Close this search box.

Supermarine Scapa

The Supermarine Scapa was a British general reconnaissance flying boat built by Supermarine that was used by the Royal Air Force between 1935 and 1939.

It was developed from the Southampton and formed the basis of the later Stranraer flying boat.

After experimenting with a three engine design of flying boat, (the Nanok/Solent/Southampton X), Supermarine’s chief designer, R.J. Mitchell, decided that the good hydrodynamic design that had been developed in the twin engined Southampton, would be the platform for the next aircraft.

A prototype designated the Southampton IV was built.

It had a hull that performed even better in the tank tests.

An Air Ministry Specification was received in November 1931.

The test pilot Joseph “Mutt” Summers took the first flight on 8 July 1932.

The name had then been changed to the Scapa.

15 Scapa’s were built before production was changed to a more powerful development, the Stranraer.

The Scapa hull was an all metal structure, while the wing and tail surfaces had metal structure with fabric covering.

The two Rolls-Royce Kestrel V-12 engines were mounted in nacelles underslung from the upper wing, and there were two fins, each placed at the mid semi-span of the tailplane.

Similar to the Southampton, there were three gun positions provided, one in the nose and two staggered in the rear fuselage.

They were provided each one with a single .303 British (7.7 mm) calibre Lewis Mk.I machine guns.






53 ft 0 in (16.15 m) on beaching gear


75 ft 0 in (22.86 m)


21 ft 0 in (6.40 m) on beaching gear

Wing area

1,300 sq ft (120 m2)

Empty weight

10,030 lb (4,550 kg)

Gross weight

16,080 lb (7,294 kg)


2 × Rolls-Royce Kestrel IIIMS,

V-12 liquid cooled piston engines,

525 hp (391 kW) each


2 bladed wooden fixed pitch propellers


Maximum speed

142 mph (229 km/h, 123 kn) at 3,280 ft (1,000 m)

Cruise speed

100 mph (160 km/h, 87 kn) at 5,000 ft (1,524 m)

Alighting speed

64 mph (56 kn; 103 km/h)


1,000 mi (1,600 km, 870 nmi) with 2,650 lb (1,202 kg) military load

Service ceiling

15,500 ft (4,700 m)

Rate of climb

625 ft/min (3.18 m/s)

Time to altitude

9,840 ft (2,999 m) in 20 minutes

Wing loading

12.3 lb/sq ft (60 kg/m2)


0.065 hp/lb (0.107 kW/kg)



3 × 0.303 in (7.7 mm) Lewis guns,

1 in bow & 2 amidships


1,000 lb (454 kg) bomb load under the wings.

Share on facebook