Ultra-low friction air pump for creating oscillatory or pulsed jets

An air pump for control of aerodynamic air flow over a surface comprising:

• an orifice opening through an aerodynamic surface of an airfoil;
• an air pump housing including a hollow space adjacent to the orifice;
• a substantially rigid movable member within the air pump housing, whereby an interior surface of the air pump housing has been coated with approximately 0.5 to 10 microns of film of ultra-low friction amorphous carbon, the movable member comprising a piston connected by a first shaft element defining an axis and wherein the piston is made substantially of composite materials and is flat and thin relative to its axis of travel and the air pump housing, the piston and housing together defining a compression chamber effective for aerodynamic flow control, the first shaft element traveling within at least one bushing which has a coating of the ultra-low friction film of amorphous carbon, the movable member being substantially symmetric in terms of its mass about a plane extending perpendicularly through the mid-point of the air pump housing, the axis extending in a direction that intersects the aerodynamic surface substantially normally so that the movable member oscillates through a neutral centered position along the axis;
• and
• the combination of the piston and a second shaft element within the hollow space defining a compression chamber open to the exterior of the aerodynamic surface, whereby the piston, first and second shaft elements and housing effectively cooperate in operation of the air pump in an ultra-low friction manner of aerodynamic flow control of the airfoil.