During World War II, the Allies supplied the P-39 Airacobra fighter to the USSR. Before the war, the Americans announced a competition for a fighter for their army. Within the framework of this competition, the aircraft was created by Bell Firm. In 1939, he was accepted into service, for lack of anything better. But the military were unhappy with him - an iron, and even a dangerous one. After the ammunition was used up, the nose was relieved, and the aircraft showed a tendency to stall into a tailspin. In short, as soon as the opportunity arose, the Aircobra began to be replaced.
Well, naturally, the firm began to look for other sales markets. In 1940, France signed a contract for the purchase of a batch of P-39, but was captured before supplies began. Bell took a hustle and agreed to deliver these planes to England. But the British said that they would not buy the plane in this form. As a result, the Aircobra was modified. Among the modifications, a 37 mm cannon was installed and the engine power was increased to 1150 hp. After that, deliveries to England began under the P-400 index.
In this configuration, the Airacobra was also supplied to the USSR, but under the designation P-39. This is where one of the mysteries of the twentieth century appears: why, in general, an unremarkable plane in the hands of Soviet pilots covered itself with unfading glory. It should be borne in mind that in the USSR they tried not to advertise the bourgeois military equipment supplied under Lend-Lease. And of course, we have not heard the official recognition of the Aircobra as one of the best fighters of the first half of the war. But in fact it was.
Let's try to solve this riddle.
You can often hear, they say, the Russians did not have standing planes, and for them the inferior one is good. Without even noticing that by this very supernatural skill is attributed to the Russian pilots. No guys. War is an objective judge; you cannot play it on chaff.
So what's the deal? From the memoirs of veterans, we know that all the Aircobras that entered the USSR before being sent to the unit were finalized:
1. Among the improvements was the "reinforcement" of the frame of the rear fuselage.
2. Improvement was made to shift the center of mass forward to reduce the tendency to spin. But the problem could not be fully resolved. What kind of revision is unknown.
3. Engine adjustments were also made on all aircraft.
We disassemble in order.
Point 1. Why is the amplification in quotation marks? This is probably not an enhancement at all. This was the same unknown revision from point 2. The task was to move the centering forward. How can I do that? Lighten the tail? Impossible, everything is already licked there, you will not find an extra gram. Pour concrete ballast into the bow? Not seriously. Move the wing back 200 mm? Not real, as part of the revision. But to move the tail forward, shortening the entire aircraft by 200-250 mm, is quite realistic. True, this will not completely solve the problem, but at least something.
The people who performed the work might not know why it was being done. We decided that for strengthening. So the legend went for a walk that the Airacobras' tails fall off every now and then during overloads. Although the Americans fought without revision, and nothing fell off them.
Item 3. What is engine tuning? When a new engine has been created, it is put on a test bench, tested and the operating mode is selected. Take a hypothetical six-liter engine for example. Once throttled, you can use it to drive a generator. Somewhere in the mountains, at an unattended weather station, giving out only 50 hp, it will work for 10 … 12 years, without a single breakdown. Then, make him a major overhaul, and it will work the same amount. The same engine with other adjustments will work on the tractor for 5-6 years, producing 80 hp. Or you can put it on a plane, squeezing out 300 hp. Only now the resource will drop to 50 hours.
In the USSR at that time the situation with engines for fighters looked like this: in order to reduce the weight of the aircraft as much as possible, every drop was squeezed out of the engines. The resource of the engines on the fighters was 100 hours. The military asked for at least 200, like the Germans, but the industry could do what it could. No, you can do 200 hours, only the power will drop by 300 horsepower. And there is no point in reducing the power, the plane will be shot down on the very first flight, and the engine's built-in resource will fly into the pipe.
And so, at this very time, the Aircobra arrives, whose motor is weak, but the motor resource is 400 mph. Well, and here it is already quite obvious what to do with him. Naturally, tighten it up, let the motor resource decrease by 200-220 m.h. But to raise the power from 1150 to 1480-1500 hp. They say that “with a good engine, the fence will fly,” and with such power, the Air Cobra will really climb into the leaders, pushing all sorts of messengers and others.
A powerful motor is certainly good. Yes, only you still need to realize its power. But here the P-39 is doing just fine. First, the variable pitch propeller matches the motor. And secondly, the landing gear with the nose strut made it possible to supply a large-diameter three-blade propeller (3200 mm), which our Yaks and La could only dream of, since they barely climbed over the three-meter barrier. Yes, in this matter I had to fight for every 100 mm. The larger the diameter of the propeller, the less angular velocity it needs to rotate in order to obtain the same thrust. And, therefore, less power loss.
And so it happened that in the USSR it was not at all the Airacobra that everyone knew. According to the passport - a gray mouse, but in fact a ferocious and toothy beast.
