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By Alan Brown Aerospace Projects Writer The Systems Research Aircraft (SRA) project team recently concluded flight validation of the Electro-Mechanical Actuator (EMA), one of three advanced control-surface actuators flown on the modified F-18 Hornet in the Electrically Powered Actuator Design (EPAD) Program. More than 25 flight hours were logged on the EMA during the flight validation phase. The unit, built by MPC Products of Skokie, Ill., drove the SRA's left aileron during the tests, operating completely independent of the F-18's
The EMA is the last of three experimental actuators to be flight tested aboard the SRA under the EPAD Program, a joint development and evaluation program sponsored by the U.S. Navy, NASA and managed by the Air Force Research Laboratory at Wright-Patterson Air Force Base in Ohio. Stephen Jensen, Dryden's principal investigator for the EMA, said EPAD sought to establish the credibility of electric actuation as a primary method of control for flight-critical control surfaces on tactical aircraft, as well as to simplify flight control systems by making the actuators completely self-contained in terms of control and power. "Electric actuators can eliminate complicated electrical and hydraulic connections," Jensen said. "They pave the way for future 'all-electric aircraft' that are free of expensive, heavy and high maintenance hydraulic systems. EMA actuators are particularly well-suited for space applications, where hydraulic seals tend to dry out and leak," Jensen explained.
A follow-on version of the EMA will be used on the prototype spaceflight-rated X-38 Crew Return Vehicle and other future spacecraft. EMA actuators are also being developed for use on the X-33 technology demonstrator. A wide variety of maneuvers representative of those an operational F-18 would perform were flown by Dryden research pilots Mark Stucky and Ed Schneider in the validation phase, along with specialized test points intended to evaluate the maximum forces the EMA is capable of handling. SRA project manager John Sharkey called the EMA a major milestone on the road to an all-electric airplane. "Besides savings in weight, costs, logistical and maintenance support for future aircraft, electrical systems promise diminished vulnerability in combat by eliminating hydraulic lines in the fuselage and wings.
The power-by-wire arrangement will also reduce complexity and improve reliability," he said. The EMA and related electrical systems could lead to a five percent to nine percent fuel savings on an all-electric passenger plane and a 30 percent to 50 percent reduction in ground equipment. Military tactical aircraft could achieve a 600 pound to 1,000 pound reduction in take-off weight, and a 14 percent reduction in the area that is vulnerable to such threats as small arms fire. |
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Responsible NASA Official: John Childress For questions, contact: Dryden Web Group Page Curator:Mel Garcia Modified:December 18, 1998 |
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