Solar Riser – The First Human Flight on Solar Power (1979)

Every big story starts small. Long before Solar Impulse 2 flew around the world, a man in California flew half a mile at 12 metres above the ground, and made history. On 29 April 1979 at Flabob Airport near Riverside, Larry Mauro took off in the Solar Riser, the first crewed aircraft to fly on solar power. Only the unmanned AstroFlight Sunrise had flown on sunlight before.

Mauro, president of Ultralight Flying Machines, started with one of his own Easy Riser biplane hang gliders, normally launched on foot. He added wheels, a Bosch electric starter motor of about 2.6 kW (3.5 hp) and a 104 cm propeller, driven through a timing belt and two pulleys. The battery was a 30-volt nickel-cadmium pack taken from a Hughes 500 helicopter. Solar panels on the upper wing delivered about 350 watts.

That was not enough to fly on solar power directly, so the Solar Riser worked like many solar e-bikes do today: charge first, ride later. About an hour and a half of bright sunshine charged the battery for a flight of 3 to 5 minutes. In theory a pilot could take off on the battery, soar in rising air while the sun recharged it, and then continue. Mauro planned to double the number of cells, since there was room on the wing, but never did.

The aircraft weighs only 56 kg empty, has a wingspan of 9.1 m and a top speed of about 32 km/h. After several demonstration flights, including at EAA AirVenture Oshkosh, it was retired to the EAA AirVenture Museum, where it is the only example. Next in line came the Gossamer Penguin (1980) and the Solar Challenger.

Technical data

Photos

• Top photo: Lestocq / Wikimedia Commons, CC BY-SA 4.0

Sources

• Wikipedia: Mauro Solar Riser