Aviation of Word War II
Medium Transport Aircraft
The DC-1 made its first flight on July 1, 1933. The aircraft was designated by the first letters from Douglas Commercial. The triumph of the next serial modification of the DC-2 aircraft was obvious, the aircraft conquered not only the American market, but also began to arrive in Europe. Just before Christmas, on December 22, 1935, Donald Douglas's new plane took off, equipped with more powerful engines and having a 50% increased passenger capacity. It was the famous DC-3. In August 1936, the DC-3 began entering service with American companies on domestic routes. In 1940, when the US Army began to issue contracts for the supply of a new transport aircraft under the designation C-47 (from Cargo), the only serious problem preventing the development of mass production was the lack of production capacity in Santa Monica, where the factory workshops were occupied. fulfillment of the European order for the production of DB-7. Consequently, the production of C-47s at a new facility in Long Beach, California.
When the US entered the war, the US military transport aircraft had only a small number of converted civilian vehicles and obsolete bombers. First of all, the military requisitioned at the factories unfinished, or not yet delivered to customers, passenger aircraft, including a large number of DC-3 of different options. From the beginning of 1942, construction began on the C-47 "Skytrain - Sky Train - Sky Train" with a cargo door on the left side and a reinforced cabin floor for transporting goods. They became the most common aircraft of the military transport aviation of the countries of the anti-Hitler coalition. As part of the Lend-Lease program, these machines were supplied to the Soviet Union. The planes supplied under Lend-Lease to England were called Dakota.
Construction . The basic design of the original production version of the C-47, built at Long Beach, remained virtually unchanged throughout production. The C-47 is a free-carrying low-wing aircraft, all-metal, with a working skin and a multi-spar wing. The wing is equipped with hydraulically driven landing flaps and light alloy ailerons and linen fabric. Pneumatic anti-icers were installed on the leading edges of the wing and tail.
Two main fuel tanks of 794 liters each and two additional ones of 760 liters each are located in the wing, it was envisaged to install additional fuel tanks in the fuselage.
Powerplant . Five series, built before the war, were equipped with two Cyclone engines SGR-1820-G2, G-2E, G-102, G-103 or G-203A from Wright with a capacity of 1000hp. (746 kW) to 1200 hp (895 kW). The C-47 "Skytrain" had 14-cylinder Pratt Whitney R-1830-93 Twin Wasp radial engines. The working volume of each is 30 liters, the rated power is 1050 hp. (783 kW) at 2290m and 1200 hp. (895 kW) on takeoff. The engines are equipped with three-bladed propellers of variable pitch "Hamilton Standard".
Comparison of C-47 and Li-2
Before the war, the Soviet Union acquired about two dozen DC-3s (As of June 1, 1941, there were 7 DC-3 in the Center units, 4 in the districts, and 7 in the Civil Air Fleet on December 1, 1940). Then they cost 115 thousand dollars. They were used both by civil aviation, which operated them on domestic and international lines, and in the Red Army Air Force, as military transport. DC-3 took part in supporting the hostilities at Khalkhin Gol and the "winter" war with Finland. They continued to serve in the years of the Great Patriotic War. In parallel with the purchase of aircraft, our country also acquired a license for the production of the DC-3-196 modification, mastered by the plant No. 84 named after V.P. Chkalov in Khimki, as PS-84 (Passenger aircraft plant No. 84). Later, with the beginning of the war, the plant was evacuated to Tashkent. During the war years, the Soviet Air Force received about 2,000 Li-2 aircraft, renamed in honor of Boris Pavlovich Lisunov, who led the development of the aircraft's production. Approximately 700 C-47 aircraft received Lend-Lease. The deliveries of C-47s from the United States stopped after the victory over Japan.
The C-47 was in many ways comparing favorably with the Li-2. The powerful engines provided higher speed and headroom as well as greater fuselage capacity. The motors were better mounted and easier to maintain. It took 62 man-hours to replace the M-82IR with the Li-2, and only 10 hours for the C-47 when removed along with the engine mount. With proper operation of the engine, its resource was developed 1.5-2 times of the guaranteed one. On the Li-2, the VISH-21 propeller had a resource before overhaul of only 50 hours, the American "Standard Hydromatic" had a guaranteed resource of 750 hours. In reality, the American propeller worked five times longer than the Soviet one.
A higher production culture also ensured a higher quality of the airframe. "American" was more reliable, its outer surfaces provided better aerodynamic characteristics. Compared to the Li-2, both the fuel and the hydraulic system were much more perfect. Unlike Soviet ones, American cranes did not flow, thus giving great pleasure to the mechanics. The cargo door of the C-47, which swung open to the sides, was much wider than the hatch with the door rising upward on the Li-2 (inherited from the experienced PS-84K and appeared in the series only in 1945). Two soft additional tanks of 375 liters each, if necessary located in the cabin, made it possible to increase the flight range to 3400 km. And the craftsmen also installed more capacious non-standard tanks. The flight duration increased to a day.
The instrumental and radio equipment of the C-47 turned out to be much more advanced than that of the Li-2. The set of instruments was much richer, they were also more accurate, more reliable, had a greater resource. The Li-2 radio operators could only be envious, looking at what was on the American cars: three different radio stations, a radio altimeter, a blind landing kit, and an automatic radio compass. At the same time, the American stations had 5-6 times more power, better stability of operation, and at the same time less weight and dimensions. On the C-47, the position of the radio operator was removed from the rotation zone of the propellers and was located in a special soundproofed wheelhouse. The only unpleasant fact is that the C-47s were exported with an incomplete set of equipment. The US Army Air Force provided its vehicles with many more, as evidenced by empty stands and unnecessary signs. But even in this form, the C-47 was much superior in this respect to both transport aircraft and bombers of the Soviet Air Force.
On the C-47, the issues of operation at low temperatures were well thought out. American designers provided for everything that existed at that time - anti-icers on the wing and empennage, washing the propeller blades and glass of the pilot's cockpit with alcohol mixtures, heating the cockpit and interior. Pneumatic anti-icers "Goodrich" worked more efficiently than domestic thermal ones. The "windshield wipers" with a hydraulic conduit were also rated higher in comparison with the electric ones on the Li-2. Hot-air heating did not require additional operations when turned on. The Li-2 had a steam-air system with a water boiler. The flight mechanic who served her was called the "stoker". He had to tinker a lot to get the "stove" to work reliably. Otherwise, this device produced a cloud of steam that filled the pilot's cabin.
Li-2 had to warm up for 40 - 45 minutes before takeoff. The Douglas had a gasoline dilution system that diluted oil not only in the engine, but also in the propeller hubs. The Americans filled the hydraulic system with a frost-resistant mixture. In the Russian frosts, the C-47 had to insulate only the breather pipes between the engine and the oil tank. The C-47 was reliable and economical. According to Soviet statistics, in the first half of 1945, the number of accidents per aircraft of this type for the C-47 was 2.5 times less than for the Li-2.
Unlike the Li-2, the C-47 did not have standard defensive weapons. This was typical of all American transport aircraft. Cases of the installation by the Americans of machine guns on the C-47 are very rare, usually they were not installed here either. But the Americans worked, as a rule, under the conditions of their air supremacy. In our country, if necessary, to act in the front-line zone and, especially over the enemy's territory, the lack of weapons became a significant disadvantage. There are known cases of the installation on the C-47 of the upper turret UTK-1 with the UBT machine gun on the model of the Li-2. There were even vehicles with an additional pair of ShKAS machine guns in the rear windows of the cockpit.