SIFT Aircraft Components and Controls 4

Question 1

What is the primary purpose of an aircraft's vertical stabilizer?

Accepted Answer

Provide directional (yaw) stability about the vertical axis

Answer

The vertical stabilizer provides weathervane-like yaw stability, keeping the aircraft aligned with the relative wind and resisting unwanted yaw movements.

Question 2

During autorotation in a helicopter, which component supplies energy to keep the rotor turning?

Accepted Answer

The stored inertia of the rotor and upward airflow through the rotor disk

Answer

In autorotation, rising air through the rotor disk (and initially rotor inertia) drives the rotor blades, providing lift for a controlled descent without engine power.

Question 3

What is the function of the 'feathering hinge' (or pitch change bearing) in a helicopter rotor blade?

Accepted Answer

Allows the blade to rotate about its spanwise axis to change pitch angle

Answer

The feathering hinge (pitch change bearing) allows each rotor blade to rotate about its spanwise axis, changing its angle of attack in response to cyclic and collective inputs.

Question 4

On a fixed-wing aircraft, what is the function of the 'elevator'?

Accepted Answer

Controls pitch by deflecting the horizontal tail surface

Answer

The elevator is the movable portion of the horizontal stabilizer that deflects up or down to pitch the nose of the aircraft up or down.

Question 5

What is 'translational lift' in helicopter flight?

Accepted Answer

The increased efficiency and lift gained as the helicopter transitions from hover to forward flight

Answer

Translational lift occurs as the helicopter moves forward and the rotor exits its own downwash, gaining more efficient airflow through the disk and a noticeable increase in lift.

SIFT Exam Practice Test

SIFT Exam Practice Test

SIFT Aircraft Components and Controls 4