The Axes of an Aircraft Flashcards
What are the three aces used to describe an aircraft?
- Longitudinal
- Lateral
- Normal
Where does the centre of gravity act?
Through the point where all the balance of aircraft weight is in equilibrium.
What is the primary effect of aileron? What is the secondary effect?
- Primary effect is roll about longitudinal axis
- Secondary effect is adverse yaw.
What is flutter?
Rapid and uncontrolled oscillation of a control surface that results from the changes in pressure distribution over the surface as AoA is altered and when the CoG is aft of the hinge line.
What can be used to increase the roll rate?
Use roll spoilers
What are some methods to reduce adverse yaw?
1) Roll spoilers moving up to increase the drag on the downgoing wing.
2) Differential ailerons
3) Coupling of controls (rudder + aileron)
4) Frist ailerons
How is motion about the lateral axis controlled?
- By the elevators.
- Also known as pitch
What is the primary effect of elevator? Are there any secondary effects?
- Pitching
- Change in speed/altitude.
When is the elevator used to control height?
With speed changes in level flight
When is the elevator used to control speed?
At a constant power setting in a climb or descent.
What are two different types of elevators?
- Elevator on horizontal stabiliser
- All moving tailplane.
What is motion about the vertical (normal) axis called?
Yaw
What is the rudder used for?
For yaw control
What is the secondary effect of rudder?
Roll
What are some factors that determine control effectiveness?
1) Size and shape of the control surface
2) Deflection angle
3) Airspeed
4) Moment Arm (Distance from CoG)
What are artificial feel units?
Provide force feedback for the pilot to determine how far he has deflected the controls.
What is a typical control harmony scale for rudder, elevator and aileron?
Aileron: 1
Elevator: 2
Rudder: 4
What are the effects of an increased power setting on the aircraft?
Will pitch nose up and yaw to the left.
What are the effects of a decreased power setting on the aircraft?
Will pitch nose down and yaw to the right.
What are some design features to reduce slipstream and torque effects?
1) Offset thrust line
2) Automatic rudder trim
3) Regulating engine power at low speeds.
What are some corresponding effects on the A/C with a change in airspeed?
- Increase in airspeed means pitch up and yaw right
- Decrease in airspeed means pitch down and yaw left
