Hawker Henley

The Hawker Henley was a British two-seat target tug derived from the Hawker Hurricane that was operated by the RAF during the Second World War.

Design and development
In 1934 Air Ministry Specification P.4/34 was issued which called for a light bomber that could also be deployed in a close-support role. Fairey, Gloster and Hawker all rushed to fulfill this need, and competition was tight to attain the highest performance possible.

As the aircraft required only a modest bomb load, and with performance being paramount, the Hawker design team chose to focus its efforts on developing an aircraft similar in size to their Hurricane fighter. The Hurricane itself was then in an advanced design stage, and it was thus beneficial both economically and production-wise if some assemblies could be common to both aircraft. This resulted in the Henley, as it was to become known, sharing identical outer wing panel and tailplane jigs with the Hurricane. Both were also equipped with the Rolls-Royce Merlin engine as it offered the best power/weight ratio as well as a minimal frontal area. The Henley’s cantilever fabric-covered monoplane wing was mid-set, retractable tailwheel type landing gear was selected, and accommodation provided for a pilot and observer/air gunner, which differed from the Hurricane’s single-seat accommodation.

Although construction of a Henley prototype began as early as mid-1935, with all priorities going to Hurricane development it was not until 10 March 1937 that it was first flown at Brooklands, powered by a Merlin "F" engine; shortly after the competing Fairey P.4/34. Subsequently the aircraft was refitted with light alloy stressed-skin wings and a Merlin I engine, and further test flights confirmed the excellence of its overall performance. It could reach a top speed of 300 mph. However, the Air Ministry had by this point decided that it no longer required a light bomber, and the Henley was thus re-designated as a target tug. Henley production was subcontracted to Gloster Aircraft, and 200 were ordered into production. The second prototype was fitted with a propeller-driven winch to haul in the drogue cable after air-to-air firing sorties, in recognition of its new role, and was first flown on 26 May 1938.

Operational history


Production aircraft, designated Henley III, entered service with Nos. 1, 5 and 10 Bombing and Gunnery Schools, as well as with the Air Gunnery Schools at Barrow, Millom and Squires Gate. Unfortunately, it was soon discovered that unless the aircraft were restricted to an unrealistically low tow speed of 220 mph (355 km/h), the rate of engine failures was unacceptably high. This resulted in Henleys being withdrawn from this role and relegated to towing larger drogue targets with anti-aircraft co-operation units. Predictably, the Henley proved to be even more unsuited to this role, and the number of engine failures increased. Several Henleys were lost after the engine cut out and the drogue could not be released quickly enough. A solution was never found to this problem, and in mid-1942 the Henley was withdrawn from service, and replaced by Boulton Paul Defiants, as well as purpose-built Miles Martinets.

Variants

 * Henley I
 * Prototype.


 * Henley II
 * Second prototype.


 * Henley III
 * Two-seat target tug aircraft for the RAF, 200 built.


 * Hawker Hotspur
 * Prototype two seater fighter variant of the Henley with a four-gun power-driven turret. This did not reach production, the requirement being met by the Defiant.

Operators

 * Royal Air Force
 * No. 264 Squadron RAF
 * No. 266 Squadron RAF
 * No. 291 Squadron RAF
 * No. 587 Squadron RAF
 * No. 595 Squadron RAF
 * No. 631 Squadron RAF
 * No. 639 Squadron RAF
 * No. 679 Squadron RAF
 * No. 695 Squadron RAF
 * No. 695 Squadron RAF