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Boulton Paul Defiant Nightfighter / Interceptor (1939)

Authored By Staff Writer | Last Updated: 11/3/2014

The Boulton Paul Defiant became a defensive-minded night-fighter platform primarily over Britian during World War 2.

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The inter-war years saw a vast shift to more modern and potent aircraft platforms. The Boulton Paul Defiant followed as only the RAF's third such monoplane aircraft and, amazingly enough, the Defiant also became the RAF's first four machine gun fighter. The defiant arose from the Air Ministry Specification F.9/35, which called for a twin-seat monoplane fighter with all of its armament concentrated in rear-mounted, hydraulically powered dorsal turret. For whatever reason, warplanners were high on the idea of a fighter aircraft sporting a battery of concentrated fire power in a powered turret system. The idea being that the aircraft could maneuver its way into enemy bomber formations and wreak havoc with its excellent armament at will, all the while being able to protect itself from pesky enemy fighters.

Boulton Paul already had some experience in producing such a concept by building some 59 of Hawker's Demon aircraft in the early-to-mid 1930s. These aircraft were fighter developments of the Hawker Hart and sported an enclosed gun turret at the rearward portion of the fuselage. The turrets were designed by Frazer-Nash and proved to be a sound solution, allowing for heavy armament and better gun sights to be fitted and work in conjunction with the gunner's tendencies. Early forms of the turret were manually powered and drafty but external power sources and enclosures of frame and glass were soon developed to evolve the design to its more traditional form.

The Defiant was an interesting concept to say the least. In many ways, it harkened back to the days of World War 1, where scout airplanes were being armed for self-defense while being sent out over the Front to spy on enemy ground movements. These early aircraft sported simple defensive armaments in a rear-placed cockpit, providing the rear gunner with an adequate field-of-fire from trailing enemy fighters. In practice, this concept worked but it is still interesting to compare that line of early-century thinking with developments in the inter-war years nonetheless.

The first of two Defiant prototypes went airborne on August 11th, 1937 with an order of 400 following. However, only three were actually in RAF hands by the outset of World War 2. Within time, deliveries eventually built up No 264 Squadron and made them the first operational Defiant group on December 8th, 1939. The aircraft and her aircrews would have to wait till May 12th, 1940 to sample their first taste of combat against the German Luftwaffe. Early results proved promising as the aircraft served up no fewer than 65 enemy air kills before the end of May 1940 thanks to its excellent armament load.

The bread and butter of the Defiant system lay in its hydraulically-powered rear turret. Unsuspecting enemy pilots, thinking the Defiant was susceptible from attacks from the rear, were greeted with a hail of hot lead from the 4 x 7.7mm (.303 caliber) Browning air-cooled machine guns. The machine guns were paired two to a side and the entire turret system could scan a 360-degree area above the aircraft. Visibility was somewhat hampered by the heavy framing around the glassy enclosure but in theory, the layout was deemed acceptable. Six-hundred rounds of 7.7mm ammunition were afforded each gun, making for a staggering total of 2,400 rounds available to the gunner. Bringing the guns to bear successfully on an enemy aircraft usually yielded favorable results to Defiant crews, that is, should an enemy fighter pilot be foolish enough to contend with the aircraft from the rear.


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Specifications for the
Boulton Paul Defiant
Nightfighter / Interceptor


Focus Model: Boulton Paul Defiant Mk II
Country of Origin: United Kingdom
Manufacturer: Boulton Paul - UK
Initial Year of Service: 1939
Production: 1,075


Crew: 2


Length: 35.33 ft (10.77 m)
Width: 39.34 ft (11.99 m)
Height: 11.32ft (3.45 m)
Weight (Empty): 6,281 lb (2,849 kg)
Weight (MTOW): 8,424 lb (3,821 kg)


Powerplant: 1 x Rolls-Royce Merlin XX piston engine developing 1,280 horsepower.


Maximum Speed: 313 mph (504kmh; 272 kts)
Maximum Range: 465 miles (748km)
Service Ceiling: 30,348 ft (9,250 m; 5.7 miles)
Rate-of-Climb: 1,900 feet per minute (579 m/min)


Hardpoints: 0
Armament Suite:
STANDARD:
4 x 7.7mm Browning machine guns in a hydraulically-powered rear turret.


Variants:
P.82 - Prototype Fighter Designation; examples produced.


Mk I - Fitted with Rolls-Royce Merlin III engine of 1,030 horsepower; 723 examples produced.

NF.Mk I - MK I models converted to night-fighter role.

NF.Mk IA - NF.MK I models with AI.Mk IV / VI radar system.

ASR.Mk I - Air-Sea Rescue model fitted to carry dingy boats for role.

TT.Mk I - Target Tug Conversions of Mk I model series; 150 converted.

NF.Mk II - Nightfighter variant with improved Merlin XX powerplant of 1,280 horsepower; increased vertical tail surface; AI Mk IV airborne interception radar; 210 examples produced.

TT.Mk III - Target-Tug Aircraft; 140 new-builds; sans turret.


Operators:
Australia; India; Canada; Poland; United Kingdom; United States (1 example)