S.A.M. #79: A Spark of Incredible

| March 9, 2013

The oddest and most unconventional contender – probably for any aerial competition – was the Piaggio-Pegna PC.7.

Piaggio Pegna PC.7

The floatplane (or should we call it a ‘foilplane’?) was built for the 1929 Schneider Trophy contest. A cantilever high-wing monoplane with long slender fuselage, it had twin hydrofoils instead of floats and was intended to float with the wing resting on the surface of the water.

Piaggio Pegna PC.7Piaggio Pegna PC.7The PC.7, designed by Giovanni Pegna, was intended to float deep in the water, with the wings resting on the surface. The engine (723kW Isotta Fraschini Special V.6) had an extra shaft and clutch controlling a water-screw at the back. The plan was for the aircraft to first operate using the water-screw and a lower rudder – like a boat. As it gained speed, the hydrofoils would generate lift and raise the aircraft, clearing the main engine/propeller above the water. The pilot would then switch to conventional controls, and the main engine clutch would be engaged…

Piaggio Pegna PC.7Piaggio Pegna PC.7Without the aerodynamic drag induced by floats or the weight they added to an aircraft, Pegna projected that the P.7 would reach high speeds. Sources differ on the speeds he predicted, claiming both 580 km/h (360 mph) and 700 km/h (434.7 mph).

Piaggio Pegna PC.7The PC.7 never flew. Although theoretically possible, the control/clutch configuration would have required a pilot with more than two arms. In practice, problems with the respective clutches prevented the P.c.7 from ever taking off, and although water trials were conducted on Lake Garda by Dal Molin of the Italian Schneider team, the construction of a second aircraft was abandoned.

Piaggio Pegna PC.7Sources: Virtual Aircraft Museum, X-Planes, Wikipedia

S.A.M. #53: Jet Power

| July 7, 2012

Jet aircraft long before the Jet Age? A turbojet? There’s no mistake: the Heinkel 178 was successfully flown on the eve of the World War II.

Heinkel He 178 c

This aircraft is assured a distinguished place in aviation history: on 27 August 1939, piloted by Flugkapitän Erich Warsitz, it made the world’s first flight by a turbojet-powered aircraft. To put this record in its true context of achievement, it should be noted that the first flight of a turbojet-powered aircraft in Britain was that of the Gloster E.28/39 on 15 May 1941.

Heinkel He 178 bThe engine to power the He 178 derived from the pioneering research work of Dr Hans Pabst von Ohain who (together with his assistant Max Hahn) had been employed by Ernst Heinkel in March 1936 and provided with the necessary facilities to continue the development of his work. By September 1937 a hydrogen-fuelled demonstration engine was being run on the bench, and in March 1938 his HeW 3 engine, using petrol as fuel, was developing about 4.89kW. In Britain the world’s first turbojet aircraft engine had been bench-run on 12 April 1937. Of particular interest is the fact that the work of von Ohain and Whittle was entirely independent.

Heinkel He 178 BundesarchivThe He 178 was designed to utilise von Ohain’s power plant. It was a shoulder-wing monoplane of composite construction. The engine was mounted in the fuselage, with a nose air-intake duct passing beneath the pilot’s seat and a long tailpipe discharging from the fuselage tailcone. Retractable tailwheel-type landing gear was installed.

Heinkel He 178 e

Erich Warsitz: “On August 27, 1939 we were ready. The machine was towed to the apron. Ernst Heinkel and his colleagues stared at the circuit I was to fly. By now it was recognized that by virtue of its longer flight endurance and greater operational reliability, it was the jet, and not the rocket aircraft, which belonged to the future.”

Heinkel He 178 f