Editing Avro Vulcan (section)

==Design==
[[File:Avro Vulcan XH558 Duxford Airshow 2012 (7977149648).jpg|thumb|Avro Vulcan XH558 at [[Imperial War Museum Duxford#Air shows and flying|Duxford Airshow]] 2012 ]]
[[File:Bomb bay of a Vulcan bomber (34010875545).jpg|thumb|Bomb bay]]

===Overview===
Despite its radical and unusual shape, the airframe was built along traditional lines. Except for the most highly stressed parts, the whole structure was manufactured from standard grades of light alloy. The airframe was broken down into a number of major assemblies: The centre section, a rectangular box containing the bomb bay and engine bays bounded by the front and rear [[Spar (aviation)|spars]] and the wing transport joints; the intakes and centre [[fuselage]]; the front fuselage, incorporating the [[Cabin pressurization|pressure cabin]]; the nose; the outer wings; the leading edges; the wing trailing edge and rear end of the fuselage; and a single swept tail fin with a single rudder was on the trailing edge.<ref>Gunston, W. T. [http://www.flightglobal.com/pdfarchive/view/1957/1957%20-%201836.html "Building the Vulcan."] ''Flight'', 13 December 1957, p. 926.</ref>

A five-man crew was accommodated within the pressure cabin on two levels; the first pilot and co-pilot sitting on [[Martin-Baker]] 3K (3KS on the B.2) [[ejection seat]]s whilst on the lower level the [[Bombardier (aircrew)|navigator radar]], [[Navigator|navigator plotter]], and air electronics officer (AEO) sat facing rearwards and would abandon the aircraft via the entrance door.<ref name="ReferenceA">''Pilot's Notes'' pt. 1, leading particulars.</ref><ref>''Aircrew Manual'' pt. 1, ch. 2, para. 2.</ref> The original B35/46 specification sought a [[Escape crew capsule|jettisonable crew compartment]], but this requirement was removed in a subsequent amendment; the rear crew's escape system was often an issue of controversy, such as when a practical refit scheme was rejected.<ref name='wynn97'>Wynn 1997, p. 50.</ref><ref name='laming64'>Laming 2002, p. 64.</ref> A rudimentary sixth seat forward of the navigator radar was provided for an additional crew member;<ref>''Pilot's Notes'' pt. 1, introduction, para 2.</ref> the B.2 had an additional seventh seat opposite the sixth seat and forward of the AEO. The visual [[Bombardier (air force)|bomb-aimer's]] compartment could be fitted with a [[Mark XIV bomb sight|T4 (Blue Devil)]] [[bombsight]],<ref name='PB&E102'>Price, Blackman and Edmonson 2010, p. 102.</ref> in many B.2s, this space housed a vertically mounted [[Vinten]] F95 Mk.10 camera for assessing simulated low-level bombing runs.<ref name='brookes65'>Brookes and Davey 2009, p. 65.</ref>

Fuel was carried in 14 bag tanks, four in the centre fuselage above and to the rear of the nosewheel bay, and five in each outer wing. The tanks were split into four groups of almost equal capacity, each normally feeding its respective engine, though cross-feeding was possible. The [[Center of mass|centre of gravity]] was automatically maintained by electric timers, which sequenced the booster pumps on the tanks.<ref name="ReferenceA"/><ref>''Aircrew Manual'' pt. 1, ch. 8, paras. 1, 2, 48.</ref> B.2 aircraft could be fitted with one or two additional fuel tanks in the bomb bay.<ref>''Aircrew Manual'' pt. 1, ch. 8, paras. 3, 12.</ref>

