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P.82 Defiant
Boulton Paul Defiant Mk I
Role Two-seat fighter, night fighter, trainer, target tug
Manufacturer Boulton Paul Aircraft
Designed by John Dudley North
First flight 11 August 1937
Introduced December 1939
Status Retired
Primary users Royal Air Force
Royal Australian Air Force
Royal Canadian Air Force
Polish Air Force
Number built 1,064

The Boulton Paul Defiant was a British fighter aircraft and bomber interceptor used early in the Second World War. The Defiant was designed and built by Boulton Paul Aircraft as a "turret fighter" and served with the Royal Air Force (RAF). Contemporary with the Royal Navy's Blackburn Roc, the concept of a turret fighter was somewhat similar to the First World War-era Bristol Fighter. In practice, the Defiant was found to be vulnerable to the Luftwaffe's more agile, single-seat Messerschmitt Bf 109 fighters; crucially, the Defiant did not have any forward-firing guns.

It was later used successfully in the night fighter role, before it was phased out of combat service in favour of the Bristol Beaufighter and de Havilland Mosquito. The Defiant finally found use in gunnery training, target towing, ECM and air-sea rescue. Among RAF pilots, it had the nickname "Daffy", probably a dimunitive of the word "Defiant".


Design and development


A pair of No. 264 Sqn. Defiants. The Squadron Leader's aircraft "A", can be seen in the image at the top of the page.

The concept of a turret-armed defensive fighter emerged in 1935, at a time when the RAF anticipated having to defend Great Britain against massed formations[1] of unescorted enemy bombers. [2]Advances in aircraft design during the 1920s and 1930s resulted in a generation of multi-engined bombers that were faster than the single-engined biplane fighters then in service. The RAF believed that its own turret-armed bombers, such as the Vickers Wellington, would be able to penetrate enemy airspace and defend itself without fighter escort and also that the German Luftwaffe would be able to do the same.

In theory, turret-armed fighters would approach an enemy bomber from below or from the side and coordinate their fire. The separation of the tasks of flying the aircraft and firing the guns would allow the pilot to concentrate on putting the fighter into the best position while the gunner could engage the enemy. Previously the Hawker Demon had tested the concept with 59 of the biplane fighters manufactured by Boulton Paul under a sub-contract, equipped with a powered rear turret while the remainder of the series already manufactured were similarly converted.[3]

Air Ministry Specification F.9/35 required a two-seater day and night "turret fighter" capable of 290 mph at 15,000 ft. It followed the earlier F.5/33 which was for a pusher design with a front turret. F.5/33 had been abandoned as it offered little over existing fighters and the Armstrong Whitworth AW.34 design which had been ordered was not completed.[1]


Boulton Paul, who had considerable experience with turrets from their earlier Overstrand bomber, submitted their P.82 design. Of the seven designs tendered, the P.82 was ranked second after Hawkers, but ahead of Armstrong Whitworths twin-engined design. The Air Ministry wanted several designs investigated and two prototypes of each. The Treasury acquiesced to seven prototypes (2 Hawker, 2 Boulton Paul, 2 Fairey and 1 Armstrong Whitworth).[4] In the event only prototypes of the P.82 and Hawker would be built. Production orders were prepared for the Hawker but the Boulton Paul turret had the Air Minsity's attention. Delays by Hawker who were more focussed on the Hurricane led to the P.82 receiving a production order in 1937 and the Hotspur order was cancelled in 1938.

The P.82 was a monocque design constructed by bolting the sections together. This was the same as BP had used on other aircraft. The tendered design had room for small bombs in recesses in the outer wing. Some of the development work from their B.1/35 tender carried over into the P.82

The central feature of the P.82 was the four-gun turret based on a design by French aviation company SAMM which had been licensed by Boulton Paul for use in the earlier Boulton Paul Sidestrand bomber, but eventually installed in the "follow-up" design, the Boulton Paul Overstrand and Blackburn Roc naval fighter.[5] The turret, the Type A, was an electro-hydraulically powered "drop-in" unit with a crank-operated mechanical backup. The Defiant was armed with a powered dorsal turret, equipped with four 0.303 in (7.7 mm) Browning machine guns. The fuselage was fitted with aerodynamic fairings that helped alleviate the drag of the turret; they were pneumatically powered and could be lowered into the fuselage so that the turret could rotate freely. The Browning guns were electrically fired, and insulated cut-off points in the turret ring prevented the guns from being activated when they were pointing at the propeller disc or tailplane. The gunner could rotate the turret directly forward and transfer firing control of the guns to the pilot, with the guns firing along each side of the cockpit canopy. However, in practice this was rarely done as the turret's minimum forward elevation was 19° and the pilot did not have a gunsight.

