Boulton Paul Defiant 1 (N1671)  [@ RAF Hendon]

Although the Gloster Meteor was extensively used to develop (and still is) the Martin-Baker ejection seat, it was the Defiant, DR944, that was first used to test the ejection seat with a dummy on the 11th May 1945 and on 24th June 1946 the UK's first dummy ejection in flight was undertaken from the Defiant. The Defiant introduced a new, and fatally flawed, concept into RAF two seat single engined fighters; having no forward firing armament and concentrating all its fire power in a rear gun turret. The concept of a turret fighter was similar to the successful WW1 Bristol Fighter and the Fleet Air Arm's contemporary Blackburn Roc but, in practice, the Defiant was highly vulnerable to the more agile Bf 109. After initial success in the early days of WW2 as a fighter and bomber interceptor the type had to be withdrawn from daylight operations for safer night skies.

The Defiant design emerged during the 1920s and 1930s when multi-engined bombers were faster than the single-engined biplane fighters of the day. It was argued that a turret-armed fighter would be able to engage unarmed enemy bombers from angles that would defeat the bombers gunners. In theory, the Defiant would approach an enemy bomber from below or beside and destroy it with a concentrated burst of fire. Thus, the Defiant was armed with a powered dorsal turret, equipped with four 0.303 in (7.7 mm) Browning machine guns.

Boulton Paul Defiant 1 (N1671)  [@ RAF Hendon]

In March 1937, Boulton Paul received a contract based upon Specification F.9/35 for 87 production examples of its design for a two-seat fighter armed with a four-gun power-operated turret, the P.82, and the name Defiant was adopted but RAF pilots knew it by the nickname "Daffy." The P.82 was designed and built in Pendeford, Wolverhampton. Its turret was hydraulically powered with a crank-operated mechanical backup. The fuselage was fitted with aerodynamic fairings that helped reduce the drag of the turret; they were pneumatically powered and could be lowered into the fuselage so that the turret could rotate freely. The 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 entered and exited via an hatch in the rear of the turret. In an emergency the gunner could not leave the Defiant quickly if the turret was rotated so that it pointed to the rear. Also, there wasn't enough space in the turret for the gunner to wear a parachute so it was stowed in the fuselage. However the gunner could transfer the firing of the guns to the pilot, but in reality this was rarely done as the turret's minimum forward elevation was 19° and the pilot did not have a gun sight.

Powered by a Rolls-Royce Merlin I the first P.82 prototype, K83110, flew on the 11th August 1937 and without its turret it resembled the Hawker Hurricane. A second prototype, K8620, equipped with a turret and a few minor modifications flew later in the year. The Defiant 1 took far longer in development than intended and as a result the type did not enter service until 8th December1939 with 264 Squadron at RAF Martlesham Heath. Now powered by the same Merlin III (photograph - right) as the Spitfire and Hurricane and with a top speed of 302 mph the early trials pointed out the disadvantage of the design concept and underlined the vital need for close cooperation between the pilot and the air gunner. The first operational sortie came on 12th May 1940 during the evacuation from Dunkirk. Early daylight engagements were successful as German fighter pilots mistook the Defiants for Hurricanes and attacked from behind, into a deadly concentration of fire. On the 29th May 1940 264 Squadron claimed 65 kills, mostly Ju 87 "Stukas" and Bf 110s, however, this type of success was short lived. The Luftwaffe changed its tactics and began to attack from the front. Mounting losses, from in particular Bf 109E attacks, forced Fighter Command to withdraw Defiants from daytime operations by August 1940. On the 19th July 1940 six out of the nine Defiants of 141 Squadron were shot down and the remaining three only survived due to the intervention of the 111 Squadron’s Hurricanes.

The P.85 was intended to be the Fleet Air Arm (FAA) version of the Defiant1, however, the Blackburn Roc was chosen instead. The FAA did eventually receive 295 Defiants, mainly conversions of RAF Defiant Is and IIs. The first Defiant to be delivered to the RN was in January 1943 to the RNDA. However the aircraft was not distributed for a year and the first second-line squadron to receive a Defiant was 792 Squadron in January 1944 at St Merryn. Most of the Defiants equipped 791and 792 Squadrons with earlier examples going to 776 and 794 Squadrons. The last Defiants in FAA service included DS147 with 778 Squadron in December 1944 with detachments in Pomigliano and DS121 of 733 Squadron in Trincomalee in April 1946.

Boulton Paul Defiant 1 (N1671)  [@ RAF Hendon]

In 1940 the P.94 was developed as a single-seat, turret-less version, of the Defiant and armed with 12, six per wing, 0.303 Browning machine guns. With a top speed of about 360 mph it made it almost as fast as a contemporary Spitfire but less manoeuvrable. Unfortunately for Boulton Paul the RAF had sufficient quantities of Hurricanes and Spitfires.

N1671 is the only complete survivor in the world and served with the Polish Air Force in Exile. Unfortunately, it is not in airworthy condition.

The NF.1 was a converted Defiant I for the night fighter role and severed with 13 RAF squadrons between 1941 and 1943. It had more success in night operations although early operations were hampered by the lack of radar. The NF.IA was an NF.1 equipped with Airborne Interception (AI) radar, while the Defiant 2 (210 built) was a two-seat night fighter powered by a Merlin XX (photograph - left) and fitted with an AI Mk IV radar. Just as radar equipped Defiants were reaching squadrons they began to be replaced by the more effective Beaufighter and Mosquito. Defiant night fighters typically attacked enemy bombers from below, usually slightly ahead or to one side rather than from directly under the tail. In fact during the Blitz on London in the winter of 1940-41 the 4 squadrons of Defiants shoot down more enemy aircraft than any other type. The fitting of Defiant style turrets to Beaufighter and Mosquito night fighters was trialled to enable these aircraft to duplicate these methods but the effect on performance was devastating that the idea was abandoned.

The Defiant was removed from combat duties in 1942 and was then used for training, target towing (TT), Electronic Counter Measures (ECM) and Air Sea Rescue (ASR). In this latter role, the variant was known as the ASR.1 and was equipped with a pair of under-wing pods that contained dinghies. Defiants also were also used by the RAF Gunnery Research Unit and Air Fighter Development Unit (AFDU) at Farnborough. A 150 Defiant 1s were converted into TT.3 target tugs while Defiant 2s were converted into TT.1s with 140 being built from new. As a target tug the Defiant ended up overseas with both the RAF and the Fleet Air Arm in the Middle East, Africa and India. 1830 Squadron, in the Eastern Fleet, was the only squadron to be equipped with the Defiant TT.1 from March to April 1944. While in Canada the Defiant was as both a target tug and trainer with the British Commonwealth Air Training Plan. The Defiant also served with U.S. Army Air Force, the Royal Australian Air Force and the Royal Indian Air Force. The total number of Defiants built was1064, of which 723 were the Defiant 1 variant.