Curtiss Hawk 75A/Mohawk. Part Eight. In service with the Royal Air Force.

 

The Curtiss Hawk 75 also served with the Royal Air Force (RAF). It all dates back when the Franco-British purchase committees decided to coordinate their activities, which proved to be an excellent idea, albeit rather risky. Aircraft production orders in the United States for both countries were closely linked, and cancelling contracts with one could mean, at best, delays in deliveries with the other. Furthermore, it would also mean the renegotiation of prices. Since Great Britain was unable to produce enough aircraft at the beginning of the war, it relied heavily on supplies from the United States. 
At the same time, by spring 1940 it was becoming obvious that France would fall soon, leaving the United Kingdom as the only bastion in Europe holding back the German war machine. In this situation, commission chairman Arthur Parvis could not allow the American contracts to fall through. On 15th June 1940 he received a confidential message from London telling that France could capitulate at any moment and therefore, appropriate measures should be taken to secure the ordered equipment which was still in American soil. 
That same day, at midnight, Purvis received authorization from London to take every steep needed to save British orders. French Colonel Jacquin, residing at the Rockefeller Center, in New York and serving on the French commission on behalf of his government, met up with Purvis on 16th June. The Frenchman was well aware that the war was already lost for his country, and after discussion, it was decided that Great Britain would take over all remaining French orders.
There was a strong need of urgency, because with the resignation government in Paris, all authority held by the commission members in the US was terminated. On 17th June the French signed the relevant documents almost simultaneously with Marshal Petain's announcement of surrender, signed four days later. By then, however, all equipment originally intended for France, already belonged to Great Britain. That same day, the equipment remaining in the US destined for shipment, was secured and all French assets were frozen.

At this same time, many French Hawk 75 were landing in England, fleeing from the German invasion, crossing the English Channel. Among them were pilots of the A-1, A-2 and A-3 versions of the Hawk 75. In this way a small numbers of them ended in the RAF. A few more A-3s came directly from the United States, but these were aircraft that did not make it to their original destination in France and the ships that they were loaded in, were diverted to England, while on sea. Alongside those, five more Hawk 75A-6 from a Norwegian order, wich was also never fully fulfilled, ended up in British hands. However, the largest number of Hawks delivered to Great Britain came from the third French order and represented the A-4 variant. 
Individual aircraft received RAF registration numbers and the name 'Mohawk', with the Mohawk Mk. I being the Hawk 75A-1, Mohawk Mk. II, the 75A-2 and so on, depending on the version. It is estimated that there were around 196 of the Mohawk Mk. IV (Hawk 75A-4). However, it should be remembered that ten Hawk 75A-9 previously intended for Persia and five A-5s manufactured in India were also designated at Mohawk Mk. IV. The total amount of A-4s coming from France remains unknown, although it is estimated at 233 to 260 (255 plus 5 Indian ones). 

Given that the earlier Mohawk I and II version, were equipped with a much less powerful engine, they were transferred to training units as training aids for mechanics. They were also frequently used for various tests. Similarly, the Mohawk IVs were not considered equal to the British Hurricanes and Spitfires, but rather served as a reserve in case of disruptions in the supply of those British fighters.
All ex-French aircraft were first transferred to Burtonwood Aircraft Repair Depot in a gradual fashion, where instruments were replaced with those calibrated in British units, and British radio equipment and armament were installed. Instead of the Belgian-made machine guns, the Mohawks were equipped with British 7.7mm (0.303 in) Browning machine guns. It also became necessary to re-adjust the throttle lever movement to the standard pattern used everywhere except in France. It was at Burtonwood where those fighter were repainted in standard RAF day fighter camouflage. 

Mohawks weren't specially popular in the RAF, just like any other radial-engined fighter, except for the Gloster Gladiator. Pilots might had fewer reservations about them, but mechanics often quibbled. American fighters required American spare parts and American tools to operate. Even if a set of tools was included with each wooden crate containing a disassembled Hawk, they wore out quickly and, it's should be pointed that not all aircraft arrived in England disassembled. Even rivets of a diameter not used in the RAF posed a problem, not to mention the Wright engines, which had not been used in British aircraft until then. Furthermore, in 1941 the production of the Hawk 75 was completely discontinued and replaced by the Curtiss P-40, ceasing consequently the production of spare parts for the Hawk 75. In this situation, the British Mohawks quickly found themselves in secondary theatres of the the war, such as Abyssinia and India-Burma. 
In this theatre it was employed by Nos. 5 and 155 Squadrons, which saw some combat against Japanese fighters during 1942. However, as obsolete as they were, the type was mainly employed in bomber escort and ground attack duties until it was retired definitely in 1944. Some few units in the British Isles, No. 510 Squadron among them, also employed some old Mohawk III as squadron hacks during 1943.

It's also worth pointing that the Hawk 75 flew comparative flight tests against the Spitfire Mk. I. These took place between 29th December 1939 and 13th January 1940 at the Royal Aircraft Establishment, with the Hawk 75A-2 (No. 188 -coming from the French order-) being declared as winner. It turned out that, aside from top speed and dive acceleration, the Hawk outperformed its rival every aspect. It was more agile, climbed faster and dived at higher speeds. Pilots also found it more pleasant to fly, take off and land thanks to its more stable landing gear. 
However, while the Hawk could easily outmanoeuvre the Spitfire and get on its tail, the British fighter could simply escape without any problems, taking advantage of its considerable speed advantage.

 

Sources:
1st AJ-Press - Monografie Lotnicze 61 - Curtiss P-36 Hawk Part 1 (translated)
2nd https://en.wikipedia.org/wiki/Curtiss_P-36_Hawk  

Supermarine Spitfire. At Royal Air Force's service. Part ten.

