Short S.20 Mercury

Short Brothers · United Kingdom · first flew 1937 · transport aircraft

Short S.20 Mercury was the upper component of the Short-Mayo Composite aircraft, a four-engine floatplane designed to be air-launched from the back of the Short S.21 Maia flying boat to achieve a transatlantic mail range impossible from a standing take-off.

Recognition (WEFT)

W — Wings	Mid-mounted, tapered
E — Engines	4 × piston, wing-mounted
F — Fuselage	15.54 m fuselage
T — Tail	Conventional

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Spot it by:

upper component of the Short-Mayo Composite — a floatplane launched from the back of a flying boat
four Napier Rapier H-24 engines on a shoulder-mounted tapered wing
twin-float undercarriage with no boat hull

Identified by the four-engine floatplane configuration with a shoulder wing of pronounced taper; mounting points on the upper fuselage for composite attachment distinguished it from conventional floatplanes.

Specifications

The Short S.20 Mercury has a length of 15.54 m (51 ft).
It has a wingspan of 22.25 m (73 ft).
Its maximum speed is 338 km/h (210 mph).
Typical crew: 2.

Figures are for the representative variant described above; marks differ. See how AircraftIQ sources figures.

History

The concept, proposed by Major Robert Mayo, addressed the conflict between fuel load and take-off performance by launching Mercury already airborne from the larger Maia. In July 1938 Mercury set a world distance record for seaplanes of 9,652 km, flying from Foynes to Montreal. The composite system proved operationally impractical and was abandoned at the outbreak of war.

Variants

Only one Mercury was built; the complementary S.21 Maia lower component was also a unique aircraft. No production variants were planned.

Where you'll see it

Operated briefly by Imperial Airways for experimental mail crossings of the North Atlantic in 1938; impressed by the RAF on the outbreak of war and scrapped in 1941.

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