White smoke is drawn at the speed the air really moves over the wing, slowed down for the film. Equal air flows between neighbouring streamlines.
Wing rigging
Area held at 174 ft² · all articles drawn to one scale
Sweep is part of the jet drawing
Angle of attack
Airspeed & q
Lift balance
Drag balance
Coefficients
Stall warning
Manometer board
X-Y plotter
Span load survey
Buffet scope
G-meter
Downwash & momentum
Density altitude
Transit clock
Flight view
Drag vs airspeed
Punch-card log
Airframe release board
Ready-room myth board
Field manual
Lift in four lines
Angle of attack and camber bend the airflow. Air over the top follows the curved surface and leaves heading down.
Bending a flow takes a pressure difference. Pressure drops over the top (most of the lift) and rises a little underneath.
Air speeds up into that low pressure. That's Bernoulli: speed and pressure change together.
The pressure that pushes the wing up also pushes the air down: downwash, Newton's third law. L = CL·½ρV²·S, and angle of attack sets CL, up to the critical angle.
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