The Max Speed was recorded by the russians for the La-5 with the M-71F engine but not for the La-7 with M-71F engine which is undfortunate. So today i wanted to do something interesting. What could the La-7 M-71F achieve if it was tested for top speed?
La-5F (M-71F)
Empty Weight: 2840kg
Loaded Weight: 3526kg
Engine: M-71F
WEP: 2200hp at SL / 2250hp at 1400m / 1975hp at 3400m
Military: 2000hp at SL / 2050hp at 1800m / 1800hp at 3800m
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Max Speed: (WEP)
612km/h at Sea Level
685km/h at 5500m
Lets see how well maths supports the Soviet Flight Test results
La-5F sources state 551-560km/h at SL with 1700hp (I find the 560 value most accurate)
So how fast would it go with 2200hp doing calculations?
2200/1700 = 1.294118
3√ 1.294118 = 1.089744
560 x 1.089744 = 610km/h
So in calculation im only 2km/h off from what the soviets achieved also meaning the M-71F engine doesnt really effect the overall drag off the plane compared to the M-82F engine.
Unfortunately for the La-7 (M-71F), there were no recorded max speed results. But not to worry lets do some maths
La-7 can do 613km/h at SL with 1850hp.
2200 / 1850 = 1.189189
3√ 1.189189 = 1.059458
613 x 1.059458 = 649km/h
So as far as aware...
La-7 (M-71F)
Empty Weight: 2849kg
Loaded Weight: 3505kg
Engine: M-71F
WEP: 2200hp at SL / 2250hp at 1400m / 1975hp at 3400m
Military: 2000hp at SL / 2050hp at 1800m / 1800hp at 3800m
-
Max Speed: (WEP)
649km/h at Sea Level
722km/h at 5500m
Now since both La-5F (M-71F) and La-7 (M-71F) have the same engine and pretty much same loaded weight, their rate of climb should be the same.
La-5F (M-71F)
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La-7 (M-71F)
La-5F (M-71F)
Empty Weight: 2840kg
Loaded Weight: 3526kg
Engine: M-71F
WEP: 2200hp at SL / 2250hp at 1400m / 1975hp at 3400m
Military: 2000hp at SL / 2050hp at 1800m / 1800hp at 3800m
-
Max Speed: (WEP)
612km/h at Sea Level
685km/h at 5500m
Lets see how well maths supports the Soviet Flight Test results
La-5F sources state 551-560km/h at SL with 1700hp (I find the 560 value most accurate)
So how fast would it go with 2200hp doing calculations?
2200/1700 = 1.294118
3√ 1.294118 = 1.089744
560 x 1.089744 = 610km/h
So in calculation im only 2km/h off from what the soviets achieved also meaning the M-71F engine doesnt really effect the overall drag off the plane compared to the M-82F engine.
Unfortunately for the La-7 (M-71F), there were no recorded max speed results. But not to worry lets do some maths
La-7 can do 613km/h at SL with 1850hp.
2200 / 1850 = 1.189189
3√ 1.189189 = 1.059458
613 x 1.059458 = 649km/h
So as far as aware...
La-7 (M-71F)
Empty Weight: 2849kg
Loaded Weight: 3505kg
Engine: M-71F
WEP: 2200hp at SL / 2250hp at 1400m / 1975hp at 3400m
Military: 2000hp at SL / 2050hp at 1800m / 1800hp at 3800m
-
Max Speed: (WEP)
649km/h at Sea Level
722km/h at 5500m
Now since both La-5F (M-71F) and La-7 (M-71F) have the same engine and pretty much same loaded weight, their rate of climb should be the same.
La-5F (M-71F)
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La-7 (M-71F)
