Advancing Vs. Retreating Blades
| retreating blade side | advancing blade side |
A rotor blade that is moving in the same direction as the aircraft is called the advancing blade and the blade moving in the opposite direction is called the retreating blade.
Balancing lift across the rotor disc is important to a helicopter's stability. The amount of lift generated by an airfoil is proportional to the square of its airspeed. In a zero airspeed hover the rotor blades, regardless of their position in rotation, have equal airspeeds and therefore equal lift. In forward flight the advancing blade has a higher airspeed than the retreating blade, creating unequal lift across the rotor disc.
A fuller treatment is provided in dissymmetry of lift.
Read more about this topic: Retreating Blade Stall
Famous quotes containing the words advancing, retreating and/or blades:
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—Jeremy Bentham (1748–1832)
“Seeing that the Senses cannot decide our dispute, being themselves full of uncertainty, we must have recourse to Reason; there is no reason but must be built upon another reason: so here we are retreating backwards to infinity.”
—Michel de Montaigne (1533–1592)
“And he gave it for his opinion, that whoever could make two ears of corn, or two blades of grass, to grow upon a spot of ground where only one grew before, would deserve better of mankind, and do more essential service to his country, than the whole race of politicians put together.”
—Jonathan Swift (1667–1745)