The gunner's hatch was in the rear of the turret, which had to be rotated to one side or the other to enable entry or exit. There was not enough room in the turret for the gunner to wear a seat-type or back pack parachute, so gunners were provided with a special all-in-one garment nick-named the "rhino suit". To quote Frederick "Gus" Platts, air gunner in 230, 282 and 208 squadrons, "The Rhino suit we had to wear on Defiants was a bear, but I couldn't come up with an alternative, even though it killed dozens of us. I forget the details of it, but we could not have sat on our chute or even keep it nearby as in other turrets, so you wore - all in one - an inner layer that fitted a little like a wetsuit of today. The chute fitted around this, and then the dinghy and the outer clothing. There was inner webbing and pockets that literally fell apart (I presume) when one bailed out".[6]

The first P.82 prototype (K8310) was rolled out in 1937 without its turret, looking superficially like the Hawker Hurricane, although it was at least 1,500 lb (680 kg) heavier. A clean, simple and compact monoplane structure had been achieved with main landing gear retracting into a broad mainplane section. The pilot's cockpit and rear turret were faired into a streamlined upper fuselage section. Fuel was carried in the wing centre section along with a large ventral radiator that completed the resemblance to the Hawker fighter. With a 1,030 hp (768 kW) Rolls-Royce Merlin I installed, the newly named "Defiant" prototype first flew on 11 August 1937, nearly a year ahead of the Hotspur. A second prototype, K8620, equipped with a turret, was modified with telescopic radio masts, revision to the canopy and changes to the undercarriage fairing plates.

Completing its acceptance tests with the turret installed, the Defiant reached a top speed of 302 mph (486 km/h) and subsequently was declared the victor of the turret fighter competition. Apart from detail changes, the production Defiant Mk I looked similar to the two Defiant prototypes. However, as Boulton Paul were busy producing the Blackburn Roc naval turret fighter, the Defiant's service entry was delayed to such an extent that only three aircraft had reached the RAF by the start of the war in September 1939. The Mk I was powered by the Rolls Royce Merlin III (1,030 hp/768 kW or 1,160 hp/865 kW)[7] with a total of 713 aircraft built.


The P.85 was Boulton Paul's tender to Specification O.30/35 for the naval turret fighter. A version of the Defiant for Fleet Air Arm (FAA); it had a deeper fuselage and leading edge slats for lower landing speeds required of carrier aircraft. The engine would be either a Bristol Hercules radial or the Merlin. Despite a higher estimated top speed, the Blackburn Roc was selected. With Blackburn already busy producing other projects, the detail design and production of the Roc was given to Boulton Paul.[8] The only FAA use of the Defiant was as the target tug version.


The first Defiant prototype had not been initially fitted with a turret, and therefore had an impressive top speed. In 1940, Boulton Paul removed the turret from the prototype as a demonstrator for a fixed gun fighter based on Defiant components. The armament offered was either 12 .303 in (7.7 mm) Browning machine guns (six per wing) or 4 20mm Hispano replacing 8 of the Brownings. The guns could be depressed for ground attack. By that time, the RAF had sufficient quantities of Hawker Hurricanes and Supermarine Spitfire and did not require a new single-seat fighter. With a calculated top speed of about 360 mph (579 km/h) at 21,700 ft, the P.94 was almost as fast as a contemporary Spitfire, although less manoeuvrable.

Operational history

Defiant Mk.I N1585, PS-A of No. 264 Sqn., RAF Kirton in Lindsey, July 1940.

In December 1939, No. 264 Squadron at RAF Manston was the first to be equipped with the Defiant Mk I. The first operational sortie came on 12 May 1940, during the evacuation of the British Expeditionary Force from Dunkirk. The Defiant was initially successful against enemy aircraft. Its high-water mark was on 29 May 1940, when No. 264 Sqn claimed 65 kills, mostly Junkers Ju 87 Stukas and Messerschmitt Bf 110 twin-engined heavy fighters.

Initially, Luftwaffe fighters suffered losses when "bouncing" flights of Defiants from the rear, apparently mistaking them for Hurricane fighters.[9] The German pilots were unaware of the Defiant's rear-firing armament and encountered concentrated defensive fire. However, with a change in Luftwaffe tactics, opposing fighters were able to out-manoeuvre the Defiant and attack it from below or dead ahead, where the turret offered no defence. Defiant losses quickly mounted, particularly among the gunners, who were often unable to leave stricken aircraft. The additional weight of the turret and the second crewman plus the aerodynamic drag, gave the Defiant lower performance than conventional fighter aircraft.[10] On 13 May, a flight of six Defiants was attacked by Bf 109Es; five of the Defiants were shot down from a frontal attack.