Despite being designed before a low [[radar cross-section]]  and other [[Stealth technology|stealth]] factors were ever a consideration,<ref name="newscientist82">{{cite magazine|magazine=New Scientist|last=Sweetman|first=Bill|title=The Bomber that radar cannot see|url=https://books.google.com/books?id=HVJyHCXAOtsC&pg=PA566|date=4 March 1982|publisher=Reed Business Information|page=566}}{{Dead link|date=November 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> an RAE technical note of 1957 stated that of all the aircraft so far studied, the Vulcan appeared by far the simplest radar-echoing object, due to its shape; only one or two components contributed significantly to the echo at any aspect, compared with three or more on most other types.<ref>Dawson 1957, p. 3.</ref>{{refn|Writing for the American Institute of Aeronautics and Astronautics, J. Seddon and E. L. Goldsmith noted that "Due to its all-wing shape, small vertical fin, and buried engines, at some angles [the Avro Vulcan] was nearly invisible to radar".<ref>Seddon and Goldsmith 1999, p. 343.</ref> While writing about radar systems, authors Simon Kingsley and Shaun Quegan singled out the Vulcan's shape as reducing the echo.<ref>Kingsley and Quegan 1999, p. 293.</ref> While aviation author Doug Richardson has credited the Vulcan as having been difficult to acquire on radar, he went on to state that this was unlikely to have conferred a great military advantage.<ref>Richardson 2001, p. 56.</ref> In contrast, [[electronic warfare]] author and ex-Vulcan AEO Dr Alfred Price maintains "the Vulcan [...] possessed a large radar signature."<ref name='PB&E113'>Price, Blackman and Edmonson 2010, p. 113.</ref>|group=N}}

===Colour schemes===
[[File:Aerial Vulcan.JPEG|thumb|Aerial view of a Vulcan B.2 in late RAF markings on static display at [[RAF Mildenhall]], 1984]]
The two prototype Vulcans were finished in gloss white. Early Vulcan B.1s left the factory in a natural metal finish; the front half of the nose [[radome]] was painted black, the rear half painted silver. Front-line Vulcan B.1s had a finish of [[anti-flash white]] and [[Royal Air Force roundels|RAF "type D" roundels]]. Front-line Vulcan B.1As and B.2s were similar, but with pale roundels.<ref name="brookes33-35">Brookes and Davey 2009, pp. 33–35.</ref>

With the adoption of low-level attack profiles in the mid-1960s, B.1As and B.2s were given a glossy sea grey medium and dark green disruptive pattern camouflage on the upper surfaces, white undersurfaces, and "type D" roundels. (The last 13 Vulcan B.2s, XM645 onwards, were delivered thus from the factory<ref name="bulman43">Bulman 2001, p. 43.</ref>). In the mid-1970s, Vulcan B.2s received a similar scheme with matte camouflage, light aircraft grey undersides, and "low-visibility" roundels. B.2(MRR)s received a similar scheme in gloss; and the front halves of the radomes were no longer painted black. Beginning in 1979, 10 Vulcans received a wrap-around camouflage of dark sea grey and dark green<ref name="brookes36-41">Brookes and Davey 2009, pp. 36–41.</ref><ref name="bulman170">Bulman 2001, p. 170.</ref> because, during [[Red Flag (United States Air Force)|Red Flag]] exercises in the US, defending [[Surface-to-air missile|SAM]] forces had found that the grey-painted undersides of the Vulcan became much more visible against the ground at high angles of bank.<ref name="Buttler p. 72" />
[[File:Avro_Vulcan_Flight_Deck.jpg|thumb|Avro Vulcan rear crew positions]]

===Avionics===
The original Vulcan B.1 radio fit was: two 10-channel [[Very high frequency|VHF]] transmitter/receivers (TR-1985/TR-1986) and an STR-18, 24-channel [[High frequency|HF]] transmitter-receiver (R4187/T4188).<ref name='Wynn137'>Wynn 1997, p. 137.</ref> The Vulcan B.1A also featured a [[Ultra high frequency|UHF]] transmitter-receiver (ARC-52).<ref name="PilotNotes" /> The initial B.2 radio fit was similar to the B.1A<ref name='PB&E112'>Price, Blackman and Edmonson 2010, p. 112.</ref> though it was ultimately fitted with the ARC-52, a V/UHF transmitter/receiver (PTR-175), and a [[single-sideband modulation]] [[High frequency|HF]] transmitter-receiver ([[Rockwell Collins|Collins]] 618T).<ref>''Aircrew Manual'' pt. 1, ch. 14, paras. 1–12.</ref>

The navigation and bombing system  comprised an [[H2S radar|H2S Mk9 radar]] and a navigation bombing computer Mk1.<ref name='Wynn137'/> Other navigation aids included a [[Marconi Company|Marconi]] radio compass ([[Radio direction finder#Automatic direction finder (ADF)|ADF]]), [[GEE (navigation)|GEE Mk3]], [[Green Satin radar|Green Satin]] [[Doppler radar]] to determine the [[groundspeed]] and [[Wind triangle|drift angle]], [[Radio altimeter|radio and radar altimeters]], and an [[instrument landing system]].<ref name='Wynn137'/> [[TACAN]] replaced GEE in the B.1A<ref>''Pilot's Notes'' pt. 1, ch. 16, para. 11.</ref> and B.2 in 1964. [[Decca Radar|Decca]] Doppler 72 replaced Green Satin in the B.2 around 1969<ref name='PB&E102/3'>Price, Blackman and Edmonson 2010, pp. 102, 103.</ref> A continuous display of the aircraft's position was maintained by a ground position indicator.<ref name='PB&E102/3'/>