 

The Spitfire had also a photo-reconnaissance  (PR)variant, the PR sub-types. These were a true revolution for the, back then, traditional reconnaissance procedures as before World War 2, common knowledge was to use converted bombers into recon aircraft, given their longer range and sturdiness, specially when compared with a fighter. Those bombers, which were also equipped with defensive armament as they were an easy target to intercept, suffered heavy losses against the Luftwaffe and the German anti-air fire. 
This was already foreseen by Flying Officer Maurice Longbottom, who, inspired by Sidney Cotton, issued a memorandum about reconnaissance over enemy territory during wartime at the Royal Air Force (RAF) in August 1939, just one month before the beginning of the war. 
In that memorandum he reached to the conclusion that airborne reconnaissance was better suited to small and faster aircraft with high service ceiling in order to avoid detection and interception. He proposed the use of Spitfires with their armament and radios removed and replaced with extra fuel tanks and cameras. Air Chief Marshal Sir Hugh Dowding approved his idea, so two Spitfires were sent to the newly created "Heston Flight", a highly secret reconnaissance unit. During the Phoney War, while the regular Spitfires flew from British bases, the first PR missions were flown from bases in France, which was initially known as "No. 2 Camouflage Unit". The first RAF high-speed, high-altitude photo-reconnaissance mission of the war took place on 18th November 1939 when Flt. Lt. Longbottom took from Seclin airfield, in France and photographed the German city of Aachen, from an altitude of 33,000 ft (10,000 m).
Those initial Spitfires were later baptised as "Mk. I PR Type A" and practically every single variant of the Spitfire had a PR sub-variant attached, with the Mk. I PR Type D being the first variant manufactured specifically for recon duties and not converted from existing airframes. 
This type was difficult to flight, as the extra fuel altered the center of gravity, but its extra long range made it possible to perform reconnaissance missions over Stettin, Marseille, Trondheim and Toulon. 
The PR Type F was an interim super-long range variant which was put into service in July 1940 while the Type D was becoming available. When operated from East Anglia, this type could reach, photograph and return from Berlin itself. 
The PR Mk. IV were recon sub-variants of the Spitfire Mk. V.
The PR Mk. I Type G was the first mixed fighter-reconnaissance version configured for low-level tactical reconnaissance, similar to the Type E, which acted as its prototype. The first PR Type G were converted from Mk. I airframes and had their Merlin Mk. II engines replaced with Merlin 45s. Late PR Type Gs were converted from Mk. V airframes and were fully armed with 8 0.303 Browning machine guns in the wings. 
In 1941 a new system of mark numbers was introduced for the PR types, so the Type C became the PR Mk. III, the Type D the PR Mk. IV , the Type E the PR Mk. V, the Type F the PR Mk. VI and the Type G the PR Mk. VII. 

Sources: 
1st https://en.wikipedia.org/wiki/Supermarine_Spitfire#Variants
2nd https://en.wikipedia.org/wiki/Supermarine_Spitfire_(early_Merlin-powered_variants)#Early_reconnaissance_(PR)_variants
3rd https://en.wikipedia.org/wiki/Supermarine_Spitfire_operational_history#Photo-reconnaissance

Messerschmitt Bf.110. Part four. The Bf.110 in British hands.

 

During World War 2 the British managed to capture a great number of German aircraft, among them, many Messerschmitt Bf.110. 
One of them, a Bf.110D (pictured below) was captured in Iraq, after the May 1941 campaign. This particular machine was abandoned in Mosul due to the lack of spare parts, which, just as many other Bf.110 of Sonderkommando Junck, made the machine not airworthy. In fact, by the date the Germans began their retreat from Iraq, there wasn't any Bf.110 in flying condition and were abandoned on the spot. 
After the British forces entered Mosul many machines were captured and at least one machine was put into operational status by Royal Air Force's (RAF) mechanics by cannibalising parts from other aircraft. 
With its new owners, this machine received the nickname of 'The Belle of Berlin' and was used as a communications aircraft and later as an unit 'hack' by No. 267 Squadron. 

Another machine, this time a Bf.110C-4, belonging to 4. (H)/Aufklärungsgruppe 14 was intercepted over Sussex, England by fighters belonging to No. 238 Squadron on 21st July 1940. Its pilot, Oberleutnant Friedrich Karl Runde was taken prisoner and his machine was sent to the Royal Aircraft Establishment (RAE) to be evaluated, after being repaired with pieces taken from another shot down Bf.100, coded 2N+EP. 
The RAE gave the machine a new serial number; AX722 and new colours and, after performing handling trials it was flown to the Air Fighting Development unit at Duxford in October 1941 to be flown in mock-up aerial combats against British fighters. 
In March 1942 this very same machine was sent to No. 1426 (Enemy Aircraft) flight, commonly known as the 'Rafwaffe'. It stayed there until January 1945 when it was sent to the Central Flying School at Tangmere, where it was employed as an educational airframe until November 1945 when it was transferred to No. 47 Maintenance Unit in Sealand until it was eventually scrapped in 1947.

After the war, a total of 37 Messerschmitt Bf.110 were captured by the British but only seven of them received RAF markings and serial numbers. One of them, a Bf.110G-4/R6, was equipped with a FuG.220 radar and was captured at Grove airfield, in Denmark. 
This machine was part of 1/Nachtjagdgeschwader 3 and served in the night defence of Denmark and Northern Germany. It was given the serial number of 'AM34' and was later evaluated by the RAE. This aircraft is nowadays preserved at the RAF's museum in Hendon.

Sources:
1st Scale Aviation Modeller International 2013-07
2nd Histoire & Collections - Avions et Pilotes 11 - Messerschmitt Bf.110 & Me.210-410 1939 -1945
3rd Wydawnictwo Militaria 71 Bf 110 vol.1

Further reading:
https://www.destinationsjourney.com/historical-military-photographs/messerschmitt-bf-110-in-british-service/

Supermarine Spitfire. At Royal Air Force's service. Part eight. The Battle of Malta, part two.

 

This is a direct continuation from our previous post.
When the Spitfires were being delivered via aircraft carrier to Malta, the situation reached a point when it was considered dangerous for the carriers to operate on the western Mediterranean region, fearing U-boat and Luftwaffe attacks, so from late October to November 1942 a total of twelve Spitfire Mk. Vc were equipped with a single 170 gallon drop tank and flew direct from Gibraltar to Malta, covering a distance of 1.000 miles (1609.34 Km) in a ferry flight which lasted more than 5 hours.
All those Spitfires fought, and eventually won, the constant aerial attacks from the Luftwaffe and the Regia Aeronautica on Malta. The most successful Spitfire pilot in Malta was the Canadian Plt. Off. George Beurling of No. 249 Squadron, who shot down 26 and a third German and Italian aircraft between June and late October 1942.
It was there, in Malta, where the Spitfire was modified to carry underwing bombs. One machine numbered EP201 from No. 229 Squadron was fitted with one 250 lb bomb under each wing in September 1942 and were employed as improvised bombers to raid fortifications and airfield in Sicily, where their bombs were released at 7,000 feet (2.134m) diving at an optimum 60º angle.

