The Straight-5 is the first multi-purpose helicopter made in China, and the beginning of helicopter research and application in the new China. It was initially codenamed "Tornado 25" and was based on the Soviet Mi-4 helicopter.
The Straight-5 can be used for material and personnel transportation, life-saving, and border patrol, and production ceased in 1980. The Straight-5 is powered by a piston-7 air-cooled star 14-cylinder engine with 1,770 hp (1,250 kW). The main propeller is 21 meters in diameter, 16.8 meters long and 4.4 meters high. The landing gear is fixed four-point type, the front landing gear lateral wheelbase 1.53 meters, the main landing gear wheel 3.82 meters, the front main wheelbase 3.79 meters. The cabin volume reaches 16 cubic meters, a side hatch, a clam rear hatch.
It could carry 11 heavily armed soldiers at a time, or eight wounded stretchers and a medical officer. The engine compartment is located in the nose and drives the main rotor at the top of the nacelle and the tail rotor at the rear via a driveshaft. The cockpit is located in the upper front part of the nose, with a two-person crew, both of whom can perform flight maneuvers independently. It can carry 1.2 tons of cargo and 1.35 tons when lifted.
The cabin of the Straight-5 can load and unload the Beijing 212A Jeep, which is often used as a carrier for the Type 78 82-millimeter recoilless gun to provide fire support for airborne troops. More powerful is the Type 75 105 mm recoilless gun, developed in 1964 to destroy main battle tanks, armored vehicles and fortified field fortifications, etc., and designed and finalized in 1975. The gun consists of two parts: the gun body and the gun frame. It adopts the principle of high and low pressure firing and the combination of muzzle retractor and reduced nozzle.
Still carried by Beijing-212A light off-road vehicle. Initial velocity (armor-breaking shells) 503 m / s, maximum range (antipersonnel blast grenades) 7,400 m, effective range (armor-breaking shells) 1,100 m; direct-fire distance (armor-breaking shells) 580 m, the rate of fire of 5 to 6 rounds / min, the gun body length of 3409 mm. The tail rotor is a 3-piece propulsive fiberglass prize blade, and the pilot's cockpit is located in the upper front of the fuselage with 2 seats in the cabin. The landing gear is 4-wheeled; power plant: 1 air-cooled 14-cylinder plug-7 engine with a maximum power of 1250 kW (1700 hp).
From 1963, when the helicopter was finalized and transferred to mass production, to 1979, when production ceased, the straight-5 helicopter ****produced 545 helicopters, including the basic model of 437, the passenger type of 86, the forestry type of 7, the water life-saving type of 13, the sea survey type of 2. 1966 is the factory's production of the most models of the straight-5, and the largest number of years. This year *** produced 102 straight-5 helicopters, including 58 basic models, 30 passenger models, 5 forestry models, 7 water-saving models and 2 aerial survey models.
Because of mass production, the production cost of the aircraft began to drop dramatically, and the selling price began to fall steadily, selling for 1,581,000 yuan in 1963, down to 970,000 yuan in 1966, and even down to 480,000 yuan in 1967.
Dimensional data: rotor diameter of 21 meters; tail rotor diameter of 3.6 meters; length of 25.015 meters; fuselage length of 16.79 meters; height of 4.4 meters; maximum width of the fuselage of 2 meters; front landing gear transverse wheelbase of 1.53 meters; the main landing gear transverse wheels of 3.82 meters, the front main wheelbase of 3.79 meters; the cockpit volume of 16 meters;
Weight data: empty weight 5121 dry grams; maximum takeoff weight of 7600 kg. Maximum takeoff weight: 7,600 kg; normal takeoff weight: 7,250 kg; maximum payload: 1,000 kg;
Performance data: Maximum level flight speed: 210 km/h; maximum rate of climb: 4.3 m/sec; dynamic ceiling: 6,000 m; hovering altitude: 2,000 m; maximum range: 520 km; endurance: 3 hours and 40 minutes;
The straight-5 series of models: prototype: 382 m lateral wheels; 379 m front main wheel spacing; cockpit volume: 16 m;