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Some rotary wing aircraft are designed to stop the rotor for forward flight so that it then acts as a fixed wing. For vertical flight and hovering it spins to act as a rotary wing or rotor, and for forward flight at speed it stops to act as a fixed wing providing some or all of the lift required. Additional fixed wings may also be provided to ...
All three classes have been studied for use as lifting rotors and several variations have been flown on full-size aircraft, although only the vertical-axis rotary wing has become widespread on rotorcraft such as the helicopter. Some types provide lift at zero forward airspeed, allowing for vertical takeoff and landing (VTOL), as in the helicopter.
An example of the effect of rotor blade number is the UH-72 (EC145 variant); the A model had four blades, but the UH-72B was changed to five blades which reduced vibration. [24] Other blade numbers are possible, for example, the CH-53K , a large military transport helicopter has a seven blade main rotor.
Conventional rotary-wing aircraft use a set of complex mechanical gearboxes to convert the high rotation speed of gas turbines into the low speed required to drive main and tail rotors. Unlike powerplants, mechanical gearboxes cannot be duplicated (for redundancy) and have always been a major weak point in helicopter reliability.
The Boeing X-50A Dragonfly, formerly known as the Canard Rotor/Wing Demonstrator, was a VTOL rotor wing experimental unmanned aerial vehicle that was developed by Boeing and DARPA to demonstrate the principle that a helicopter's rotor could be stopped in flight and act as a fixed wing, enabling it to transition between fixed-wing and rotary-wing flight.
The Broken Wing Award is a United States Army award for successful execution of an autorotation under emergency conditions. The requirements for the award, as stated in Army Regulation 672-74, are, "An aircrew member must, through outstanding airmanship, minimize or prevent aircraft damage or injury to personnel during an emergency situation.
A wing is a ballroom dance move, in the silver syllabus of competition waltz.It is a transitional movement that repositions the follower to the leader's left side. Thus, while many dance moves can precede a wing, only a reverse movement can follow a wing, such as a reverse turn, double reverse spin, Telemark, fallaway reverse, or drag hesitation.
It is a non-categorized, index list of specific dances. It may also include dances which could either be considered specific dances or a family of related dances. For example, ballet, ballroom dance and folk dance can be single dance styles or families of related dances. See following for categorized lists: List of dance style categories