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Back to: "F"flapping
- Definição1
- The vertical movement of a blade about a flapping hinge.
- Fonte1
- FEDERAL AVIATION ADMINISTRATION. Rotorcraft flying handbook (FAA-H-8083-21). Washington, DC: FAA, 2000. Disponível em: http://www.faa.gov/library/manuals/aircraft/media/faa-h-8083 -21.pdf. Acesso em: 10 fev. 2012.
- Definição2
- The up and down movement of rotor blades about a hinge on a fully articulated rotor system.
- Fonte2
- INTERNATIONAL CIVIL AVIATION ORGANIZATION. Manual of aircraft accident and incident investigation. Montreal, 2014. (Doc. 9756)
- Nota adicional1
- At high forward speeds in certain helicopter designs, retreating blade stall can progress to main rotor blowback and excessive blade flapping, resulting in mast bumping or blade-to-fuselage contact if not arrested immediately. Excessive lateral speed (sideslip) will also contribute to excessive blade flapping and the possibility of mast bumping.
- Contexto
- SEMIRIGID ROTOR SYSTEM: A semirigid rotor system allows for two different movements, flapping and feathering. This system is normally comprised of two blades, which are rigidly attached to the rotor hub. The hub is then attached to the rotor mast by a trunnion bearing or teetering hinge. This allows the blades to see-saw or flap together. As one blade flaps down, the other flaps up. Feathering is accomplished by the feathering hinge, which changes the pitch angle of the blade.
- In a low G condition, improper corrective action could lead to the main rotor hub contacting the rotor mast. The contact with the mast becomes more violent with each successive flapping motion. This, in turn, creates a greater flapping displacement. The result could be a severely damaged rotor mast, or the main rotor system could separate from the helicopter.
- If the CG is too far aft of the mast, the nose tilts up. If flight is continued with CG aft, the helicopter may be impossible to fly in the upper allowable airspeed range due to inadequate forward cyclic authority to maintain a nose-low attitude. With extreme aft CG, gusty or rough air could accelerate the helicopter to a speed faster than that produced with full forward cyclic control. In this case, dissymmetry of lift and blade flapping could cause the rotor disc to tilt aft. With full forward cyclic control already applied a rotor blade strike on the tailboom could occur.
- Subárea1
- Rotorcraft
- Related Term
- flapping angle
- flapping hinge
- Português
- batimento