Flight dynamics
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This article is missing information about aircraft and spacecraft performance and control.(May 2020) |
Flight dynamics in aviation and spacecraft, is the study of the performance, stability, and control of vehicles flying through the air or in outer space.[1] It is concerned with how forces acting on the vehicle determine its velocity and attitude with respect to time.
For a fixed-wing aircraft, its changing orientation with respect to the local air flow is represented by two critical angles, the angle of attack of the wing ("alpha") and the angle of attack of the vertical tail, known as the sideslip angle ("beta"). A sideslip angle will arise if an aircraft yaws about its centre of gravity and if the aircraft sideslips bodily, i.e. the centre of gravity moves sideways.[2] These angles are important because they are the principal source of changes in the aerodynamic forces and moments applied to the aircraft.
Spacecraft flight dynamics involve three main forces: propulsive (rocket engine), gravitational, and atmospheric resistance.[3] Propulsive force and atmospheric resistance have significantly less influence over a given spacecraft compared to gravitational forces.
Aircraft
Flight dynamics is the science of air-vehicle orientation and control in three dimensions. The critical flight dynamics parameters are the
Aircraft engineers develop
Roll, pitch and yaw refer, in this context, to rotations about the
A fixed-wing aircraft increases or decreases the lift generated by the wings when it pitches nose up or down by increasing or decreasing the angle of attack (AOA). The roll angle is also known as bank angle on a fixed-wing aircraft, which usually "banks" to change the horizontal direction of flight. An aircraft is streamlined from nose to tail to reduce drag making it advantageous to keep the sideslip angle near zero, though aircraft are deliberately "side-slipped" when landing in a cross-wind, as explained in slip (aerodynamics).
Spacecraft and satellites
The forces acting on space vehicles are of three types:
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.
See also
- Aerodynamics – Branch of dynamics concerned with studying the motion of air
- Aircraft flight control system – How aircraft are controlled
- Fixed-wing aircraft – Heavier-than-air aircraft with fixed wings generating aerodynamic lift
- Flight control surfaces – Surface that allows a pilot to adjust and control an aircraft's flight attitude
- Flight dynamics (fixed-wing aircraft)– Science of air vehicle orientation and control in three dimensions
- Moving frame – Generalization of an ordered basis of a vector space
References
- ^ Stengel, Robert F. (2010), Aircraft Flight Dynamics (MAE 331) course summary, retrieved November 16, 2011
- ISBN 1 85310 870 7, p.145
- ^ a b Depending on the vehicle's mass distribution, the effects of gravitational force may also be affected by attitude (and vice versa),[citation needed] but to a much lesser extent.