Harmon Der Donnerschlag

The Harmon Der Donnerschlag (Thunderclap) is an American homebuilt aircraft that was designed and produced by Harmon Engineering of Howe, Texas. The aircraft was intended for amateur construction.

Design and development
Der Donnerschlag features a wire-braced shoulder-wing, a single-seat open cockpit, fixed landing gear and a single engine in tractor configuration.

The aircraft's 19.5 ft span wing has two beam-type spars and employs a 16% airfoil at the wing root, tapering to a 12% airfoil at the wingtip. The standard engine used is the 75 hp Volkswagen air-cooled engine automotive conversion, driving a two-bladed wooden propeller.

The aircraft has an empty weight of 350 lb and a gross weight of 600 lb, giving a useful load of 250 lb. With full fuel of 10 u.s.gal the payload is 190 lb.

The aircraft was later developed into the Harmon Mister America.

Operational history
By October 2013 there were no examples registered in the United States with the Federal Aviation Administration and none may exist anymore.