A small product’s big potential

BY DOUG KINNEARD

In a world where nanotechnology allows progressively smaller "stuff," one small invention at the Boeing facility in Mesa, Ariz., is hitting the market with much larger appeal.

What's the "big" news? It's the previously guarded electromagnetic oscillatory jet actuators.

The unique flow-control devices, which generate streams or even "sheets" of rushing air or water, are under consideration for potential use in a wide range of aerospace and non-aerospace applications, including the unmanned and manned Canard Rotor/Wing aircraft, the proposed Boeing 7E7 airliner, helicopters, ships, submarines, torpedoes, motorboats, and even pressurized water-storage tanks onboard the International Space Station. The market for this product appears unlimited.

The flow-control devices incorporate unique electromagnet designs along with high-energy rare earth magnets, known as Neodymium Iron Boron, said Boeing Technical Fellow Ahmed Hassan, who has been developing the actuators in Mesa since 1994.

"This combination allows these flow-control devices to be miniaturized, providing amazing compactness and weight savings," he said. Boeing has patented the proprietary family of flow-control devices, which so far have received two Boeing Special Invention Awards. Already the actuator has shrunk to as small as half an inch wide and high—extending to any length.

Mesa originally developed the devices to direct airflow that improved the high-lift, high-speed aerodynamics of rotor blades and wings. Additionally, "we sought to alleviate the high-speed impulsive noise of helicopter rotor blades and reduce the drag on helicopter fuselages" using the technology, said Hassan. The team has realized these objectives through successful tests and demonstrations.

The actuators are also suitable for myriad potential fixed-wing airplane applications. Their directed airflow can improve safety and efficiency, increase wing lift and reduce wing drag at stall, increase the effectiveness of flaps, and reduce the complexity of traditional high-lift flap systems on jetliners. They also reduce the drag of fuselages with loading ramps by creating smooth sheets of air to energize the flow behind the blunt rear surface of the loading ramp door during flight.

Boeing has demonstrated the device successfully for underwater propulsion—on a model boat. It closely guarded the technology's extension to marine applications while the team of researchers in Mesa were filing patents and making assessments.

Dubbed the low-noise underwater propulsion device in its marine application, the electromagnetic pump-like actuator produces thrust through the oscillatory motion of a piston. "Water is ingested into then expelled from the actuator very rapidly," said Hassan. Based on a phenomenon called "acoustic streaming" observed in the early 1940s, this oscillation creates a rush of water (rather than air) that is used in this case to propel and/or steer the boat.

Other technologies this invention can complement:

• Stealth and unmanned air vehicles. "Since stealth and small-scale unmanned aerial vehicles require aerodynamic surfaces with minimal or no control surface discontinuities, they can capitalize on this new product by avoiding the use of flaps and ailerons to control the attitude of the vehicle," Hassan explained.

• Weapons. The device achieved a 25 percent drag reduction on torpedo simulations.

• Commercial trucking. Having demonstrated a 17 percent reduction in drag, Boeing already has applied to license these devices to the trucking industry where, just as on aircraft with rear loading ramps, they reduce turbulence behind the flat rear trailer door.

"Our product may be small," Hassan said, "but our potential is unlimited."

doug.kinneard@boeing.com