AA1201 Forces and Lift Flashcards
Definition of angle of attack
The angle between the chordline of an airfoil and the relative wind
Define static pressure
Force produced by the random movement of air molecules (static port)
Define dynamic pressure
Measure of impact pressure molecules (pitot tube)
Define total pressure and how it relates to aircraft systems
The sum of static and dynamic pressure. An aircraft pitot-static system measures the difference between total and static pressure
What are the 4 aerodynamic forces?
Lift, weight, thrust, and drag
What is the relationship of the 4 forces in straight and level unaccelerated flight?
lift = weight, thrust=drag
What is the relationship of the 4 forces in a descent?
lift
What is the relationship of the 4 forces in climb?
lift > weight
What is the relationship of the 4 forces in a decceleration?
thrust
What is the affect of increasing airspeed on lift?
If CAS increases, so does lift
What does lowering flaps on a symmetric airfoil do?
Turns it into a cambered airfoil
What are two things flaps do for a symmetric airfoil?
Cause an increase in coefficient of lift and slight decrease in stall AOA
Define stall angle of attack
The maximum lift available at a given airspeed (L/D max)
How is level-flight stall speed affected by a change in weight?
Increased weight requires increased lift which increases stall speed
How is level-flight stall speed affected by a change in flap setting?
Stall speeds are lower with flaps down since flaps change the lift-producing properties of the wing
How is stall speed affected by a change in bank angle?
Higher bank angles require more lift to maintain level flight (accelerated stall), therefore stall speed increases as bank increases
Lift on a wing is caused by what?
Lower static pressure on top surface than bottom surface
On a graph of coefficient of lift versus AOA, the stall AOA is the AOA where ____ is maximized
coefficient of lift
Lift is the portion of net aerodynamic force which acts ___ to relative wind
perpindicular
Between symmetric and cambered airfoils, which stalls at lower AOA
cambered
If AOA is constant, what effect does increasing airspeed have on lift?
Lift increases
For a constant airspeed, an increase in AOA has what effect on lift?
Lift increases