Vulcan B.2s were eventually fitted with the free-running [[Gyroscopes|dual-gyroscopic]] heading reference system (HRS) Mk.2, based upon the [[Inertial navigation system|inertial platform]] of the Blue Steel missile, which had been integrated into the system when the missile had been carried.<ref name='PB&E102/3'/> With the HRS a navigator's heading unit was provided, which enabled the navigator plotter to adjust the aircraft heading, through the autopilot, by as little as 0.1 degrees. The B.2 (MRR) was additionally fitted with the [[LORAN]] C navigation system.<ref name="Brookes83"/>

The original ECM fit of the B.1A and B.2 was one Green Palm voice communications jammer; two Blue Diver metric jammers; three [[Red Shrimp]] S-band jammers; a Blue Saga [[Radar warning receiver|passive warning receiver]] with four aerials; a [[Red Steer]] [[tail warning radar]]; and [[Chaff (countermeasure)|chaff]] dispensers.<ref name='Wynn321'>Wynn 1997, p. 321.</ref> The bulk of the equipment was carried in a large, extended tail cone, and a flat ECM aerial counterpoise plate was mounted between the starboard tailpipes.<ref name='Wynn151'>Wynn 1997, p. 151.</ref>{{refn|Some B.2 aircraft armed with Blue Steel had an additional aerial plate fitted between the port tailpipes as the Blue Steel fin, in the lowered position, blanked signals from the starboard side.<ref name='bulman153'>Bulman 2001, p. 153.</ref>|group=N}} Later equipment on the B.2 included: an [[L band]] jammer (replacing a Red Shrimp); the ARI 18146 X-band jammer;<ref name='PB&E106'>Price, Blackman and Edmonson 2010, p. 106.</ref> replacing the Green Palm; the improved Red Steer Mk.2; [[Flare (countermeasure)|infra-red decoys]] (flares); and the ARI 18228 PWR with its aerials that gave a squared top to the fin.<ref name='PB&E112'/><ref name='brookes57'>Brookes and Davey 2009, p. 57.</ref>

===Controls===
[[File:Vulcan B1 XA890 1955.jpg|thumb|Vulcan B.1 XA890 in early silver scheme landing at Farnborough in September 1955 after [[Roly Falk]]'s "aerobatic" display: Note the lower starboard airbrakes, inner and outer. The lower outer airbrakes were later deleted.]]

The aircraft was controlled by a fighter-type control stick and rudder bar, which operated the powered flying controls, which each had a single electrohydraulic-powered flying control unit, except the rudder, which had two, one running as a back-up. Artificial feel and auto stabilisation in the form of pitch and yaw dampers were provided, as well as an auto Mach trimmer.<ref>''Aircrew Manual'' pt. 1, ch. 7, paras. 1, 7, 10, 24, 48.</ref>

The flight instruments in the B.1 were traditional and included ''G4B'' compasses;<ref>''Pilot's Notes'' pt.1, ch. 16, para. 1</ref> Mk.4 artificial horizons;<ref>''Pilot's Notes'' pt.1, ch. 20, para. 3b</ref> and zero reader flight display instruments.<ref>''Pilot's Notes'' pt.1, ch. 16, para. 3b</ref> The B.1 had a [[GE Aviation Systems|Smiths]] Mk10 autopilot.<ref>''Pilot's Notes'' pt. 1, ch. 10.</ref> In the B.2, these features were incorporated into the Smiths Military Flight System (MFS), the pilots' components being: two beam compasses; two director-horizons; and an Mk.10A or Mk.10B [[autopilot]].<ref>''Aircrew Manual'' pt.1, ch. 12, para. 1.</ref> From 1966, B.2s were fitted with the ''ARI 5959''  TFR, built by [[General Dynamics]],<ref>[http://www.nationalarchives.gov.uk/catalogue/search.asp "National Archive file AVIA 2347."] ''National Archives.'' Retrieved: 11 September 2012.</ref> its commands being fed into the director-horizons.<ref>''Aircrew Manual'' pt. 1, ch. 15, p. 5.</ref>

