The English Electric Lightning is a British fighter aircraft that served as an interceptor during the 1960s, the 1970s and into the late 1980s. It remains the only UK-designed-and-built fighter capable of Mach 2. The Lightning was designed, developed, and manufactured by English Electric, which was later absorbed by the newly-formed British Aircraft Corporation. Later the type was marketed as the BAC Lightning. It was operated by the Royal Air Force (RAF), the Kuwait Air Force (KAF) and the Royal Saudi Air Force (RSAF).
A unique feature of the Lightning's design is the vertical, staggered configuration of its two Rolls-Royce Avonturbojet engines within the fuselage. The Lightning was initially designed and developed as an interceptor to defend the V bomber airfields[3] from attack by anticipated future nuclear-armed supersonic Soviet bombers such as what emerged as the Tupolev Tu-22, but it was subsequently also required to intercept other bomber aircraft such as the Tupolev Tu-16 and the Tupolev Tu-95.
The Lightning has exceptional rate of climb, ceiling, and speed; pilots have described flying it as "being saddled to a skyrocket".[1] This performance and the initially limited fuel supply meant that its missions are dictated to a high degree by its limited range.[4] Later developments provided greater range and speed along with aerial reconnaissance and ground-attack capability.
Following retirement by the RAF in the late 1980s, many of the remaining aircraft became museum exhibits. Until 2009, three Lightnings were kept flying at "Thunder City" in Cape Town, South Africa. In September 2008, the Institution of Mechanical Engineers conferred on the Lightning its "Engineering Heritage Award" at a ceremony at BAE Systems' site at Warton Aerodrome.[5]
Overwing fuel tank fittings were fitted to the F6 variant only and offered the aircraft extended range. The maximum speed of the aircraft was ultimately affected and limited the top speed to a reported 1000mph. [6]
Contents
The Lightning possessed a remarkable climb rate. It was famous for its ability to rapidly rotate from takeoff to climb almost vertically from the runway, though this did not yield the best time-to-altitude. The Lightning's trademark tail-stand manoeuvre exchanged airsp
The Lightning possessed a remarkable climb rate. It was famous for its ability to rapidly rotate from takeoff to climb almost vertically from the runway, though this did not yield the best time-to-altitude. The Lightning's trademark tail-stand manoeuvre exchanged airspeed for altitude; it could slow to near-stall speeds before commencing level flight. The Lightning's optimum climb profile required the use of afterburners during takeoff. Immediately after takeoff, the nose would be lowered for rapid acceleration to 430 knots (800 km/h) IAS before initiating a climb, stabilising at 450 knots (830 km/h). This would yield a constant climb rate of approximately 20,000 ft/min (100 m/s).[56][nb 4] Around 13,000 ft (4,000 m) the Lightning would reach Mach 0.87 (1,009 km/h) and maintain this speed until reaching the tropopause, 36,000 ft (11,000 m) on a standard day.[nb 5] If climbing further, pilots would accelerate to supersonic speed at the tropopause before resuming the climb.[35][56] A Lightning flying at optimum climb profile would reach 36,000 ft (11,000 m) in under three minutes.[56]
Fighter Command organised interception trials on Lockheed U-2As at heights of around 60,000–65,000 ft (18,000–20,000 m), which were temporarily based at RAF Upper Heyford to monitor Soviet nuclear tests.[75][76][77] Climb techniques and flight profiles were developed to put the Lightning into a suitable attack position. To avoid risking the U-2, the Lightning was not permitted any closer than 5,000 ft (1,500 m) and could not fly in front of the U-2. For the intercepts, four Lightning F1As conducted 18 solo sorties. The sorties proved that, under GCI, successful intercepts could be made at up to 65,000 ft (20,000 m). Due to sensitivity, details of these flights were deliberately avoided in the pilot log books.[78]
In 1984, during a NATO exercise, Flt Lt Mike Hale intercepted a U-2 at a height which they had previously considered safe (thought to be 66,000 feet (20,000 m)). Records show that Hale also climbed to 88,000 ft (27,000 m) in his Lightning F.3 XR749. This was not sustained level flight but a ballistic climb, in which the pilot takes the aircraft to top speed and then puts the aircraft into a climb, exchanging speed for altitude. Hale also participated in time-to-height and acceleration trials against Lockheed F-104 Starfighters from Aalborg. He reports that the Lightnings won all races easily with the exception of the low-level supersonic acceleration, which was a "dead heat".[79] Lightning pilot and Chief Examiner Brian Carroll reported taking a Lightning F.53 up to 87,300 feet (26,600 m) over Saudi Arabia at which
