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For a tailless aircraft, the neutral point coincides with the aerodynamic center, and so for such aircraft to have longitudinal static stability, the center of gravity must lie ahead of the aerodynamic center. [13] For missiles with symmetric airfoils, the neutral point and the center of pressure are coincident and the term neutral point is not ...
For longitudinal stability in pitch and in speed, aircraft are designed in such a way that the centre of mass (centre of gravity) is forward of the neutral point. The nose-down pitching moment is compensated by the downward aerodynamic force on the elevator and the trimable horizontal stabilizer.
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 .
The aerodynamic center of an airfoil is usually close to 25% of the chord behind the leading edge of the airfoil. When making tests on a model airfoil, such as in a wind-tunnel, if the force sensor is not aligned with the quarter-chord of the airfoil, but offset by a distance x, the pitching moment about the quarter-chord point, / is given by
When power setting is kept the same but airspeed fluctuates, aircraft tends to return to its original airspeed at point A, magnify the speed change at point B, and remain at its new speed at point C. An aircraft in cruise flight is typically speed stable. If speed increases, drag increases, which will reduce the speed back to equilibrium for ...
In aircraft, the directional stability determines such features as dihedral of the main planes, size of fin and area of tailplane, but the large number of important stability derivatives involved precludes a detailed discussion within this article. The missile is characterised by only three stability derivatives, and hence provides a useful ...
The move compromised the aircraft's balance to the point that control of the aircraft was lost. [6] In July 2013, a de Havilland Canada DHC-3 Otter departed Soldotna, Alaska, stalled after rotation and crashed 2,300 ft (700 m) away from its brake-release point as it was overloaded by 418 lb (190 kg) and its CG was well aft of the rear limit ...
The horizontal stabilizer contributes extra stability and this allows the center of gravity to be a small distance aft of the aerodynamic center without the aircraft reaching neutral stability. The position of the center of gravity at which the aircraft has neutral stability is called the neutral point.