The B.1 had four [[Elevator (aircraft)|elevators]] (inboard) and four [[aileron]]s (outboard).<ref>''Pilot's Notes'' pt. 1, ch. 10, para. 1(a).</ref> In the B.2, these were replaced by eight [[elevon]]s.<ref>''Aircrew Manual'' pt. 1, ch. 7, para. 7.</ref> The Vulcan was also fitted with six electrically operated three-position (retracted, medium drag, high drag) [[Air brake (aircraft)|airbrakes]], four in the upper centre section and two in the lower.<ref>''Aircrew Manual'' pt. 1, ch. 7, para 70.</ref> Originally, four lower airbrakes were used, but the outboard two were deleted before the aircraft entered service.<ref name='darling1999'>Darling 1999, p. 19.</ref> A brake parachute was installed inside the tail cone.<ref>''Aircrew Manual'' pt. 1, ch. 7, para. 77.</ref>

===Electrical and hydraulic systems===
The main electrical system on the B.1/B.1A was 112 V [[Direct current|DC]] supplied by four 22.5[[Watt#Kilowatt|kW]] engine-driven [[starter-generators]]. Backup power was provided by four 24 V 40 [[Ampere hour|Ah]] batteries connected in series providing 96 V. Secondary electrical systems were 28 V DC, [[Single-phase electric power|single-phase]] 115 V [[Alternating current|AC]] at 1600&nbsp;Hz, and [[Three-phase electric power|three-phase]] 115 V AC at 400&nbsp;Hz, driven by [[transformer]]s and [[Inverter (electrical)|inverters]] from the main system. The 28 V DC system was backed up by a single 24 V battery.<ref>''Pilot's Notes'', ch. 7.</ref>

For greater efficiency and higher reliability,<ref name='blackman100101'>Blackman 2007, pp. 100, 101.</ref> the main system on the B.2 was changed to three-phase 200 V AC at 400&nbsp;Hz supplied by four 40 [[Volt-ampere|kVA]] engine-driven [[Constant Speed Drive|constant-speed]] [[alternator]]s. Engine starting was then by air-starters supplied from a [[Turbomeca Palouste|Palouste]] compressor on the ground. Standby supplies in the event of a main AC failure were provided by two primary systems: A [[ram air turbine]]  driving a 17 kVA alternator was stowed in the underside of the port wing and could operate from high altitudes down to {{convert|20000|ft|m|abbr=on}}. In addition an [[Auxiliary power unit|airborne auxiliary power plant]],<ref name='ACMch4'/> a [[Rover Company|Rover]]<ref name="laming p62"/> gas turbine driving a 40kVA alternator was fitted within the starboard wing, and could be started once the aircraft was below an altitude of {{convert|30000|ft|m|abbr=on}}. Secondary electrical supplies were by transformer-rectifier units for 28 V DC and rotary frequency converters for the 115 V 1600&nbsp;Hz single-phase supplies.<ref name='ACMch4'>''Aircrew Manual'', ch. 4.</ref>

The change to an AC system was a significant improvement. Each PFCU had a hydraulic pump that was driven by an electric motor, in modern terminology, this is an [[electro-hydraulic actuator]].<ref>''Aircrew Manual'', ch. 7.</ref> Because no manual reversion existed, a total electrical failure would result in a loss of control. The standby batteries on the B.1 were designed to give enough power for 20 minutes of flying time, but this proved to be optimistic and two aircraft, XA891 and XA908, crashed as a result.<ref name="lamingp60"/>

The main hydraulic system provided pressure for undercarriage raising and lowering and bogie trim; nosewheel centring and steering; wheel brakes (fitted with [[Maxaret]]s); bomb doors opening and closing; and (B.2 only) AAPP air scoop lowering. Hydraulic pressure was provided by three hydraulic pumps fitted to Nos. 1, 2 and 3 engines. An electrically operated [[Pump|hydraulic power pack]] (EHPP) could be used to operate the bomb doors and recharge the [[Hydraulic accumulator#Compressed gas (or gas-charged) closed accumulator|brake accumulators]]. A compressed air (later nitrogen) system was provided for emergency undercarriage lowering.<ref>''Aircrew Manual'' pt. 1, ch. 10, paras. 1–3, 48.</ref>

