Lift Flashcards
what is the coefficient of lift (CL)?
a number/multiplier that refers to an aerofoils potential to generate lift
whats the formula for lift?
lift = CL 1/2pV^2 S
whats the simplified formula for lift?
Lift = IAS x AoA
cambered aerofoils produce lift at 0 degrees AoA, so the zero-lift angle is actually ___
approx. -3 degrees
what is the effect of a high CL max? (in ref to critical angle, lift, and CL)
a higher potential to generate lift, so a higher critical angle, and more lift at all normal operating AoAs, as compared to a normal/low CL max
whats the effect of camber in relation to CL max?
a higher camber results in a higher CL max
whats the effect of surface roughness on CL max?
smoother surfaces increase CL max
what is spanwise flow?
airflow that flows toward the wingtips, due to the spanwise pressure distribution (higher pressure at the wingroots than the wingtips)
how are wingtip vortices formed?
air spilling from high pressure to low pressure (bottom to top) around the wingtips
how are trailing edge vortices produced?
airflow meeting the trailing edge at slightly different angles, resulting in in twisting airflows
the formation of vortices is least at (high/low) speed and (high/low) AoAs
high, low
what is aspect ratio?
wingspan over chord
high aspect ratio results in? (with regards to CL max)
higher CL max
(in relation to vortices, CL max, and stalling angle) higher AR means:
less wingtip vortices, higher CL max, lower geometric stalling angle
