Hawker Hornbill
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The Hawker Hornbill was the last Hawker military aircraft designed under the direction of George Carter. The design was started in 1925 and the first flight took place in July 1925.Template:Sfn The Hornbill did not achieve service in the Royal Air Force due to problems in its power plant and radiator. Only one aircraft was built.
Development and design
In 1924, H.G. Hawker Engineering made a proposal to the British Air Ministry to build a new single-seat fighter powered by the Rolls-Royce Condor engine. As a result, the Air Ministry placed an order for a single prototype, drawing up Specification 7/24 to cover the aircraft. Many of the normal requirements included in fighter specifications were omitted with the hope of resulting in an aircraft with higher performance.Template:Sfn The specification required a speed of Template:Cvt at sea level and a service ceiling of Template:Cvt, with an armament of a single machine gun.Template:SfnTemplate:SfnTemplate:Sfn The new design, named the Hawker Hornbill, was produced under the supervision of Hawker's Chief Designer W. G. Carter, shortly before he resigned and was replaced in his role by Sydney Camm.Template:Sfn[lower-alpha 1]
The Hornbill was a single-bay biplane of mixed metal and wood construction. The front fuselage structure and engine mount was made of steel tube, and was covered with duralumin cladding, while the fuselage from the cockpit rearwards had a wooden structure with fabric covering.Template:SfnTemplate:Sfn The wings had spruce spars and ribs and were also covered in fabric.Template:Sfn The water-cooled Rolls-Royce Condor engine was tightly coweled to minimise drag, and drove a two bladed propeller (initially a fine-pitch Watts). The engine was cooled by a pair of semi-circular radiators beneath the lower wings.Template:SfnTemplate:Sfn The pilot sat in an open cockpit behind the engine and fuel and oil tanks, with a cut-out in the upper wing trailing edge to improve his view.Template:Sfn A single Vickers machine gun could be mounted low on the port side of the fuselage.Template:Sfn
Testing
The prototype, powered by a Script error: No such module "convert". Condor III engine, made its first flight in the summer of 1925 with F. P. Raynham at the controls, probably early in July that year.Template:SfnTemplate:Sfn[lower-alpha 2] The Condor III engine was not compatible with Synchronization gear so the gun was not fitted.Template:SfnTemplate:Sfn Test pilot duties soon passed to George Bulman, who reported that performance was disappointing. As a result, the propeller was replaced by a coarser-pitch metal Fairey-Reed propeller, but this had little effect.Template:SfnTemplate:Sfn Another problem was that the engine suffered from over-cooling, with part of the radiators blanked off as a result.Template:SfnTemplate:Sfn
In February 1926, the Hornbill was returned to Hawker's works at Kingston-on-Thames for modifications to be made. The engine was replaced by a Script error: No such module "convert". Condor IV fitted under a modified, longer, cowling, while the two radiators were replaced by a single semicircular radiator under the fuselage, and the fin and rudder were modified, giving a slightly larger area.Template:Sfn The modified prototype returned to flight in May 1926,Template:Sfn and was displayed at the RAF Display at Hendon Aerodrome in July that year.Template:Sfn The aircraft was then sent to RAF Martlesham Heath for testing and service trials.Template:Sfn While the aircraft was much faster than the contemporary Armstrong-Whitworth Siskin at low altitudes,Template:Sfn performance dropped off above Template:Cvt and the aircraft's ceiling was well below the Template:Cvt required by the specification.Template:Sfn Handling at high speeds was poor, with the aircraft lacking stability. At Script error: No such module "convert". or above, steep turns could not be made without applying full rudder.Template:Sfn Engine overheating occurred during flight tests, which may have been a result of using normal service fuel for extended high power runs.Template:Sfn The cockpit was extremely cramped, with it not being possible for the pilot to reach the machine gun's cocking handle or the aircraft's compass or map case, while escape from the cockpit by parachute was considered to be difficult.Template:SfnTemplate:Sfn The type was considered to be unsuitable for use as an interceptor, with Hugh Trenchard, the Chief of the Air Staff claiming that "...for war it would be practically useless".Template:Sfn
The Air Ministry transferred the prototype Hornbill to the Royal Aircraft Establishment, where it was used as a testbed, being fitted with leading-edge slats on the upper wing, and undergoing extensive evaluation of its stability at and below the aircraft's stall speed. The aircraft completed its final trials in November 1932, and flew for the last time on 18 May 1933.Template:Sfn
Specifications (Hornbill)
Notes
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- ↑ The Hornbill is often stated to have been designed by Camm - this can be attributed to a report in Flight magazine of 1 July 1926, that was corrected two weeks later.Template:Sfn
- ↑ The Hornbill was certainly flying by August 1925, when it was photographed by a photographer from Flight magazine, but these photographs were embargoed until next year, leading to frequent statements that the Hornbill first flew in May 1926.Template:Sfn
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Footnotes
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Bibliography
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