National Geographic : 1981 Jan
use of composites, William P. Lear, inven tor of the Learjet, has gone all the way. Be fore he died in 1978, Lear designed a turboprop corporate airplane structured al most entirely of graphite epoxy. Now his company, LearAvia of Reno, Nevada, is evaluating a prototype, the Lear Fan. On paper Lear's venturesome airplane flies far ther, more quietly, and with greater fuel ef ficiency than its corporate cousins. If it proves out in the air, competitors may take off for their drawing boards. Loaded Harrier Gets an Assist * Aerodynamics: While the Tiger and most other airplanes make rolling takeoffs and landings, the maverick British Aerospace Harrier can take off and land vertically. Through movable nozzles, the engine's ex haust is directed downward for vertical flight and aft for horizontal flight. But there's a catch. The Harrier's engine, generating 21,500 pounds of thrust, cannot lift the airplane vertically when it is fully loaded with weapons and fuel at 25,000 pounds. So a short takeoff roll is necessary. For aircraft-carrier operations, the re sourceful British have taken this an incredi ble step further-a full-payload takeoff from a ski-jump ramp 130 feet long and just 40 feet wide. "Coming off the ramp, you're not yet flying," explained Harrier expert John Fozard, "but like a ski jumper, your momentum is upward. Meanwhile you are rotating the engine nozzles aft, and the air craft is accelerating to flying speed. "So you've bought yourself a runway in the sky," Fozard continued. "And from a pi lot's point of view, there's all that lovely, dry air between you and the horrid, wet sea." When Harrier test pilot Mike Snelling briefed me before a demonstration ride off the ski jump at the 1978 Farnborough Air Show, he stated that it would be "unevent ful." However, he advised, in the remote chance of engine failure as we came off the ramp, "there will be no time for a conference. You will see me eject, and you may take that as your cue that all is no longer well." All went well, however, and the Harrier's ski-jump takeoff is something of an aero nautical event. The U. S. Marine Corps plans portable ski jumps for battlefield use that can be set up in just six hours. The Navy figures that there may be a place in its future for small ski-jump carriers to augment its big-deck force. * Controls: The Air Force's new fighter, the General Dynamics F-16, is the first produc tion airplane in which the cable-and-pulley control system of the Tiger has been entirely replaced with electronics. Signals speed from the control stick along wires to a com puter, and thence roundabout to the control surfaces of the 48-foot-long fighter. This fly-by-wire control system opens a whole JAM.. A. AUIAN WII H Nr.LSUN . AKUWN (UtPPUSITE) Son ofSST? McDonnell Douglas'smodel of an advanced supersonic transport(fac ing page) is readiedfor wind-tunnel test ing at a NASA facility. The wing design promises as much as 40 percent betterfuel economy than the Concorde's. Lockheed chief engineers Bard Allison (above, at right) and Russell Hopps hold models of a subsonic transportwith ca nards and a second-generationSST.