The Spitfire Mk. VI was a high altitude variant designed to combat the Luftwaffe high-altitude bombers, such as the Junkers Ju.86P which, in 1940, could achieve higher altitudes than most fighters of the time, so it was decided that a new Spitfire variant would be needed.
During a meeting the Air Ministry asked for a Spitfire provided with a pressure cabin capable of maintaining high pressures at high altitudes.
That cabin was used to counter the physiological problems found by pilots at high altitudes and it was designed to be locked with four toggles and sealed with an inflatable rubber tube. It could be jettisoned by the pilot in case of emergency. The windscreen was the same as the ones from Mk. III and some Mk. V. 
It was powered by a Rolls-Royce Merlin 47 driving a four-bladed propeller and featured extended and pointed versions of the B-Type wings with an extended wingspan.
However, the threat of the Luftwaffe did not come to fruition and only 100 Mk. VI were manufactured by Supermarine. Eventually only two squadrons, Nos. 124 and 616 were fully equipped with the Mk. VI, albeit many other units employed the type in small numbers as an interim fighter, when transitioning to other marks of the Spitfire or other fighters. 
In most of the cases the Mk. VI were employed at low altitudes, where it was discovered that any given Mk. V could outperform the Mk. VI and, at those altitudes, pilots often flew without the canopy (it was removed before flight) because the cockpit got uncomfortably hot and they were reluctant about its capacity to jettison in case of emergency. 

Sources:
1st Signal Squadron - Aircraft In action 39 - Supermarine Spitfire in Action
2nd https://en.wikipedia.org/wiki/Supermarine_Spitfire_operational_history#Mediterranean_service
3rd https://en.wikipedia.org/wiki/Supermarine_Spitfire_(early_Merlin-powered_variants)

Supermarine Spitfire. At Royal Air Force's service. Part seven. The Battle of Malta, part one.

 

During January 1942 the first Westland-built Spitfire flew for the first time, pushing the number of manufactured-Spitfires to more than 3300 at the end of the year. By June 1942 there were 59 Spitfire Mk.V squadrons based in Great Britain, and seven additional more in the Mediterranean. In August there were no less than 42 Spitfire Mk. V squadrons to cover the Dieppe Raid.
The Mk. V was the most numerous of the Spitfire variants and eventually equipped more than 100 Squadrons of the Royal Air Force (RAF). It saw action on every battle front were the RAF or Allied' air forces were present.
By 1942 the threat of a land invasion of England fell considerably and the main focus of the war turned to the USSR and the Mediterranean. It was in Malta, where by the spring 1942 the defence of that island was becoming critical. Only the Spitfires could challenge the German fighters on equal terms, so the first tropicalized Spitfires Mk. Vs were delivered via the aircraft carriers such as USS Wasp or HMS Eagle. The first Spitfire flight in the Mediterranean took place earlier, on 7th March 1942 when 15 Mk. Vs took off from HMS Eagle aircraft carrier, off the coast of Algeria to land on Malta. 
Provided with a large and peculiar under-nose fairing over the Vokes Multi-vee filter for the carburetor air intake, the Mk. Vc was also equipped with enlarged oil and radiator intakes to optimize cooling in tropical and desert climates. The improve its range, three sizes of fuselage slipper tanks -30 gal. for short range, 90 gal. for long range and 170 gal. for ferrying could be attached in the belly. 
During the spring months of 1942 around 275 Mk. Vb and Mk. Vcs were delivered to Malta. In order to make possible the Spitfire to take off from an aircraft carrier wooden wedges were used to allow the Spitfires to leave the carrier with partial take-off flap settings, so, when the aircraft gained enough altitude, the pilot opened the flaps completely, the wedges fell out and then the flaps could be closed. 
On 20th April 1942 the code-named "Operation Calendar" took place, when a total of forty-seven Spitfires and pilots from Nos. 601 and 603 Squadrons flew from USS Wasp to Malta. In "Operation Bowery", on 9th May, additional 50 Spitfires flew from USS Wasp and 14 from HMS Eagle, sixty of them managed to land safely on Malta, with one Spitfire with a defective long range fuel tank landing back on USS Wasp, despite not having a tailhook. In "Operation Style", on 3rd June, further 32 Spitfires flew to Malta from HMS Eagle, although they were intercepted while on route and four were shot down. 

Sources:
1st Signal Squadron - Aircraft In action 39 - Supermarine Spitfire in Action
2nd https://en.wikipedia.org/wiki/Supermarine_Spitfire_operational_history#Mediterranean_service

Supermarine Spitfire. At Royal Air Force's service. Part six. The Spitfire Mk.V

 

(This post is a direct continuation from our previous post) 
As we wrote, a new complete redesign was not desirable for Spitfire because it disrupted the production lines, so in February 1941 No. 92 (East India) Squadron of the Royal Air Force (RAF) became the first one to receive examples of the Mk. V which was, at first, considered as an interim fighter. This was followed by No. 91 (Nigeria) Squadron in March. Those machines were part of the initial production order for 1.000 Mk. Vs.
The Mk. V was an Mk. I/II airframe strengthened with longerons to fit a Merlin 45 engine rated at 1470 hp and by June production of the Mk. Va terminated in favour of the Mk. Vb which featured two 20mm cannons plus four 0.303 in machine guns in the wings. 
Early examples of the Mk. Vb had the same span of the Mk. I/II, although, in order to improve performance at low altitudes, clipped wings were introduced later. The number of small improvements that the Mk. Vb got was very high throughout its manufacture lines and at service levels. One of the most significant was a jettisonable cockpit canopy with more bulbous edges, replacement of metal-covered ailerons and the replacement of flame-damping exhaust stubs.
By September 1941 a total of twenty-seven RAF squadron were operating the Mk. Vb, while very operated the Va. In December those numbers rose to forty-six. 

