The SPL (''Samolyet dlya Podvodnikh Lodok'' – aeroplane for submarine boats) (a.k.a. OSGA-101, and Gidro-1) was a submarine borne flying boat designed and built in the

USSR The Union of Soviet Socialist Republics. (USSR), commonly known as the Soviet Union, was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 until Dissolution of the Soviet ...

from 1931.

Development

After successful trials by the

Royal Navy The Royal Navy (RN) is the naval warfare force of the United Kingdom. It is a component of His Majesty's Naval Service, and its officers hold their commissions from the King of the United Kingdom, King. Although warships were used by Kingdom ...

, with submarine borne aircraft, using the

Parnall Peto The Parnall Peto was a small seaplane designed to the British Air Ministry's specification 16/24 in the early 1920s for use as a submarine-carried reconnaissance aircraft. Design and development Two examples were designed and built by George ...

and the

M-class submarine Two ship class, classes and a one-ship class of submarine are known as the M class * Soviet M-class submarine, a class of 148 Soviet Navy submarines built between 1933 and 1947 * British M-class submarine, a class of 3 Royal Navy submarine monitors ...

s, the V-MF (''Voenno-morskoj flot'' – Naval Fleet") wanted to deploy aircraft from cruiser submarines for open sea reconnaissance. In 1931 Chyetverikov had given a proposal for a submarine-launched folding flying boat to the head of TsKB (''Tsentrahl'noye Konstrooktorskoye byuro'' – central construction bureau) but nothing was heard for two years until the NII (''Naoochno-Issledovatel'skiy Institoot '' – scientific test institute) placed an order for two prototypes of the SPL. To prove the design, aerodynamically and hydrodynamically, Chyetverikov designed and built a non-folding version of the SPL with manually retracting landing gear designated OSGA-101. Completed in 1934 the OSGA-101 was flown for the first time by A.V. Krzhizhevskii and completed flight trials satisfactorily. The OSGA-101 was of mixed construction with wooden wings and hull but Welded steel tube booms carrying the fabric covered

Duralumin Duralumin (also called duraluminum, duraluminium, duralum, dural(l)ium, or dural) is a trade name for one of the earliest types of age hardening, age-hardenable aluminium–copper alloys. The term is a combination of ''Düren'' and ''aluminium'' ...

tail unit. Accommodation was for three with two pilots side by side and a third seat to the rear of the pilots. The SPL was very similar but included shorter span wings which folded to lie alongside the fuselage, only two seats in the cockpit, and a pivoting engine nacelle which folded rearwards to lie between the tail-booms. The folded SPL was to be fitted in a water-tight cylinder 2.5m (8 ft 2½in) in diameter and 7.45m (24 ft 5¼in) long, with five minutes allowed for withdrawal and preparation for flight. Flight trials of the SPL commenced at

Sevastopol Sevastopol ( ), sometimes written Sebastopol, is the largest city in Crimea and a major port on the Black Sea. Due to its strategic location and the navigability of the city's harbours, Sevastopol has been an important port and naval base th ...

early in 1935, piloted by A.V. Krzhizhevskii, and were completed by August 1935, but the SPL was rejected due to poor seaworthiness. After the trials the prototype was rechristened ''Gidro-1'', given to

Osoaviakhim DOSAAF (), full name ''Volunteer Society for the Assistance to the Army, Aviation, and Navy'' (), was a paramilitary sport organization in the Soviet Union that was concerned mainly with weapons, automobiles and aviation. The society was establ ...

, and used to set various class records.

Variants

* OSGA-101 – The non folding first prototype of the SPL. * Gidro-1 – The SPL prototype renamed after transfer to

Specifications (SPL)

References

Bibliography

* * Gunston, Bill. "The Osprey Encyclopaedia of Russian Aircraft 1875–1995". London, Osprey. 1995. * * Taylor, Michael J. H. "Jane's Encyclopedia of Aviation". Studio Editions. London. 1989. {{Soviet miscellaneous aircraft designations 1930s Soviet military reconnaissance aircraft Flying boats SPL Abandoned military aircraft projects of the Soviet Union Submarine-borne aircraft Single-engined tractor aircraft High-wing aircraft Aircraft first flown in 1934 Twin-tail aircraft

Development

Variants

Specifications (SPL)

See also

References

Bibliography