AJD 21103 TOPIC 4 - AUXILIARY

What is the primary function of airflow control devices on swept wings?

To control the spanwise flow of the boundary layer air over the top of the wing.

Where are wing fences typically located?

About mid-span, on the leading edge of the wing.

What is the purpose of a saw tooth leading edge on military aircraft?

To form an invisible 'wall' of high-velocity air, straightening the spanwise flow over the wing.

How do winglets improve aircraft performance?

By reducing drag and improving airflow control at higher speeds.

What type of vortex is created by vortex generators?

A tip vortex that helps delay flow separation and aerodynamic stalling.

What is the function of stall wedges on aircraft wings?

To disrupt boundary layer airflow at large angles of attack, ensuring wing root stalls before wing tips.

What does active load control sense in aircraft?

Disturbances in the air that may cause discomfort to passengers and crew.

What is 'flutter' in the context of control surfaces?

A phenomenon where air load distorts the control surface, causing it to lag behind and produce aerodynamic forces.

What are the three principal methods of achieving aerodynamic balancing?

Horn balance, inset hinge, and pressure balancing.

How does a horn balance operate on a control surface?

It assists movement away from the neutral position by utilizing airflow on the control surface.

What is the function of an adjustable plate in pneumatic stall warning systems?

To coincide with the stagnation point of the wing during normal flight attitude.

How does the electrical stall warning system provide alerts?

It uses a micro-switch and vane that detect changes in angle of attack to illuminate a warning light and sound an alarm.

What is the purpose of a stick shaker device in aircraft?

To alert pilots of an impending stall by shaking the control column.

What is the role of the stick pusher in stall prevention systems?

To pitch down the aircraft by pushing the control column in response to high angles of attack.

What is boundary layer control and how does it enhance aircraft performance?

Methods to delay flow separation and improve airflow over control surfaces, enhancing lift.

What is a vortex generator and where is it typically installed?

A device that creates a tip vortex to improve airflow, usually installed on the front third of a wing.

Define stall in the context of aircraft performance.

A condition where the angle of attack increases to a point that lift begins to decrease.

What materials are commonly used for mass balance weights?

Lead or depleted uranium.

What systems are used to warn pilots of impending stalls?

Pneumatic and electrical stall warning systems.

How does the stall warning horn operate in light aircraft?

It emits a noise when the angle of attack exceeds a certain threshold, indicating an impending stall.

What is the advantage of using a blended winglet compared to a conventional wingtip?

It creates a smaller vortex, leading to less drag.

How does a leading-edge stall warning system function in larger aircraft?

Using a vane and micro-switch to detect changes in airflow at the stall angle.

What design principle underlies the function of horn balances?

To reduce pilot control loads by balancing aerodynamic forces around the hinge line.

What happens to a stick shaker when an aircraft approaches a stall angle?

It activates to shake the control column, alerting the pilot.

What is the purpose of using a plenum chamber in pneumatic stall warning systems?

To detect low-pressure areas caused by increasing angles of attack.

What is the benefit of a saw tooth leading edge compared to a wing fence?

It reduces drag and weight while maintaining airflow control.

In the context of stall prevention, what is the desired outcome of using stall wedges?

To ensure that the wing root stalls before the tips, providing safer handling characteristics.

How does a pilot override a stick pusher system?

By using a switch located at the control column.

What is one common external feature of all stall warning systems?

They aim to alert pilots to prevent loss of control before a stall.

Why is aerodynamic balancing important for larger aircraft controls?

To reduce high stick forces experienced by pilots at higher speeds.