The Coleoptere (“beetle”) is one of the strangest-looking aircraft ever designed. With a ring-shaped wing wrapped around a fuselage, it was capable of vertical takeoff and landing. In fact, the designer theorized that it might be capable of supersonic speeds once it was airborne.
However, the Coleoptere had problems from its very beginning. In early hovering tests, pilot Auguste Morel complained that it was nearly impossible to determine his vertical height. He had to listen for changes in the engine’s hum to gauge the aircraft’s altitude. Even later versions of the Coleoptere had a distressing tendency to spin vertically.[
The only time that the Coleoptere achieved horizontal flight (instead of a vertical takeoff and landing) was accidental. On its ninth and final flight, the aircraft wobbled wildly during descent and ended up accelerating away horizontally—and briefly. The pilot ejected, the Coleoptere wrecked and burned up, and the project was discontinued.