The Short Mayo Composite was a piggy-back long-range

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 tech ...

and

flying boat A flying boat is a type of seaplane with a hull, allowing it to land on water. It differs from a floatplane in having a fuselage that is purpose-designed for flotation, while floatplanes rely on fuselage-mounted floats for buoyancy. Though ...

combination In mathematics, a combination is a selection of items from a set that has distinct members, such that the order of selection does not matter (unlike permutations). For example, given three fruits, say an apple, an orange and a pear, there are ...

produced by

Short Brothers Short Brothers plc, usually referred to as Shorts or Short, is an aerospace company based in Belfast, Northern Ireland. Shorts was founded in 1908 in London, and was the first company in the world to make production aeroplanes. It was particu ...

to provide a reliable long-range air transport service to

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

and, potentially, to other distant places in the British Empire and the Commonwealth.

Development

Short Brothers had built the

Empire flying boat The Short Empire was a medium-range four-engined monoplane flying boat, designed and developed by Short Brothers during the 1930s to meet the requirements of the growing commercial airline sector, with a particular emphasis upon its usefulness ...

s which were capable of operating long range routes in the

British Empire The British Empire comprised the dominions, Crown colony, colonies, protectorates, League of Nations mandate, mandates, and other Dependent territory, territories ruled or administered by the United Kingdom and its predecessor states. It bega ...

but could only attempt the trans-Atlantic route by replacing passenger and mail-carrying space with extra fuel. It was known that aircraft could maintain flight with a greater payload than that possible during take-off. Major Robert Mayo, the Technical General Manager at

Imperial Airways Imperial Airways was an early British commercial long-range airline, operating from 1924 to 1939 and principally serving the British Empire routes to South Africa, India, Australia and the Far East, including Malaya and Hong Kong. Passengers ...

, proposed mounting a small, long-range seaplane on top of a larger carrier aircraft, using the combined power of both to bring the smaller aircraft to operational height, at which time the two aircraft would separate, the carrier aircraft returning to base while the other flew on to its destination. The British

Air Ministry The Air Ministry was a department of the Government of the United Kingdom with the responsibility of managing the affairs of the Royal Air Force and civil aviation that existed from 1918 to 1964. It was under the political authority of the ...

issued Specification "13/33" to cover this project.

Design

The Short-Mayo composite project, co-designed by Mayo and Shorts chief designer

Arthur Gouge Sir Arthur Gouge (3 July 1890 – 14 October 1962) was a British engineer and aircraft designer from Kent, who worked notably for Short Brothers where he designed the "C-class" Empire and Sunderland flying boats. Early life Gouge was born in No ...

, comprised the Short S.21 Maia, (''G-ADHK'') which was a variant of the Short "C-Class" Empire flying-boat, fitted with a trestle or pylon on the top of the fuselage to support the Short S.20 Mercury(''G-ADHJ''). Although generally similar to the Empire boat, ''Maia'' differed considerably in detail: the hull sides were flared and had "

tumblehome Tumblehome or tumble home is the narrowing of a Hull (watercraft), hull above the waterline, giving less beam (nautical), beam at the level of the main deck. The opposite of tumblehome is flare (ship), flare. A small amount of tumblehome is nor ...

" rather than being vertical as on the Empire to increase the planing surface (necessary for the higher take-off weights); larger control surfaces; an increase in total wing area from to ; the engines were mounted further from the wing root to clear ''Mercury's'' floats and the rear fuselage was swept up to raise the tailplane relative to the wing. Like the ''Empire'' boats, ''Maia'' could be equipped to carry 18 passengers. ''Maia'' first flew (without ''Mercury'') on 27 July 1937, piloted by Shorts' Chief

Test Pilot A test pilot is an aircraft pilot with additional training to fly and evaluate experimental, newly produced and modified aircraft with specific maneuvers, known as flight test techniques.Stinton, Darrol. ''Flying Qualities and Flight Testin ...

