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Beardmore Inflexible

William Beardmore and Company had acquired a licence for the use of the Rohrbach principle for stressed-skin construction.

Using these principles and drawings supplied by Rohrbach for the RoVI, the Beardmore company designed, what was then a massive all metal three engine transport, the Beardmore Inflexible.

The aircraft was built in sections at Dalmuir between 1925 and 1927 and these were sent by sea to Felixstowe and from there delivered by road to the Aeroplane & Armament Experimental Establishment at Martlesham Heath Airfield where it first flew on 5 March 1928, appearing at the Hendon RAF Display later in the year.

The aircraft was structurally advanced for its time and had good flying qualities.

It was also a very large aircraft for the time, having a wingspan of 157 feet (48 m), around 16 feet (4.9 m) greater than the Boeing B-29 Superfortress heavy bomber of World War II.

However, with an all up weight of 37,000 pounds (17,000 kg).

It suffered from being underpowered and, with no interest in production, the aircraft was dismantled at Martlesham Heath in 1930.

It was then used to investigate the effects of corrosion on light-alloy stressed skin structures.



75 ft 6 in (23.02 m)


157 ft 6 in (48.05 m)


21 ft 2 in (6.45 m)

Wing area

1,967 sq ft (182.8 m2)

Empty weight

24,301 lb (11,022 kg)

Max take-off weight

37,000 lb (16,783 kg)


3 × Rolls-Royce Condor II V12 piston engine,

650 hp (485 kW) each


Maximum speed

109 mph (175 km/h, 95 kn).


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