Explanations: Assembly and Rigging Flashcards
On a single-rotor helicopter with an antitorque tail rotor, in what direction does the main rotor tend to rotate the fuselage?
In a clockwise direction as viewed from above.
The tail rotor compensates for this by attempting to rotate the fuselage in a counterclockwise direction.
Decreasing the pitch of the tail rotor allows the torque of the main rotor to rotate the fuselage in a clockwise direction about the main-rotor axis.
What does blade tracking show?
The purpose of blade tracking is to bring the tips of all blades into the same tip path throughout their entire cycle of rotation.
Tracking shows only the relative position of the blades, not their flight path.
What do the foot operated pedals of a helicopter do?
They change the pitch of the tail rotor blades and thus the thrust they produce.
Why does the angle of attack of the advancing blade and the retreating blade differ in a single-rotor helicopter in forward flight?
The difference in the angle of attack between the two blades compensates in the difference in the airspeed of the two blades and provides uniform lift around the rotor disk, preventing dis-symmetry of lift.
Why does the freewheeling unit disconnect the engine from the rotor system in case of engine failure?
The freewheeling unit allows the engine to drive the rotor, but if the rotor speed ever exceeds that of the engine, the freewheeling unit prevents the rotor from driving the engine.
This allows the main rotor and tail rotor to continue turning at normal in-flight speeds.
What is lateral stability?
stability of an aircraft about its longitudinal axis.
How is a wing washed in?
by increasing its angle of incidence, increasing the lift it produces.
How is a wing washed out?
by decreasing its angle of incidence, decreasing the amount of lift it produces.
How does the center of pressure of a symmetrical airfoil change as the angle of attack changes?
It does not. It only changes on an asymmetrical airfoil.
What force balances out the nose-heavy tendancy of an airplane?
the downward aerodynamic tail load.
When the nose pitches up, the aircraft slows down and the tail load decreases. Longitudinal stability causes the nose to drop back to the level flight attitude.
If the nose pitches down, the airspeed builds up and the tail load increases. The increased tail load brings the nose back to the level flight attitude.
What are fowler flaps?
They slide out first, the downward from the trailing edge of the wing. The increases the wing area as well as the wing camber.
What does the elevator trim tab do?
It adjusts the steady-state inflight balance of an aircraft about its lateral axis.
Describe an aircraft with good longitudinal stability.
An aircraft with good (positive) longitudinal stability automatically generates a restoring force anytime it pitches either nose up or down.
If the amount of pitching increases, the aircraft has dynamic longitudinal instability.
What do wing slats do?
allow an aircraft to fly at a higher angle of attack before it stalls, reducing the stalling speed.
How is a cable terminal swaged?
The barrel of a swaged control cable terminal slips over the steel cable, and when the terminal is swaged, its inside diameter is reduced enough that the metal grips the cable tight enough that the swaged fitting provides 100 percent of the strength of the cable.
To ensure that the terminal is properly swaged, its diameter should be checked with a go-no-go gauge before and after it is swaged.
Then once you swage the swaged fitting with the swaged cable you swage the swaged go-no-go gauge with a swaging device that is also swaged. Then once it’s all swaged you can go swage yourself. Swage.