, John Lankester Parker. The upper component, ''Mercury'', was a twin-float, four-engine seaplane crewed by a single pilot and a navigator, who sat in tandem in an enclosed cockpit. It could carry of mail and of fuel. Flight controls, except for elevator and rudder trim tabs, were locked in neutral until separation. ''Mercury's'' first flight, also piloted by Parker, was on 5 September 1937. The mechanism that held the two aircraft together allowed for a small degree of movement. Lights indicated when the upper component was in fore-aft balance so trim could be adjusted prior to release. The pilots could then release their respective locks. At this point the two aircraft remained held together by a third lock which released automatically at . The design was such that at separation ''Maia'' would tend to drop while ''Mercury'' would climb.''Flight'' 17 February 1938

Operations

The first successful in-flight separation was carried out from the Shorts works at Borstal, near Rochester, Medway, on 6 February 1938, ''Maia'' piloted by Parker and ''Mercury'' by Harold Piper. Following further successful tests, the first transatlantic flight was made on 21 July 1938 from

Foynes Foynes (; ) is a town and major port in County Limerick in the midwest of Ireland, located at the edge of hilly land on the southern bank of the Shannon Estuary. The population of the town was 512 as of the 2022 census. Foynes's role as sea ...

, on the

Shannon Estuary The Shannon Estuary in Ireland () is a large estuary where the River Shannon flows into the Atlantic Ocean. The estuary has Limerick City at its head and its seaward limits are marked by Loop Head to the north and Kerry Head to the south. Th ...

, west coast of Ireland, to

Boucherville Boucherville () is a city in the Montérégie region in Quebec, Canada. It is a suburb of Montreal on the south shore of the Saint Lawrence River. Boucherville is part of both the urban agglomeration of Longueuil and the Montreal Metropolitan ...

, near

Montreal Montreal is the List of towns in Quebec, largest city in the Provinces and territories of Canada, province of Quebec, the List of the largest municipalities in Canada by population, second-largest in Canada, and the List of North American cit ...

Quebec Quebec is Canada's List of Canadian provinces and territories by area, largest province by area. Located in Central Canada, the province shares borders with the provinces of Ontario to the west, Newfoundland and Labrador to the northeast, ...

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

, a flight of . ''Maia'', flown by Captain A.S. Wilcockson, took off from Southampton carrying ''Mercury'' piloted by Captain Don Bennett. As well as ''Mercury'', the launch aircraft ''Maia'' was also carrying 10 passengers and luggage. ''Mercury'' separated from her carrier at 8 pm to continue what was to become the first commercial non-stop East-to-West transatlantic flight by a heavier-than-air machine. This initial journey took 20 h 21 min at an average ground speed of . Maia and Mercury

The ''Maia''-''Mercury'' composite continued in use with

, including ''Mercury'' flying to

Alexandria, Egypt Alexandria ( ; ) is the List of cities and towns in Egypt#Largest cities, second largest city in Egypt and the List of coastal settlements of the Mediterranean Sea, largest city on the Mediterranean coast. It lies at the western edge of the Nile ...

, in December 1938. After modifications to extend ''Mercurys range, it established a record flight for a seaplane of from

Dundee Dundee (; ; or , ) is the List of towns and cities in Scotland by population, fourth-largest city in Scotland. The mid-year population estimate for the locality was . It lies within the eastern central Lowlands on the north bank of the Firt ...

in Scotland to Alexander Bay, in South Africa between 6 and 8 October 1938. Only one example of the Short-Mayo composite was built, the S.21 Maia with the registration ''G-ADHK'' and the S.20 Mercury ''G-ADHJ''. The development of a more powerful and longer-range Empire boat (the Short S.26), the increase in allowable all-up weights with the standard "C-Class", the further development of in-flight refuelling and the outbreak of the Second World War combined to render the approach obsolete. ''Maia'' was destroyed in

Poole Harbour Poole Harbour is a large natural harbour in Dorset, southern England, with the town of Poole on its shores. The harbour is a drowned valley ( ria) formed at the end of the last ice age and is the estuary of several rivers, the largest being th ...

by German bombers on 11 May 1941. ''Mercury'' was flown to

Felixstowe Felixstowe ( ) is a port town and civil parish in the East Suffolk District, East Suffolk district, in the county of Suffolk, England. The estimated population in 2017 was 24,521. The Port of Felixstowe is the largest Containerization, containe ...

