Call it Kismet, but three aircraft builders in wide-spread locations have recently announced similar approaches to putting a pusher propeller on the tail boom of three different ultralight sailplanes. Each enjoys the benefits of mounting a propeller on a rear portion of a pod-and-boom fuselage: streamlining the folded propeller into the wake of fuselage/wing junction, enabling use of a large propeller, and turning the prop slowly to get the greatest efficiency from a small motor. Moyes Tempest from Down Under “Bodex,” a pilot in Brisbane, Australia write, “A mate and I managed to acquire two old Moyes Tempests last year. Although they fly well for what they are, we wanted to see if it could be converted to electric in the hope of getting a self-launch from it. “Originally the idea was going to mount the motor behind the fuselage under the boom, but ground clearance was a problem. Then we thought nose mounting, ground clearance again…even with a dolly …
Sunexelec – Recharging in Flight
The Club d’Ultra Léger d’Alsace is a group of French enthusiasts in Strasbourg, on the German border about halfway between Luxembourg and Switzerland. They have been building ultralight aircraft since 1983, tackling technological innovations such as carbon fiber leading edges, motorization, electrification, and now solar power. They were the first to motorize a Swift, and with one of their craft electrically powered, mounted strips of photovoltaic cells to the upper wing surface. Finding that worked to boost battery duration, the group went on to mount 6.1 square meters of solar cells on an Alpaero Exelec, an ultralight self-launching sailplane. After making 60 flights on battery power between May and April of this year, the group installed the solar cells on the wings, flying 18 times on solar assist between May 21 and July 20. These included eight launches in which the solar cells recharged the airplane’s LiFePO4 batteries during the flight, making the possibility of endless cross-country flight a realizable …