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WorksheetsCPL PoF Lift Revision 2
Total questions: 15
Worksheet time: 8mins
Lift acts:
90° to weight
90° to the RAF
To assist motion
180° to Drag
What is aspect ratio?
Ratio of aircraft length to wingspan
Ratio of depth to length of an aerofoil
Ration of main wingspan to tail plane span
Ratio of wingspan to chord of a wing
How is aspect ratio usually measured?
Wingspan/wing area²
(Wingspan/wing area)²
Wingspan²/wing area²
Wingspan²/wing area
Pick all the correct statements:
Low aspect ratio decreases CL max and the geometric stalling angle
Low aspect ratio decreases CL max and increases the geometric stalling angle
Low aspect ratio increases CL max and increases the geometric stalling angle
High aspect ratio increases the CL max and decreases the geometric stalling angle
A rough surface condition will cause:
The separation and transition point to move rearwards
The separation point to move forwards but the transition point to move rearwards
The separation point and transition point to move forwards
CL to increase
Which of the following is an example of a high aspect ratio aircraft
A glider
An Alpha
A Helicopter
An Ag aircraft
Does aspect ratio effect the effective stalling angle
Yes, a high aspect ratio aircraft will stall at a lower effective AoA than 16°
No, an aircraft will still stall at the same effective AoA
Yes
Yes, a low aspect ratio aircraft will stall at a higher effective AoA than 16°
The static pressure of an aerofoil is:
(Tick all that apply)
Higher on the upper surface
Lower on the upper surface
Higher on the lower surface
Lower on the lower surface
Does centre of pressure move rearwards or forwards with a decrease in AoA
Rearwards
Forwards
By having an aerofoil with a low minimum Cd:
Higher cruise speed attainable
Higher takeoff speed required
Higher power setting required to maintain S&L
Can operate in higher temperatures
Induced downwash is caused by
Wingtip vortices
A turbulent boundary layer
Flying to fast
Wingroot vortices
Select all answers that make up the lift formula
CL
CD
½pV²
S²
S
Which point on the graph would indicate the zero lift angle for a general purpose aerofoil?
A
B
C
D
Which point on the graph would indicate CL max
A (16° AoA)
B (4° AoA)
C (0° AoA)
D(-4° AoA)
Ice build up on the leading edge:
Will cause the aircraft to stall later because ice if lighter than air
Will cause the airflow to break away earlier
Will cause the transition point to move rearward
Will decrease wingtip vortices
