The U.S.Air Force's first X-21A, the jet with air-breathing wings, made its maiden flight today?
Film shows the plane on the ground, in flight and making landings, plus animation of how the air breathing wing works.
Script is copyright Reuters Limited. All rights reserved
Background: The U.S.Air Force's first X-21A, the jet with air-breathing wings, made its maiden flight today (April 18) from the Northrop Corporation plant in Hawthorne, Calif.
Its destination: Edwards Air Force Base for flight testing to demonstrate how to reduce friction drag on wings by using the Northrop Laminar Flow Control method.
Laminar Flow Control is expected to increase the range, payload capacity or flight duration of large aircraft by at least 50 per cent.
This is how it works:
The thin boundary layer of air next to the wing surface is turbulent on conventional airplanes.Turbulence creates friction drag.On the X-21A, a small portion of the boundary layer is sucked through paper-thin slots that run from fuselage to wingtip.Small turbopumps--mounted in two pods under the wings--pull the air through the slots, into some 800,000 pin-size holes and then into ducts that lead to the pumps.The air then shoots out the rear of the pumping pods.
With friction drag reduced, the plane's engines have less work to do.The military payoff could be longer-range, higher payload transports or missile-carrying aircraft capable of staying aloft several days at a time without refuelling.