In 1984, during a NATO exercise, Flt Lt Mike Hale intercepted a U-2 at a height which they had previously considered safe (thought to be 66,000 feet (20,000 m)). Records show that Hale also climbed to 88,000 ft (27,000 m) in his Lightning F.3 XR749. This was not sustained level flight but a ballistic climb, in which the pilot takes the aircraft to top speed and then puts the aircraft into a climb, exchanging speed for altitude. Hale also participated in time-to-height and acceleration trials against Lockheed F-104 Starfighters from Aalborg. He reports that the Lightnings won all races easily with the exception of the low-level supersonic acceleration, which was a "dead heat".[79] Lightning pilot and Chief Examiner Brian Carroll reported taking a Lightning F.53 up to 87,300 feet (26,600 m) over Saudi Arabia at which level "Earth curvature was visible and the sky was quite dark", noting that control-wise "[it was] on a knife edge".[80]
Carroll compared the Lightning and the F-15C Eagle, having flown both aircraft, stating that: "Acceleration in both was impressive, you have all seen the Lightning leap away once brakes are released, the Eagle was almost as good, and climb speed was rapidly achieved. Takeoff roll is between 2,000 and 3,000 ft [610 and 910 m], depending upon military or maximum afterburner-powered takeoff. The Lightning was quicker off the ground, reaching 50 ft [15 m] height in a horizontal distance of 1,630 ft [500 m]". Chief test pilot for the Lightning Roland Beamont, who also flew most of the "Century Series" US aircraft, stated his opinion that nothing at that time had the inherent stability, control and docile handling characteristics of the Lightning throughout the full flight envelope. The turn performance and buffet boundaries of the Lightning were well in advance of anything known to him.[81]
Early Lightning models, the F.1, F.1A, and F.2, had a rated top speed of Mach 1.7 (1,815 km/h) at 36,000 feet (11,000 m) in an ICAO standard atmosphere, and 650 knots (1,200 km/h) IAS at lower altitudes.[33][82] Later models, the F.2A, F.3, F.3A, F.6, and F.53, had a rated top speed of Mach 2.0 (2,136 km/h) at 36,000 feet (11,000 m), and speeds up to 700 knots (1,300 km/h) indicated air speed for "operational necessity only".[34][35][37][83] A Lightning fitted with Avon 200-series engines, a ventral tank and two Firestreak missiles typically ran out of excess thrust at Mach 1.9 (2,328 km/h) on a Standard Day;[84] while a Lightning powered by the Avon 300-series engines, a ventral tank and two Red Top missiles ran out of excess thrust at Mach 2.0.[56] Directional stability decreased as speed increased, there were potentially hazardous consequences in the form of vertical fin failure if yaw was not correctly counteracted by rudder use.[nb 6] Imposed Mach limits during missile launches protected stability;[nb 7] later Lightning variants had a larger vertical fin, giving a greater stability margin at high speed.[86]
Supersonic speeds also threatened inlet stability. The inlet's central shock cone served as a compression surface, diverting air into the annular inlet. As the Lightning accelerated through Mach 1, the shock cone generated an oblique shock positioned forward of the intake lip. Known as a subcritical inlet cond
Supersonic speeds also threatened inlet stability. The inlet's central shock cone served as a compression surface, diverting air into the annular inlet. As the Lightning accelerated through Mach 1, the shock cone generated an oblique shock positioned forward of the intake lip. Known as a subcritical inlet condition, this was stable, but produced inefficient spillage drag. Around the Design Mach speed, the oblique shock was positioned just forward of the inlet lip and efficiently compressed the air without spillage. When travelling beyond the Design Mach, the oblique shock became supercritical, and supersonic airflow entered the inlet duct, which could only handle subsonic air. In this condition, the engine generated drastically less thrust and may result in surges or compressor stalls, these could cause flameouts or damage.
