De Havilland Hornet

The de Havilland DH.103 Hornet, developed by de Havilland, is 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 envisaged early on and was procured by the Fleet Air Arm of the Royal Navy.

Development

Origins

In the autumn of 1941, de Havilland found that it had the spare design capacity to work on a new project. At this point, the Mosquito had entered full-rate production and preliminary work on a jet-propelled fighter aircraft, which became the Vampire, was waiting for the production of prototype engines. The company promptly recognised a need for a high-speed, unarmed, night bomber powered by a pair of large Napier Sabre piston engines and a design for such an aircraft was first proposed under the designation D.H. 101 in October 1941. A design team led by R. E. Bishop with C. T. Wilkins assisting, was assembled with the aim of developing the D.H. 101, which was initially pursued as a private venture.

The Sabre engine was suffering from availability problems at that point and the DH. 101 was soon replaced by a lower-powered design, with the internal designation D.H. 102. This proposal was intended to be powered by a pair of Rolls-Royce Griffon or Rolls-Royce Merlin engines but either engine would have meant that the aircraft would be somewhat slower and less attractive than the Mosquito. The two propellers were driven in opposite directions to improve take-off and landing characteristics and high-drag flaps were integrated to provide for greater power during approaches. Flight tests of RR915 led to it achieving a recorded speed of 485 mph (780 km/h) in level flight.

Towards the end of 1944, the assembly line for the Hornet F.1, the initial production model, was being established at Hatfield and orders had already been received for the Royal Air Force (RAF). On 28 February 1945, PX210, the first of 60 production F.1 aircraft was delivered to the Aeroplane and Armament Experimental Establishment (A&AEE) at RAF Boscombe Down. On 29 October 1945, a production Hornet F.1, PX237, was used for the type's first public appearance at an open day at RAE Farnborough. PX239, originally built as a Hornet F.20, was outfitted with power-operated folding wings and a large dorsal fillet, which was later fitted to all production aircraft to comply with a new requirement to provide "feet off" directional stability with one engine stopped. On 25 October 1948, the first deck trials commenced on board ; these were so successful that testing rapidly proceeded to the night trials phase. On 16 May 1947, PX230 was lost during service trials when the aircraft disintegrated in mid flight; the pilot bailed out following the breakup of the aircraft.

Hornet F.3, PR.2 and FR.4

The wings of the Hornet F.3 were stressed to carry external weapons; two to four 60 lb (27 kg) RP-3 rockets could be carried under each wing; it was also possible to carry a combination of four rockets with one bomb of up to 1,000 lb (454 kg), or an additional drop tank on each wing, ranging in capacity up to 200 Imp gal (909 L).

The Hornet PR.2 was intended to operate as a long-range photo-reconnaissance aircraft.

Merlin 133/134s (derated from to ) were fitted to all Sea Hornets. Other specialised naval equipment (mainly different radio gear) was fitted and provision was made for three camera ports, one on each side of the rear fuselage and one pointing down. Sea Hornet F.20s also incorporated the modifications of the Hornet F.3, although the internal fuel capacity was 347 Imp gal (1,557 L), slightly reduced from that of the F.1. The modifications added some 550 lb (249 kg) to the weight of the aircraft. Maximum speed was decreased by 11 mph (18 km/h). After being reduced to components TT193 is to be restored to fly by Pioneer Aero Ltd at Ardmore, New Zealand.

Flying the Sea Hornet

thumb|de Havilland Sea Hornet F.20s of No.728 Fleet Requirements Unit, Hal Far, [[Malta.]]

Captain Eric "Winkle" Brown, former fighter pilot and officer of the Fleet Air Arm, was one of the world's most accomplished test pilots and he held the record for flying the greatest number of aircraft types.

Just after VE Day the first semi-naval Sea Hornet PX 212 arrived at the RAE, Farnborough. Eric Brown initiated "work-up to deck-landing" trials. 37 years later, he was still impressed:

:"...the next two months of handling and deck landing assessment trials were to be an absolute joy; from the outset the Sea Hornet was a winner!"

:"The view from the cockpit, positioned right forward in the nose beneath a one-piece aft-sliding canopy was truly magnificent. The Sea Hornet was easy to taxi, with powerful brakes... the takeoff using 25 lb (2,053 mm Hg, 51" Hg) boost and flaps at one-third extension was remarkable! The Merlin 130/131 engines fitted to the prototypes were to be derated to 18 lb (1,691 Hg, 37" Hg) boost and as Merlin 133/134s in production Sea Hornets, but takeoff performance was to remain fantastic. Climb with 18 lb boost exceeded "...

