Yakovlev Yak-24
| Yakovlev Yak-24 | |
|---|---|
 in the Monino Museum |
|
| Type: | Transport helicopter |
| Design country: | |
| Manufacturer: | |
| First flight: |
3rd July 1953 |
| Commissioning: |
1955 |
| Number of pieces: |
40 to 100 |
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The Jakowlew Jak-24 ( Russian Яковлев Як-24 ) from the Soviet design office Jakowlew was a helicopter with a tandem rotor arrangement . The first flight took place on July 3, 1953. The model became known as the flying wagon (Летающий вагон) and carried the NATO code name "Horse", in German horse .
The data on the Yak-24 from various sources are inconsistent and sometimes contradictory.
development
In the late summer of 1952, the Soviet Union decided to close the gap in the development of large transport helicopters that had resulted from the discontinuation of helicopter development in World War II with the United States . It therefore awarded two development contracts. An order for a twelve-seater machine in a main / tail rotor arrangement went to the design office Mil , the second order for the development of a 24-seater helicopter with a tandem configuration of the rotors went to the Jakowlew office. The task was to get the respective test samples into the air within a year.
Jakowlew made two prototypes for flight tests, and two more were built for static and dynamic tests on the ground. The two engines and the dynamic components of the rotors came from the Mil Mi-4 or were identical. Each engine was able to drive one or both rotors. However, this arrangement, which was also intended to serve as safety in the event of an engine failure, caused strong vibrations. Right from the start, these vibrations hindered further development. They were favored by the insufficient rigidity of the central part of the covered steel lattice fuselage and the fabric-covered aluminum rotor blades. So it happened that during the dynamic load test, when the helicopter was hovering just above the ground with no crew attached to steel cables, the attachment of the rear engine broke after only 178 hours. According to one engineer, this caused the rear rotor to tip forward and start to dismember the machine. With another machine, the test pilots Sergei Browzew and Yegor Miljutitschew finally carried out the first flight after several short test jumps, during which strong vibrations also occurred. The cause could ultimately be identified and the problem solved by shortening the rotor blades by 50 centimeters. In the winter of 1953, the second prototype went into state testing and was also lost there when all four steel cables tore during further unmanned tests and the Jak-24 fell from a height of eight meters and was destroyed. With the last airworthy specimen, the testing could finally be brought to an end.
Production and use
The series machines were delivered with steel rotor blades lengthened to 21 m and an aluminum-clad fuselage. The chassis consisted of four wheels. The transport capacity was up to 40 armed soldiers or 18 injured.
Production probably began as early as 1954, other sources speak of delays of 30 months and a full start of series production in 1955. In July 1955, the machine was presented to the public for the first time at the flight day in Tuschino when four helicopters were exhibited.
In December 1955, a Jak-24 set two new world records for payload height for its class when it brought a load of 2000 kg to an altitude of 5082 m and a load of 4000 kg to 2902 m.
The first machines had a V-tail, but they were later changed to horizontal guide surfaces with rectangular end plates. Designs with and without small additional control surfaces were observed on both guide surfaces.
In 1957 the Jak-24U version was introduced as the standard model. She had an improved rotor, a reinforced hull with more cargo capacity and could also carry external loads. The helicopter could lift 3.5 t vertically.
Civil models for Aeroflot were also planned, but probably never carried out. The helicopter was only used by the Soviet military. About 100 pieces were built, other sources speak of only about 40 pieces. The company was overshadowed by various accidents.
Versions
- Jak-24A: Aeroflot model for 30 passengers of Aeroflot, was not executed
- Jak-24K: Aeroflot luxury model for eight to nine passengers, was not executed
- Jak-24P: Aeroflot model for 39 passengers with two 1500 HP Isotow engines, was not executed
- Jak-24U: Standard model of the Soviet Army
Technical specifications
(Partly contradicting information from other sources in brackets)
| Parameter | Data |
|---|---|
| Years of construction | 1953–? |
| Rotor diameter | 21.00 m |
| length | 21.34 m (24.40 m) |
| Empty mass | 10,600 kg |
| Takeoff mass | 14,270 kg (15,830 kg) |
| payload | 3,000 kg |
| Top speed | 195 km / h |
| Summit height | 5,000 m |
| Range | 430 km |
| Passengers | 30 soldiers or 18 injured lying down |
| crew | 1 |
| Engines | two Schwezow - Sternmotoren ASch-82 W |
| power | each 1250 kW (1,700 PS) |
| Armament | 1 machine gun 12.7 mm |
