MacCready won flight prize with a crashable plane

For 18 years after the Kremer Prize for human-powered flight was announced, every team that attempted it built the strongest, most aerodynamically refined aircraft its engineers could design — a reasonable instinct, since a fragile aircraft seemed like the last thing you'd want attempting a genuinely difficult, failure-prone challenge. But building for strength and optimization meant every crash, and crashes were common on a problem this hard, cost a team months of rebuilding before it could try again.

A team that could only attempt the challenge every few months, because each failed attempt destroyed months of work, could only learn from a handful of real tests across years of effort. The actual constraint on solving the problem wasn't the quality of any single attempt — it was how many attempts a team could realistically run and learn from.

Paul MacCready designed the Gossamer Condor as a deliberately flimsy, ultralight aircraft built from foam, mylar film and thin aluminum tubing — cheap materials fast and inexpensive to repair rather than robust enough to survive hard landings. The design let his team fly, crash and rebuild within hours instead of months, running roughly 222 test flights over a period of months and refining the aircraft after each failure far faster than any team optimizing for survivability ever could.

Built the aircraft deliberately flimsy and cheap to repair, so crashes cost hours instead of months, letting the team run more test flights and learn faster than rivals.

Cheap materials made repairs take hours, not months.

Fast rebuilds allowed 222 test flights in months.

Each crash yielded data that improved the next attempt.

Rapid iteration compounded learning faster than rare, refined attempts.

When the bottleneck is iteration speed, optimize for cheap failure and fast rebuilds, not for robustness.

On 23 August 1977, pilot Bryan Allen flew the Gossamer Condor's 223rd flight, completing the required figure-eight course around two markers half a mile apart in 6 minutes and 22 seconds, winning the £50,000 Kremer Prize for the first sustained, controlled human-powered flight.