Thermal and structural limits were also present. Air is heated considerably when compressed by the passage of an aircraft at supersonic speeds. The airframe absorbs heat from the surrounding air, the inlet shock cone at the front of the aircraft becoming the hottest part. The shock cone was composed of fibreglass, necessary because the shock cone also served as a radar radome; a metal shock cone would have interfered with the AI 23's radar emissions. The shock cone was eventually weakened due to the fatigue caused by the thermal cycles involved in regularly performing high-speed flights. At 36,000 feet (11,000 m) and Mach 1.7 (1,815 km/h), the heating conditions on the shock cone were similar to those at sea level and 650 knots (1,200 km/h) indicated airspeed,[nb 8] but if the speed was increased to Mach 2.0 (2,136 km/h) at 36,000 feet (11,000 m), the shock cone was exposed to higher temperatures[nb 9] than those at Mach 1.7. The shock cone was strengthened on the later Lightning F.2A, F.3, F.6, and F.53 models, thus allowing routine operations at up to Mach 2.0.[87]
The small-fin variants could exceed Mach 1.7,[nb 10] but the stability limits and shock cone thermal/strength limits made such speeds risky. The large-fin variants, especially those equipped with Avon 300-series engines could safely reach Mach 2, and given the right atmospheric conditions, might even achieve a few more tenths of a Mach. All Lightning variants had the excess thrust to slightly exceed 700 knots (1,300 km/h) indicated airspeed under certain conditions,[56][84][89] and the service limit of 650 knots (1,200 km/h) was occasionally ignored. With the strengthened shock cone, the Lightning could safely approach its thrust limit, but fuel consumption at very high airspeeds was excessive and became a major limiting factor.[nb 11]
The Lightning was fully aerobatic and was capable of rates of roll far in excess of that which could be normally tolerated by a pilot.[90]
Operational history
The first aircraft to enter service with the RAF, three pre-production P.1Bs, arrived at RAF Coltishall in Norfolk on 23 December 1959, joining the Air Fighting Development Squadron (AFDS) of the Central Fighter Establishment, where they were used to clear the Lightning for entry into service.[91][92] The production Lightning F.1 entered service with the AFDS in May 1960, allowing the unit to take part in the air defence exercise "Yeoman" later that month. The Lightning F.1 entered frontline squadron service with 74 Squadron under the command of Squadron LeaderJohn "Johnny" Howe at Coltishall from 11 July 1960.[93]
The aircraft's radar and missiles proved to be effective and pilots reported that the Lightning was easy to fly. However, in the first few months of operation the aircraft's serviceability was extremely poor. This was due to the complexity of the aircraft systems and shortages of spares and ground support equipment. Even when the Lightning was not grounded by technical faults, the RAF initially struggled to get more than 20 flying hours per aircraft per month compared with the 40 flying hours that English Electric believed could be achieved with proper support.[91][94] In spite of these concerns, within six months of the Lightning entering service, 74 Squadron was able to achieve 100 flying hours per aircraft.[95]
In addition to its training and operational roles, 74 Squadron was appointed as the official Fighter Command aerobatic team for 1961, flying at air shows throughout the United Kingdom and Europe.[96] Deliveries of the slightly improved Lightning F.1A, with improved avionics and provision for an air-to-air refuelling probe, allowed two more squadrons, 56 and 111 Squadron, both based at RAF Wattisham to convert to the Lightning in 1960–1961.[91][94] In spite of these concerns, within six months of the Lightning entering service, 74 Squadron was able to achieve 100 flying hours per aircraft.[95]
