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The tail rotor is powered by the helicopter's main power plant, and rotates at a speed proportional to that of the main rotor. In both piston and turbine powered helicopters, the main rotor and the tail rotor are mechanically connected through a freewheeling clutch system , which allows the rotors to keep turning in the event of an engine ...
However, the rear rotor works in the aerodynamic shadow of the front rotor, which reduces its efficiency. This loss can be minimized by increasing the distance between the two rotor hubs, and by elevating one hub over the other. [4] [5] Tandem-rotor helicopters tend to have a lower disk loading than single-rotor helicopters. [6]
The Boeing Vertol CH-46 Sea Knight is a medium-lift tandem-rotor transport helicopter, furnished with a set of counter-rotating main rotors in a tandem-rotor configuration. It was typically powered by a pair of General Electric T58 turboshaft engines, which were mounted on each side of the rear rotor pedestal; power to the forward rotor was ...
For storage, the V-22's rotors fold in 90 seconds and its wing rotates to align, front-to-back, with the fuselage. [111] Because of the requirement for folding rotors, their 38-foot (12 m) diameter is 5 feet (1.5 m) less than would be optimal for an aircraft of this size to conduct vertical takeoff, resulting in high disk loading. [108]
Tiltrotor design combines the VTOL capability of a helicopter with the speed and range of a conventional fixed-wing aircraft. For vertical flight, the rotors are angled so the plane of rotation is horizontal, generating lift the way a normal helicopter rotor does. As the aircraft gains speed, the rotors are progressively tilted forward, with ...
Most-produced Western helicopter; nicknamed "Huey". UH-1Y derivative in production. 1959–1976 Bell 206 Jetranger: 8,460: manufactured at Bell plants in United States and Canada: Also made under licence by Agusta in Italy and Commonwealth Aircraft Corporation in Australia: 1966–2010 Eurocopter AS350: 7,000 + [1] France: Airbus Helicopters ...
Sikorsky states that the X2 has the same noise level at 200 knots that a regular helicopter has at 100 knots. Above 200 knots, the rotor speed is reduced from 446 to 360 RPM [35] [36] to keep tip speed below Mach 0.9, the rotor disc is slightly nose-up, and the lift-to-drag ratio is about twice that of a conventional helicopter. Hands-off ...
A coaxial-rotor aircraft is an aircraft whose rotors are mounted one above the other on concentric shafts, with the same axis of rotation, but turning in opposite directions (contra-rotating). This rotor configuration is a feature of helicopters produced by the Russian Kamov helicopter design bureau.