In 1922 the Air Ministry issued Specification 37/22 calling for a three-seat fleet reconnaissance aircraft for the Royal Navy. Several aircraft manufacturers responded including Hawker who began work in1923 on what would become the sole Hawker Hedgehog.
Powered by a single 398 hp Bristol Jupiter IV nine-cylinder radial engine, the Hedgehog was a single-bay unstaggered biplane of equal span and chord (distance between the wing’s leading and trailing edges) with dihedral on the outer sections. Of conventional fabric-covered wooden construction, the Hedgehog was designed to accommodate the pilot, observer and air gunner in separate tandem cockpits directly beneath, and to the rear of, the upper wing. It featured folding wings for ease of use and carrier operations.
The Hedgehog made its first flight in February 1924 at Brooklands in the hands of test pilot F.P. Raynham, wearing B Conditions marking T-2.
The Hedgehog then underwent extensive trials until late August of that year when it was sent to the Aeroplane & Armament Experimental Establishment (A&AEE) at Martlesham Heath for Service evaluation trials.
The A&AEE pilots found the Hedgehog to be 'exceptionally light and pleasant to handle in the air' and reported that it was entirely satisfactory and eminently suitable for its prospective role.
In February 1925, the Air Ministry purchased the sole example which had been built by Hawker as a private venture and given a Royal Navy serial (N187). By this time, however, the original specification had been cancelled as the Air Ministry considered none of the aircraft tested represented a sufficient advance over contemporary types.
The aircraft returned to Martlesham Heath for further trials, most notably for research into its unusual drooping ailerons and it appeared in the New Types Park wearing the number '4' at the RAF Display at Hendon in June 1925. It was then converted to a floatplane and tested by the Marine Aircraft Experimental Establishment at Felixstowe that summer.
Converted back to landplane configuration it was used for deck-landing trials aboard HMS Argus in September 1925 before being fitted with a 450 hp Jupiter VI engine the following year and receiving the designation Hedgehog II. By December 1926 the Hedgehog was back at the A&AEE and then moved on to the Royal Aircraft Establishment at Farnborough by the spring of 1927.
Its ultimate fate is unclear although it is known that it suffered an accident in which it tipped on to its nose during landing on 9th May 1927. This may have been the end of its flying career but there appears to be little information on when it was finally withdrawn from service and scrapped.
Variants & Numbers
One aircraft only, N187, flown flown both as a landplane and a seaplane.
|Powerplant||One 398 hp Bristol Jupiter IV nine-cylinder radial engine driving a two-bladed wooden propeller; One 450 hp Bristol Jupiter VI (Hedgehog II)|
|Maximum weight||4,791 lb normal, 4,800 lb overload|
|Capacity & Armament||Three crew: pilot, observer, air gunner; One forward-firing Vickers gun and one Lewis gun on gunner’s Scarff ring|
|Maximum speed||120 mph at sea level|
The sole Hawker Hedgehog is believed to have been written off after an accident whilst being tested as a seaplane.