Stipa-Caproni Airplane

By looking at these two pictures you can see how the Stipa Caproni got the nickname of “the flying barrel” but this 1932 aircraft was quite revolutionary for its time. The Stipa-Caproni was designed by Luigi Stipa and first flew on October 7, 1932 with Caproni company test pilot Domenico Antonini at the controls.
The airplane is revolutionary due to the then advanced design where the engine was placed (completely enclosed) within the fuselage. Stipa called this “intubed propeller” which is the precursor to the ducted fan jet engine. Stipa felt that by using Bernoulli’s principle of fluid motion and by tapering the inside of the fuselage (forming a venturi) the compressed engine exhaust and propeller thrust exiting the rear of the aircraft would increase efficiency.

The airplane is constructed mainly of wood with a relatively small rudder and elevator which, when placed inline with the ducted fuselage, are very efficient and provide for extra stability. The wings are elliptical and pass through the fuselage. Because of the efficiency of the engine location within the fuselage it was determined that a 120 horsepower de Havilland Gipsy III engine would be sufficient to power the aircraft.

The airplane was stable and performed efficiently as predicted but perhaps too efficiently. It was difficult to change course or maneuver in turns because of the 360° balanced lift effect of the fuselage. The aerodynamic drag produced by the fuselage was so great that it only had a top speed of 81 mph.

On the positive side, the airplane was very quiet and did have short takeoff and landing capabilities. It also had a very slow stall speed (30 mph) and out climbed similarly powered, conventionally configured, aircraft of the day.

Although the Stipa had a fashionable contemporary blue and cream racing paint job it wasn’t enough to go any further with development and the Regia Aeronautica decided to cancel the project and no further prototypes were ordered. Luigi Stipa had proven his theory, the airplane was efficient but did not perform noticeably better than conventional aircraft designs; the Italian government wanted speed and maneuverability and the barrel-like Stipa-Caproni was a dead end project in their view.

Specifications Stipa-Caproni

• Crew: 1
• Capacity: 2
• Length: 19 ft. 4 in. (5.88 m)
• Wingspan: 46 ft. 10 in. (14.28 m)
• Loaded weight: 1760 lb. (800 kg)
• Powerplant: 1 × de Havilland Gipsy III inline piston engine, 120 hp (90kW)
• Number built: 1

Performance

• Stall speed: 30 mph.; 26 kt; 48 km/h
• Landing speed: 42 mph.; 26 kt; 68 km/h
• Maximum speed: 81 mph.; 131 km/h

Here is some footage of an early test flight: