Search results
Results from the WOW.Com Content Network
Longitudinal stability refers to the stability of an aircraft in pitch. For a stable aircraft, if the aircraft pitches up, the wings and tail create a pitch-down moment which tends to restore the aircraft to its original attitude. For an unstable aircraft, a disturbance in pitch will lead to an increasing pitching moment.
The longitudinal stability of an aircraft, also called pitch stability, [2] refers to the aircraft's stability in its plane of symmetry [2] about the lateral axis (the axis along the wingspan). [1] It is an important aspect of the handling qualities of the aircraft, and one of the main factors determining the ease with which the pilot is able ...
Most aircraft trimmed for straight-and-level flight, if flown stick-fixed, will eventually develop a tightening spiral-dive. [2] If a spiral dive is entered unintentionally, the result can be fatal. A spiral dive is not a spin; it starts, not with a stall or from torque, but with a random perturbation, increasing roll and airspeed.
Stability derivatives, and also control derivatives, are measures of how particular forces and moments on an aircraft change as other parameters related to stability change (parameters such as airspeed, altitude, angle of attack, etc.). For a defined "trim" flight condition, changes and oscillations occur in these parameters.
The flight dynamics of spacecraft differ from those of aircraft in that the aerodynamic forces are of very small, or vanishingly small effect for most of the vehicle's flight, and cannot be used for attitude control during that time. Also, most of a spacecraft's flight time is usually unpowered, leaving gravity as the dominant force.
The figure on the right shows the variation of moment with AoA for a stable airplane. The negative slope for positive α indicates stability in pitch. The combination of the two concepts of aerodynamic center and pitching moment coefficient make it relatively simple to analyse some of the flight characteristics of an aircraft. [1]: Section 5.10
The position of all three axes, with the right-hand rule for describing the angle of its rotations. An aircraft in flight is free to rotate in three dimensions: yaw, nose left or right about an axis running up and down; pitch, nose up or down about an axis running from wing to wing; and roll, rotation about an axis running from nose to tail.
A diagrammatic representation of a fixed-wing airplane in phugoid. In aviation, a phugoid or fugoid (/ ˈ f juː ɡ ɔɪ d / ⓘ) is an aircraft motion in which the vehicle pitches up and climbs, and then pitches down and descends, accompanied by speeding up and slowing down as it goes "downhill" and "uphill".