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How does CG location affect stability?
The aircraft becomes less stable as the CG is moved rearward. Any CG movement further aft results in an unstable aircraft. A forward CG location increases the need for greater back elevator pressure. The elevator may no longer be able to oppose any increase in nose-down pitching.
How does forward CG affect stability?
A forward CG with the increase in stability will make it easier to recover from a stall, however moving the CG forward will also increase drag and with drag comes a reduction in cruise speeds and fuel efficiency.
Where should the CG of a plane be?
As a very general rule of thumb the CG will be about one-quarter to one-third of the wing chord (width) back from the leading edge of the wing. The main spar, if there is one, often lies in this general area.
What does an aft CG do to aircraft performance and stability?
Aft CG. The relationship between aircraft performance and CG location is simple: by moving the CG forward and aft, you change the amount of tail down force and lift you need for stable flight. If you need more lift, you create more induced drag, and your performance goes down.
What is forward CG?
A forward CG may occur when a heavy pilot and passenger take off without baggage or proper ballast located aft of the rotor mast. This situation becomes worse if the fuel tanks are located aft of the rotor mast because as fuel burns the weight located aft of the rotor mast becomes less.
Why is stalling speed higher when the CG is moved forward?
As the CG moves forward, the wing must now produce more lift, and hence the stalling airspeed increases (as the square root of the effective wing loading). On the other hand, as the CG moves rearward, less tail downforce is required and the stalling speed decreases.
How does the CG position affect pitch stability?
An aircraft’s horizontal tail size and position, and the CG position are the dominant factors controlling the aircraft’s pitch stability, which is the tendency to automatically maintain an angle of attack and airspeed. The basic effects of moving the CG position are:
How is CG location related to aircraft performance?
The relationship between aircraft performance and CG location is simple: by moving the CG forward and aft, you change the amount of tail down force and lift you need for stable flight. If you need more lift, you create more induced drag, and your performance goes down. But why are lift and CG located related? Your Airplane’s Balancing Act
Why are far-forward CG positions so difficult to control?
However, far-forward CG positions make the aircraft difficult to control, and in fact the aircraft becomes increasingly nose heavy at lower airspeeds, e.g. during landing. The further back the CG is moved the less statically stable the aircraft becomes.
How does the control and stability of an aircraft work?
Control and Stability of Aircraft. The position of the centre of pressure (CP). The centre of pressure is the point at which the aerodynamic lift forces are assumed to act if discretised onto a single point. Thus, if the CP does not coincide with the CG, pitching moments will naturally be induced about the CG.