Quantum's Electric Aircraft Project

This WEB site is dedicated to describing the building of a Cumulus motor glider prototype conversion from gas to electric propulsion. The project could eventually result in production electric aircraft.

The Cumulus is a kit produced by Ultralight Soaring Aviation. The electric propulsion Cumulus is a product of Quantum Associates and is expected to have the following Characteristics:

Cumulus Motor Glider Dimensions

Wing Span

43 ft (13.1m)

Wing Area

140 sq ft (12.7 sq m)

Aspect Ratio



350 lbs Empty /Gross Weight 640 lbs
with 90 pounds of batteries

Useful Load

290 lbs


20 ft/Height 4.5ft

Cumulus Motor Glider Speeds

Max Speed(Vmax)

90 mph

Cruise Speed Range

35-70 mph

Stall (best flaps)

32 mph

Cumulus Motor Glider Performance

Best Sink Rate

190 fpm @ 34 mph

Best Glide Angle

20:1 @ 43 mph

Rate of Climb

1000 fpm, max


1.5 hours with 3 to 4000 watt-hour batteries

Takeoff Roll

250 ft

Roll Rate

4.5 sec

Cumulus Motor Glider Structure

Limit Load

+4.4/-2.0 G min

Wing/Tail Cover



4130 chrome-moly steel

Wing Loading



4.56 lbs/sq ft


550 A123 cells (ANR26650 M1a)
weighing 80 lbs

This WEB site is under construction. No other pages, except "Contacting Quantum", contains useful information.