Flight mechanics
The flight mechanics is one of the engineering and describes the behavior of bodies in the atmosphere with the help of aerodynamic move the aircraft . In contrast to aerodynamics, flight mechanics does not describe the physical processes on individual aircraft components, but the behavior of the entire system, the aircraft. The basic task of flight mechanics is to calculate the position, attitude and speed of a missile at any point in time. This is done with the help of motion equations (equations of motion) consisting of a system of coupled differential equations exist. The aircraft is usually treated as a rigid body .
Education
Flight mechanics is part of the aerospace engineering and aircraft construction engineering courses .
Basics
The theoretical basis for flight mechanics is aerodynamics . With their help, flight mechanics make statements about which flight characteristics an aircraft has and which flight performance it can provide. The main influencing variables are the dynamic lift generated by the wings , the air resistance , the weight acting on the center of gravity and the thrust generated by the drive . In addition, forces generated by control surfaces and the aeroelasticity of the wings influence the movements of the aircraft. Since the air does not hold the aircraft in an externally predefined position, it is often useful to combine opposing forces into torques . The aircraft's mass and moments of inertia about its main axes of inertia determine how quickly an imbalance of forces or torque can affect the movement and orientation of the aircraft.
Since the systems of equations to be solved are usually very complex, one has to rely on powerful computers to solve them numerically. In order to estimate individual properties of an aircraft, however, it is common to simplify the equations and thus solve sub-problems. For example, it is common to split the movement of the aircraft into pure longitudinal movement, in which the aircraft only rotates around the transverse axis ( definition of the transverse axis ), and the lateral movement, in which a rotation takes place around the longitudinal and yaw axes .
In addition, a distinction is made between transient and stationary processes . In the case of transient processes, it is primarily the immediate reaction of the aircraft to control inputs or disturbances in the flight condition, for example due to wind shear . A stationary flight condition is a condition that occurs when all forces remain constant over a longer period of time. A simple example of a stationary flight condition is the unaccelerated horizontal flight in a straight line, in which the aircraft moves in one direction at a constant speed and altitude. However, a flight in a curve with a constant radius and leaning angle can also be a stationary flight condition. In reality, such stationary flight conditions often only occur after long settling times. The aircraft oscillates between different flight modes until it finally remains in a stationary flight mode. Based on the calculation of such processes, statements can be made about the static stability of an aircraft.
The stationary flight conditions also essentially determine the flight performance of the aircraft. These are the possibilities of the aircraft in terms of maximum and minimum speed, summit altitude, take-off and landing distance, maximum take-off mass and other things. Partial aspects of flight services are summarized in flight envelopes . These are graphical representations of the limits within which an aircraft can move.
Sub-areas
Flight mechanics provides the basis for a variety of sub-areas in the field of aerospace:
Flight performance : Typical questions here are e.g. B. Minimum speeds, range, maximum flight time, excess thrust, acceleration, take-off and landing distance and much more
Flight guidance : A distinction is made here between flight guidance by a person and automatic flight guidance. Automatic flight guidance is understood to mean the autopilot, but also systems for increasing stability and fly-by-wire systems.
Flight simulation : In flight simulation, the equations of motion are used to simulate aircraft movements , often before the associated aircraft has been built. The flight characteristics of a construction can be assessed in advance on the basis of the flight mechanical calculations.