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SIAI S.51.jpg
Role Racing flying boat
National origin Italy
Manufacturer SIAI
First flight 1922
Primary user Italy
Number built 1

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 race.

Design and development[edit]

The S.51 was a single-seat sesquiplane flying boat. Its 224-kilowatt (300-horsepower) Hispano-Suiza 8A V8 engine, mounted on two N struts above the hull and below the upper wing, drove a two-bladed propeller in a pusher configuration. 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.[1]

SIAI later based the design of the hull of its S.58 flying boat fighter of 1924 on that of the S.51's hull.[2]

Savoia-Marchetti S.51 I-BAIU Passaleva.jpg

Operational history[edit]

Italy entered the S.51 in the 1922 Schneider Trophy race along with two Macchi M.17 flying boats in competition with a British Supermarine Sea Lion II flying boat. The race was held at Naples on 12 August.[3][4]

The S.51 capsized in an accident during the seaworthiness trials before the race.[5] 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 370 km (230 mi), over which the S.51 averaged 229.57 km/h (142.65 mph).[3][4]

On 28 December 1922 the S.51, flown again by Passaleva, set a world speed record for seaplanes of 280.155 km/h (174.080 mph).[6][7]


 Kingdom of Italy


General characteristics

  • Crew: 1
  • Length: 8 m (26 ft 3 in)
  • Wingspan: 10 m (32 ft 10 in)
  • Height: 2.5 m (8 ft 2 in)
  • Wing area: 23 m2 (250 sq ft)
  • Empty weight: 780 kg (1,720 lb)
  • Gross weight: 1,080 kg (2,381 lb)
  • Powerplant: 1 × Hispano-Suiza 8F (Type 42) V-8 water-cooled piston engine, 220 kW (300 hp)
  • Propellers: 2-bladed


  • Maximum speed: 280 km/h (170 mph, 150 kn)
  • Cruise speed: 230 km/h (140 mph, 120 kn)

See also[edit]

Related lists


  1. ^ "Artwork of Savoia S.51 by Hideaki Ozawa". Retrieved 2015-11-04.
  2. ^ Green and Swanborough, p. 527.
  3. ^ a b "La semaine d'hydraviation de Naples et la Coupe Jacques Schneider". L'Aérophile: 311–12. 1–15 October 1922.
  4. ^ a b "Le semaine d'Hydraviation de Naples". L'Aéronautique: 297–8. September 1922.
  5. ^ "Schneider victor's welcome home". Flight. XIV (35): 495. 31 August 1922.
  6. ^ "IPMS Racing & Record Aircraft SIG - Record List". Archived from the original on 2012-03-02. Retrieved 2012-07-31.
  7. ^ "The Baltimore navy seaplane meeting". Flight. XVI (47): 733. 20 September 1924.