The Spitfire Mk. III was a prototype variant, of which a single example was completed, N3297. It was the first significant redesign of the type and differed from previous marks by having clipped wings, a strengthened fuselage, a retractable tailwheel, an internal bullet-proof windshield and 88 lbs of armour plating. Two additional inches more forward rake was added to the strengthened undercarriage and the wheels were fully enclosed by doors when retracted.
Priority for the Hawker Hurricane Mk. II was given, so the Spitfire Mk. III wasn't put into production and was employed as a test-bed for different engines (among them the Merlin 60 and 61 - the same one that would eventually power the Mk. IX) and armaments until September 1944. 

The Spitfire F.IV was the prototype for the 'F' sub-mark which was powered by the Roll-Royce Griffon engine. Its inception dates back to 4th December 1939 when Supermarine design staff printed a brochure where they proposed the idea of converting the Spitfire to the Rolls-Royce Griffon engine, expecting many performance improvements. However, the problematic development of the Griffon engine meant that the prototype of this machine would not be ready until late 1941.
The Griffon IIB which the Mk. IV was fitted with was a single-stage supercharged engine of 1735 hp. This required stronger longerons to cope with the weight of the engine, as well as bigger radiator and oil cooler, although it kept the asymmetric under-wing radiator layout of the single stage Merlin engine. The lower thrust line and larger capacity of the Griffon engine required a complete redesign of the engine cowling, with more prominent blisters over the cylinder heads and a third tear-drop shaped blister on the upper forward cowling to clear the magneto, and a deeper curve down to the spinner, which was much longer than previous marks. A four-bladed Rotol propeller was employed. This propeller catch a lot of pilots out because it rotated in the opposite direction to that of the Merlin: to the left from the pilot's perspective, instead of to the right, meaning that the sliptstream swung the Spitfire to the right on the ground, requiring the rudder to be turned to the left during take-off.
The Mk. IV DP845 flew for the first time on 27th November 1941 and was equipped with the full-span C type wing. It featured a small tail unit and retractable tailwheel. It had also external bracket hinges under the wings, denoting the installation of braking flaps, which were soon removed and the F.IV was soon also fitted with a mock-up six-cannon armament, three per wing. The aircraft was renamed to 'Mk. XX' to prevent confusion with a PR. Type and, then it became the Mk. XII. 

Sources:
1st Signal Squadron - Aircraft In action 39 - Supermarine Spitfire in Action
2nd https://en.wikipedia.org/wiki/Supermarine_Spitfire_(Griffon-powered_variants)
3rd https://en.wikipedia.org/wiki/Supermarine_Spitfire_(early_Merlin-powered_variants)

Supermarine Spitfire. At Royal Air Force's service. Part five. After the Battle of Britain.

 

The Spitfire Mk. II was, externally, identical to the Mk. I. It incorporated all the improvements made to the Mk. I. It was powered by the Merlin XII engine rated at 1.175 hp, which employed 100 octane fuel, instead of the 87 octanes one. The Mk. II was manufactured at Castle Bromwich, Birmingham with the first airframe being completed in June 1940 and the first 750 Mk. IIs were equipped with the "a" type wing, while the remaining 170 had the "b" type wing. Cockpit protection was improved and self-sealing fuel tanks were also introduced, albeit many Mk. Is were already retrofitted with them.
Some few experiments were carried out on Mk. IIs, specially aimed to increase Spitfire's operational range of 395 miles (636 km). This was done because the Spitfire was designed as a home-based defence fighter with the smallest possible airframe, so it had little space for extra fuel tanks. Therefore, various external fuel tank configurations were tested, including a 40 gal (151 L) tank faired into the wing leading edge. The Spitfire Mk. II (LR), as it was denominated (LR stands for 'Long Range'), was employed by Nos. 66, 118 and 152 squadrons for a few operations. However, the fact that the tanks couldn't be jettisoned and had an adverse effect on handling the aircraft, caused them to be withdrawn in favour of the fuselage 'slipper' tank.
The Spitfire Mk. II was also the first Spitfire to carry bombs, although of the non-lethal smoke ones. When the last fifty-two examples became Mk. IICs (the letter "C" meant a change in role instead of a wing configuration). These Mk. IICs were officially known as 'Sea Rescue Type E' and carried a small dinghy boat and food supplied to be parachute-dropped. They were employed by five squadrons and redesignated as ASR (Air Sea Rescue) Mk. IIs in late 1942.

After the end of the Battle of Britain, Royal Air Force's (RAF) Fighter Command put to rest many of the squadrons that carried the bulk of the fight and prepared for a campaign of offensive sweeps across the Channel. During this period of time, the Hawker Hurricane was gradually phased out and, in many cases, replaced by the Spitfire. For those fighter sweeps, day fighter squadrons developed a framework of code-names, the most important of which were "Rhubabr" - small scale attacks by fighters of fighter-bombers; "Circus" - heavy escort to light bombers which acted as bait to attract enemy fighters into the battle; "Ramrod" - just like Circus but with the main objective of destroying the bombers' target; "Roadstead" - an attack by bombers with fighter escort on shipping targets; "Rodeo" - a straightforward fighter sweep over enemy territory and finally "Ranger" - a freelance penetration of enemy airspace in squadron or wing strength with the objective of wearing down the defences. 
Such operations were risky for both men and machines and, although the Spitfire squadrons were able to hold against the German Messerschmitt Bf.109E and F variants, the advent of the Focke-Wulf Fw.190 in autumn 1941 and the many ground anti-air fire of all calibres, changed the odds. In fact, many Spitfires were lost to ground fire of all calibre, ranging from rifle rounds to purpose-built flak guns. Among those victims were 'Paddy' Finucane and Bob Stanford-Tuck, aces of the Battle of Britain.
During early 1941, the Spitfire was equipping most operational fighter squadrons and every effort was made behind the scenes, to ensure that it remained at least equal to its Luftwaffe adversaries. Nonetheless, it was undesirable to disrupt production of the Spitfire by introducing radical changes, so a new mark, Mark V was put underway. (To be continued)

