27.Farber 5./JG27.Farber is offline
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Quote:
Originally Posted by Crumpp View Post
Those are the same as the Bf-109E Flugzeug-Handbuch.
Yes I know, thats why I bold'd the T for blind people I did not have those figures to hand but I did have those, so i used them to giver people an idea. It was just an example. If you are told best climb speed is 250km/h and you stick to that IAS throughout your test surely you have done it wrong? Same for spit, hurricane and flying pigs...

Last edited by 5./JG27.Farber; 05-30-2012 at 05:21 PM.
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  #9  
Old 05-30-2012, 06:01 PM
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Crumpp Crumpp is offline
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Quote:
Because there is a severe problem with the FM.
Where?

I don't see it in terms of speed and climb numbers. All aircraft performance is a percentage range even under fixed standard conditions.

Aircraft performance comparision is all relative.

The relative performance appears correct. All aircraft have a similar margin of error applied.

What more do you want? That is the most important thing in a "simulation".

It is much more important than specific performance. You can get the specific performance absolutely right within the percentage range and completely screw up the relative performance.

Quote:
If you are told best climb speed is 250km/h and you stick to that IAS throughout your test surely you have done it wrong? Same for spit, hurricane and flying pigs...
Today 09:57 AM
Exactly.

You were correct and I only posted to confirm you had the same ones as found for the Bf-109E.

You are correct too in not only do you to have to maintain the correct climb speed, you have to fly the test correctly.

Climb test generally are conducted by begining at a lower altitude and do not start until the climb is stabilized as well as at the starting target altitude. They end at a target altitude, too. That becomes a raw data point for that altitude band. Typically this is a 1000 foot band with the test airplane begining its climb 500 feet below and ending it 500 feet above that 1000 foot band. In otherwords, 2000 feet of altitude are required to estabilish climb rate data in a 1000 foot band.

Those "climb charts" guys like to quote are extrapolated from a few of these points and the raw data converted to standard conditions. There is insturment error, flight error, and pilot error in all it.

The pilot does not hop in and start from the runway to reach altitude with the stop watch running and marking the VSI. The chart is an idealized extrapolation of a few data points.

Last edited by Crumpp; 05-30-2012 at 06:05 PM.
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  #10  
Old 05-29-2012, 12:11 PM
Ernst Ernst is offline
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The relative climb speeds, i.e., the difference between the climb speeds of all aircraft each other are in good agreement with RL.

Since to me there is no difference in the "fighting" aspect if the strategy used was to degrade RAF fighters or upgrade the LW ones.

Obviously I prefer that the LW ones upgraded to its RL curves. But if someone is complaining that they were being shot down because the RAF are uncompetitive in climb area I disagree.
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