Also to consider - response of engine to throttle. Direct injection engine had good throttle response, so power available quicker. Its only real power that accelerates. Take off on other hand is not very good measure of accelerate - it is effected, but, there is also other factor. Like flap etc.
Nothing new?
Well from soviet tests*:
Time to reach
0.95Vmax from
0.7Vmax at 1000 m height horizontal , in
minutes.
1)Yak-9 with M-105PF-2:
0.88
2)Yak-9 with M-107A:
0.45
3)Me-109 G-2:
0.7
4)FW-190
1.12
Speed increase from 0.7Vmax for 1 minute after putting on full gaz manifold, in
Km/h
1) 144
2) 175
3) 150
4) 128
Time to decrease speed from 0.9Vmax to 07Vmax, in minutes
1) 0.35
2) 0.37
3) 0.48
4) 0.52
So?
- It's unsurprising that the FW-190 has the bigger inertia due to it's weight, and the poorest acceleration due to low power to weight ratio (hp/kg).
-Between all reasons that can lead to delay in acceleration the response to throttle exists, but at the last places by order of importance.
The poorest engine respunse belongs to the klimov 107 A but it plays at 2-3 secund difference.
The
main factor is the power to weight ratio. I have already furnished the acceleration F=m "gamma" formula. So "gamma" is high when
F (thrust (~ power) is high, and
m low.
I swear that the best Fiat Panda with a 45 hp FIRE (Fully Integrated Robotized Engine) even controlled with a Cray-One computer 1000 cc will
never reach a 300 hp Ferrari acceleration, even with a single (big) carburettor taken from mower.
Unfortunately i don't have the
mesured La-5 FN acceleration.
But we can make rough estimation; suppose both FW and La-5 are cruising on 300 km/h. Now they see each other, in order to fight they need to reach 600 km/h.
To simplify they have the same Cd.
You need to increase power by 2^3 and thrust by2²!
It will make you the classical differential equation formula: 1 -exp (t) etc...So the La-5 will be 1.23 faster in speed acceleration and make more than some about minute difference, even if pilot is loosing some secunds more to adjust pressure, throttle and gaz...
* Yak fighters
Stepanets
1992