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In aerodynamics, the pitching moment on an airfoil is the moment (or torque) produced by the aerodynamic force with respect to the aerodynamic center on the airfoil . The pitching moment on the wing of an airplane is part of the total moment that must be balanced using the lift on the horizontal stabilizer. [1]: Section 5.3 More generally, a ...
The aerodynamic center is the point at which the pitching moment coefficient for the airfoil does not vary with lift coefficient (i.e. angle of attack), making analysis simpler. [ 1 ] d C m d C L = 0 {\displaystyle {dC_{m} \over dC_{L}}=0} where C L {\displaystyle C_{L}} is the aircraft lift coefficient .
On aircraft with swept wings, wing tip stall also produces an undesirable nose-up pitching moment which hampers recovery from the stall. Washout may be accomplished by other means e.g. modified aerofoil section, vortex generators, leading edge wing fences, notches, or stall strips. This is referred to as aerodynamic washout.
A stability derivative. This is an example of a common shorthand notation for stability derivatives. The "M" indicates it is a measure of pitching moment changes. The indicates the changes are in response to changes in angle of attack.
In February 1976, work commenced to automate the methods contained in the USAF Stability and Control DATCOM, specifically those contained in sections 4, 5, 6 and 7.The work was performed by the McDonnell Douglas Corporation under contract with the United States Air Force in conjunction with engineers at the Air Force Flight Dynamics Laboratory in Wright-Patterson Air Force Base.
A control system includes control surfaces which, when deflected, generate a moment (or couple from ailerons) about the cg which rotates the aircraft in pitch, roll, and yaw. For example, a pitching moment comes from a force applied at a distance forward or aft of the cg, causing the aircraft to pitch up or down.
The motion is a rapid pitching of the aircraft about the center of gravity, essentially an angle-of-attack variation. The short-period mode is an oscillation with a period of only a few seconds that is usually heavily damped by the existence of lifting surfaces far from the aircraft’s center of gravity, such as a horizontal tail or canard.
where y is the spanwise dimension, θ is the elastic twist of the beam, GJ is the torsional stiffness of the beam, L is the beam length, and M’ is the aerodynamic moment per unit length. Under a simple lift forcing theory the aerodynamic moment is of the form ′ = (+),