In addition to its training and operational roles, 74 Squadron was appointed as the official Fighter Command aerobatic team for 1961, flying at air shows throughout the United Kingdom and Europe.[96] Deliveries of the slightly improved Lightning F.1A, with improved avionics and provision for an air-to-air refuelling probe, allowed two more squadrons, 56 and 111 Squadron, both based at RAF Wattisham to convert to the Lightning in 1960–1961.[91] The Lightning F.1 would only be ordered in limited numbers and serve for a short time; nonetheless, it was viewed as a significant step forwards in Britain's air defence capabilities. Following their replacement from frontline duties by the introduction of successively improved variants of the Lightning, the remaining F.1 aircraft were employed by the Lightning Conversion Squadron.[97]
An improved variant, the F.2 first flew on 11 July 1961[98] and entered service with 19 Squadron at the end of 1962 and 92 Squadron in early 1963. Conversion of these two squadrons was aided by the use of the two seat T.4 trainer, which entered service with the Lightning Conversion Squadron (later renamed 226 Operational Conversion Unit) in June 1962. While the OCU was the major user of the two seater, small numbers were also allocated to the front-line fighter squadrons.[99] More F.2s were produced than there were available squadron slots so later production aircraft were stored for years before being used operationally; some Lightning F.2s were converted to F.2a's. They had some of the improvements added to the F.6.[100]
The F.3, with more powerful engines and the new Red-Top missile (but no cannon) was expected to be the definitive Lightning, and at one time it was planned to equip ten squadrons, with the remaining two squadrons retaining the F.2.[101] On 16 June 1962, the F.3 flew for the first time.[102] It had a short operational life and was withdrawn from service early due to defence cutbacks and the introduction of the F.6, some of which were converted F.3s.[103]
The Lightning F.6 wa
The F.3, with more powerful engines and the new Red-Top missile (but no cannon) was expected to be the definitive Lightning, and at one time it was planned to equip ten squadrons, with the remaining two squadrons retaining the F.2.[101] On 16 June 1962, the F.3 flew for the first time.[102] It had a short operational life and was withdrawn from service early due to defence cutbacks and the introduction of the F.6, some of which were converted F.3s.[103]
The Lightning F.6 was a more capable and longer-range version of the F.3. It initially had no cannon, but installable gun packs were made available later.[104] A few F.3s were upgraded to F.6s. Author Kev Darling suggests that decreasing British overseas defence commitments had led to those aircraft instead being prematurely withdrawn.[103] The introduction of the F.3 and F.6 allowed the RAF to progressively reequip squadrons operating aircraft such as the Gloster Javelin and retire these types during the mid-1960s.[105]
A Lightning was tasked with shooting down a pilot-less Harrier over West Germany in 1972. The pilot had abandoned the Harrier which continued flying towards the East German border. It was shot down to avoid a diplomatic incident.[107] During British Airways trials in April 1985, Concorde was offered as a target to NATO fighters including F-15 Eagles, F-16 Fighting Falcons, F-14 Tomcats, Mirages, and F-104 Starfighters – but only Lightning XR749, flown by Mike Hale and described by him as "a very hot ship, even for a Lightning", managed to overtake Concorde on a stern conversion intercept.[79]
