The Saunders-Roe Cloud was one of the inspirations for Folland to begin design work on a series of amphibians in 1930. This example, K2681, was fitted with a Monospar wing and is seen here at an RAF pageant at Hendon.

The exceptionally aerodynamically clean Gloster VI, Folland’s first monoplane design. A contemporary newspaper remarked that “it seems more the conception of an artist who can create with the stroke of a brush than the work of a designer who is bound by engineering principles and the inelasticity of timber and metal”.

Folland's first design for the Gloucestershire Aircraft Company was the Mars I, given the nickname “Bamel”. The aircraft’s streamlined appearance was evidence of the designer’s ethos to reduce head resistance as much as possible. On December 19, 1921, the Bamel set a British speed record of 196-4 m.p.h.

The ST-3, seen here in skeletal form, was the first complete aircraft to take the Monospar wing and was built by Gloster at Brockworth. Danish-born Helmuth Stieger’s concept was to use a simple Warren-braced form of girder to create a mainspar that would resist bending and torsion by means of a system of lightweight bracing.

The author’s three-dimensional rendering of Folland’s 14-seat amphibian design, bearing the spurious registration G-AEGZ, which was allocated to a British licence-built Sikorsky S.42 but was never taken up. The name City of Gloucester beneath the cockpit is also bogus, but in line with Imperial Airways policy of the time.

The author’s illustrations to accompany this feature are all based on newly-discovered documents in the Royal Aero Club Trust Archive, which includes previously unpublished drawings of Folland’s 1930s monoplanes. Inspired by Saunders-Roe’s Cutty Sark, Cloud and Windhover amphibian designs, Folland began work on a series of his own, beginning with a three-seat design intended mainly for private owners - although he did submit the three-seat design, along with the larger designs, to Imperial Airways.

The largest of Folland’s amphibians was to be powered by two supercharged Armstrong Siddeley Jaguar 14-cylinder two-row radial engines of 680 h.p. each, as fitted to Gloster’s single-engined Grebe biplane fighter. All three of the amphibians were to be fitted with a wing of Monospar construction, and both companies may have had a hand in the design. Folland presented the amphibian designs to Imperial Airways but the airline showed little interest.

Folland’s second amphibian design was a scaled-up version of the three-seater, the span increasing from the 39ft (11-9m) of the latter to 58ft (17-7m). The proposed powerplant for the eight-seater was to be a pair of supercharged Armstrong Siddeley Lynx Major radial engines. Note Folland’s adoption of Frank Duncanson’s ingenious amphibian undercarriage arrangement, in which the wing floats incorporated the wheels and could be raised or lowered accordingly.

Three-dimensional renderings of Folland’s high- and low-wing designs to the Imperial Airways specification for a charter airliner. The low-wing variant bears civil registration G-ACNB (not taken up at the time but used in 1982 for an Avro 504K) and is painted in Gloster’s signature colours of Cambridge blue and old gold. The high-wing variant is seen in a speculative RAF scheme.

In response to a specification issued by Imperial Airways in 1931, Folland submitted a pair of monoplane designs for a four-to-five-passenger charter airliner, one of high-wing configuration and one with a low wing. Both were intended to be powered by a pair of Armstrong Siddeley Serval engines (initially known as the Double Mongoose), capable of 340 h.p. at 2,000 r.p.m. at sea level. The designs were to be Folland’s last attempts at passenger-carrying aircraft, although he was concurrently working on a high-speed mailplane.