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The term rigid rotor usually refers to a hingeless rotor system [16] [17] with blades flexibly attached to the hub. Irv Culver of Lockheed developed one of the first rigid rotors, which was tested and developed on a series of helicopters in the 1960s and 1970s. In a rigid rotor system, each blade flaps and drags about flexible sections of the root.
The Lockheed XH-51 (Model 186) is an American single-engine experimental helicopter designed by Lockheed Aircraft, utilizing a rigid rotor and retractable skid landing gear. The XH-51 was selected as the test vehicle for a joint research program conducted by the United States Army and United States Navy to explore rigid rotor technology.
Lockheed designed the Cheyenne as a compound helicopter, which combines a helicopter with fixed-wing features for increased performance, usually speed. The design included features such as a rigid main rotor, low-mounted wings, and a pusher propeller. The Cheyenne was powered by a General Electric T64 turboshaft engine.
Helicopters using or topics about use of the rigid helicopter rotor system Pages in category "Rigid rotor helicopters" The following 4 pages are in this category, out of 4 total.
In the mid-1960s, the helicopter was test flown by a number of government and military agencies, and also the military. The stability offered by the rigid rotor control system made the helicopter easy to fly, [2] and the lessons learned from the CL-475 rigid rotor were later used to develop the Lockheed XH-51 and AH-56 Cheyenne.
A rigid rotorhead has no flapping or lag hinges but does have pitch change bearings. The flapping and lagging movement is accommodated by flexible sections (commonly elastomeric bearings) at the blade root or blade attachment. When using composite blades, the blades can also flex to provide a flapping motion. Benefits of rigid rotor system are:
A far more serious problem was discovered on 7 September, when it was found that a blade from each rotor had collided while the aircraft was in flight. The Air Force therefore ordered Kellett to design a new, rigid rotor system for the XR-8. In the meantime, the two-bladed rotor system was trialled on the second prototype, beginning in March 1945.
The test program was broken down into stages as the Bo 105 comprised a new airframe, new rotor system, and a new engine; thus the flying Bo 105 prototype was initially equipped with a main rotor from Westland Helicopter's Scout rotorcraft and a pair of Allison Model 250 turboshaft engines instead of their production counterparts. [7]