Sources:
1st Signal Squadron - Aircraft In action 1039 - Supermarine Spitfire in Action
2nd https://en.wikipedia.org/wiki/Supermarine_Spitfire_operational_history#European_offensive_1941–1943

Supermarine Spitfire. At Royal Air Force's service. Part four. Battle of Britain

 

The Battle of Britain constituted the first major test for the Supermarine Spitfire, whose performance was often compared to that of the Hawker Hurricane, the main fighter of Royal Air Force's (RAF) Fighter Command. 
The Hurricane had thicker wings and its eight 0,303 in machine guns were easier to install and set-up than the Spitfire thanks to having a thicker wing and being closer the one from the other. Some veteran pilots from the Battle of France requested the machine guns to be harmonised, so their combined fire bursts could concentrate in 250 yards (228.6 m) ahead instead of the official 400 yards (365.76 m). This made the Hurricane a better gun platform than the Spitfire.
The Hurricane shot down more enemy aircraft than the Spitfire, thanks to its higher proportion in the skies. In fact, during the Battle of Britain, seven out of ten German aircraft were shot down by Hurricane pilots. However, losses were also higher among the many Hurricane squadrons. According to post-war studies, the kill-ratio of the Spitfire was, however, slightly better than that of the Hurricane.
Most of the Spitfires were armed with a total of eight 0,303 in machine guns, four per wing. It was very common for Luftwaffe's pilots to return home with 0,303 in bullet holes in their fuselages, without having sustained critical damage as their main fighter, the Messerschmitt Bf.109, had received armour plating in critical areas and self-sealing fuel tanks became common in their bombers. 
Those improvements made to German aircraft, required some improvement in armament, so many Spitfires Mk. I of No. 19 Squadron (the first unit to employ them) were fitted with two 20mm Hispano-Suiza cannons. This arrangement, however, proved to be unreliable, as the cannons often failed to fire, or they got jammed very easily. After complaints, those cannons were replaced with conventional machine guns in September 1940. This arrangement was, however, the forerunner of the Mk. Ib variant, which would become standard shortly later and would name, retrospectively, the not-cannon-armed Mk. I variant as the "Mk. Ia". 

The Merlin III engine was rated, theoretically, at 1.030 hp, however it required 100 octane fuel from the United States, which became available only from early 1940. This meant that the emergency boost could last only for five minutes, The extra boost wasn't dangerous as long as the pilot's notes were acknowledged. Anyway, as a precaution, if the boost had been used, the pilot had to report it upon landing, so it could be noted in the engine's log book. This extra boost became standard and more optimized on subsequent variants of the Spitfire. 
Between 1st August and 31st October 1940 a total of 208 Spitfires were lost in combat, seven of them destroyed on the ground and 42 in accidents.

The Speed Spitfire, as we have seen in a previous post, was a speed record variant which was pushed into RAF's service and fitted with photographic cameras, thanks to its high speed. It was one of the fastest aircraft in the world, however it suffered from reduced fuel capacity, so it was, eventually, used as a high-speed hack for the personal use of Air Commodore Boothman. 
It was eventually struck off charge on 14th June 1946 and scrapped. 

Sources:
1st https://en.wikipedia.org/wiki/Supermarine_Spitfire_operational_history#Battle_of_Britain
2nd https://en.wikipedia.org/wiki/Aircraft_of_the_Battle_of_Britain
3rd https://en.wikipedia.org/wiki/Supermarine_Speed_Spitfire

Supermarine Spitfire. At Royal Air Force's service. Part three. The Spitfire in the Battle of France.

 

The Spitfire Mk. III, pictured below, was an attempt to improve the basic Spitfire design. It was powered by a Rolls-Royce RM 2SM, which was later known as the Merlin XX and yielded 1,390 hp of power, thanks to its two-speed supercharger and reduced wingspan. In order to increase ground stability, the undercarriage was raked forward, and had flaps to completely enclose the wheels when retracted. The tailwheel was fully retractable too. 
The windscreen was remodelled, with a built-in internal bulletproof glass panel, and was armed with the "c-type" wing, which could host four 20 mm cannons, eight 0.303 in machine guns or two cannons and four machine guns. Maximum speed was increased to 385 mph (620 km/h).
The first prototype, registered as N3297 flew for the first time on 16th March 1940 and was thoroughly tested and, although the Mk. III was ordered for mass production, it was soon cancelled as the Merlin XX engine was in short supply and was needed for the Hawker Hurricane Mk. II, which was the workhorse of the Royal Air Force. In the meantime Rolls-Royce developed the Merlin 45, a similar engine in terms of performance, which could be fitted in the fuselage of a Spitfire Mk. I or a Mk. II. The Mk. III was abandoned in favour of the Mk. V, although the improvements first seen in the Mk. III were incorporated in later marks of the Spitfire. The airframe of the Mk. III was used to test the Merlin 61 engine, which later powered the marks VII, VIII and IX, making the Mk. III the true ancestor of those marks.

Some other Spitfires were also altered, one of those was R6722,  which, when the Germans invaded Norway in April 1940, the RAF showed interest in the concept of floatplane fighters, which could be useful in those areas were airfields were not immediately available, so R6722 was taken from the Woolston factory, to be fitted with floats taken from a Blackburn Roc naval fighter. The conversion was made by No. 12 Maintenance Unit at RAF Kirkbride in Cumbria and later, tank tests were carried out at Farnborough, employing a scale model, finding that the concept was solid even if some changes were to be made, such as enlarging vertical tail surfaces to counter-balance the side area of the floats. The "Narvik Nightmare", that's how this Spitfire was commonly known, was reverted back to a regular Mk. I when the Battle of Norway ended and, eventually, it was upgraded to a Mk. V. 

