Vickers Wellington Variants

Mk I

The Wellington Mk I was the version serving with Bomber Command at the outbreak of war in 1939. It was powered by two 1,050 hp Pegasus XVIII engines. Defensive armament was powered by three Vickers turrets, each with two .303in machine guns, one at the front, one at the rear, and one retractable ventral turret. The Vickers turret was not a great success, and had a limited arc of fire.

Vickers Wellington I
Vickers Wellington I

The Mk I had a very short front line career. The prototype first flew on 23 December 1937. Production was split between Weybridge, Blackpool and Chester. 181 Mk Is were produced, with the first delivery to squadrons coming on 10 October 1938. At the outbreak of war, eight operational and two reserve squadrons were equipped with the Mk I, but it was already on the way out. The Mk I was phased out in the first few months of the war, and had been replaced by the Mk IA by December 1939.


The Mk IA was actually an early version of the Mk II, rather than a development of the Mk I. The Mk II was to be a rather heavier aircraft, using more powerful engines, and so the Mk IA was also slightly larger than the Mk I (3 inches wider and 6 inches longer), with a fuselage strengthened in preparation for the increase in weight planned for the Mk II. The Mk IA and Mk IC were produced to provide an improved Wellington while the RAF waited for the improved engines planned to go in the Mk II and Mk III versions were undergoing development.

The problematic Vickers turrets were replaced by turrets produced by the specialist firm of Frazer Nash. They provided FN5 nose and tail turrets and a FN25 retractable ventral turret, each with two .303 inch machine guns. Although an improvement on the defensive arrangements in the Mk I, this configuration left the Wellington vulnerable to any attack from above and to the side – the nose gun could only turn to ninety degrees, while the ventral gun could only fire level or down. It would be the 187 Mk IAs that would take the brunt of the early bomber offensive, suffering heavy losses while doing it. The Mk IA had replaced the Mk I by December 1939.


The IB was an alternative solution to the problems caused by the Vickers turrets that had been solved in the IA. The IB was either indistinguishable from the IA, or more likely never produced.


Vickers Wellington IC of No.149 Squadron
Vickers Wellington IC
of No.149 Squadron
Vickers Wellington IC after raid
Vickers Wellington IC after raid

The Mk IC was the second most numerous version of the Wellington (after the Mk X) – a total of 2,685 were built between 1940 and 1942. It was very similar to the Mk IA, but with one significant change. The retractable ventral turret was removed, and replaced by two machine guns firing from the side windows. At first the Vickers “K” guns were used, located just in front of the wings, but the majority of the Mk ICs carried a pair of belt-fed Browning .303in machine guns carried further back down the fuselage. Yet another advantage of the geodesic construction of the Wellington was the ease with which extra windows could be added to the aircraft just by removing part of the fabric covering of the aircraft. The MK IC also had improved hydraulics and electrical systems. Production of the Mk IC continued into the autumn of 1942. The Mk IC was the first version of the Wellington to be equipped with Lorenz blind landing equipment (although it was later added to some Mk IAs). The Mk IC entered squadron service in April 1940. By this time day bombing had been abandoned and night bombing was the norm. 


The Mk II was first proposed in January 1938 as part of a long term plan to use more powerful engines in the Wellington. The Mk II would use the Rolls Royce Merlin X engine, the Mk III the even more powerful Hercules engines. Neither of these engines were available in 1938, so the increase in fuselage size, improved Frazer-Nash turrets, side guns and improved electrical and hydraulic systems designed for the Mk II were introduced in the Mk IA and IC.

Vickers Wellington Mk.II from the Right
Vickers Wellington Mk.II from the Right

The Merlin engine was ready for testing by 1939. The first Wellington Mk II prototype flew on 3 March 1939. The new engines provided 1,145 hp, an increase of 100 hp over the Pegasus engine, but were much heavier – the weight of the Mk II increased by 4,500 lbs when compared to the otherwise similar Mk IC. The Mk II was faster and had a higher service ceiling, but the bomb load and maximum range were both reduced. The Mk II entered service at the end of 1940. Ironically, the Mk II was produced in much smaller numbers than the interim Mk IC. A total of 401 Mk IIs were built.

