SIFT Principles of Helicopter Flight Questions and Answers

Question 1

The tendency of a single-rotor helicopter's fuselage to rotate in the opposite direction of the main rotor is known as the torque effect. What is the primary component that counteracts this force?

Accepted Answer

The anti-torque system (tail rotor)

Answer

The cyclic pitch control

Answer

The horizontal stabilizer

Answer

The main rotor's flapping hinges

Question 2

A helicopter pilot accelerating from a hover experiences a noticeable vibration and a tendency for the aircraft to roll to the right (in a counter-clockwise rotor system) between 10-20 knots. This phenomenon, which precedes Effective Translational Lift, is known as:

Accepted Answer

Transverse Flow Effect

Answer

Retreating Blade Stall

Answer

Translating Tendency

Answer

Ground Effect

Question 3

A helicopter requires significantly less power to hover at five feet above a runway compared to hovering at 100 feet. Which principle explains this increase in performance near the surface?

Accepted Answer

In-Ground Effect (IGE)

Answer

Dissymmetry of lift

Answer

Effective Translational Lift

Answer

Gyroscopic Precession

Question 4

During the transition from a hover into forward flight, at approximately 16-24 knots, a helicopter experiences a significant increase in lift and efficiency, often resulting in a slight climb without any increase in power. This aerodynamic phenomenon is called:

Accepted Answer

Effective Translational Lift (ETL)

Answer

Autorotation

Answer

Translating Tendency

Answer

Coning

Question 5

Due to the thrust produced by the tail rotor to counteract torque, a single-rotor helicopter in a hover has a natural tendency to drift sideways. This is known as:

Accepted Answer

Translating tendency

Answer

Retreating blade stall

Answer

Transverse flow effect

Answer

Coriolis effect

Question 6

The principle that a force applied to a rotating object will manifest its effect approximately 90 degrees later in the direction of rotation is fundamental to helicopter flight controls. What is this principle called?

Accepted Answer

Gyroscopic Precession

Answer

Bernoulli's Principle

Answer

Venturi Effect

Answer

Newton's Third Law

The tendency of a single-rotor helicopter's fuselage to rotate in the opposite direction of the main rotor is known as the torque effect.What is the primary component that counteracts this force?

The tendency of a single-rotor helicopter's fuselage to rotate in the opposite direction of the main rotor is known as the torque effect.
What is the primary component that counteracts this force?