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For Release: Dec. 22, 1998

Keith Henry
Langley Research Center
(757) 864-6120/24

Dave George
Boundary Layer Research, Inc.
Everett, Washington
Ph: (425) 353 6591

RELEASE NO. 98-097

NASA Licenses Technology for Improving Helicopter Performance

NASA has licensed technology to a Washington state company for improving the performance, stability and control of helicopters.

Under the agreement, Boundary Layer Research, Inc., Everett, Wash., will commercially market an aerodynamic device called "tailboom strakes." The license will allow the company to market the NASA-patented device to civil and military operators of single rotor helicopters.

For the past year Boundary Layer Research has been working with NASA Langley Research Center, Hampton, Va., to explore the viability of helicopter strake technology developed by a NASA-Army team of researchers. The technology is applicable to all single rotor helicopters and is patented by NASA as a "Low Speed Anti-Torque System."

The company has applied for Federal Aviation Administration certification to make the technology available to civil operators and owners.

"It's always exciting and gratifying to see one of our ideas embraced by a vigorous, young company," said Henry Kelley, an Army researcher working in NASA Langley's Research and Technology Group and lead researcher on the project.

The upper and lower tailboom strakes run the entire length of the tailboom on the port side only. The strakes are typically 10 to 15 feet long and extend diagonally from the surface about three inches, one near the top of the tailboom and one near the bottom of the tailboom. At slow airspeeds, these narrow surfaces provide resistance to the air coming down from the main, overhead, rotor to create a high-pressure area on the port side of the tailboom. This significantly counteracts a single-rotor helicopter's natural tendency to turn due to torque, improving the pilot's control over the helicopter.

Benefits are reported as improved stability, less horsepower needed for the tail rotor, improved yaw (side-to-side) control, improved altitude performance, increased payload capability at altitude, reduced fatigue for tailboom and related flight critical components, and reduced maintenance costs.

Boundary Layer Research president Robert Desroche said, "We are very pleased to be selected by NASA to further develop this technology and are anxious to get it to the operators where it can do some good. Operators work a very delicate profit margin and this technology will help tip the scale in their favor since it can reduce maintenance costs and increase performance. The fact that it improves safety by improving yaw control margins is just icing on the cake."

Last month the company shipped a set of helicopter strakes to the U.S. Army Flight Test Evaluation Center at Ft. Rucker, Ala. The strakes will be evaluated for the Army’s fleet of single rotor helicopters. In the past few months the Royal New Zealand Air Force and the Australian Defence Force have each outfitted UH-1H helicopters with strakes after learning of the technology from Army researchers at NASA and conducting their own evaluations with close collaboration with NASA.

The device represents the company’s first venture into the rotorcraft modification market. Recently the company announced a reorganization and the hiring of key staff to facilitate the anticipated growth of the new Rotary Wing Division.

Boundary Layer Research designs and develops products that enhance performance of personal and business aircraft. Modifications include vortex generators, winglets, wing tanks, airframe strakes, stall strips and landing gear upgrades. These and other products have been applied to more than 60 models of airplanes since the company was founded in 1990.

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