Aviation of Word War II

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Po-2M

On a Three-float Chassis

Polikarpov

Po-2M, (Po-2P - float) . Released in 1944. It was an improved version of the U-2 with the M-11F engine, mounted on a three-float (one main and two underwing) chassis designed by NN Polikarpov. The main float, designed in accordance with the recommendations of TsAGI, had a displacement of 2310 liters and dimensions of 6.4 × 1.0 × 0.65 m. To lift the aircraft to land, a trolley on 2 wheels was brought under the main float. The aircraft was equipped with a variable pitch propeller and equipment for air starting the engine. Small arms consisted of a pivot mount for ShKAS or DT machine guns. Bombs - 200 kg. An additional radio was installed from the equipment. The motor was hooded.

Tests of the aircraft were delayed due to the absence of a test pilot in the design bureau. Polikarpov turned to I.V. for help. Chetverikov, but that also did not have a free pilot. The plane with the M-11D engine successfully passed state tests from July 8 to September 8, 1944. It was not built in series.



Po-2M Specification
Crew 2
Dimensions
Wing span, m 11.40
Wing area, m² 33.20
Length, m 8.90
Powerplant
1 × PE radial M-11D, power hp 1 × 127
Weight, kg
Empty weight 849
Loaded weight 1350
Performance
Maximum speed, km/h 144
Cruising speed, km/h 126
Service range, km 500
Service ceiling, m 2500
Armament
1 × 7.62-mm machine gun DT (DA) or ShKAS, bombs, kg 100 (4×25)

The aircraft itself has been significantly improved. The ailerons and elevators of the Po-2M were equipped with aerodynamic compensation, as was done on the Po-2ShS; a trimmer was installed on the left elevator to reduce the load in flight, and the control cables in the tail section were hidden in the fuselage. The engine hood has been improved, the variable pitch propeller VISH-327 with a diameter of 2.5 m is equipped with a fairing spinner. To increase the flight range, an enlarged fuel tank with a capacity of about 200 liters, a GS-350 generator, and an RSI-4 transceiver radio station were installed on a single-float aircraft.

Armament included 100 kg of bombs - 4 FAB-25 on underwing holders and a DT machine gun on a pivot mount. A new NP-Po-2 night bomber sight, mounted on the starboard side, was used.

Powerplant. Subsequently, it was planned to install a more powerful M-11F engine of 150 hp. with air launch, but in its absence, M-11D 127 hp was installed.

During the tests, the aircraft performed 17 flights. According to its flight data, the aircraft, with an alignment of 31.7% of the MAR, did not have noticeable differences from the ground version of the Po-2VS. The longitudinal and lateral stability was assessed as sufficient, the stability on planing was good, the exit to the redan was easy and smooth, the water landing was soft. Takeoff and landing on water, according to the pilot, turned out to be easier than that of the land version. Thanks to the water rudder, the seaplane was well controlled on the water, at low gas the turning radius was 18-20 meters. When assessing seaworthiness, the testers allowed its subsequent operation with a wind wave of up to 0.5 m.

The longitudinal stability turned out to be somewhat worse than that of the wheeled Po-2, so in the future it was assumed to increase the area of ​​the vertical tail.

Photo Description

Drawing Po-2M

Po-2M

Bibliography

  • World of Aviation №1 2000 /Vladimir Ivanov, Andrey Korshunov, Vladimir Perov, Oleg Rastrenin/
  • Polikarpov U-2: "Heavenly slug" /Mikhail Maslov/