Aviation dictionary. 2014.
lead-lag motion — An angular oscillation of a rotor blade in the plane of rotation about a substantially vertical axis. The fore and aft movement of the tip of a helicopter rotor blade in its plane of rotation. Lead lag motion is the freedom given to each blade of … Aviation dictionary
delta-three hinge — A hub hinge arrangement that is a coupling effect between either the flapping or lead lag hinge and a blade pitch. A blade has a delta three hinge if the movement of the blade in either axis causes the blade pitch to change. Pitch change rod… … Aviation dictionary
alpha hinge — The hinge at the root of a helicopter rotor blade with its axis perpendicular to the plane of rotation. It allows the blade tip to move back and forth in its plane of rotation. Movement about the alpha hinge is called drag. Drag dampers oppose… … Aviation dictionary
blade grips — That part of a helicopter rotor hub into which the blades are attached by a lead lag hinge pin. Blade grips also called blade forks … Aviation dictionary
Hook’s joint effect — The movement of a rotor blade to reposition itself relative to the other blades when a cyclic stick is applied. This situation arises when the plane of the rotor disc and the drive shaft are not normal to each other. In I and II, the helicopter… … Aviation dictionary
hunting — In applications to aircraft flight, engines, and instruments: An uncontrollable oscillation about a neutral point on a continuous basis, the amplitude of which remains approximately constant. Hunting can be in the case of governed RPM, governed… … Aviation dictionary
Helicopter rotor — This article is about helicopter main rotor systems. For antitorque control, see tail rotor. Helicopter rotor The rotor head of a Sikorsky S 92 A helicopter main rotor or rotor system is a type of fan that is used to generate both the aerodynamic … Wikipedia
dragging — The freedom given to each blade of a rotor to allow it to move in the plane of rotation independently of other blades. It is basically the angular oscillation of a rotor blade in the plane of rotation about a substantially vertical axis. This is… … Aviation dictionary
blade damper A device — installed on the vertical (lead lag or drag) hinge to diminish or dampen blade oscillation or hunting around this hinge … Aviation dictionary
Helicopter — For other uses, see Helicopter (disambiguation). Helicopter An LAPD Bell 206 … Wikipedia
