Performance Tests-And somewhat odd results

[USARStarkey]

So I decided to do some top speed and acceleration tests in DCS with the Su-27 and F-15 in a clean configuration. I expected to find the F-15 faster at all altitudes, as virtually every source including the dcs encyclopedia states the F-15 is faster at sea level and at high alt. Here are the results I got:

 

auto pilot was used to keep aircraft level

 

SL: 797knots both aircraft

 

1000ft- 806knots F-15 810knots-Su27

 

10000ft- 918knots F-15 920knots Su-27

 

20000ft- 1040 F-15 Su-27- 1050

 

30000ft- 1280 F-15 Su-27 -1135

 

trend continues above 30k, with f-15 remaining much faster, but i cant remember all the data lol

 

Acceleration tests on the other hand were as i expected: F-15 wins even when top speeds are close. Being faster to speed right except for the the last couple of knots before max. At alts where it is also faster, it simply leaves the flanker floundering behind. Not surprising since it has a better T/W ratio.

 

 

I think it is very odd that the F-15 is practically neck and neck with the 27 up to 30k, particularly at sea level, where it is often quoted as being faster. Does anyone know anything about this? I put very high stock in ED's FM's, although all sims are subject to error. What is going on here.

[TAW_Blaze]

Those top speeds are irrelevant in 99% of the cases.. btw, how much fuel did u have in the su and the eagle?

[Silver_Dragon]

and F-15C and Su-27 only have SFM meanwhile AFM has in develop.

[Bourrinopathe]

As stated above it may be some imperfections related to the SFM.

Check the graphics on this page.

The fuel load is also very important (for example, the official T/W ratio for the Su-27 was mesured with 56% fuel load).

 

It will be interesting to compare the improvements with the new AFMs.

And being as close as possible to the real data is a difficult task and that's partly why it takes so much time to release the AFMs.

 

I tested a few simple performances myself for the Su-27 (takeoff distance on full AB, climb rate, max speed, and it has a remarkable level of fidelity - with my very simple tools).

[USARStarkey]

Thanks for the response guys. This was bothering me a little since before now I have never noticed any discrepancies in the FM's. Thanks especially for the graphs and stuff. I think it is cool that ED actually shows the differences between their FM and the Real plane instead of trying to hide it like so many other companies do.