The Spitfire was first used at an operational level over western Europe on 13th May 1940, during the German invasion of the Netherlands. Since three days earlier, German paratroopers were pinned down by the Dutch Army in the Battle of Hague, so the Royal Air Force sent No. 66 Squadron, equipped with Spitfires to escort No. 264 Squadron, equipped with Boulton Paul Defiants, to provide ground support for the Dutch army. The Spitfires encountered German Junkers Ju.87 Stukas belonging to IV (St.)./Lehrgeschwader 1 and shot down four of them. However, they were soon intercepted by Bf.109 from 5./Jagdgeschwader 26 that shot down five Defiants and one Spitfire, for the loss of just one Bf.109.On 23rd May 1940 other German Bf.109s were shot down by Spitfires of No. 54 Squadron over Calais Marck airfield, on the northern shore of France.
During the Battle of France a total of 67 Spitfires were lost on French soil, most of them during attempts to prevent the Luftwaffe from bombing the evacuation beaches at Dunkirk. During this period, every Spitfire unit was based in Great Britain, as Air Vice Marshal Hugh Dowding ordered, however, from late 1939 some Spitfire PR.I, specially modified for photo reconnaissance duties, belonging to No. 2 Camouflage Unit, were operating from Seclin, northern France, close to the border with Belgium, performing photo-intelligence gathering of German defences and cities. 

The Battle of Britain began on 10th July 1940 and became the first major test for both the Spitfire and the RAF Fighter Command. During this time, very important lessons were learned about Spitfire's capabilities and setbacks, but that's for another post.

Sources:
1st https://en.wikipedia.org/wiki/Supermarine_Spitfire_operational_history
2nd https://en.wikipedia.org/wiki/Supermarine_Spitfire_(early_Merlin-powered_variants)
3rd https://www.historyofwar.org/articles/weapons_spitfire_mkIII.html
4th https://en.wikipedia.org/wiki/Supermarine_Spitfire_(late_Merlin-powered_variants)
5th https://www.solentsky.org/post/secret-files-the-spitfire-floatplanes
6th https://allspitfirepilots.org/aircraft/R6722

Supermarine Spitfire. At Royal Air Force's service. Part two. Prototypes and early Spitfires.

 

After the disappointment of the Type 224, Mitchell and his design staff, began to draw cleaner designs using the experience with the Schneider Trophy seaplanes as a departing point. This, eventually led to the Type 300, which featured retractable undercarriage and a reduced wingspan. This original design was submitted to the Air Ministry but it was rejected, so it had to undergo a series of changes such as an enclosed cockpit, oxygen-breathing gear, smaller and slimer wings, and it was to be powered by the, back then, cutting edge Rolls-Royce PV XII V-12 engine, which was later commonly known as the Rolls-Royce Merlin. 
In November 1934, Mitchell was given permission from Vickers-Armstrong (Supermarine's parent company) to develop and reife the Type 300 and on 1st December he was given £ 10,000 from the Air Ministry for the construction of the Type 300, under contract AM 361140/34. 
On 5th March 1936 the first prototype, registered as K5054, took-off for the first time at Eastleigh Aerodrome, Hampshire. At the controls was Cpt. Joseph "Mutt" Summers, chief test pilot for Vickers, who praised the design. 
The initial prototype was later fitted with a new propeller and it was flown again on 10th March 1936, where the undercarriage was retracted for the first time and, after a fourth flight, a new engine was fitted. After overcoming many small failures and improving the design, it was flown again to RAF Martlesham Heath where it was handed to Squadron Leader Anderson of the Aeroplane & Armament Experimental Establishment (A&AEE) to be delivered to the Royal Air Force (RAF). Soon after the Air Ministry placed a production order for 310 Spitfires.
Although it was presented to the public on 27th June 1936, numerous problems hindered the mass production of the Spitfire and the first production aircraft wasn't completed until mid-1938 and it was delivered to No. 19 Squadron at RAF Duxford on 4th August 1938 and during the next weeks No. 66 Squadron also received the type, albeit at a slower pace. The next unit to receive the Spitfire was No. 41 Squadron at RAF Catterick and the first public sight of the Spitfire in RAF's colours and markings took place on Empire Air Day, on 20th May 1939. Later, more squadrons were gradually equipped with the type.
When World War 2 began, there were a total of 306 Spitfires in service with the RAF, seventy-one of them in reserve and 2.000 under manufacture with 36 written off due to accidents.
On 6th September 1939, shortly after the outbreak of the war, a friendly-fire incident known as the Battle of Barking Creek took place where two Hawker Hurricanes of 56 Squadron were shot down by Spitfires of 74 Squadron over the river Medway, Kent. One of the victims of this incident, P/O Montague Leslie Hulton-Harrop, was the first British pilot fatality of the World War II. This incident placed the manufacture of IFF (Identification Friend or Foe) equipment as a top priority.
On 16th October 1939 the Spitfire clashed against the German Luftwaffe for the first time when three aircraft from 602 and 603 Squadrons intercepted three Junkers Ju.88 belonging to 1./KG.30 over Rosyth (Fife, Scotland) trying to attack the cruiser HMS Southampton and HMS Edinburgh on the Firth of Forth. Two of the Ju.88 were shot down and another one was heavily damaged.

The PR (Photo-Reconnaissance) variants of the Spitfire, was a sub-variant dedicated for photo-reconnaissance missions. Before the war, military aerial doctrine dictated that the best option for long-range reconnaissance duties was to employ converted bombers, as they had defensive armament, however, it was soon discovered that Bristol Blenheims and Westland Lysanders were easy targets for German fighters so, following a memorandum made back in August 1939 by Flying Officer Maurice Longbottom, two Spitfires, N3069 and N3071 were released from RAF Fighter Command and sent to the Heston flight, a secret reconnaissance unit. 
Those two Spitfires were stripped from their armament and radio gear, two F24 ventral cameras were installed, heating equipment was added to prevent photographic cameras from freezing and the lenses from frosting. These Spitfires were later known as Spitfire Mk. I PR Type A and achieved a high speed of 390 mph (627 km/h) and were employed for the first in late 1939 to perform photographic reconnaissance flights over western Germany.

The Speed Spitfire was an racer-built variant which was built in late 1938 to achieve world speed records, mainly against German aircraft such as the Messerschmitt Bf.109 V13, Heinkel He.100 V2 and the Messerschmitt M.209 V1, which eventually got the prize achieving a top speed of 755.14 km/h (469.22 mph) on 26th April 1939.
It featured many design changes to make the type more aerodynamic and lacked radio equipment and armament to make it lighter. The Speed Spitfire was eventually handed to the RAF at the beginning of World War 2 where it was suited for photographic reconnaissance, given its high top speed. 