During the 1960s, as strategic awareness increased and a multitude of alternative fighter designs were developed by Warsaw Pact and NATO members, the Lightning's range and firepower shortcomings became increasingly apparent. The transfer of McDonnell Douglas F-4 Phantom IIs from Royal Navy service enabled these much longer-ranged aircraft to be added to the RAF's interceptor force alongside those withdrawn from Germany as they were replaced by SEPECAT Jaguars in the ground attack role.Harrier over West Germany in 1972. The pilot had abandoned the Harrier which continued flying towards the East German border. It was shot down to avoid a diplomatic incident.[107] During British Airways trials in April 1985, Concorde was offered as a target to NATO fighters including F-15 Eagles, F-16 Fighting Falcons, F-14 Tomcats, Mirages, and F-104 Starfighters – but only Lightning XR749, flown by Mike Hale and described by him as "a very hot ship, even for a Lightning", managed to overtake Concorde on a stern conversion intercept.[79]
Durin
During the 1960s, as strategic awareness increased and a multitude of alternative fighter designs were developed by Warsaw Pact and NATO members, the Lightning's range and firepower shortcomings became increasingly apparent. The transfer of McDonnell Douglas F-4 Phantom IIs from Royal Navy service enabled these much longer-ranged aircraft to be added to the RAF's interceptor force alongside those withdrawn from Germany as they were replaced by SEPECAT Jaguars in the ground attack role.[108] The Lightning's direct replacement was the Tornado F3s, an interceptor variant of the Panavia Tornado. The Tornado featured several advantages over the Lightning, including a far larger weapons load and considerably more advanced avionics.[109] Lightnings were slowly phased out of service between 1974 and 1988. In their final years the airframes required considerable maintenance to keep them airworthy due to the sheer number of accumulated flight hours.
On 21 December 1965, Saudi Arabia, keen to improve its air defences owing to the Saudi involvement in the North Yemen Civil War and the resultant air incursions into Saudi airspace by Egyptian forces supporting the Yemeni Republicans, placed a series of orders with Britain and the US to build a new integrated air defence system. BAC received orders for 34 multirole single-seat Lightning F.53s that could still retain very high performance and reasonable endurance, and six two-seat T.55 trainers, together with 25 BAC Strikemaster trainers, while the contract also included new radar systems, American HAWK surface-to-air missiles and training and support services.[44][112]
To provide an urgent counter to air incursions, with Saudi towns near the border being bombed by Egyptian aircraft, an additional interim contract, called "Magic Carpet", was placed in March 1966 for the supply of six ex-RAF Lightnings (four F.2s and two T.4 trainers, redesignated F.52 and T.54 respectively[nb 12]), six Hawker Hunters, two air defence radars and a number of Thunderbird surface-to-air missiles.[44][112] The "Magic Carpet" Lightnings were delivered to Saudi Arabia in July 1966. One lost in an accident was later replaced (May 1967). The Lightnings and Hunters, flown by mercenary pilots, were deployed to Khamis Mushait airfield near the Yemeni border, resulting in the curtailing of operations by the Egyptian Air Force over the Yemeni-Saudi border.[40][112]
Kuwait ordered 14 Lightnings in December 1966, comprising 12 F.53Ks and two T.55Ks. The first Kuwait aircraft, a T.55K first flew on 24 May 1968 and deliveries to Kuwait started in December 1968.[114] The Kuwaitis somewhat overestimated their ability to maintain such a complex aircraft, not adopting the extensive support from BAC and Airwork Services that the Saudis used to keep their Lightnings operational, so serviceability was poor.[115]
