Editing Vickers Wellington (section)

==Design==
[[File:Wellington tail turret 1942 IWM CH 13880.jpg|thumb|upright=1|The tail turret of a Wellington, with gunner, in 1942]]
The Vickers Wellington was a twin-engined long-range [[medium bomber]], initially powered by a pair of [[Bristol Pegasus]] radial engines, which drove a pair of [[de Havilland Propellers|de Havilland]] [[Blade pitch|two-pitch]] propellers. Various engines and propeller combinations were used on variants of the aircraft, which included models of the [[Bristol Hercules]] and the [[Rolls-Royce Merlin]] engines.<ref name = "andrew 7"/> Recognisable characteristics of the Wellington include the high [[Aspect ratio (aeronautics)|aspect ratio]] of its [[Chord (aeronautics)#Tapered wing|tapered wing]], the depth of its fuselage and the use of a tall single [[vertical stabilizer|fin]] on its tail unit, which reportedly aided in recognition of the type.<ref name = "andrew 10"/>

The Wellington typically had a crew of five, the bomb-aimer being located in the aircraft's nose.<ref name = "andrew 7"/> The Wellington could be fitted with dual flight controls, and specialised dual-control conversion sets were developed for the purpose of performing training upon the type.<ref name = "andrew 7"/> The cockpit also contained provisions for [[Environmental control system (aircraft)|heating]] and [[de-ice|de-icing]] equipment, which was introduced on later models of the Wellington.<ref name = "andrew 7"/> The Wellington Mk I had a maximum offensive bomb load of {{convert|4,500|lb|abbr=on}}, more than one-fifth of the aircraft's {{convert|21,000|lb|abbr=on}} all-up weight.<ref name = "andrew 7"/> Additional munitions and an expanded bombing capacity were changes in many of the wartime variants of the Wellington, including the carrying of larger bombs.<ref name = "andrew 12 13"/>

[[File:Vickers Wellington - Royal Air Force Bomber Command, 1939-1941. CH478.jpg|thumb|upright=1|left|A crew member inside rear of Wellington fuselage]]
Defensive armament comprised the forward and tail turret gun positions, along with a retractable revolving ventral turret. Due to the high cruising speeds of the Wellington, it had been realised that fully enclosed turrets, as opposed to semi-enclosed or exposed turrets, would be necessary; the turrets were also power-operated to traverse with the speed and manoeuvrability necessary to keep up with the new generations of opposing fighter aircraft.<ref name = "andrew 4"/> The Vickers design put the gunner in a fixed seat behind the guns (a pair of [[.303 British|.303&nbsp;in (7.7&nbsp;mm)]] Browning machine guns.<ref name="andrew 7" /> ) which were mounted on a pillar with a [[Nash & Thompson]] control unit, and fired through a moving slot in the framed canopy. Although roomy, there were problems with malfunctions and poor gunnery and Vickers were given a directive by the Air Staff to replace them. At the same time a development contract was placed with Nash & Thompson for a turret that could be used for both front and rear positions. The resulting FN.5 was also used on [[Short Stirling]] and [[Avro Manchester]]<ref>{{cite book |last=Clarke |first=R. Wallace |title=British Aircraft Armament |date=1993 |publisher=Patrick Stephens |pages=94, 109}}</ref>

Due to the specialised nature of increasingly advanced turrets, these were treated as ancillary equipment, being designed and supplied independently and replacing Vickers' own turrets developed for the aircraft.<ref name="andrew 4" /> The Vickers-built ventral turret of the Mk I was replaced by a Nash & Thompson-built FN.25 counterpart as standard.<ref name="andrew 11" /> The squadrons were critical of the ventral turrets; when extended they slowed the aircraft by 10&nbsp;mph, the single narrow window pane limited visibility and sometimes froze in place and had to be jettisoned. The ventral turrets were not fitted after the first batch of Wellington IA<ref>Clarke 1993 pp. 126–127</ref>

[[File:Vickers wellington frame.jpg|thumb|upright|Vickers Wellington fuselage during restoration showing its geodetic airframe]]
A novelty of the Wellington was its [[Geodesic airframe|geodetic]] construction, devised by aircraft designer and inventor [[Barnes Wallis]]. The [[fuselage]] was built from 1,650 elements, consisting of [[duralumin]] [[I-beam|W-beams]] which formed into a metal framework. Wooden [[batten]]s were screwed to the beams and were covered with [[Irish linen]]; the linen, treated with layers of [[aircraft dope|dope]], formed the outer skin of the aircraft. The construction proved to be compatible with significant adaptations and alterations including greater all-up weight, larger bombs, tropicalisation and long-range fuel tanks.<ref name = "andrew 13"/>

The metal lattice gave the structure considerable strength, with any [[longeron|stringer]] able to support a portion of load from the opposite side of the aircraft. Damaged or destroyed beams on one side could still leave the aircraft structure viable; as a result, Wellingtons with huge areas of framework missing were often able to return when other types would not have survived, leading to stories of the aircraft's "invulnerability".<ref name = "andrew 5">Andrews 1967, p. 5.</ref> The effect was enhanced by the fabric skin occasionally burning off leaving the naked frames exposed. A further advantage of the geodetic construction of the wings was its enabling of a unique method for housing the fuel, with each wing containing three fuel tanks within the unobstructed space provided between the front and rear [[Spar (aeronautics)|spars]] outboard of the engines.<ref name = "andrew 7"/> A disadvantage of the geodetic fuselage structure was its insufficient lengthwise stiffness: when fitted with attachment for towing cargo gliders, its structure "gave" and stretched slightly.<ref>{{Cite web|url=https://www.bbc.co.uk/history/ww2peopleswar/stories/24/a4119824.shtml|title= WW2 People's War – The Horsa Glider|website=BBC}}</ref>