The hang glider, with its wire stays and nonrigid wing, provided a model of light construction for the Condor. 
streamlined, cantilever-wing mono- 
planes — aircraft that looked like pro- 
peller-driven sailplanes. It is a safe 
bet that if other designers had been 
offered plans for the Gossamer Con- 
dor, they would have rejected this 
primitive, wire-festooned aircraft with 
amusement and disdain. 
No doubt, MacCready’s experience 
building wire-braced model airplanes 
influenced him. He was also familiar 
with early full-size airplanes that had 
wings braced with exposed wire stays 
radiating from a king post. In fact — 
ironically — some of his open-minded- 
ness toward the Condor’s structure 
can be attributed to his isolation from 
current airplane design. Since taking 
his Ph.D. in 1952, he had had almost 
no direct involvement with aeronau- 
tical structural engineering. Unlike 
other designers of human-powered air- 
craft, he was able to concentrate on 
the problems of flight without the need 
to produce a “modern” vehicle. Cer- 
tainly the original sketches for the 
Gossamer Condor contained more of 
MacCready’s past than of aviation’s 
present. 
In the beginning little more than 
the huge wing and bracing booms were 
envisioned for the plane. MacCready 
wanted to use as few components as 
possible to keep the airframe light. 
He hoped to stabilize the plane in 
pitch — fore-and-aft rotation about the 
wingspan axis — by placing the pilot 
well below the wing where his weight 
would act as a pendulum stabilizer, 
a technique still used to control some 
flying scale models. 
Between August 10 and August 20, 
1976, MacCready built a second balsa 
model of his design. A block of wood 
and some modeling clay represented 
the weight of a pilot at the base of 
the bottom post, and the wing was 
covered only on its upper side, again 
like an indoor model or a hang glider. 
(Later on, the design evolved to in- 
clude covering on the underside of 
the wing as well.) The models had 
bowsprits carrying small stabilizers, 
but the first test glides showed that 
they were unstable in pitch. 
At this point MacCready asked his 
friend and colleague Peter Lissaman 
for some advice about stabilizer size, 
and the nucleus of the “Gossamer 
Squadron” was formed. Although 
most of his work was concerned with 
large aircraft and fluid mechanics, 
Lissaman knew all about the Kremer 
Prize. When MacCready broached the 
giant hang glider idea, Lissaman was 
skeptical: “Lots of people have tried 
lots of technology.” Still, it took him 
only a few moments to calculate, on 
the back of the proverbial envelope, 
that the pendulum effect of a pilot’s 
weight would not provide enough sta- 
bility in pitch; a fair-sized external 
stabilizer was needed. 
The second model was soon fitted 
with a larger stabilizer and test glided 
successfully. “Oh, it flies backward!” 
the Condor and Albatross teams 
would become used to hearing from 
nonaeronautical observers reacting to 
the stabilizer’s forward position. But 
this feature, known as a canard sta- 
bilizer, did not look unusual to Mac- 
Cready, who had used it many times 
on the models he had built as a boy. 
It even flew. “Not a brilliant model,” 
MacCready says, “but good enough 
to convince me that it was worth while 
to go ahead.” 
MacCready called his brother-in- 
law Kirke Leonard and announced, 
“I’d like to build a human-powered 
airplane.” Leonard thus began adding 
his years of engineering experience 
69 
