Acceleration comparisons

[gaunt1]

Originally Posted by horseback

The tables in Soviet Combat Aircraft Volume 1 by Yefim Gordon and Dmitri Khazanov show a top speed of 573 kph at sea level for the -5FN and 551 kph for the -5F, and I got a (rounded off) 560 kph indicated at 100m for the -5FN and a (rounded off) 530 kph for the -5F. True airspeed would be somewhere north of 578 kph and 548 kph respectively, so both aircraft models appear to be close to the RL records. Further reading seems to indicate that the -5F was flown most often with the canopy open in practice, due to accumulated exhaust fumes and (possibly) poor visibility, so there may be some compensation for that in the FM.

However, this is an acceleration comparison, and the extra horsepower of the M-82FN translated into better acceleration even more than better top speed, which with the similar airframes meant about the same major limiter to top speed; the -5FN reaches its intervals sooner (and really, it is only a second and a fraction difference at the initial stages, but the differences are cumulative--they add up over time).

Let's look at another indicator of the added power of the M-82FN taken from the same book I referred to earlier; the takeoff runs of the production La-5F were measured at 350m--compare that to the production La-5FN's 290m. That's a good deal more than a 10-12% difference right there, and I think it means that the FMs for these two aircraft are fairly accurate in this respect within the limits of the game engine.

cheers

horseback

That book is a good source, the data matches the NII VVS test results.
Regarding the exhaust fumes, I think the FN still had the same problem.
Im not a too good pilot, so I used IL2 compare for La-5F and FN speed data, and it shows close to prototype performance for the FN. Turn performance is also corresponds to prototype La-5FN. This is why I think that acceleration is also based on that.
I dont know how accurate IL2 compare is, but one thing is sure, all Lavochkins benefit from using Forsazh at all altitudes, while in reality it could be used only up to ~2700-3000m.