The Air Ministry’s Specification 23/25 called for a single-engine landplane day bomber for short-range high-altitude sorties, capable of carrying a 520lb bomb-load or, when under 'extra load' conditions, 1,040lb of bombs. Along with Blackburn, Gloster, Handley Page, Fairey and Westland, Hawker set about coming up with a design to meet the requirement.
The result was the two-seat Harrier, a large single-bay biplane with staggered wings of constant chord and unequal span. Its construction was similar to that of the later production versions of its torpedo-bomber stablemate the Horsley, which had first flown in March 1925. The structure was a steel and duralumin frame with fabric covering and the new bomber was to be powered by a 440 hp Bristol Jupiter VIII geared radial engine.
The prototype Harrier, wearing B Conditions markings (T-60), made its maiden flight at Brooklands in the hands of Hawker test pilot P.W.S. Bulman in February 1927.
It remained at Brooklands until that November 1927 whereafter it was sent to the Aeroplane & Armament Experimental Establishment (A & AEE) at Martlesham Heath for Service trials and load tests. The latter tests revealed that the Harrier was somewhat underpowered, largely because of the high power absorption of the engine’s reduction gear.
In January 1929, the aircraft (now serialled J8325) was converted to a torpedo-bomber, the company wishing the Harrier to be considered for Specification 24/25 for a Horsley replacement.
The bomb gear was replaced by torpedo crutches and although the engine’s power had been increased to 583 hp, it was still found to be sluggish on take-off, generally underpowered when carrying a 2,500lb plus torpedo.
In November 1929, the Harrier was sent to the Bristol Engine Company to serve as a test-bed for the latter’s Hydra and Orion engines. After completing numerous trials over the next three years, the sole Harrier was finally retired and struck off charge in early 1933.
Variants & Numbers
|Powerplant||One 440 hp Bristol Jupiter VIII geared radial engine driving a 12ft 3in diameter Watts two-bladed wooden propeller; later uprated to 583 hp. Also fitted with Bristol Hydra and Orion engines as testbed|
|Maximum weight||With bombs: 5,656lb. With torpedo: 7,179lb|
|Capacity||1 x pilot; 1 x observer/navigator/air gunner|
|Armament||1 x fixed forward-firing Vickers gun in nose; 1 x Lewis gun on Scarff ring in rear cockpit; 4 x 250lb bombs or 8 x 112lb bombs. Later 1 x 2,844lb Admiralty Type VIII torpedo|
|Maximum speed||With bombs: 136 mph at 5,000ft. With torpedo: 127 mph at 5,000ft|