The SIAI S.51, Savoia Marchetti S.51 or Savoia S.51 was an Italian racing flying boat built by SIAI for the 1922

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 annually (and later, biennially) to the winner of a race for seaplanes and flying ...

race.

Design and development

The S.51 was a single-seat

sesquiplane A biplane is a fixed-wing aircraft with two main wings stacked one above the other. The first powered, controlled aeroplane to fly, the Wright Flyer, used a biplane wing arrangement, as did many aircraft in the early years of aviation. While a ...

flying boat. Its 224-

kilowatt The watt (symbol: W) is the unit of power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantify the rate of energy transfer. The watt is named after Jame ...

(300-

horsepower Horsepower (hp) is a unit of measurement of power, or the rate at which work is done, usually in reference to the output of engines or motors. There are many different standards and types of horsepower. Two common definitions used today are th ...

)

Hispano-Suiza Hispano-Suiza () is a Spanish automotive–engineering company. It was founded in 1904 by Marc Birkigt and Damian Mateu as an automobile manufacturer and eventually had several factories in Spain and France that produced luxury cars, aircraft en ...

V8 engine A V8 engine is an eight- cylinder piston engine in which two banks of four cylinders share a common crankshaft and are arranged in a V configuration. The first V8 engine was produced by the French Antoinette company in 1904, developed and u ...

, mounted on two N struts above the

hull Hull may refer to: Structures * Chassis, of an armored fighting vehicle * Fuselage, of an aircraft * Hull (botany), the outer covering of seeds * Hull (watercraft), the body or frame of a ship * Submarine hull Mathematics * Affine hull, in affi ...

and below the upper

wing A wing is a type of fin that produces lift while moving through air or some other fluid. Accordingly, wings have streamlined cross-sections that are subject to aerodynamic forces and act as airfoils. A wing's aerodynamic efficiency is exp ...

, drove a two-bladed

propeller A propeller (colloquially 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 ...

in a

pusher configuration In an aircraft with a pusher configuration (as opposed to a tractor configuration), the propeller(s) are mounted behind their respective engine(s). Since a pusher propeller is mounted behind the engine, the drive shaft is in compression in no ...

. The inclined interplane struts were mounted in a V configuration. The lower wings had small stabilizing floats mounted on inclined struts so that they hung below and outboard of the outer tips of the lower wing. SIAI later based the design of the hull of its S.58 flying boat fighter of 1924 on that of the S.51s hull. Savoia-Marchetti S

Operational history

Italy entered the S.51 in the 1922 Schneider Trophy race along with two

Macchi M.17 The Macchi M.17 was an Italian racing flying boat built by Macchi for the 1922 Schneider Trophy race. Design and development The M.17 was the first purpose-built racing seaplane that Macchi company designer Alessandro Tonini designed. It was a s ...

flying boats in competition with a British

Supermarine Sea Lion II The Supermarine Sea Lion II was a British racing flying boat built by the Supermarine Aviation Works. Designed by Reginald Mitchell, it was a modification of Supermarine's Sea King II. Sea Lion II was powered by a Napier Lion engine. En ...

flying boat. The race was held at

Naples Naples (; it, Napoli ; nap, Napule ), from grc, Νεάπολις, Neápolis, lit=new city. is the regional capital of Campania and the third-largest city of Italy, after Rome and Milan, with a population of 909,048 within the city's adminis ...

on 12 August. The S.51 capsized in an accident during the seaworthiness trials before the race. Righted by its crew, it completed the race, piloted by Alessandro Passaleva but could only take second place, with the Sea Lion a comfortable 2 min 22 s ahead. The course required 13 laps, a total distance of , over which the S.51 averaged . On 28 December 1922 the S.51, flown again by Passaleva, set a world speed record for

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 tec ...

s of .

Operators

;

Specifications

Notes

References