Module 11a,b,cd

What enables aircraft to rotate about its axes?

Flight controls

What is the point that the 3 axes pass through

CoG

What is the CoG

Where the entire weight of the aircraft is concentrated

What is the axis passing through the fuselage from nose to tail?

Longitudinal axis

What is the motion about the longitudinal axis?

Roll

What is roll control provided by?

Ailerons/roll spoilers

What is the axis passing through the CG at right angles to the longitudinal and vertical axis, from wing tip to wing tip.

Lateral axis

What is rotary motion about the lateral axis called?

Pitching

What is pitch control provided by?

Elevators

What is control about the lateral axis called?

Longitudinal control

What is control about the longitudinal axis called?

Lateral control

What is the (axis) straight line passing through the CG at right angles to the longitudinal and lateral axes?

Vertical axis

What is the rotary motion about the vertical axis?

Yaw

What is yaw control provided by?

Rudder

What is control about the vertical axis called?

Directional control

What are the primary flight controls?

Ailerons, Elevator, Rudder

What are secondary flight controls?

Flaps, Slats, Trim Tabs, Adjustable stabiliser, High lift devices

What are the flight controls of an aircraft limited to physically?

Do no more than modify the camber, or aerodynamic shape of the surface to which they are attached

What direction do ailerons move in when trying to roll the aircraft?

Opposite, one goes up, one goes down

What mechanical component controls ailerons in the cockpit?

Control wheel

How does the control wheel of the ailerons function when operated?

When the wheel is turned to the left, the left aileron moves up and the right aileron moves down. Vice versa

Which aileron when rolling creates the most aileron drag, or has the most influence?

The aileron that moves downwards

What is adverse yaw (aileron drag?)

When the drag created by the aileron that moves downwards pulls the nose of the aircraft opposite the direction of roll.

How can adverse yaw be minimised?

Using differential ailerons and frise ailerons

What is differential ailerons?

The aileron moving upwards travels a greater distance than the one moving downwards, the extra travel creates enough parasite drag to counteract the induced drag caused by the lower aileron

What are Frise ailerons?

Extending the leading edge of the up aileron below the lower surface of the wing produces additional parasite drag, counteracting the increased induced drag caused by the down-going aileron on the opposite wing

What are roll spoilers?

Hinged surfaces located ahead of the flaps on the upper surface of the wing

Why do the roll spoilers deploy on the up moving aileron automatically?

To decrease the lift on the wing that is moving down

Do roll spoilers aid in opposing adverse yaw? And if so, why?

Yes, with parasite drag

What type of aircraft use spoilers as part of the secondary flight control system?

Transport category aircraft

When a large amount of aileron is used, how much do the spoilers account for the roll rate?

80% of the roll rate

When the control wheel is moved back, how does the elevator act?

Trailing edge of elevator moves upwards and deflects the airstream upwards, increases the download on the tail and rotates the nose of the aircraft upwards

What is a stabilator?

One form of horizontal tail surface, that has no fixed stabiliser, but has an almost full-length anti-balance tab on its trailing edge

The area ahead of the hinge line makes stabilators overly sensitive, how is this counteracted?

Anti-balance tab helps decrease sensitivity

How is the stabilator moved?

Control wheel

What happens when the Stabilator control wheel is pulled back?

The leading edge of the stabilator moves down and increases the downward force produced by the tail, rotating the nose up

What is the purpose of a adjustable stabiliser?

Maintain a balance of forces to prevent undesired rotation along the pitch axis

Is the CoG fixed?

No

What does the CoG depend on?

Fuel, passengers, cargo

What happens to the CoG during flight?

Will move slowly in the direction of the nose of the aircraft as a result of fuel consumption

With a combination of the position of the CoG and the pressure point (Lift), the aircraft nose will either pitch up or down, how is this counteracted?

A stabiliser must create an opposite force

Where type of aircraft are variable incidence horizontal stabilisers used in?

High-speed transport category aircraft

Why is the trim stabiliser used instead of the elevator trim to correct pitch?

Using stabiliser trim decreases parasite drag generated

What on the elevator, and what stabiliser reduces drag?

Forces of air and adjustable

In terms of drag why is a trimmable stabiliser used instead of a elevator trim to correct pitch trim?

To reduce the amount of parasite drag generated

How does a canard configuration plane stall?

Canard stalls first, causing the nose to drop and the aircraft to build up speed. The canard regains full lift and the nose comes back up. The CG does not change, and full aileron control is always available, eliminating the chance of inadvertent stall/spin accident