Bristol Beaufighter, part thirteen. Beaufighter Mk. IF

 

As the Luftwaffe switched from day to night bombing at the Fall of 1940, airborne radar sets were given priority, specially installed in a suitable night fighter airframe. The Royal Air Force (RAF) had few aircraft suitable for that role, although the Bristol Blenheim was being employed as an interim night interceptor. The situation called for a large aircraft which could host the radar installation with its correspondent operator, and with enough performance to catch up with the German intruder aircraft, something that the Blenheim couldn't do it effectively, so the Beaufighter offered the RAF an ideal answer.
Back in late 1940, aircraft's performance in night fighting combat wasn't so important and the Fighter Interception Unit (FIU) at RAF Ford managed to fit an Airborne Interception (AI) Mk. IV radar into a single Beaufighter Mk. IF (the letter 'F' stands for 'Fighter') for trials.
Beaufighter Mk. IF R2059 flew the first night interception sortie of the type, while still assigned to the FIU on the night of 4th to 5th September 1940. The first interception mission performed by a RAF Beaufighter squadron was on 17th to 18th September when No. 29 squadron based at RAF Digby sent up R2077 on patrol. However no enemy aircraft were found during that first sortie. Anyway, on 25th October No. 219 squadron recorded the first night kill by a Beaufighter. This was followed by some more victories, albeit the Beaufighters in which they were scored were not equipped with an AI radar, so it wasn't until 19th November 1940 when an AI assisted kill was achieved. During the following six months, radar-equipped Beaufighters took down around twelve enemy aircraft. 
A total of four squadrons were equipped, total or partially, with the Beaufighter, to test the effectiveness of the AI radar, those were, Nos. 29, 25, 219 and 604 squadrons. On 8th September 1941 No. 600 Squadron, which was specialized in night fighting, also received its first Beaufighters IFs. 
On 7th December 1940 the 100th Beaufighter was completed at Filton factory and the 200th exemplar was followed on 10th May 1941. By that date production was licensed to Fairey's shadow factory at Stockport and the Ministry of Aircraft Production plant at Weston-super-Mare at a steady pace. 

An experimental variant of the Beaufighter, the Mk. V was, basically a Beaufighter Mk. II with the turret taken from a Boulton-Paul Defiant attached. During March 1941 this experiment was carried out because, theoretically, it gave the Beaufighter more defensive firepower in the form of four 0.303 inch Browning machine guns. Furthermore, that turret was going to replace not just all of the wing guns, but also one pair of cannons. The observer's dorsal blister was faired flush with the fuselage which retained the lower edge 'scoop out' of the original design. 
Even if the turret arrangement showed its merit when attacking Luftwaffe's bombers at night, as proved by the Defiants and, on the other side, by the Schrage Musik upward firing cannon, the advantages were not obvious enough to justify a serial production of the Mk. V and it was realized that the standard Beaufighter could undertake interception duties with its standard armament well enough.
Two Mk. II airframes, powered by the Rolls-Royce Merlin, were fitted and operationally tested, the first one assigned to the Aeroplane and Armament Experimental Establishment (A&AEE) and the FIU and then passed on to No. 406 Squadron of the Royal Canadian Air Force (RCAF). The second machine was assigned straight to No. 600 Squadron where it served until it was lost to an accident on 29th September 1941.
A&AEE wrote a handling report about the turret Beaufighter in August 1941, where it stressed the drop in top speed of the Mk. V variant. Squadron usage reports also revealed that the turret obstructed the pilot's scape hatch, so all Beaufighters Mk. V were modified with a floor hatch which could be unlocked in case of emergency and forced back by the slipstream to form a windshield for the crew, each member of which then dropped straight through the hatch. However, no further Mk. Vs were built. 

Sources:
1st Signal Squadron - Aircraft In action 153 - Bristol 'Beaufighter' in Action
2nd Scale Aircraft Modelling - Modellers Datafile 6 - Bristol Beaufighter
3rd https://en.wikipedia.org/wiki/Bristol_Beaufighter