According to the book The Turret Fighters by aviation historian Alec Brew, 264 Sqn. developed effective countermeasures against single-seat aircraft such as the Bf 109. By flying in an ever-descending Lufberry circle, Defiant crews sacrificed the advantage of height but eliminated the possibility of attack from underneath, while giving 360° of defensive fire.[11] This tactic was used successfully by 264 Sqn. but when the Defiants of 141 Sqn. were committed to combat a few months later during the Battle of Britain, 141 Sqn. chose to ignore their advice, with devastating consequences. On 19 July 1940, six out of nine Defiants of 141 Sqn. were shot down and the remaining three only survived due to the intervention of Hurricanes of 111 Sqn.[12] Although 264 Sqn. claimed an astonishing 48 kills in eight days over Dunkirk (recent research by Brew suggests no more than 12 to 15 enemy aircraft were actually destroyed; the turret's wide angle of fire meant that several Defiants could engage the same target at one time), the cost was high at 14 Defiants lost.

264 Squadron lost two aircraft on 26 August, then another five on 28 August with the deaths of nine crew members. With these losses, the Defiant - which had been intended from the start as a day and night fighter - was quickly transferred from daylight operations to night fighting duties and there the Defiant achieved some success. Defiant night fighters typically attacked enemy bombers from below, in a similar manoeuvre to the later successful German Schräge Musik methods. Defiants attacked more often from slightly ahead or to one side, rather than from directly under the tail. During the winter Blitz on London of 1940–41, the Defiant equipped four squadrons, shooting down more enemy aircraft than any other type.[13] The turret-fighter concept was not immediately discarded and the fitting of Defiant-type turrets to Beaufighter and Mosquito night fighters was trialled to enable these aircraft to duplicate these methods, but the effect on performance proved drastic, and the idea was abandoned.[14] The Defiant Mk II model was fitted with the AI Mk IV airborne interception radar and a Merlin XX engine. A total of 207 Mk II Defiants were built.

After trials in 1940 with the School of Army Co-operation to assess its capabilities in that role, the Defiant was re-evaluated as a high-speed gunnery trainer, with the Air Ministry agreeing to keep the production lines open. The Defiant was removed from combat duties in 1942 and, thereafter, used for training, target towing, Electronic countermeasures and air-sea rescue. The Defiant was used to carry the Mandrel noise jammer to combat the German Freya early warning radar.[15] Sweeps by a few Defiants with Mandrel could mimic large formations of bombers.

In the air-sea rescue role, the Defiant was equipped with a pair of under-wing pods that contained dinghies. A further 140 Defiant Mk III aircraft were built; this model lacked the dorsal turret and was used as a target tug. Many of the surviving Mk I and Mk II Defiants also had their turrets removed.

In this final target towing variant, the Defiant ended up with a number of overseas assignments with both the RAF and Fleet Air Arm in the Middle East, Africa and India.[5] Further deployments occurred to Canada, where the Defiant was used as both a target tug and trainer with the British Commonwealth Air Training Plan.

Defiants were also utilized for "special" work including tactical evaluations with the RAF Gunnery Research Unit and Air Fighter Development Unit (AFDU) at Farnborough. Two Defiants were issued for ejection seat development work; to R Malcolm Ltd and Martin-Baker. On 11 May 1945, Martin-Baker used Defiant, DR944, to test their first ejection seat with dummy launches.[5]

The last operational use of Defiants was in India, where they were used as target tugs.[16]


Defiant Mk I
Two-seat turret fighter for the RAF, powered by a 1,030 hp (768 kW)[7] Rolls-Royce Merlin III piston engine; 723 built.
Defiant NF Mk I
Defiant Mk I converted into night fighters
Defiant NF Mk IA
NF Mk I with Airborne Interception radar.
Defiant ASR Mk I
Mk I carrying air-dropped dingies for air-sea rescue.
Defiant TT Mk I
Defiant Mk IIs converted to target tugs; 150 conversions.
Defiant Mk II
Two-seat night fighter for the RAF, powered by a 1,280 hp (954 kW) Roll-Royce Merlin XX piston engine, and fitted with the AI Mk IV airborne interception radar; 210 built.
Defiant TT Mk III
Dedicated turret-less target tug; 140 built from new.