Kuwait Air Force Lightning F.53 in 1969 with both underwing and overwing SNEB pods
Saudi Arabia officially received F.53 Lightnings in December 1967, although they were kept at Warton while trials and development continued and the first Saudi Lightnings to leave Warton were four T.55s delivered in early 1968 to the Royal Air Force 226 Operational Conversion Unit at RAF Coltishall, the four T.55s were used to train Saudi aircrew for the next 18 months.[116] The new-build Lightnings were delivered under Operation "Magic Palm" between July 1968 and August 1969. Two Lightnings, a F.53 and a T.55 were destroyed in accidents prior to delivery, and were
To provide an urgent counter to air incursions, with Saudi towns near the border being bombed by Egyptian aircraft, an additional interim contract, called "Magic Carpet", was placed in March 1966 for the supply of six ex-RAF Lightnings (four F.2s and two T.4 trainers, redesignated F.52 and T.54 respectively[nb 12]), six Hawker Hunters, two air defence radars and a number of Thunderbird surface-to-air missiles.[44][112] The "Magic Carpet" Lightnings were delivered to Saudi Arabia in July 1966. One lost in an accident was later replaced (May 1967). The Lightnings and Hunters, flown by mercenary pilots, were deployed to Khamis Mushait airfield near the Yemeni border, resulting in the curtailing of operations by the Egyptian Air Force over the Yemeni-Saudi border.[40][112]
Kuwait ordered 14 Lightnings in December 1966, comprising 12 F.53Ks and two T.55Ks. The first Kuwait aircraft, a T.55K first flew on 24 May 1968 and deliveries to Kuwait started in December 1968.[114] The Kuwaitis somewhat overestimated their ability to maintain such a complex aircraft, not adopting the extensive support from BAC and Airwork Services that the Saudis used to keep their Lightnings operational, so serviceability was poor.[115]
Saudi Arabia officially received F.53 Lightnings in December 1967, although they were kept at Warton while trials and development continued and the first Saudi Lightnings to leave Warton were four T.55s delivered in early 1968 to the Royal Air Force 226 Operational Conversion Unit at RAF Coltishall, the four T.55s were used to train Saudi aircrew for the next 18 months.[116] The new-build Lightnings were delivered under Operation "Magic Palm" between July 1968 and August 1969. Two Lightnings, a F.53 and a T.55 were destroyed in accidents prior to delivery, and were replaced by two additional aircraft, the last of which was delivered in June 1972.[113][117] The multirole F.53s served in the ground-attack and reconnaissance roles as well as an air defence fighter, with Lightnings of No 6 Squadron RSAF carrying out ground-attack missions using rockets and bombs during a border dispute with South Yemen between December 1969 and May 1970. One F.53 (53–697) was shot down by Yemeni ground fire on 3 May 1970 during a reconnaissance mission, with the pilot ejecting successfully and being rescued by Saudi forces.[117][118] Saudi Arabia received Northrop F-5E fighters from 1971, which resulted in the Lightnings relinquishing the ground-attack mission, concentrating on air defence, and to a lesser extent, reconnaissance.[119]
Kuwait's Lightnings did not have a long service career. After an unsuccessful attempt by the regime to sell them to Egypt in 1973, the last Lightnings were replaced with Dassault Mirage F1s in 1977.[120] The remaining aircraft were stored at Kuwait International Airport, many were destroyed during the Invasion of Kuwait by Iraq (August 1990).[121]
Until 1982, Saudi Arabia's Lightnings were mainly operated by 2 and 6 Squadron RSAF (although a few were also used by 13 Squadron RSAF), but when 6 Squadron re-equipped with the F-15 Eagle then all the remaining aircraft were operated by 2 Squadron at Tabuk.[122]Dassault Mirage F1s in 1977.[120] The remaining aircraft were stored at Kuwait International Airport, many were destroyed during the Invasion of Kuwait by Iraq (August 1990).[121]