"In level flight the Sea Hornet's stability about all axes was just satisfactory, characteristic, of course, of a good day interceptor fighter. Its stalling characteristics were innocuous, with a fair amount of elevator buffeting and aileron twitching preceding the actual stall"...

:"For aerobatics the Sea Hornet was absolute bliss. The excess of power was such that manoeuvres in the vertical plane can only be described as rocket-like. Even with one propeller feathered the Hornet could loop with the best single-engine fighter, and its aerodynamic cleanliness was such that I delighted in its demonstration by diving with both engines at full bore and feathering both propellers before pulling up into a loop!"|group=N

During this series of tests Captain Brown found that the ailerons were too heavy and ineffectual for deck landing and there were some problems with throttle movement, brakes and the rubber-in-compression undercarriage legs were still fitted. De Havilland were quick to modify the aircraft. Eric Brown:

:"Landings aboard had been made without any crash barrier... Yet, in the case of the Sea Hornet, I had felt such absolute confidence that I was mentally relaxed... Indeed, there was something about the Sea Hornet that made me feel that I had total mastery of it; I revelled in its sleek form and the immense surge of power always to hand..."

:"Circumstances had conspired against the Sea Hornet in obtaining the recognition that it justly deserved as a truly outstanding warplane...in my book the Sea Hornet ranks second to none for harmony of control, performance characteristics and, perhaps most important, in inspiring confidence in its pilot. For sheer exhilarating flying enjoyment, no aircraft has ever made a deeper impression on me than did this outstanding filly from the de Havilland stable."

Design

thumb|A de Havilland Hornet F.1 banking steeply

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.

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 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.

thumb|left|An RAF Hornet F.1 in level flight

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). |group=N 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. Below and behind the cockpit floor was a bay housing the aircraft's principal armament of four 20 mm cannon, which had a maximum of 190 rounds per cannon which fired through short blast tubes. The Sea Hornet had a similar armament to its land-based counterparts.

Operational history

Hornet

In mid-1946, the Hornet entered squadron service with 64 Squadron, based at RAF Horsham St Faith. On 30 July 1949, PX286 participated in the National Air Races (GB) at Elmdon Airport; when flown by Geoffrey Pike, it clocked the fastest lap at and attained second place overall. On 21 May 1955, the last operational Hornet sortie was flown; by mid-1956, all Hornets had been recorded as having been withdrawn from operational service. No complete examples of the Hornet remain in existence today.

Sea Hornet

thumb|DH.103 Sea Hornet NF.21 displayed at [[RNAS Stretton in 1955 with wings folded. Also shown are the "handed" propellers of Hornets and Sea Hornets]]

On 1 June 1947, 801 Naval Air Squadron was reformed to become the first squadron to operate the Sea Hornet, based at RNAS Ford.

On 20 January 1949, 809 Squadron became the first squadron to be equipped with the Sea Hornet NF 21, having been reformed specifically to operate the type, based at RNAS Culdrose.

Variants

;Hornet F.1

:Fighter version, 60 built.

;Hornet PR.2

:Photo-reconnaissance version, five built.

;Hornet F.3

:Fighter version, 132 built.

;Hornet FR.4

:Fighter-reconnaissance version, 12 built.

;Sea Hornet F.20

:A navalised version for service on British aircraft carriers, 79 built.

;Sea Hornet NF.21

:Fleet Air Arm night fighter powered by Merlin 133/134 engines, 72 built.

;Sea Hornet PR.22

:Photo-reconnaissance version, 23 built.

Operators

;

Royal Australian Air Force used one Sea Hornet F.20 for evaluation and tropical trials.

;

Royal Canadian Air Force operated briefly one former Royal Navy Sea Hornet F.20 (TT193) in 1948 for test purposes. It was operated by CEPE Canadian Experimental and Proving Establishment, at RCAF Namao, Edmonton, Alberta, in company with a Hawker Sea Fury. When surplused, it was purchased by Spartan Air Services and operated until one of the engines failed. It was scrapped sometime in the 1950s.