===Engine===
{{main|Rolls-Royce Olympus}}
[[File:Royal Air Force Museum Hendon (14195378374).jpg|thumb|Air intake integrated in the wing, for the Olympus jet engines]]

The [[Rolls-Royce Olympus]], originally known as the "Bristol BE.10 Olympus",<ref>Baxter 1990, p. 18.</ref>{{refn|Bristol Aero Engines merged with [[Armstrong Siddeley]] in 1959 to form [[Bristol Siddeley]], which in turn was taken over by [[Rolls-Royce Limited|Rolls-Royce]] in 1966.<ref>Baxter 1990, p. 11.</ref>|group=N}} is a two-spool, [[axial-flow]] [[turbojet]] that powered the Vulcan. Each Vulcan had four engines buried in the wings, positioned in pairs close to the fuselage. The engine's design began in 1947, intended to power the [[Bristol Aeroplane Company]]'s own rival design to the Vulcan.<ref>Baxter 1990, p. 13.</ref>

[[File:Bristol Olympus 101 gas flow diagram.jpg|thumb|Gas-flow diagram of an Olympus Mk 101 engine]]

As the prototype Vulcan VX770 was ready for flight prior to the Olympus being available, it first flew using [[Rolls-Royce Avon]] RA.3 engines of {{convert|6500|lbf|kN|abbr=on}} thrust. These were quickly replaced by [[Armstrong Siddeley Sapphire]] ASSa.6 engines of {{convert|7500|lbf|kN|abbr=on}} thrust.<ref>Laming 2002, pp. 45, 46.</ref> VX770 later became a flying test bed for the [[Rolls-Royce Conway]].<ref>Laming 2002, p. 108.</ref> The second prototype VX777 first flew with Olympus 100s of {{convert|10000|lbf|kN|abbr=on}} thrust. It was subsequently re-engined with Olympus 101 engines.<ref>Laming 2002, p. 47.</ref> When VX777 flew with a Phase 2C (B.2) wing in 1957, it was fitted with Olympus 102 engines of {{convert|12000|lbf|kN|abbr=on}} thrust.<ref>Laming 2002, p. 63.</ref>

Early B.1s were equipped with the Olympus 101. Later aircraft were delivered with Olympus 102s. All Olympus 102s became the Olympus 104 on overhaul and ultimately {{convert|13500|lbf|kN|abbr=on}} thrust on uprating.<ref>Baxter 1990, pp. 44–46.</ref> The first B.2 flew with the second-generation Olympus 200,<ref>Baxter 1990, p. 50.</ref> design of which began in 1952.<ref>[http://www.flightglobal.com/pdfarchive/view/1957/1957%20-%200198.html?tracked=1 "16,000 lb Thrust."] ''Flight,'' 15 February 1957, p. 200.</ref> Subsequent B.2s were engined with either the uprated Olympus 201 or the Olympus 301. The Olympus 201 was designated 202 on being fitted with a rapid air starter.<ref>Baxter 1990, pp. 50–64.</ref> The engine would later be developed into a [[reheat]]ed (afterburning) powerplant for the cancelled TSR-2 strike/reconnaissance aircraft and the [[supersonic transport|supersonic passenger transport]] [[Concorde]].<ref name="Buttler p. 72">Buttler 2007, p. 72.</ref>

Around 90% power, the engines in the Vulcan would emit a distinctive "howl"-like noise<ref>[http://www.vulcantothesky.org/news/526/82/We-all-love-the-howl.html "We all love the howl"] {{Webarchive|url=https://web.archive.org/web/20140111044750/http://www.vulcantothesky.org/news/526/82/We-all-love-the-howl.html |date=11 January 2014 }} ''Vulcan To The Sky Trust'', 13 December 2013.</ref>  due to the air intake arrangement, which became an attraction at public airshows.<ref>[http://www.bournemouthecho.co.uk/news/4823500.Will__howl__of_the_Vulcan_bomber_be_heard_over_Bournemouth_again_/ "Will 'howl' of the Vulcan bomber be heard over Bournemouth again?"] The Daily Echo, 30 December 2009.</ref><ref>[https://www.youtube.com/watch?v=H_ARSE8jEHQ "Vulcan XH558 Awesome Howl Sounds"] ''YouTube'', 28 October 2012.</ref>