10/31/2007. To proof the theory of Mayor R.H. Mayo (Technical Advisor
to Imperial Airways) to extend the range of one aircraft by assisting
it into the air on another. The Short Mayo Composite, consisting of
the S.20 and
the S.21, was ordered by the Air Ministry.
Powered by four 920 hp Bristol Pegasus XC nine-cylinder air-cooled
radials, the S.21 was first flown in September 1937. The S.20 was
initially powered by four 340 hp Napier Rapier V sixteen-cylinder
air-cooled H-engines (later replaced by the 370 hp Rapier VI) and flew
for the first time on September 5, 1937.
The first flight of the composition was made at Rochester on January 4,
1938, the first seperation in the air was made on February 6. On July
21, 1936, the composite took off from Foynes, Ireland, and at cruise
altitude the S.20 (flown by Captain D.C.T. Bennett) was released and
arrived 20 hr 20 min and 2,860 mls (4,603 km) later at Boucherville,
The last seperation was made at Dundee, Scotland, on October 6, 1938,
when Bennett flew the S.20 non-stop to the Orange River, South Africa,
establishing a world distance record for seaplanes of 6,045 mls
Both aircraft were passed on to BOAC in April 1940, the S.20 was
broken up at Rochester on August 21, 1941, the S.21 was destroyed in
an air raid at Poole on May 11, 1942.