TOO LATE TO SEE WAR SERVICE - THE DH HORNET

e9781783469543_i0211.jpg

The final assembly shop at Hatfield. The machine on the assembly line has PX236 roughly chalked on the rear fuselage. The aircraft went to serve with 64 Sqn.

The De Havilland Hornet was designed as a private venture for a long-range fighter destined for the Pacific Theatre in the war against Japan, Specification F.12/43 was written around the type. From an early stage it was also envisaged that the Hornet could be adapted for naval use, operating from aircraft carriers. As a result priority was given to ease of control, especially at low speeds, and good pilot visibility. Construction was of mixed balsa/plywood similar to the Mosquito, but the Hornet differed in incorporating stressed Alclad lower-wing skins bonded to the wooden upper wing structure using the then-new adhesive Redux. The two wing spars were redesigned to withstand a higher safety factor of 10 versus 8.

The Hornet prototype RR915 first flew on 28 July 1944 with Geoffrey de Havilland Jr. at the controls. Powered by a pair of R-R Merlin engines, it was the fastest piston-engined fighter in Royal Air Force service. The Hornet also had the distinction of being the fastest wooden aircraft ever built and the second fastest operational twin propeller-driven aircraft — being slightly slower than the unconventional German Dornier Do 335 of 1945. The prototype achieved 485 mph in level flight, which came down to 472 mph in production aircraft.

e9781783469543_i0212.jpg

One of the main wing assemly fixtures showing the two spars and interspar ribs in position. The similarity to the Mosquito wing is noticable.

The DH.103 Hornet further exploited the wooden construction techniques pioneered by de Havilland’s classic Mosquito. Entering service at the end of the Second World War, the Hornet equipped postwar RAF Fighter Command day fighter units in the UK and was later used successfully as a strike fighter in Malaya. The Sea Hornet was a carrier-capable version.

It entered service in 1946 with 64 Squadron based at RAF Horsham St Faith in Norfolk. Next to convert to the Hornet was 19 Squadron at RAF Wittering, followed by 41 Squadron and 65 Squadron, both based at RAF Church Fenton. 65 Sqn was to participate in one of the first official overseas visits by an RAF unit when they visited Sweden in May 1948. Pilot conversion to the Hornet was provided by 226 Operational Conversion Unit.

Apart from the revised structure, the Hornet’s wings were a synthesis of aerodynamic knowledge gathered since the Mosquito’s design process, being much thinner in cross section, with de Havilland designers adopting a laminar flow profile similar to the P-51 Mustang and Hawker Tempest. The control surfaces consisted of hydraulically operated split flaps extending from the wing root to outboard of the engine nacelles; as in the Mosquito, the rear of the nacelles were part of the flap structure. Outboard, the Alclad-covered ailerons extended close to the clipped wing tips and provided excellent roll control.

Fitting the between-the-skin members to the inner skin in the second stage of fuselage assembly. Note the large cut-out for the cockput glazing.

e9781783469543_i0213.jpg

e9781783469543_i0214.jpg

Left: using a jig to drill the fuselage for the wing attachment fittings.

The Hornet used ‘slimline’ Rolls-Royce Merlin engines that were versions with engine ancillaries repositioned to achieve a minimum frontal area and less drag. The aircraft was somewhat unusual for a British design in that it had propellers that rotated in opposite directions. To achieve this, the engines used slightly different gearboxes, hence the double Merlin marks of 130/131. This feature effectively cancelled out the variable and cumulative torque effect of two propellers turning in the same direction that had affected earlier designs such as the Mosquito. It also reduced the amount of adverse yaw caused by aileron trim corrections and generally provided more stable and predictable behaviour in flight. Initially, the propellers were ‘handed’ to rotate inboard, rising towards the fuselage, but this was found to reduce the effectiveness of the rudder so propellers rotating outboard were used instead.

Because of the revised induction arrangements of the Merlin 130 series, the supercharger and carburettor air intakes could be placed in the leading edges of the wings, outboard of the nacelles. Other versions of the Merlin, which used ‘updraft’ induction arrangements, required that the intakes be placed in a duct below the main engine cowling. The main radiators were also mounted in the inboard leading edges of the wings. Internal fuel, to a maximum capacity of 432 Imp gallons, was stored in four self-sealing wing tanks which were accessed through detachable panels forming part of the lower wing surfaces.

The interior of the Hornet was drilled from wooden templates for the ferrules which were used to attach the various items of equipment. Below left: the drill template in position. Below right: the ferrules after assembly.

e9781783469543_i0215.jpg

To aid the pilot’s field of view the unpressurised cockpit was mounted well forward in the fuselage and was housed under an aft sliding, perspex blister canopy. The three-panel windscreen was designed so that refraction through the panels meant that there were no obvious blind spots caused by the corner tie-rods;  all three panels were bullet-proof laminated glass. An armour-plated bulkhead - hinged near the top to provide access to the back of the instrument panel and the rudder pedals - was part of the nose structure, with the pilot’s back and head being protected by another armoured bulkhead built into the cockpit. Below and behind the cockpit floor was a bay housing the built-in armament of four short-barrelled 20 mm Hispano V cannon, firing through short blast tubes.

Installing the equipment at the electical circuits stage of half-shell assembly.

e9781783469543_i0216.jpg

e9781783469543_i0217.jpg

Fore and after views of the Hornet fuselage on the boxing up fixture.

If you find an error or have any questions, please email us at admin@erenow.org. Thank you!