MICHAEL PHELAN / LONDON
Boeing's Mesa, Arizona, facility has revealed the results of 10 years of work on tiny electromagnetic oscillatory jet actuators. The manufacturer hopes to use the actuators to reduce aircraft drag, aid stealth and potentially eliminate control surfaces on some aircraft.
The miniature flow-control devices generate streams or sheets of high-velocity directed air that improve the high-lift aerodynamics of wings.
The devices consist of a tiny jet actuator, equipped with a vibrating membrane, fitted inside a slot along an aerodynamic surface. On activation they rapidly suck air into the slot and jet it out again. This creates an outward jet of air and the effect can be used to replace moving control surfaces such as ailerons, elevators and rudders. The slots have no moving parts and a lower radar profile and are lighter.
Boeing has patented the flow-control devices, and says it is their small scale that makes them useful. The current actuators are about 12mm (0.5in) in width and height, and can be made to fill a slot of any length.
Boeing says the devices could be used on canard rotor/wing aircraft, helicopters and even the proposed 7E7 airliner. On fixed-wing applications the directed airflow can increase wing lift and reduce drag at stall, increase the effectiveness of flaps, and reduce the complexity of high-lift systems. The devices could also reduce the drag of rear loading ramps by creating smooth sheets of air to energise the flow behind a ramp's blunt rear surface.
Source: Flight International