Hawker Nimrod

Nimrod
Hawker Nimrod at El Amriya, 1936
Role	Naval fighter
Manufacturer	Hawker
Designer	Sydney Camm
First flight	14 October 1931[1]
Introduction	1933
Primary user	Fleet Air Arm
Number built	92

This article is about a 1930s fighter aircraft. For the modern maritime patrol aircraft, see Hawker-Siddeley Nimrod.

The Hawker Nimrod was a British carrier-based single engine, single seat biplane fighter aircraft built in the early 1930s by Hawker Aircraft.

Design and development

In 1926 the Air Ministry specification N.21/6 was intended to produce a successor to the Fairey Flycatcher, then in its fourth year of Naval service. By the time it was replaced by the Nimrod in 1932, the Flycatcher had become so obsolete in terms of its speed that RAF officers who flew it often joked that a sprightly fly might actually give the aircraft a run for its money. None of the aircraft designed to this specification were selected for production after trials in 1928, but the radial engined Hawker Hoopoe, not actually designed to N.21/26, was considered promising enough to be further developed. Despite the Navy's traditional preference for radial engines, Hawker's designer Sydney Camm was convinced by his experience with the landplane Hawker Fury that the future for shipborne aircraft also lay with inline engines and began such a design, powered by a Rolls-Royce Kestrel. Before it was completed Air Ministry specification 16/30 was written around it. It flew under the initial name Norn early in 1930, received a production contract and was renamed Nimrod.^[2]

The Nimrod had an overall similarity with the Fury: it was a single-seater biplane with an open cockpit, fixed undercarriage and guns firing through the propeller. Its unswept, constant chord, round tipped wings had unequal span and strong stagger, the latter partly to enhance the pilot's view. It was a single bay biplane braced with outward leaning N-form interplane struts, the upper plane held a little above the upper fuselage by cabane struts. The fabric covered wings had metal spars and spruce ribs and carried balanced ailerons only on the upper wings.^[2]

The Nimrod's fuselage was a Warren girder structure of tubular steel and aluminium, surrounded by stringers which defined its oval cross section. The Rolls-Royce F.9MS engine, later renamed the Kestrel IIMS was closely cowled in aluminium and the rest of the fuselage fabric covered. As with the Fury, the upper fuselage line was highest at the cockpit, placed between the trailing edges of the upper and lower planes. Its twin machine guns were mounted in the upper fuselage between pilot and engine, firing through the propeller using the standard interrupter gear. The tailplane was mounted on top of the fuselage and carried split horn balanced elevators; the vertical tail had Hawker's familiar curved shape, with a deep, wide chord, unbalanced rudder extending to the keel.^[2]

The Nimrod had a conventional undercarriage of cross axle type on trailing struts, with compression legs almost at right angles to the fuselage and a tailskid aft. It could also operate as a floatplane on single step, cross braced floats mounted on N-form struts. With floats fitted the maximum speed was reduced by 47 mph (76 km/h), or 25%. The Kestrel engine's bath type radiator was mounted on the lower fuselage between the undercarriage struts.^[2]

After testing in 1930, the prototype went with HMS Eagle to Buenos Aires, flying as part of the British Empire Trade Exhibition there in March 1931. It returned to RAF Martlesham Heath for final testing. A production order for 35 was placed and the first of these flew on 31 October 1931. The following year another contract for a further 19 Nimrod Is was signed.^[2] With a top speed of 193 mph (311 km/h) it was only marginally slower than its land-based counterpart, the Hawker Fury. A headrest fairing was added retrospectively to the Nimrod Is, to ease pilot strain during catapult launches. Aircraft from the later production batch were fitted with arrester hooks. Experiments with the first of this batch, refitted with swept upper and lower wings, lead to the Nimrod II. As well as the swept wings, this had at first an uprated Kestrel II engine. Later, these were replaced with Kestrel Vs. Later Nimrod IIs had a slight increase in rudder area to improve spin recovery of inverted, float equipped aircraft. Originally it was intended that the Nimrod II should have a corrosion resistant stainless steel, but only three of these were built. The first of 27/33 Nimrod IIs was delivered in March 1933.^[2]

Operational history

The first production Nimrod Is entered service in 1932 with No.408 Flight on HMS Glorious. Others went to No.s 402 and 409 Flights soon after. Fleet Air Arm flights were reorganized into Squadrons early in 1933, with the Nimrods joining No.s 801, 802 and and 803 Squadrons RAF.^[2]

The Nimrod II followed in September 1934.^[2]

Few Nimrods were exported, though one aircraft was supplied to Japan and one to Portugal. Two went to Denmark, where they were known as the Nimrodderne. They were intended as pattern aircraft for proposed licence building and were essentially Nimrod Is, though powered by Kestrel IIIS engines. One, unusually, was fitted with spats.^[2]

The Nimrod had been replaced by more modern designs such as the Sea Gladiator by May 1939, before the start of World War II.^[2]

Variants

Nimrod II K3661 flying in 2007

Nimrod I

FAA: 477 hp (356 kW) Rolls-Royce Kestrel IIMS piston engine; 57 built.

