C.Barnes Short Aircraft since 1900 (Putnam)
Short Tractor Seaplanes (1912-14)
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After 81’s early debut the next tractor seaplane due out of Eastchurch was S.68, Frank McClean’s entry for the 1913 Daily Mail Circuit of Britain seaplane race. It was basically similar to the 100 hp Gnome seaplanes already in production, but was to have a 100 hp Green water-cooled six-in-line engine. Its wing-span was over 60 ft, and at first the lower wing was shorter than the upper, but later it appeared necessary to reduce the wing-loading, so a new set of wings with equal upper and lower spans, reduced gap and slightly wider chord was made. By mid-August the aircraft was complete, but the engine vibrated badly, causing the radiator to leak and the water to boil away so quickly that, on one engine run, a piston seized and a new cylinder was needed. Eventually it was flown for about half an hour, but found to be too slow and under-powered for racing, so the entry was scratched at the last moment.
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S.68 - Span 61 ft (18-6 m); length 40 ft (12-2m); area 600 sq ft (55-8 m2), later 660 sq ft (614 m2); weights and speed not recorded.
M.Goodall, A.Tagg British Aircraft before the Great War (Schiffer)
Deleted by request of (c)Schiffer Publishing
S68. Tractor biplane for 1913 Seaplane Circuit of Britain
This was McClean's aircraft No. 15, built specially to compete for the Daily Mail ?500 prize, the contest to start on the 16 August 1913. Vibration problems could not be resolved in time and the entry, No.4, was withdrawn. The machine proved to be slow and was soon abandoned.
The type was an individual design, but included features from other Short types and resembled an enlarged version of the S60, apart from the installation of the inline engine and its radiators. The aircraft was built initially with top wing overhang and single acting ailerons, but later the lower wings, which had rounded tips, were increased to a span equal to that of the top wings. The exhaust pipes for the six-cylinders were carried vertically up to a collector box exhausting over the top wing. Large radiators were mounted fore and aft on the center section struts and these were a source of leakage.
It is possible that this aircraft was impressed into the Navy as No. 182 with Gnome engine.
Power: 100hp Green six-cylinder inline water-cooled.
Data
Span 61ft
Length 40ft
Area 600 sq. ft later increased to 660 sq. ft