The reduced maximum bomb load was still high enough to all the Wellington Mk II to be used to test the new 4,000 lb “Blockbuster” bomb that was replaced the small ineffective bombs then in use. This new bomb required a series of changes to be made to the bomb bay, including the removal of a central structure that had divided the bomb bay in two, and the removal of part of the bomb bay doors. The 4,000 lb was first used against Emden on 1 April 1941, and was soon adopted by all of Bomber Command. It was the first of a series of increasingly large bombs that would end with Barnes Wallis’s own “Grand Slam” bombs, carried by the Avro Lancaster.


The Mk III saw another change of engine, to the 1,590 hp Hercules XI. The new engine helped maintain the performance of the Wellington as its weight slowly increased. The prototype Mk III first flew on 19 May 1939, only two months after the first flight of the Mk II, but it took rather longer to enter service, not reaching the front line until June 1941. Other changes made to the Mk III included the fitting of de-icing equipment, and the capacity to tow gliders. The Mk III also saw the rear turret changed from the two gun FN-10 to the four gun FN-20, although this still used the .303 in machine guns, limiting the effectiveness of the increase in the number of guns. The Mk III remained in Bomber Command service until October 1943. Many of the surviving aircraft were then transferred to training units. In total 1,519 Mk IIIs were constructed.


Two hundred and twenty Mk IV Wellingtons were built using the Pratt & Whitney Twin Wasp R-1830-S3C4-C engine, giving 1,050 hp. The project had first been proposed in later 1939, but work was delayed until February 1940 by American neutrality. The prototype flew in December 1940, and squadron deliveries began in August 1941. The Mk IV was used by three Polish squadrons (Nos. 300, 301 and 305), two Australian squadrons (Nos. 458 and 460) and No. 142 Squadron. It was phased out by March 1943. The Mk IV was equipped with the same two guns turrets as the 1C. Its range and bomb load were similar to the Mk III, although its top speed was much higher, at 299 mph.

Mk V

The Mk V and Mk VI were both attempts to produce a high altitude version of the Wellington. The two versions were visually distinctive. The front of the aircraft was remodelled to include a pressurised cabin, somewhat resembling a single cigar case, in line with the top of the fuselage, with a bubble canopy for the pilot (the basic outline somewhat resembles the shape of fighter aircraft such as the Spitfire, with the crew pod where the engine would be).

The Mk V used two 1,425 hp Hercules III engines. Three prototype Mk Vs were constructed, but the Hercules engines was not a great success as high altitude, and so work was abandoned in favour of the Rolls Royce Merlin powered Mk VI.


The Mk VI was developed at the same time as the Mk V, but using Rolls Royce Merlin 60 engines, providing 1,600 hp. These proved more successful than the Hercules III engines used in the Mk V, but high altitude flight provided problems of its own, as many of the liquids used in the aircraft froze in the extreme cold. Sixty four Mk VIs were produced, and it was intended to use them with pathfinder squadrons to mark targets for the main bomber force, but by the time the Mk VI was ready for service the Mosquito had appeared, and was very obviously better suited to the role. The surviving Mk VIs were scrapping in 1943.


The Mk VII was intended to be an improved version of the Mk II, using more powerful Merlin XX engines. One prototype was completed but the type was not adopted by the RAF, and the prototype was given to Rolls Royce.


Vickers Wellingtons of No.37 Squadron
Vickers Wellington GR Mk VIII Torpedo Bomber

The GR Mk VIII was a naval version of the Mk IC. It was produced in three distinct variants of its own.  Most numerous was the torpedo bomber version. 271 of these were produced, equipped with the ASV Mk II Stickleback air to surface radar. The torpedo bomber version was used in the Mediterranean, where it played an important role in cutting off German and Italian supplies to Rommel in the crucial period before El Alamein.

A smaller number of Mk VIIIs were produced for anti-submarine warfare. Fifty eight Mk VIIIs had the Leigh Light as well as their radar. This was designed to solve one problem when using radar against submarines – at ranges of under a mile radar contact was due to interference from the surface of the sea. A Leigh Light equipped anti-submarine warfare aircraft would use radar to discover the U-boat, and close to the limit of radar range, and then turn on the Leigh light for the final approach, by which time it would be too late for the U-boat to dive to safety. The first confirmed U-boat kill came on 5 July 1942 in the Bay of Biscay.

Finally, sixty-five Mk VIIIs were produced as normal bombers, making them similar to the standard Mk IC.


One Mk IA was converted to serve as a troop carrier and given the designation Mk IX.