Nimrod II

FAA: modified swept wing version, powered by a 608 hp (453 kW) Rolls-Royce Kestrel IIS or VFp piston engine; 30 built.

Danish Nimrod

Hawker built pattern aircraft, powered by a Rolls-Royce Kestrel IIIS piston engine; two built and exported to Denmark.

Nimrodderne

Single-seat fighter aircraft for the Royal Danish Navy; ten built under licence in Denmark.

AXH1

A single Hawker Nimrod I supplied to the Imperial Japanese Navy Air Service for evaluation in 1934.

Operators

 Denmark

• Marinens Flyvevæsen (Royal Danish Navy Aviation) received 2 aircraft called Nimrødderne. A further 10 were built locally under licence between 1934-35 at Orlogsværftet; called L.B.V (Landbased Biplane 5). The 8 survivors were German spoils of war in 1940.

 Japan

• Imperial Japanese Army Air Service received one aircraft, designated AXH.

 Portugal

• Portuguese Air Force received one aircraft.

Nimrod II at the Duxford 90th anniversary show 2008

 United Kingdom

• Fleet Air Arm
  • No.713 Squadron RAF
  • No.759 Squadron RAF
  • No.780 Squadron RAF
  • No.781 Squadron RAF
  • No.800 Squadron RAF
  • No.801 Squadron RAF
  • No.802 Squadron RAF
  • No.803 Squadron RAF
  • 404 (Seaplane) Flight
  • 408 (Seaplane) Flight
  • No. 1 Flying Training School RAF

Survivors

Two Nimrods survive, both airworthy and both based at the Imperial War Museum's Duxford Aerodrome, Cambridgeshire. Both served with No. 802 Squadron^[3]

Nimrod I;

S1581, G-BWWK is operated by The Fighter Collection.^[3] It is the fourth production Mk. I, dating from late 1931 and from the first batch built.^[4]

Nimrod II;

K3661, G-BURZ is operated by the Historic Aircraft Collection.^[3] It is the penultimate FAA Nimrod, built in early 1934.^[4]

Specifications (Nimrod Mk.II)

Data from Holmes, 2005. p. 89.

General characteristics

• Crew: one
• Length: 26 ft 6 in (8.09 m)
• Wingspan: 33 ft 7 in (10.23 m)
• Height: 9 ft 10 in (3.00 m)
• Wing area: 300 ft² (27.96 m²)
• Empty weight: 3,110 lb (1,413 kg)
• Max takeoff weight: 4,050 lb (1,841 kg)
• Powerplant: 1 × Rolls-Royce Kestrel VFP inline piston engine, 525 hp (391 kW)

Performance

• Maximum speed: 168 kn (194 mph, 311 km/h)
• Range: 265 nmi (305 mi, 488 km)
• Service ceiling: 28,000 ft (8,535 m)

Armament

• 2 × forward firing fixed .303 in (7.7 mm) machine guns
• 4 × 20 lb (9 kg) bombs on underwing racks

See also

Related development

• Hawker Fury
• Hawker Norn
  

References

Notes

1. ^ Holmes, 2005. p. 89.
2. ^ ^{a b c d e f g h i j} Mason 1961 pp.184-190
3. ^ ^{a b c} Ellis 2010 pp.24-5
4. ^ ^{a b} Mason 1961 p.399

Bibliography

• Crawford, Alex. Hawker Fury & Nimrod. Sandomierz, Poland/Redbourn, UK: Mushroom Model Publications, 2007. ISBN 83-8945-041-8.
• Ellis, Ken (2010). Wrecks & Relics. Manchester: Crecy. ISBN 9 780859 791502. 
• Hannah, Donald. Hawker FlyPast Reference Library. Stamford, Lincolnshire, UK: Key Publishing Ltd., 1982. ISBN 0-946219-01-X.
• Holmes, Tony (2005). Jane's Vintage Aircraft Recognition Guide. London: Harper Collins. p. 89. ISBN 0 0071 9292 4. 
• James, Derek N. Hawker, an Aircraft Album No. 5. New York: Arco Publishing Company, 1973. ISBN 0-668-02699-5. (First published in the UK by Ian Allan in 1972.)
• Mason, Francis K. Hawker Aircraft since 1920. London: Putnam, 1961.
• Mason, Francis K. Hawker Aircraft since 1920. London: Putnam, 1991. ISBN 0-85177-839-9

External links

• Fleet Air Arm Archive