FM's the State of Play with empasis on Climb performance.

[Crumpp]

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.

the Bf109T

Those are the same as the Bf-109E Flugzeug-Handbuch.

[Al Schlageter]

250mph IAS at 50 ft is not the same as 250mph IAS at 10,000ft?

[von Brühl]

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.

[Crumpp]

This was another 100 page argument with folks on this forum.

above

[robtek]

And don't you forget, german plane = km/h NOT mph!

[IvanK]

Reducing IAS climb schedules were used in all the climb tests as per source documentation.

Here is the source data used for the Spit II climb. IAS is in actuality in MPH not KNOTS The line under knots is actually a misaligned strikeout line that should be going through the KNOTS label ... as it does on all other pages of the document. Given the test was only done to 16,000ft the IAS reduction was only in the order of 5 MPH and then only in the later portion of the test climb.



As reported previously based on timed climb segments the VSI on the Spitfire and Hurricane is over reading by around 500fpm.

[SEE]

Many thanks IvanK, I have the utmost respect for you and the tests you carried out - I hope that your assessment of the beta FM has been passed on to the devs (if not already noted by them).

[5./JG27.Farber]

Originally Posted by Crumpp

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...

[Crumpp]

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.

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.

[5./JG27.Farber]

Crump are the fligth models for the SpitIa and Hurri rotol correct then?