;

Royal Air Force
No. 19 Squadron RAF F.1 & F.3 (1946–1951)
No. 33 Squadron RAF F.3 (1951–1955)
No. 41 Squadron RAF F.1 & F.3 (1948–1951)
No. 45 Squadron RAF F.3 (1952–1955)
No. 64 Squadron RAF F.1 & F.3 (1946–1951)
No. 65 Squadron RAF F.1 & F.3 (1946–1951)
No. 80 Squadron RAF F.3 (1951–1955)
No. 226 Operational Conversion Unit RAF F.1, F.2 & F.3 (1946-49)
Royal Navy: Fleet Air Arm
703 Naval Air Squadron FR.20, NF.21 & PR.22 (1947-53)
728 Naval Air Squadron FR.20 (1952-57)
736 Naval Air Squadron FR.20 (1950-51)
738 Naval Air Squadron FR.20 & PR.22 (1950-51)
739 Naval Air Squadron FR.20 & PR.22 (1949-50)
759 Naval Air Squadron FR.20, NF.21 & PR.22 (1951-53)
771 Naval Air Squadron FR.20 & NF.21 (1950-52)
778 Naval Air Squadron FR.20 (1946-48)
787 Naval Air Squadron PR.22 (1947-50)
792 Naval Air Squadron NF.21 (1950)
801 Naval Air Squadron FR.20 & PR.22 (1947-51)
806 Naval Air Squadron FR.20 (1948)
809 Naval Air Squadron FR.20, NF.21 & PR.22 (1949-54)
1833 Naval Air Squadron PR.22 (1951-52)

Surviving aircraft

Sea Hornet F.20 TT193 was under restoration to flying condition by Pioneer Aero Ltd in 2017, at Ardmore, New Zealand.

Specifications (Hornet F.1)

thumb|Sea Hornet NF.21 (with second cockpit for observer) 3-view drawing

References

Notes

Citations

Bibliography

Birtles, Philip J. The De Havilland Hornet (Profile Publications No. 174). Leatherhead, Surrey, UK: Profile Publications Ltd., 1967.
Bowman, Martin W. Sting of the Hornet. Air Classics, Vol. 33, No. 6, June 1997.
Bridgman, Leonard, ed. "The D.H. 103 Hornet" Jane’s Fighting Aircraft of World War II. London: Studio, 1946. .
Brown, Eric (Captain, CBE DSC AFC RN). "Viewed from the Cockpit: Sea Hornet Supreme". Air International, Vol. 23, No. 4, October 1982, pp. 192–199.
Buttler, Tony. de Havilland Hornet and Sea Hornet (Warpaint Series no. 19). Newcastle, UK: Hall Park Books, 2000.
Buttler, Tony. de Havilland Hornet & Sea Hornet. Aeroplane Monthly, Vol. 10, Autumn/Fall 2003.
Buttler, Tony. Type Analysis: de Havilland Hornet and Sea Hornet. International Air Power Review Monthly, Vol. 33, No. 6, June 2005.
Buttler, Tony, David Collins and Martin Derry. Hornet and Sea Hornet. Stamford, UK: Dalrymple and Verdun Publishing, 2010. .
Caruana, Richard. The De Havilland Hornet Scale Aviation Modeller International, October 2002, pp. 943–951.
Clark, J. H. Forties Favorites 5 – de Havilland D.H 103. Aeroplane Monthly (Article first appeared in The Aeroplane, 25 January 1946), Vol. 15, No. 9, September 1987.
Cooper, Lewis G. The Hornet File. Tonbridge, Kent, UK: Air-Britain (Historians) Publications, 1992. .
Hall, Alan W. Aircraft In Detail: de Havilland DH.103 Hornet. Scale Aircraft Modelling, Vol. 12, No. 8, 8 May 1990.
Jackson, A.J. De Havilland Aircraft since 1909. London: Putnam, Third edition 1987. .
Malayney, Norman, Canada's Only Sea Hornet, Canadian Aviation Historical Society Journal, Fall, 1994, pages 86–89.
Milberry, Larry. Sixty Years: The RCAF and Air Command 1924–1984. Toronto: Canav Books, 1984. .
Mondey, David. British Aircraft of World War II (Hamlyn Concise Guide). London: Bounty Books, 1982. .
Moss, Charles J. "Aeronautical Engineering: Bonding with Redux." The Aeroplane No. 329, 20 September 1946.
White, Ian. End of the Line: DH Hornet – Last of the Fleet Air Arm's Piston Night-fighters. Air Enthusiast 111, May/June 2004, pp. 50–55.
Wixey, Ken. Ahhhh! Hornet! FlyPast, No. 156, July 1994.

External links

Hornet and Sea Hornet
the de Havilland Hornet & Sea Hornet
Hornet 50th Anniversary Last Flight Celebration
The DH Hornet – Flight archive – 1946
"Rolls-Royce Merlin 130 Series" a 1946 Flight article on the Hornet's Merlin 130 engines
Warbird News article about TT193
Article about the engine failure on TT193