Sources:
1st https://en.wikipedia.org/wiki/Supermarine_Spitfire
2nd https://en.wikipedia.org/wiki/Supermarine_Spitfire_operational_history
3rd https://en.wikipedia.org/wiki/Supermarine_Speed_Spitfire
4th https://en.wikipedia.org/wiki/Supermarine_Spitfire_variants:_specifications,_performance_and_armament
5th https://en.wikipedia.org/wiki/Supermarine_Spitfire_(early_Merlin-powered_variants)

Bristol Beaufighter, part sixteen. Very late & post-war Beaufighters.

 

When World War 2 came to an end in Europe on 8th May 1945, there were fifteen Royal Air Force's (RAF) squadrons equipped with the Bristol Beaufighter. All of those units except for four were UK-based. In the Far East Theatre of Operations, two squadrons, Nos. 42 & 85 operated their Beaufighters and No. 45 Squadron was based at Kuala Lumpur and remained in action until the Japanese surrender in August 1945.
Not listening to the Japanese Emperor, many Japanese soldiers kept on fighting beyond 15th August 1945, when the surrender date for Japan was set, so No. 27 Squadron was allocated as an Air Jungle Search & Rescue unit during that month, undertaking the search & rescue role while offering also support to forward army units engaged with the remnants of the Japanese army. 
No. 27 Squadron was based at Akyab, Burma and, although they were informed during August that they were going to be disbanded, the order was soon rescinded when civil uprisings in Indonesia took place and the squadron was rebased to Mingaladon (Burma) with detachments to Batavia, Bayan Lepas, Kemajoram and Penang. This unit also performed some leaflet-dropping sorties to advise the Japanese troops to surrender, continuing on this type of sorties in some remote regions, like the Shan States as late as January 1946. 
The detachment in Batavia performed some ground-strikes against Indonesian rebels, with the first one taking place on 20th November 1945. The detachment was active in the area until February 1946, when it returned to Mingaladon to be disbanded together with the rest of the squadron.
A new RAF Beaufighter squadron was set up in the UK during the post-war years. This unit was No. 42 Squadron at RAF Thorney Island. This was formed by renumbering No. 254 Squadron and lasted just one year with the Beaufighter TF.X as it was disbanded on 15th October 1947.
During this time period, there were two Beaufighter units stationed in the Far East; No. 84 Squadron at Seletar (Singapore) and No. 45 at Negombo (Ceylon). Both of those units were soon sent to fight communist guerrillas in Malaya under Operation Firedog.

Just after the war, the situation in Malaya was complicated. It was a region formed by nine separate states, each run by its own Sultan, with a lot of help from the British government. The main political party in the whole country was the Malayan Communist Party (MCP), which was lead by the Chinese communist Chin Ping, who sparked an armed insurrection from the end of the war. 
In 1948 the MCP killed some European rubber plantation owners and therefore, in June a state of emergency was enforced in the region. Both British and Commonwealth forces were involved in what would be an anti-communist operation that would last for twelve-years and named 'Operation Firedog'.
The first sortie made by a Beaufighter in this context was performed by No. 84 Squadron, which had a detachment in Kuala Lumpur on the 19th August 1948. This unit maintained a  crew rotation system between their main base at Ceylon and the Kuala Lumpur detachment and, in June 1949 the whole squadron was based at Kuala Lumpur, with detachments at Butterworth (Penang) and Tengah. In October 1949 the unit began to transition to the new Bristol Brigand, but kept operating the Beaufighter side-by-side, until it was moved back to Tengah in December 1949 and finally replaced all of their Beaufighters with Brigands in February 1950. 
No. 84 Squadron was initially equipped with the Beaufighter TF.X from November 1946 and and was moved to Changi (Singapore) in October 1947 before being rebased back to Tengah in February 1948. A detachment was sent to Kuala Lumpur where they joined No. 45 Squadron in Operation Firedog from July of that same year. Here they did not employ the Beaufighter very much as by October 1948 most of the squadron's crews were in the UK training and collecting for the new Bristol Brigand. At that time the squadron was rebased to Habbaniya (Iraq), where it was retrained and fully re-equipped with the Brigand. The squadron did not return to Malaya until April 1950 where they resumed Operation Firedog, this time with the Brigands.

By 1949 the frontline career of the Beaufighter was clearly declining, although the type remained in RAF's inventory in the Far East until 1956. 
The last operational version of the Beaufighter was the target-towing TT. Mk. X, which were airframes converted from existing Mk. Xs, with the prototype for the series being NT813. This variant was stripped from armament and was equipped with a wind-driven winch mounted in the rear fuselage, with its associated windmill projecting from the starboard fuselage side. A total of fifty-nine additional machines were converted and were employed by gunnery co-operation units and many Advanced Flying Schools in the UK and abroad.
In the Middle and Far East the TT. Mk. X was also employed in Flights in Cyprus, Gibraltar and Malta as well as Seletar. It was here where the Seletar Base Flight made the last operational sortie with a Beaufighter, when on 12th May 1960 TT. Mk. X registration number RD761 took off from Seletar for a farewell salute. On landing the aircraft was grounded, struck off charge and scrapped four days later, marking an end to the Beaufighter's career with the RAF.

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

Bristol Beaufighter, part fifteen. Beaufighter TF.X

 

Initially, just like the Mk. VI, the Mk. X was at first a designation employed to distinguish Coastal Command Mk. VIs powered by the Hercules XVII engines modified for low altitude attacks. The Mk. X, which was the successor to the Mk. VI on the factory lines in May 1943, had the centimetric AI Mks. VII or VIII radar installed inside a thimble nose radome.
Thanks to its heavy armament and its ability to perform a wide variety of roles, the Mk. X became a true multipurpose aircraft which served the Royal Air Force (RAF) well for the rest of the war. 
Alternatively to the torpedo for anti-shipping strikes, the Mk. X could also carry two 500 pound (227 Kg) under the fuselage plus one 250 pound (114 Kg) under each wing. A 200 gallon (909 L) drop tank could also replace the torpedo on the central fuselage rack.
Late production variants of the Mk. X had a prominent dorsal fin extension carried forward almost to the observer's cupola, and the wings stressed (taken from a proposed Mk. XII bomber version) to take a 1,000 pound (454 Kg) bomb on each side outboard of the engine nacelles. 
In total, 2.205 Beaufighters Mk. X were manufactured, with the last aircraft being delivered on 21st September 1945 with SR919 as serial number.

