Hello,
It would be a pity to let this thread die without an interesting link from a russian language site:
Ôîðóì ñàéòà www.airforce.ru: Ñòàòüÿ
This are TsAGI (soviet NACA) calculations for Yak-1 equipped with foreign engines in 1943.
What for? Tha
facts are that soviet asked the highest level* to
stop Hurricane deliveries in autumn 1942, and
P-40 deliveries in summer 1943 in favor of the others planes. Nevertheless deliveries of
unwanted fighters were to be continuated until the end, for economical and industrial reasons.
(* personal letter from Stalin to Churchill)
So if they were
not interested from Hurricanes and P-40's soviets made an attempt at least to recover their engines for local produced planes, scrapping airframes for spart pieces and metalurgy.
Concerning the Yak-1
With different engines: first column M-105PF, Secund column Merlin XX, Third with Allison V-1710
Dry weight: 600, 650, 635
Section: 0.74,...
Power at height (scd stage of the supercharger): 1180, 1200,....
Rated hight (with dynamic pressure): 3700, 6800,...
Power at SL (nominal = Cont Course): 1210, 1135, 900
Combat Power at SL (3 minutes): No CP, 1300, 1135
Max speed at SL at CC: 530, 515, 480
Max speed ar SL at CP: _ , 540, 520
Max speed at height: 597, 665, 615
Max range at 0.9 Vmax: 650, 720, 780 at height
In conclusion it appears that Merlin XX equipped Yak-1 was the fastest at height (665 km/h). Unfortunately such result was obtained at 6000-7000m, and presented no interest for soviet air forces, since 90% of all airfights took place under 4000m height. At low and medium altitudes the M-105PF Yak-1 reminded the best, except near SL, if combat power of Merlin XX was used.
Range with the Merlin engine increases from 70 extra km.
By the other side with the ViSh 3.1m prop, take off distance increased in 130 extra meters. It was not possible to adapt a 3.45 m prop. for a small airframe as the Yakovlev 1. Using a experimental max. 3.25 m prop, take off distance was increasing in 80 meters only, but the real solution was to adapt a new reduction gear and modified crankshaft for synchronisation system.
AFAIK, allied LL comissions refused to adapt any engine production to soviet requests, and also refused for important engines deliveries without airframes.
But, on the other side why allied comission never asked for comparative trials of the soviet planes?
I'm not shure that Yakovlev's fighter was better than Hurricanes and Wharhawks at all points. At least it could have been a match to the Bf 109F or G in 1942-43 either wih Merlin or Allison engines. J'm sorry for the Hurrie and P-40 supporters, but at that point in 1943 they were not competitors anymore.
Regards
VG-33