Gossamer Condor I
In 1976 Paul MacCready was thinking about trying for the £50,000 Kremer Prize for manpowered flight. The wing loading would be very light and that it would operate a lift coefficient of only .9 (compared to 1.4, or better, for previous MPAs). This meant a single-surface airfoil would have low drag.
Construction began in the Rose Parade float shed down in the Arroyo Seco not far from Pasadena. Two inch diameter .035in. thick alloy tubes in 12ft sections that were joined to make an 88ft span wing.
On 9th October 1976, though the lightly misting rain added a lot of weight, the craft acted more like a balloon than an airplane. They walked with it at 5 mph; it lifted easily and strained at the ropes attached to all corners. Nothing broke. The structural idea was reasonable.
The 96ft span craft was moved to Mojave Airport soon after the tubing was chemically milled down from 22 thousandths at the centre to 14 thousandths of an inch at the outer sections of the wing.
First flights with Paul's son Tyler (a hang glider pilot) on board were promising. Tyler pedalled rather easily making 45-second flights with a push start. Greg Miller, a new rider of racing cyclist championship quality could take off on his own and, after a good deal of flying practice, made a tremendously encouraging flight of two-and-a-half minutes while covering over a thousand foot distance.
The next time, MacCready measured and marked the one-mile figure-eight course, practised taking off and flying over the 10 ft barrier, and called out the officials. After several trials, Greg's best flight was 2 minutes and 30 seconds. It had to stay up three times longer, and the matter of control was even more critical - a full turn had yet to be made. Winds of 2 to 4 mph and the slightest gustiness would limit flights to only 30 or 40 seconds. Thin, single-surface airfbils have low drag at only one angle of attack. For the Condor, a low-drag spike occurred at about 8.2 mph. Above or below that speed, the drag rose impossibly high.
The Condor I conducted 332 flights.
With budgetary problems NASA was having trying to keep its space program alive and well, NASA/ Dryden Flight Research Center established a NASA test program is to study the unusual aerodynamic performance, stability and control characteristics of large but very lightly-loaded and slow-flying aircraft. Data acquired will be used in the design of future aircraft for extremely low-speed flight at any altitude, and particularly for low-power flight in very low densities at high altitudes up to 100,000 feet. Not that they expect Bryan to crank his way into the stratosphere - they just wonder what it would be like to f ly a homebuilt aircraft like the G.A. in the thin air of Mars.
Under Project Manager Dale Reed, in mid February 1980 the 55-pound man-powered aircraft finally got off the ground, between midwinter rains, with Bryan Atlen doing the legwork.
When the rains let up, they hooked up an electric motor and to make it an EPA (electric powered aircraft), preparatory to installing solar cells on the wings.
Aspect ratio: 8.3.
Span: 96 ft.
Chord: 115 in.
Wing area: 1056 sq.ft.
Prop dia: 12 ft.
Weight: 84 lb