Until 1982, Saudi Arabia's Lightnings were mainly operated by 2 and 6 Squadron RSAF (although a few were also used by 13 Squadron RSAF), but when 6 Squadron re-equipped with the F-15 Eagle then all the remaining aircraft were operated by 2 Squadron at Tabuk.[122][123] In 1985 as part of the agreement to sell the Panavia Tornado to the RSAF, the 22 flyable Lightnings were traded in to British Aerospace and returned to Warton in January 1986.[122] While BAe offered the ex-Saudi Lightnings to Austria and Nigeria, no sales were made, and the aircraft were eventually disposed of to museums.[117][124]
A Lightning T.5, XS451 (civil registration ZU-BEX) belonging to Thunder City crashed after developing mechanical problems during its display at the biennial South African Air Force Overberg Airshow held at AFB Overberg near Bredasdorp on 14 November 2009.[128] The Silver Falcons, the South African Air Force's official aerobatic team, flew a missing man formation after it was announced that the pilot had died in the crash.[129]
The Anglo-American Lightning Organisation, a group based at Stennis Airport, Kiln, Mississippi, is returning EE Lightning T.5, XS422 to airworthy status. As of November 2013 the aircraft was capable of running its engines. The aircraft was formerly with the Empire Test Pilots' School (ETPS) at Boscombe Down in Wiltshire, UK.[132]
Surviving aircraft
English Electric Lightning (XS929), displayed as a gate guardian at RAF Akrotiri in Cyprus
British journalist and TV presenter Jeremy Clarkson borrowed a Lightning (serialXM172) which was temporarily placed in his garden and documented on Clarkson's 2001 television series Speed.[176]
In a 2010 episode of the BBC TV programme Wonders of the Solar System, Professor Brian Cox had a South African Lightning (XS451) climb to a very high altitude, allowing Cox to show the curvature of the Earth and the relative dimensions of the atmosphere.[177] This aircraft crashed in November 2009, a month after the episode was filmed, when it developed mechanical problems during an air show at South Africa's AFB Overberg.[128]
^The SB5 was allocated serial number WG768 on 27 July 1950.
^The ventral cannon installation was designed for the export aircraft but was later adopted by the RAF for the F.6 and F.2A.[40]
^All fuel tank volumes are listed in Imperial gallons
^The Lightning would increase forward velocity during the climb, the angle of the climb lessening from about 27 deg to 19 deg at 13,000 ft (4,000 m).
^The true airspeed associated with a given indicated airspeed increases with altitude. Below the tropopause, the true airspeed associated with a given Mach number decreases with altitude. The Lightning's Air Data System automatically corrected for errors in position and speed. Following correction, 450 KIAS was equal to Mach 0.87 (1,009 km/h) at 13,000 ft (4,000 m).[56]
^Along with directional stability, rudder effectiveness decreased at higher Mach numbers; timely and larger deflections of the rudder were required to counter any yaw, especially under increased g-loading.[33][35] Two Lightning prototypes, XL628 and XM966, were lost to vertical fin failure during roll testing at high Mach numbers.[85]
^Firestreak firing limits were Mach 1.3 with the small fin, Mach 1.7 with the large fin. Red Top limit was Mach 1.8.[33][35]
^On a standard day, the temperature of the air at the tip of the shock cone (stagnation temperature) was 156 °F (69 °C) at Mach 1.7 (1,815 km/h) and 36,000 feet (11,000 m). At sea level and 650 knots (1,200 km/h) indicated airspeed, this temperature was 151 °F (66 °C).
^At Mach 2.0, the stagnation temperature was 242 °F (117 °C).
