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:
“There is a disease to which plays as well as men become liable with advancing years. In men it is called doting, in plays dating. The more topical the play the more it dates.”
—George Bernard Shaw (1856–1950)
“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)
“The virtue of making two blades of grass grow where only one grew before does not begin to be superhuman.”
—Henry David Thoreau (1817–1862)