Defiant N1671, RAF Museum, 2008

The single surviving complete example of the type is a Defiant I, N1671, on display as a night fighter at the Royal Air Force Museum in Hendon, London.[5][17] It was delivered to No. 307 Polish Night Fighter Squadron at RAF Kirton in Lindsey, Lincolnshire, England on 17 September 1940 with three other Defiants.[18] The aircraft was moved on 20 May 2009 to Rochester airport where it will be restored by the Medway Aircraft Preservation Society (MAPS). [19]

Major parts of at least two other Defiants survive; N1766 and N3378, both Mk Is.[18]

Specifications (Mk I)

Orthographic projection of the Defiant Mk I

General characteristics

  • Crew: 2: pilot, gunner
  • Length: 35 ft 4 in (10.77 m)
  • Wingspan: 39 ft 4 in (11.99 m)
  • Height: 12 ft 2 in (3.71 m)
  • Wing area: 250 ft² (23 m²)
  • Empty weight: 6,078 lb (2,755 kg)
  • Loaded weight: 8,318 lb (3,773 kg)
  • Powerplant:Rolls-Royce Merlin III liquid-cooled V12 engine, 1,030 hp[7] (768 kW)



See also

Comparable aircraft

Related lists



  1. ^ a b Buttler 2004, p. 51.
  2. ^ Mondey 2002, pp. 40–41.
  3. ^ Mondey 2002, p. 41.
  4. ^ Buttler 2004, p. 54.
  5. ^ a b c d Bowyer 1970, p. 270.
  6. ^ Nijboer 2001, p. 150.
  7. ^ a b c The normal rating used for Battle of Britain Hurricane Mk.Is, Spitfire Mk.Is and Defiants was 1,030 hp (768 kW); however, from June 1940, supplies of 100 octane fuel from America became available, increasing the available power.
  8. ^ Buttler 2004, p. 55.
  9. ^ Green 1961, p. 12.
  10. ^ Winchester 2005, p. 16.
  11. ^ Brew 2002, p. 56.
  12. ^ Brew 2002, pp. 65–66. Note: This action is sometimes called "slaughter of the innocents."
  13. ^ Taylor 1969, p. 326.
  14. ^ Brew 2002, p. 105.
  15. ^ Price 1979, pp. 124–125.
  16. ^ Aircraft of the Indian Air Force - Boulton-Paul Defiant TT I & TT III
  17. ^ "Boulton Paul Defiant 1." Royal Air Force Museum. Retrieved: 12 January 2008.
  18. ^ a b Simpson, Andrew. "Boulton Paul Defiant I N1671/837OM: museum accession no. 74/A/16." Royal Air Force Museum. Retrieved: 12 January 2008.
  19. ^ "Rare WWII fighter plane to land for restoration." Kent News Retrieved: 22 May 2009.


  • Ansell, Mark. Boulton Paul Defiant. Redbourn, Herts, UK: Mushroom Model Publications, 2005. ISBN 83-89450-19-4.
  • Bowyer, Michael J.F. "The Boulton Paul Defiant." Aircraft in Profile, Vol. 5. London, Profile Publications Ltd., 1966.
  • Brew, Alex. The Turret Fighters - Defiant and Roc. Ramsbury, Marlborough, Wiltshire, UK: Crowood Press, 2002. ISBN 1-86126-497-6.
  • Brew, Alex. The Defiant File. Tunbridge Wells, Kent, UK: Air-Britain (Historians) Ltd., 1996. ISBN 0-85130-226-2.
  • Buttler, Tony. British Secret Projects: Fighters & Bombers 1935-1950. Hinckley, UK: Midland Publishing, 2004. ISBN 1-85780-179-2.
  • Green, William. War Planes of the Second World War: Fighters, Vol. 2. London: Macdonald & Co., 1961. No ISBN.
  • Green, William and Gordon Swanborough. WW2 Aircraft Fact Files: RAF Fighters, Part 1. London: Macdonald and Jane's Publishing Ltd., 1978. ISBN 0-354-01090-5.
  • Hall, Alan W. and Andrew Thomas. Boulton Paul Defiant (Warpaint Series No. 42). Luton, Bedfordshire, UK: Warpaint Books, 2003. ISBN X-9999-0042-X.
  • Mondey, David. The Hamlyn Concise Guide to British Aircraft of World War II. London: Chancellor Press, 2002. ISBN 1-85152-668-4.
  • Nijboer, Donald. Gunner: an illustrated history of World War II aircraft turrets and gun positions. Boston Mills Press (Canada) and Airlife Publishing Company Limited, Shrewsbury, England, 2001. ISBN 1-84037-3040
  • Price, Alfred. Instruments of Darkness: The History of Electronic Warfare. St Albans, UK: Granada, 1979. ISBN 0-586-04834-0.
  • Taylor, John W.R. "Boulton Paul Defiant." Combat Aircraft of the World from 1909 to the present. New York: G.P. Putnam's Sons, 1969. ISBN 0-425-03633-2.
  • Whitehouse, Les. "The Disappointing Defiant." AirEnthusiast Five, November 1977-February 1978. Bromley, Kent, UK: Pilot Press Ltd., 1977.
  • Winchester, Jim. "Boulton Paul Defiant." The World's Worst Aircraft: From Pioneering Failures to Multimillion Dollar Disasters. London: Amber Books Ltd., 2005. ISBN 1-904687-34-2.

External links

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