anngle of attack

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Questions and Answers

What directly affects the amount of lift produced by an aircraft wing?

Altitude of the aircraft

The craft's overall weight

Angle of attack, air density, and aerofoil design (correct)

Wind speed and direction

What happens to the angle of attack as aircraft weight increases?

It becomes irrelevant

It must be maintained at a higher value (correct)

It remains constant

It decreases

Which of the following signals a stall condition in an aircraft?

Increased airspeed

Buffeting and pitch down attitude change (correct)

Gentle pitch up attitude

Loss of altitude

What is the critical angle of attack?

The angle indicating a complete stall Signup and view all the answers

To recover from a stall, what must be done?

Decrease the angle of attack Signup and view all the answers

What does not directly contribute to the stalling of an aircraft?

Type of engine used Signup and view all the answers

What is Total Air Temperature (TAT) in aircraft operating at high Mach numbers?

Maximum temperature rise when air is brought to rest Signup and view all the answers

What material is commonly used for TAT probes to ensure good thermal conductivity and strength?

Nickel-plated beryllium copper Signup and view all the answers

Which of the following best describes the design purpose of the inner tube of the TAT probe?

To minimize thermal strain during operation Signup and view all the answers

What precaution should be taken when handling TAT probes?

Fit covers to prevent insect contamination Signup and view all the answers

During flight, how does the air pressure within the TAT probe compare to the air pressure outside?

Higher than the outside pressure Signup and view all the answers

What is the function of the axial wire wound heating element in some TAT probes?

To prevent ice formation on the probe Signup and view all the answers

What primarily causes the vane-type sensor to move?

The equal airflow over either side of the vane Signup and view all the answers

Which feature is included in angle of attack sensors to prevent in-flight issues?

A heater element to prevent freezing Signup and view all the answers

What is the function of index pins in the vane-type sensor?

To align the complete unit accurately Signup and view all the answers

Why is care advised when moving the vane-type sensor?

To avoid damaging the fine movement of the transmitter shaft Signup and view all the answers

What is the significance of the stagnation point in aircraft aerodynamics?

It is where air separates to flow above or below the wing Signup and view all the answers

How does the heater element in angle of attack sensors adjust under specific conditions?

It switches to half power when the wheels are on the ground Signup and view all the answers

What is primarily the function of the probe-type sensor in aircraft?

To provide information about the aircraft's attitude Signup and view all the answers

What action should be taken when installing angle of attack probes?

Correctly align and locate them according to datum points Signup and view all the answers

What happens to the current in winding B when the temperature of the sensor Rx increases?

It decreases. Signup and view all the answers

In a ratiometer, what effect does the constant torque of winding A have when the current ratio changes?

It rotates the measuring element into the weaker part of the field. Signup and view all the answers

What is generated when the junction of two dissimilar metals is heated in a thermocouple system?

An Electromotive Force (EMF). Signup and view all the answers

How does the operating mechanism of thermocouple systems differ from variable resistance systems?

Thermocouples convert heat energy directly into electrical energy. Signup and view all the answers

What is necessary for the operation of a thermocouple system?

Heating of one junction. Signup and view all the answers

What role does the iron core play in the ratiometer construction?

It enhances the magnetic field concentration. Signup and view all the answers

When the measuring element stabilizes in a ratiometer, what does the angular deflection represent?

The balance of torques at a new current ratio. Signup and view all the answers

What factors influence the magnitude of the EMF produced in a thermocouple circuit?

Temperature difference and metal combination. Signup and view all the answers

What is a suitable application for thermocouple systems?

Very high temperature applications. Signup and view all the answers

What occurs when the torques produced by both windings of a ratiometer become balanced?

The angular position stabilizes. Signup and view all the answers

Study Notes

Aircraft Stall and Angle of Attack

Aircraft can stall at any airspeed, flight attitude, or weight due to the angle of attack (AOA).
Lift production depends on air density, aerofoil design, angle of attack, and the aircraft's weight and speed.
Lower speeds and heavier weights necessitate a higher AOA to maintain lift, increasing the risk of reaching the critical angle of attack and stalling.
Stall occurs when the AOA causes airflow to separate from the leading edge, leading to a complete loss of lift at the critical angle.

Stall Recovery

To recover from a stall, reduce the angle of attack below the critical threshold to restore smooth airflow.

Angle of Attack Indicators

Aircraft warn of impending stalls through buffeting, pitch attitude changes, or wing drops.
Direct sensing of angle of attack is beneficial for preventing stalls, often achieved with potentiometer outputs to cockpit indicators.

Vane-Type Angle of Attack Sensor

Composed of a counterbalanced aerodynamic vane, this sensor rotates in response to airflow changes, indicating the angle of attack.
The vane is shielded against ice formation and correctly aligned using index pins.

Angle of Attack Sensor Precautions

AoA sensors feature heating elements to prevent freezing and may adjust power when the aircraft is on the ground to avoid overheating.
Care is essential to avoid damage to probe and vane-type sensors during handling and installation.

Stall Warning Systems

The stagnation point is where airflow separates at a wing's leading edge, critical in stall detection.

Thermocouple Systems

Thermocouples generate an Electromotive Force (EMF) when dissimilar metals are heated, allowing temperature measurement without external power.
These systems are suitable for high-temperature applications like engine turbine and cylinder head temperatures.

Total Air Temperature Measurement

Total Air Temperature (TAT) reflects maximum temperature rise in high Mach number flights and is measured when airflow is nearly at rest.
TAT probes are made from nickel-plated beryllium copper, featuring an integrated heating element to prevent ice formation.
Careful handling of TAT probes is crucial to avoid damage.

Modern Cockpit Technologies

Glass cockpits replace traditional mechanical gauges with displays driven by flight management systems, enhancing navigation and operation.
Electronic Attitude and Heading Reference Systems (AHRS) and Air Data Computers (ADCs) improve reliability and customization.
Glass cockpits may include Synthetic Vision Systems (SVS) and Enhanced Vision Systems (EVS) for improved situational awareness.
General aviation aircraft increasingly adopt glass cockpit technologies, exemplified by the Garmin G1000 in models like the Cessna 172.

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Description

This quiz focuses on the principles of lift and stalling in aircraft, emphasizing that stalling can occur at any airspeed, attitude, or weight. Understanding the angle of attack and its relation to lift is crucial for pilot training and aircraft performance.