for use by 320 (Netherlands) Squadron RAF, a unit of the

Royal Air Force The Royal Air Force (RAF) is the Air force, air and space force of the United Kingdom, British Overseas Territories and Crown Dependencies. It was formed towards the end of the World War I, First World War on 1 April 1918, on the merger of t ...

formed from the personnel of the Royal Netherlands Naval Air Service. This squadron was based at the time at RAF Pembroke Dock. When this squadron was re-equipped with

Lockheed Hudson The Lockheed Hudson is a light bomber and coastal reconnaissance aircraft built by the American Lockheed Aircraft Corporation. It was initially put into service by the Royal Air Force shortly before the outbreak of the Second World War and ...

s, ''Mercury'' was returned to Shorts at Rochester on 9 August 1941 and broken up so that its

aluminium Aluminium (or aluminum in North American English) is a chemical element; it has chemical symbol, symbol Al and atomic number 13. It has a density lower than that of other common metals, about one-third that of steel. Aluminium has ...

could be recycled for use in the war effort.

Legacy

On the Tay Embankment close to the there is a bronze plaque attached to the seawall. This commemorates the world record long-distance seaplane flight, at a location where the estuary and hills behind the take-off waters are seen. The plaque shows in raised relief the two aircraft still joined but reaching the altitude at which they would have separated. The plaque also contains wording including: - ″Commemoration of the 1938 flight of Captain Bennett from the Tay Estuary to South West Africa... The world record long-distance flight by a seaplane was achieved by the aircraft "Mercury", the upper component of the Short Mayo... The two experimental planes ...were built by

for

and designed to carry mail long distances without refueling... This tribute to the epic flight by Captain D.C.T. Bennett and First Officer Ian Harvey was unveiled by Captain Bennett's wife Mrs Ly Bennett and Lord Provost Mervyn Rollo on 4 October 1997.″ The concept also had an unusual legacy, since in 1976

NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...

needed to transport the

Space Shuttle The Space Shuttle is a retired, partially reusable launch system, reusable low Earth orbital spacecraft system operated from 1981 to 2011 by the U.S. National Aeronautics and Space Administration (NASA) as part of the Space Shuttle program. ...

between the

Kennedy Space Center The John F. Kennedy Space Center (KSC, originally known as the NASA Launch Operations Center), located on Merritt Island, Florida, is one of the NASA, National Aeronautics and Space Administration's (NASA) ten NASA facilities#List of field c ...

and

Edwards Air Force Base Edwards Air Force Base (AFB) is a United States Air Force installation in California. Most of the base sits in Kern County, California, Kern County, but its eastern end is in San Bernardino County, California, San Bernardino County and a souther ...

between each mission, and to get the craft airborne for gliding tests. Jim McLaughlin, Chief Weights Engineer for Boeing 747 program, who was assisting NASA with the SCA Program, was previously the Chief Weights Engineer for Short Brothers and had been involved in the development of the Mayo Composite design at Shorts, and reminded a NASA engineer of the concept which enabled NASA to modify a second-hand

Boeing 747 The Boeing 747 is a long-range wide-body aircraft, wide-body airliner designed and manufactured by Boeing Commercial Airplanes in the United States between 1968 and 2023. After the introduction of the Boeing 707, 707 in October 1958, Pan Am ...

as the carrier aircraft accordingly.

Operators

** No. 320 Squadron RAF

Specifications (S.20 Mercury)

Specifications (S.21 Maia)

Notes

;Notes ;Citations

References

* * * *
Composite Aircraft ''Flight'' 1935

*

External links

"Flying Boat Launches Sea Mail Plane in Air"
''Popular Mechanics'', April 1935, article with drawing explaining concept of purposed Short Mayo Composition.

Irish Inland Waterway News, Winter 2001

Download link for "The Guild of Aircraft Pilots and Navigators of London 1929 - 2004"
* {{Short Brothers aircraft Articles containing video clips 1930s British airliners Composite aircraft Eight-engined tractor aircraft Parasite aircraft Flying boats Mayo Composite Aircraft first flown in 1937 Floatplanes