US Aviation Cumulus
AMERICAN MOTORGLIDER
The US Aviation Cumulus is an American low-wing, single-seat, open cockpit motor glider that was designed by Dave Ekstrom and produced by US Aviation, supplied in kit form for amateur construction.Vandermeullen, Richard: 2011 Kit Aircraft Buyer's Guide, Kitplanes, Volume 28, Number 12, December 2011, page 73.