The Piaggio P.7, also known as the Piaggio-Pegna P.c.7, was an Italian

racing In sports, racing is a competition of speed, in which competitors try to complete a given task in the shortest amount of time. Typically this involves traversing some distance, but it can be any other task involving speed to reach a specific g ...

seaplane A seaplane is a powered fixed-wing aircraft capable of takeoff, taking off and water landing, landing (alighting) on water.Gunston, "The Cambridge Aerospace Dictionary", 2009. Seaplanes are usually divided into two categories based on their tech ...

designed and built by

Piaggio Piaggio Group () is an Italian motor vehicle manufacturer, which produces a range of two-wheeled motor vehicles and compact commercial vehicles under five brands: Piaggio, Vespa, Aprilia, Moto Guzzi and Derbi. Its corporate headquarters are ...

for the 1929

Schneider Trophy The Coupe d'Aviation Maritime Jacques Schneider, also known as the Schneider Trophy, Schneider Prize or (incorrectly) the Schneider Cup is a trophy that was awarded first annually, and later biennially, to the winner of a race for seaplanes and ...

race.

Design and development

Seeking to avoid the

aerodynamic drag In fluid dynamics, drag, sometimes referred to as fluid resistance, is a force acting opposite to the direction of motion of any object moving with respect to a surrounding fluid. This can exist between two fluid layers, two solid surfaces, or b ...

induced by floats in seaplanes of

floatplane A floatplane is a type of seaplane with one or more slender floats mounted under the fuselage to provide buoyancy. By contrast, a flying boat uses its fuselage for buoyancy. Either type of seaplane may also have landing gear suitable for land, ...

design,

Ing Ing, ING or ing may refer to: Art and media * '' ...ing'', a 2003 Korean film * i.n.g, a Taiwanese girl group * The Ing, a race of dark creatures in the 2004 video game '' Metroid Prime 2: Echoes'' * "Ing", the first song on The Roches' 199 ...

Giovanni Pegna Giovanni Pegna (4 January 1888 – 19 May 1961) was an important figure in the development of Italian aviation. He was the head of the construction department of Piaggio Aero Industries, Piaggio and later of the Reggiane, Officine Meccaniche Reg ...

of the

company designed a very unusual seaplane to represent Italy in the 1929 Schneider Trophy race. A

cantilever A cantilever is a rigid structural element that extends horizontally and is unsupported at one end. Typically it extends from a flat vertical surface such as a wall, to which it must be firmly attached. Like other structural elements, a cantilev ...

shoulder-wing

monoplane A monoplane is a fixed-wing aircraft configuration with a single mainplane, in contrast to a biplane or other types of multiplanes, which have multiple wings. A monoplane has inherently the highest efficiency and lowest drag of any wing con ...

, known both as the Piaggio P.7 and the Piaggio-Pegna P.c.7, his design floated up to its

wing A wing is a type of fin that produces both Lift (force), lift and drag while moving through air. Wings are defined by two shape characteristics, an airfoil section and a planform (aeronautics), planform. Wing efficiency is expressed as lift-to-d ...

s on its long, slender, watertight fuselage with the wings resting on the water, and employed twin high- incidence

hydrofoil A hydrofoil is a lifting surface, or foil, that operates in water. They are similar in appearance and purpose to aerofoils used by aeroplanes. Boats that use hydrofoil technology are also simply termed hydrofoils. As a hydrofoil craft gains sp ...

s to get itself off the water during takeoff runs.Vašiček, Per. ''Aviation History'', September 2002, p. 35. Sources differ on the P.7s engine; it is described both as an

Isotta Fraschini Isotta Fraschini () is an Italian luxury car manufacturer, also producing trucks, as well as engines for marine and aviation use. Founded in Milan, Italy, in 1900 by Cesare Isotta and the brothers Vincenzo, Antonio, and Oreste Fraschini, in 195 ...

Special V6 rated at and as an Isotta Fraschini AS-5 of .Vašiček, p. 35. The engine was connected both to a two-bladed automatic variable-pitch tractor

propeller A propeller (often called a screw if on a ship or an airscrew if on an aircraft) is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon a working flu ...

by a long metal shaft and by another shaft to a smaller marine propeller, similar to those used on

motorboat A motorboat or powerboat is a boat that is exclusively powered by an engine; faster examples may be called "speedboats". Some motorboats are fitted with inboard engines, others have an outboard motor installed on the rear, containing the inter ...

s, mounted beneath the aircraft's tail. To take off, the pilot would start the engine with the flight propeller feathered and the normal

carburettor A carburetor (also spelled carburettor or carburetter) is a device used by a gasoline internal combustion engine to control and mix air and fuel entering the engine. The primary method of adding fuel to the intake air is through the Vent ...

air intake closed and use a

clutch A clutch is a mechanical device that allows an output shaft to be disconnected from a rotating input shaft. The clutch's input shaft is typically attached to a motor, while the clutch's output shaft is connected to the mechanism that does th ...

to engage the tail propeller and get the aircraft moving through the water. The two hydrofoils, mounted beneath the fuselage on struts just forward of the wings similar to the way in which floats were mounted on floatplanes, would cause the P.7 to rise out of the water almost immediately. After the aircraft had risen on its hydrofoils and the flight propeller had cleared the water, the pilot would open the carburettor air intake, again employing the clutch to disengage the marine propeller, and use another clutch to engage the flight propeller, which automatically would switch from feathered to flight pitch. Driven by its flight propeller, the aircraft then would engage in a conventional takeoff, riding on its submerged hydrofoils until it reached takeoff speed. Without the aerodynamic drag induced by floats or the weight they added to the 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).

Testing

Piaggio manufactured one P.7 and turned it over to the Italian Schneider Trophy racing team. Although some pilots refused to fly the aircraft, the Italian Schneider teams Tommaso Dal Molin conducted some water tests on

Lake Garda Lake Garda (, , or , ; ; ) is the largest lake in Italy. It is a popular holiday location in northern Italy, between Brescia and Milan to the west, and Verona and Venice to the east. The lake cuts into the edge of the Eastern Alps, Italian Alp ...

in northern Italy. The spray the hydroplanes generated made seeing during takeoff difficult, and persistent problems with both clutches ensued. The aircraft never became airborne. Not ready in time, the P.7 was excluded from the 1929 Schneider Trophy race, in which a Macchi M.52R and two Macchi M.67 seaplanes represented Italy. Piaggio and Pegna abandoned plans to build a second P.7.

Operators

;

Specifications

Notes

References