page_title: De Havilland Hornet
section_title: Design
hierarchical_section_title: De Havilland Hornet / Design
caption_attribution_description: English: DH.103 Hornet F.1
context_page_description: The de Havilland DH.103 Hornet, developed by de Havilland, was a fighter aircraft driven by two piston engines. It further exploited the wooden construction techniques that had been pioneered by the de Havilland Mosquito. Development of the Hornet had started during the Second World War as a private venture. The aircraft was to conduct long range fighter operations in the Pacific Theatre against the Empire of Japan but the war ended before the Hornet reached operational squadron status.
  The Hornet entered service with RAF Fighter Command where it equipped several day fighter units and was commonly stationed in the British mainland. It saw combat in the Far East, being used as a strike fighter as part of the British military action taken during the Malayan Emergency. A naval carrier-capable version, the Sea Hornet, had been envisioned early on and was procured by the Fleet Air Arm of the Royal Navy.
context_section_description: The de Havilland Hornet bore a family resemblance to the larger Mosquito, but it was an entirely fresh design albeit one that drew extensively upon experiences from, and the design of, the Mosquito. It was powered by a pair of highly developed Rolls-Royce Merlin engines, producing 2,070 hp (1,540 kW) each, which drove four-bladed propellers (manufactured by de Havilland Propellers). According to aviation author P.J. Birtles, the efficiency and power of this configuration gave the Hornet "a higher performance than any other propeller driven aircraft". The Hornet's principal armament was four short-barrelled 20 mm (.79 in) Hispano V cannons, while other typical weapon loads included various rockets and bombs.
  Fuselage construction was identical to the earlier Mosquito: a balsa wood "pith" sandwiched between plywood sheets which were laid in diagonal panels. Aerolite formaldehyde cement was the bonding agent. The fuselage halves were built on large concrete or wood patterns and equipment was fitted in each half; they were then joined along the top and bottom centre lines using wooden reinforcing strips. The entire fuselage was then tightly wrapped in fine aviation fabric which was doped in place. The tailfin which had the trademark gracefully-curved de Havilland shape, was an integral part of the rear fuselage. On late F.1s and further models of production aircraft, a fin fillet was added to the base of the unit. The horizontal tail unit was an all-metal structure, again featuring the distinctive de Havilland shape, which was later repeated on the Chipmunk and Beaver.
  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 new adhesive Redux. The two wing spars were redesigned to withstand a higher load factor of 10 versus 8. Apart from the revised structure, the Hornet's wings were a synthesis of aerodynamic knowledge that had been gathered since the design of the Mosquito, being much thinner in cross-section, and with 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 on the Mosquito, the rear of the nacelle was part of the flap structure. Outboard, the Alclad-covered ailerons extended close to the clipped wing tips and gave excellent roll control.
  The Hornet used "slimline" Merlin engines of types 130 and 131, which had engine ancillaries repositioned to minimise frontal area and drag. It was unusual for a British design in having propellers that rotated in opposite directions; the two engine crankshafts rotated in the same direction but the Merlin 131 added an idler gear to reverse its propeller's rotation (to clockwise, viewed from the front). This cancelled the torque effect of two propellers turning in the same direction that had affected earlier designs (such as the Mosquito).  It also reduced adverse yaw caused by aileron trim corrections and generally provided more stable and predictable behaviour in flight. De Havilland tried propellers that rotated outward at the tops of their arcs (as in the P-38 Lightning), but this configuration blanketed the fin and reduced rudder effectiveness at low speeds, compromising ground handling. On production Hornets the conventionally rotating Merlin 130 was on the port wing with the Merlin 131 on the starboard.
  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 gal (1,964 l) (F.3) was stored in four self-sealing wing tanks, which were reached through detachable panels forming p
caption: A de Havilland Hornet F.1 flying at a steep bank angle
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