As the 1930s proceeded, aeronautical technology was developing at a pace which numerous British companies had been unable to fully grasp.  The Bristol Aeroplane Company had taken its own step into the future with the design and production of a twin engine executive passenger aircraft.  Known as the Type 142, it first flew in April 1935.  A military option soon appeared, known as the Type 142M and in due course was given the name ‘Blenheim’.  It was designed as a bomber but was used in a number of roles in the early stages of WW2, including as a night fighter.  The company then exploited its new found expertise in a variety of military projects, one of which was the Beaufort; a general reconnaissance bomber/torpedo bomber and mine laying aircraft.  The Beaufort entered RAF service in December 1939 and continued operating in small numbers until 1944.

By the time of the Munich Crisis, in September 1938, it was disturbingly apparent that Britain was deficient in a number of key military airborne capabilities.  The RAF lacked performance, capacity and range in both fighters and bombers and in the night fighter role.  The Bristol Aeroplane Company had, by that time, entered a design theme phase, notably the use of a stressed skin structure throughout with a high aspect ratio wing, carrying twin radial engines.  Bristol visualised that a long range escort fighter could be developed from the Beaufort, using a high degree of component commonality.  The ungraceful lines of the Beaufort were cleaned up and modifications made to the airframe and engines, to give a long range escort fighter that could also function as a night interceptor.

Work on the new Type 156 design, given the name ‘Beaufighter’, was initially conducted without Air Ministry support but in November 1938 the company received a contract to build four prototypes.  The required performance was to be met using the Hercules III engine being developed by the Bristol Engine Company; a relatively new powerplant which was in short supply.  The Hercules was a 14 cylinder, two-row, sleeve valve, air-cooled radial engine.  The first Beaufort flight took place on 17 July 1939.  It achieved a top speed of 335 mph at 16,800 ft at a low weight of 16,000lb.  At realistic operating weights, the performance figures proved disappointing.  To reclaim the situation, the Rolls Royce Merlin engine was prescribed but this was also in short supply, being urgently needed for the single seat fighter production lines.  The engine company responded by accelerating its Hercules development programme.  Mk I production Beaufighters went on to employ the Hercules XI engine, able to deliver 1,500 hp using high octane fuel.  This enabled the Beaufighter to match the performance of the Hawker Hurricane.  It was appreciated early on, that the aircraft was unsuitable as a daytime home defence fighter but that it would meet the principal operational requirements of a night fighter, inclusive of its specification for a 2 man crew.

The first production Beaufighter came with heavy armament for its day, having four 20mm Hispano cannons mounted in the nose.  By the 50^th unit off the production line it also carried six Browning 0.303mm wing mounted machine guns – four starboard and 2 port.  Operating as a night fighter, the aircraft’s excellent firepower was allied to its good payload capacity.  This enabled the (initially) heavy and bulky AI (Airborne Intercept) radar to be carried, whilst offering a good duration and range for engaging Luftwaffe bombers at night.  Beaufighter delivery to RAF night interceptor squadrons commenced slowly in September 1940.  The cannon ammunition was drum fed, requiring the second crew man to manually change the limited capacity drums.  In September 1941 it was modified to use a belt fed system.

The first night operations preceded the fitting of the AI radar, demanding whatever ground support was available, such as searchlight and observation, together with aircrew vigilance.  The AI radar greatly improved the engagement probability and this gain continued as the system was developed.  During 1941 the aircraft was exacting a worthy toll against night bombing raids.  Its most impressive achievement was on the night of 19/20 May 1941, with 24 London targeting Luftwaffe bombers acquired and engaged.

As the balance of forces changed, the Beaufighter became available for new duties, such as night time intruder missions into occupied France, to attack German airbases.  With the build up in aircraft numbers, it was deployed for both day and night missions against varied target types.  The progress of the war found the aircraft used for long range fighter cover, anti-shipping and ground attack.  To add to its very effective cannon fire, the Beaufort was developed to carry bombs, torpedoes and under-wing rocket launchers, with a maximum take-off weight then exceeding 25,000 lb.  In this adaptive role, it played an important part in both the Mediterranean campaigns and the Far East.  The Japanese gave it the nickname of ‘Whispering Death’ because the low noise from its Hercules engines allowed it to fly in quietly prior to the attack.

Almost 6,000 Beaufighters were manufactured, inclusive of those built under licence in Australia.

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© 2011 Victor K L Marshall M Sc, C Eng, M I Mech E