Mk X

The Mk X was the last version of the Wellington to be designed as a strategic bomber. It was similar to the Mk III, but used the Hercules VI or XVI engine, providing 1,675 hp. The weight of the fuselage was reduced by the use of new light alloys in place of the steel used in earlier versions. The Mk X had a longer range than the Mk III, but a smaller bomb load, although at 4,000lbs this was still enough to carry the “blockbuster” bomb. The Mk X had a very short career as a front line bomber with Bomber Command in Britain – it first entered service in late 1942, equipped twelve squadrons by March 1943, and had been entirely replaced by the new four engined heavies by the end of 1943. It remained in use as a bomber in Italy and the Far East throughout 1944. In all 3,803 Mk Xs were produced, and some remained in use until the 1950s. The Mk X flew its last Bomber Command mission in October 1943, at the time as the Mk III.


Vickers Wellington in Italy, 1944
Vickers Wellington
in Italy, 1944

While the Mk X was the last version of the Wellington developed for Bomber Command, Coastal Command continued to develop the aircraft. The Mk XI was a torpedo bomber developed from the Mk X. It carried the Type 454 ASW Mk II Radar, but was otherwise similar to the Mk X. 180 GR Mk XI Wellingtons were built. The Mk XI appeared during 1943.


The Mk XII also appeared during 1943, and was also developed from the Mk X. It was equipped with the ASV Mk III radar. Unlike the Mk II, which used external aerials, this radar set was carried within a teardrop fairing attached to the nose of the Wellington. This meant that the forward turret had to be removed. Experience soon proved this to be a mistake, as U-Boats were increasingly heavily armed, and so a pair of flexibly mounted Browning machine guns were added to the Mk XII. Fifth eight Mk XIIs were produced.


The Mk XIII and Mk XIV were the ultimate maritime versions of the Wellington. Both used the 1,735 hp Hercules XVII engine, and were produced in similar numbers (844 Mk XIIIs and 841 Mk XIVs). The Mk XIII was a torpedo bomber. It used the ASV Mk II radar, and retained its forward turret.


Vickers Wellington Mk.XIV from the Left Vickers Wellington Mk.XIV from the Left

The Mk XIV was an anti-submarine aircraft. It carried the same ASV Mk III as the Mk XII, and also lacked the forward turret. The Mk XIV used the same Hercules XVII engine as the Mk XIII. The Mk XIV was heavily used to support the D-Day invasion.


The C Mk XV was a transport aircraft developed from the Mk 1A, and originally designated the C Mk IA. In this role the turrets were removed, and a new entrance door added to the side of the aircraft. An unknown number of Wellingtons were converted to the transport version to help solve a serious shortage of dedicated transport aircraft that lasted for much of the war.


The C Mk XVI was a transport aircraft developed from the Mk 1C. It was otherwise very similar to the Mk XV.


The Mk XVII was a trainer aircraft created by converting a Mk XI. Both turrets were removed and the nose turret replaced by an airborne interception radar set, used to train night fighter crews.


The Mk XVIII was a custom built trainer, designed to help train radio operators and navigators. Eighty Mk XVIIIs were built. A number of Mk Xs were also used as training aircraft after the war, under the designation T Mk 10.


The Mk XIX was a trainer produced by converting standard Mk Xs. It was used to train bomber crews.

Production Figures

Mk I












Mk V









1 (conversion)

Mk X











Unknown (converted from others)


Unknown (converted from others)


Converted trainer




Converted trainer



Performance Stats.






86ft 2in

86ft 2in

86ft 2in


64 ft 7in

64 ft 7in

64 ft 7in


Pegasus XVII

Bristol Hercules XI

Hercules VI of XVI


1,050 hp



Max Speed

235 mph

255 mph at 12,500 ft


Service Ceiling

18,000 ft

19,000 ft

22,000 ft


2,550 miles

1,540 with 4,000lb

2,085 miles


4,500 lb

4,500 lb

4,000 lb

Wellington in Action, Ron Mackay. A well illustrated guide to the development and service career of this classic British bomber. Mackay looks at the early development of the Wellington and the unusual geodetic frame that gave it great strength, the period when the Wellington was the mainstay of Bomber Command and the many uses found for the aircraft after it was replaced in the main bomber stream.
cover cover cover

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How to cite this article: Rickard, J (1 June 2007), Vickers Wellington Variants,

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