SoLong and the Eternal Aircraft

By Deane Barker on May 17, 2005

A Plane That Never Needs to Land?: A solar-powered plane recently stayed aloft for 24 hours. The inventor is in a quest for the “eternal aircraft” — one that goes up but never comes down.

SoLong is a real piece of work, deftly integrating the latest in high-efficiency componentry: hot-rod photovoltaic cells that convert 20% of the sunlight that strikes them into electricity; a bespoke motor-drive system that spins the propeller with 88% electrical efficiency; an autopilot of Cocconi’s own design; and a pack of 96 cylindrical lithium-ion rechargeable batteries.