^Roland Beamont took the Lightning P.1B XA847, a prototype of the F.1, to Mach 2.0. Prior testing had determined that the aircraft had the excess thrust to achieve this speed, given the right atmospheric conditions of a high tropopause and lower-than-standard temperature. The test flight was to check for inlet stability and monitor temperatures at higher Mach. The aircraft was equipped with a temperature probe to monitor the stagnation temperature, up to a never-exceed temperature of 115 °C. On 28 November 1958, the weather availed a high tropopause and a substandard −67 °C at 40,000 feet (12,000 m). This was sufficient to allow Beamont to achieve Mach 2.0 (2,125 km/h) in a British aircraft for the first time, reached only 7 minutes after takeoff, but the record dash left the Lightning critically short of fuel.[88] The Machmeter fitted to service Lightning F.1s and F.1Bs had a scale that stopped at Mach 1.8 – with a redline at 1.7.[33]
^At 30,000 feet (9,100 m), a Lightning F.6 required approximately 1 minute and 1,250 pounds (570 kg) of fuel to accelerate from 650 to 675 knots (1,204 to 1,250 km/h) indicated airspeed.[56]
^A single F.1 was supplied as a ground instructional airframe.[113]
^The value for "empty weight" is zero fuel weight, which includes equipped pilot, Red Top missiles, cannon and ammunition. The weight without these items is 27,759 lb.[56]
^Above 45,000 lb, the mainwheel tyres were single use.[35]
^An F.6 equipped with Red Top missiles can reach Mach 2.0 on an ICAO standard day at 36,000 ft. True performance was not in pilot notes due to sensitivity during the Cold War. The F.6 is noted to reach Mach 2.27 at 40,000 ft [174][verification needed]
^This is based on a maximum-range subsonic intercept radius of 370 nm (425 mi, 625 km). An F.6 equipped with Red Top missiles can climb to 36,000 ft and cruise at Mach 0.87 to a loiter or intercept area 370 nmi (690 km) distant. It then has 15 minutes on station to complete the intercept or identification task before returning to base. The afterburners are not used during this profile, and the total mission time is 112 min.[56]
^An F.6 equipped with Red Top missiles can climb to 36,000 ft, accelerate to Mach 1.8, and intercept a target at 135 nmi (250 km) only 10.7 min after brake release. A 2g level turn allows a second attack from the rear-quarter 1.6 min later. Following a best-range cruise and descent, the Lightning can enter the landing pattern with 800 lb of fuel remaining with a total mission time of 35 min.[56]
^From Part 3, Page 11 in Operating Data Manual; at standard atmosphere, full fuel, and 2 Red Top missiles, from sea level, adhering to aforementioned 450 kn (830 km/h) IAS -> M0.87 climb profile. When clean, this climb rate increases to 22,000 ft/min (110 m/s).
^From brake release. Identical page, configuration, and profile as loaded sustained climb rate above. Time following initial acceleration (0.7 min) to climb speed is 2.1 min. When clean, these times shorten to 2.7 min from brake release, or 2.0 min after acceleration.
^Wing loading can range between 86–67 lb/ft2 over the duration of a mission, depending on fuel load.
^Note: at the time, the V bombers carried Britain's nuclear deterrent and thus were the likely first-strike targets of a Soviet air attack on the UK. In addition to the Lightning, last line-of-defence for the airfields was to be what became the Bristol Bloodhound guided missile.
^Note: the original specification only called for a 150-mile radius of action from the V bomber bases the aircraft was defending. Roland Beamont later called for the Lightning's fuel capacity to be greatly increased, which it was.
British journalist and TV presenter Jeremy Clarkson borrowed a Lightning (serialXM172) which was temporarily placed in his garden and documented on Clarkson's 2001 television series Speed.[176]
In a 2010 episode of the BBC TV programme Wonders of the Solar System, Professor Brian Cox had a South African Lightning (XS451) climb to a very high altitude, allowing Cox to show the curvature of the Earth and the relative dimensions of the atmosphere.[177] This aircraft crashed in November 2009, a m
^The SB5 was allocated serial number WG768 on 27 July 1950.
^The ventral cannon installation was designed for the export aircraft but was later adopted by the RAF for the F.6 and F.2A.[40]
^All fuel tank volumes are listed in Imperial gallons
^The Lightning would increase forward velocity during the climb, the angle of the climb lessening from about 27 deg to 19 deg at 13,000 ft (4,000 m).
^The true airspeed associated with a given indicated airspeed increases with altitude. Below the tropopause, the true airspeed associated with a given Mach number decreases with altitude. The Lightning's Air Data System automatically corrected for errors in position and speed. Following correction, 450 KIAS was equal to Mach 0.87 (1,009 km/h) at 13,000 ft (4,000 m).[56]
^Along with directional stability, rudder effectiveness decreased at higher Mach numbers; timely and larger deflections of the rudder were required to counter any yaw, especially under increased g-loading.[33][35] Two Lightning prototypes, XL628 and XM966, were lost to vertical fin failure during roll testing at high Mach numbers.[85]