Gloster Grebe - Design

Design

In 1923 Gloster modified a Gloster Sparrowhawk fighter trainer with new wings to test a layout proposed by chief designer Henry Folland, combining a thick, high lift section upper wing and a thinner, medium lift lower wing, with the intention of combining high lift for take-off with low drag. After the Grouse demonstrated that the new layout was a success, the British Air Ministry placed an order for three prototype fighters based on the Grouse (and therefore derived ultimately from Folland's Nieuport Nighthawk fighter of 1919), but powered by a 350 horsepower (260 kW) Armstrong Siddeley Jaguar III radial engine, as the "Nighthawk (thick-winged)".

The first of the prototypes (Gloster built a fourth machine as a company owned demonstrator), by now known as the Grebe I, flew during May 1923. The performance of these prototypes during testing at RAF Martlesham Heath was good, and the Air Ministry decided to order the type into production as the Grebe II, this having a 400 horsepower (300 kW) Jaguar IV engine.

Like the Sopwith Snipe it replaced, the Grebe was a single-seat, single-engined biplane of fabric-covered wood construction. The fuselage had ash longerons and spruce stringers joined to plywood formers, while the single-bay wings (which had a considerable overhang outboard of the struts), had fabric covered spruce spars and ribs. Two synchronised .303 in (7.7 mm) Vickers machine guns were mounted on the fuselage top decking.