ACFT - The Aerofoil & Lift Flashcards
What is an Aerofoil? (1)
Any part of an aircraft designed to produce lift > when moved through the air, it can produce lift
What is the Leading Edge, Trailing edge, and Chord Line? (3)
What is Angle of incidence and Longitudinal axis? (2)
What is the Angle of attack? (1)
How is Bernoulli’s Principle applied? (4)
- The aerofoil is designed to increase the velocity of the airflow over its top surface
- The air has further to travel over the curved upper surface so accelerates
- Bernoulli’s principle tells us that this acceleration causes a reduction in pressure
- The reduction of pressure on the top surface produces LIFT
What is the Boundary layer? (1)
The air directly in contact with the surface of the aerofoil
What is the Laminar? (1)
When the boundary layer remains in contact with the surface
What is the Laminar Aerofoil? (1)
An aerofoil designed for minimum drag and a smooth flow of the boundary layer
Can the Laminar flow be always maintained? (1)
NO - As the boundary layer begins to separate from the surface, the flow
becomes turbulent and eventually separates from the wing
What is the Transition point? (1)
The point at which flow becomes turbulent
What is the Separation point? (1)
The point at which flow separates
How is lift affected in turbulent flow? (4)
- As the flow over the top of the aerofoil becomes turbulent, its velocity reduces
- Bernoulli’s principle tells us that this will increase pressure
- The pressure above and below the wing equalises, lift is reduced and is eventually lost altogether
- When lift is lost, the aerofoil is described as stalled
When can Stalling occur? (1)
When the critical angle of attack is exceeded (Normally 15°)
When can an Aircraft stall? (2)
Any:
1. Airspeed
2. Attitude (Banking)
What is Stalling (2)
When LIFT IS LOST on an aerofoil
When the critical angle of attack of a given aerofoil remains the same regardless of weight, dynamic pressures, airspeed etc. but the amount of lift required to sustain an aircraft in flight will vary
