Harmon Der Donnerschlag

Der Donnerschlag
General information
Type	Homebuilt aircraft
National origin	United States
Manufacturer	Harmon Engineering Company
Status	Production completed
History
Variant	Harmon Mister America

The Harmon Der Donnerschlag (English: Thunderclap) is an American homebuilt aircraft that was designed and produced by Harmon Engineering of Howe, Texas. The aircraft was intended for amateur construction. ^[1]

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. ^[1]

The aircraft's 19.5 ft (5.9 m) 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 (56 kW) Volkswagen air-cooled engine automotive conversion, driving a two-bladed wooden propeller. ^{[1] [2]}

The aircraft has an empty weight of 350 lb (160 kg) and a gross weight of 600 lb (270 kg), giving a useful load of 250 lb (110 kg). With full fuel of 10 U.S. gallons (38 L; 8.3 imp gal) the payload is 190 lb (86 kg). ^[1]

The aircraft was later developed into the Harmon Mister America. ^[1]

Operational history

By October 2013 there were no examples registered in the United States with the Federal Aviation Administration and none may exist anymore. ^[3]

Specifications (Der Donnerschlag)

Data from Plane and Pilot ^[1]

General characteristics

• Crew: one
• Length: 14 ft 6 in (4.42 m)
• Wingspan: 19 ft 6 in (5.94 m)
• Empty weight: 350 lb (159 kg)
• Gross weight: 600 lb (272 kg)
• Fuel capacity: 10 U.S. gallons (38 L; 8.3 imp gal)
• Powerplant: 1 × Volkswagen air-cooled engine four cylinder, air-cooled, four stroke automotive-conversion engine, 75 hp (56 kW)
• Propellers: 2-bladed wooden

Performance

• Maximum speed: 120 mph (190 km/h, 100 kn)
• Cruise speed: 110 mph (180 km/h, 96 kn)
• Stall speed: 55 mph (89 km/h, 48 kn)
• Range: 500 mi (800 km, 430 nmi)
• Service ceiling: 10,000 ft (3,000 m)
• Rate of climb: 800 ft/min (4.1 m/s)

References

1. Plane and Pilot: 1978 Aircraft Directory, page 142-143. Werner & Werner Corp, Santa Monica CA, 1977. ISBN   0-918312-00-0
2. Lednicer, David (2010). "The Incomplete Guide to Airfoil Usage". Archived from the original on April 20, 2010. Retrieved October 10, 2013.
3. Federal Aviation Administration (October 10, 2013). "Make / Model Inquiry Results". Archived from the original on June 11, 2015. Retrieved October 10, 2013.