SIFT Aircraft Components and Controls 5

Question 1

What happens to the tail rotor's anti-torque requirement when main rotor pitch (collective) is increased?

Accepted Answer

It increases because more engine torque is needed to drive the rotor at higher pitch

Answer

Increasing collective requires more engine torque to maintain rotor RPM, which increases the torque reaction the tail rotor must counteract.

Question 2

The 'T-tail' configuration on a fixed-wing aircraft places the horizontal stabilizer:

Accepted Answer

At the top of the vertical stabilizer

Answer

A T-tail mounts the horizontal stabilizer at the top of the vertical fin, keeping it out of the wing's disturbed wake but creating risk of deep stall.

Question 3

What is the primary purpose of a 'mixing unit' (or mixing lever) in a helicopter flight control system?

Accepted Answer

Prevents a cyclic input from also changing overall (collective) blade pitch

Answer

The mixing unit mechanically separates cyclic and collective inputs so that moving the cyclic doesn't inadvertently change the average (collective) pitch of all blades.

Question 4

What is 'adverse yaw' in a fixed-wing aircraft?

Accepted Answer

The tendency of the aircraft to yaw toward the lowered (rising) aileron during a roll input

Answer

Adverse yaw occurs because the down-going aileron (on the rising wing) generates more drag than the up-going aileron, pulling the nose toward the rising wing instead of the direction of roll.

Question 5

In a tandem-rotor helicopter (e.g., CH-47 Chinook), how is torque typically counteracted?

Accepted Answer

By the two rotors spinning in opposite directions, canceling each other's torque

Answer

Tandem-rotor helicopters use two counter-rotating rotors whose torques cancel each other out, eliminating the need for a tail rotor.

SIFT Exam Practice Test

SIFT Exam Practice Test

SIFT Aircraft Components and Controls 5