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

Bristol Beaufighter, part fourteen. Beaufighters Mk. IV & VIF

 

The Bristol Beaufighter Mk. IV was a 'slim fuselage' type Beaufighter, powered by two Rolls-Royce Griffon engines, however, this variant remained only experimental and no production followed.

The Beaufighter Mk. VI was an improved variant of the regular Beaufighter thanks to the better Bristol Hercules VI engines, which had an increased output of 1,670 hp and that by late 1941 there were enough engines to put the new variant, the Mk. VI, into production. Powered by the new engines, the top speed of the Beaufighter rose to 333 mph (536 km/h) at 15,600 ft (4.754 m) high with a cruising speed of 243 mph (391 km/h).
The airframe received some minor modifications too, the most visible one being the installation of a single defensive Vickers .303 inch K gun in the observer's canopy. This cockpit had to be reinforced and redesigned by framing to place the gun mount. Underwing bomb racks were also introduced and the horizontal tail plane was modified with 12 degree of dihedral.
The Mk. VIC (the letter 'C' stands for 'Coastal') had also extra fuel capacity thanks to its extra wing fuel tanks which gave the type a range of 1,810 miles (2.912 km), while the standard Mk. VIF had a range of 1,480 miles (2.382 km). The suffixes F and C meant the role the variant was intended for, on one hand Mk. VIF (the letter 'F' stands for 'Fighter') was faster at higher altitude, where the extra speed was important, specially when the airframe was adapted to fit the centimetric AI Mk. VI of Mk. VII radar sets in the elongated 'thimble' nose radome. 
On the other hand, those built for the Coastal Command sought for lower altitude performance, as their attacks took place below 500 feet (152 m) or even lower. This made Bristol to crop the impellers and lock the blowers of the Hercules VI engine, which lead to the creation of the Hercules XVII radial engine variant, which gave a considerable performance boost at low levels. 

The transition from both the Mk. IF and the Mk. IIF to the Mk. VIF was gradual, so there is not a definite date to pinpoint when the earlier versions went out of date and the new ones took over. This meant that the Mk. VIF flew side-by-side both with the Mk. I & II in the night fighter roles.
The first successful interception of a Mk. VIF was performed by the Fighter Interception Unit (FIU) when they claimed a Dornier Do. 217 shot down on 5th April 1942, being No. 68 Squadron the first operational unit of the Royal Air Force (RAF) to be equipped with the Mk. VIF in March 1942. This was followed by Nos. 604 and 219 squadrons, out of a total of twenty-two fighter squadrons based in the United Kingdom. 
Most squadrons operated the Mk I & IIF in the night fighter role, but during mid-1942 the De Havilland Mosquito night fighter started to be available in numbers, so the Beaufighter was released from home defence duties and was sent to serve overseas. Squadrons. Those squadrons not re-equipped with the Mosquito, were sent to the North African Theatre to support Operation Torch in November 1942. During the Battle for Tunisia a Beaufighter shot down five German Junkers Ju.52 in just ten minutes on 20th April 1943. 
Operating from Malta, the Beaufighter could reach almost every point in the Mediterranean Theatre. Albeit initially there were only Mk. IF squadrons based there, those were soon replaced by the Mk. VIF and they were joined by two additional squadrons. 

Overall, in every theatre of war, the Beaufighter proved useful as a night fighter and also as other capabilities, such as a strike fighter, where, acting in the Far East, became very popular among its crews thanks to its ruggedness and reliability, albeit being heavy to control and not easy to fly. 

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

Bristol Beaufighter, part fourteen. Beaufighter Mk. IC

 

As the bombing campaign over mainland Europe increased after the Battle of Britain, both Bristol Aeroplane Company and the Royal Air Force (RAF) began to consider additional roles for the Beaufighter, as it was seen the ideal long range fighter to strike upon enemy bases and shipping lanes in such far places as Norway. 
To this purpose long range fuel tanks were fitted on a Beaufighter Mk. I registered as R5152, which had its guns replaced by fuel tanks. This was accompanied by additional changes such as an extra table and instruments being added in the rear position to help the navigator in long over-water flights, a D/F loop in lieu of the gun camera. An initial batch of eighty modified Beaus Mk. I were completed, with the suffix of a letter 'C' (standing for 'Coastal') added to the Mk. I official denomination. The machines of this initial batch had a temporal Wellington fifty gallon (227 L) fuel tank mounted on the fuselage floor between the gun bays. Standard wing fuel tanks were not ready until later.
The Mk. IC saw service for the first time in late March 1941 serving with No. 252 Squadron, shooting down a Focke-Wulf Fw. 200 on 16th April, and marking it as the first victim of the Mk. IC. In June 1941 No. 143 Squadron became the second unit to employ the Mk. IC. 
The Mk. IC became so important in RAF's Coastal Command that Bristol adapted the airframe to carry various fittings for the singular task of striking enemy shipping and kept on allocating the 'C' for 'Coastal'. 
Due to the troubling situation growing in the Mediterranean, No. 252 Squadron was sent with its Beaufighters to Malta in May 1941 and was soon followed by No. 272 Squadron with its Mk. ICs and Nos. 46 and 89 with Mk. IFs. When on Malta, No. 252 saw heavy action when escorting convoys and supporting the Syria-Lebanon Campaign. Later, they were rebased to Egypt, where they claimed their first enemy aircraft shot down on 24th July. 
As the Beaufighter showed that effective night interception was possible when the right aircraft and equipment were ready, the Mk. I performed a wide variety of roles including reconnaissance, ground attack and maritime strikes, relying primarily in its heavy armament. 
A total of 954 Beaufighters Mk. I were manufactured and were employed a by twenty-eight RAF squadrons, operating in most of World War 2's theatres of war. 

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

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