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Monday, May 18, 2015

English Electric Lightning

From Wikipedia, the free encyclopedia

Lightning
Lightning.inflight.arp.750pix.jpg
Lightning F.3 in 1964
Role Interceptor
National origin United Kingdom
Manufacturer English Electric
British Aircraft Corporation
First flight 4 August 1954 (P.1A)
4 April 1957[1]
Introduction December 1959
Retired 1988 (RAF)
Primary users Royal Air Force
Kuwait Air Force
Royal Saudi Air Force
Number built 337 (including prototypes)[1]
The English Electric Lightning is a supersonic fighter aircraft of the Cold War era. It was designed, developed, and manufactured by English Electric, which was subsequently absorbed by the newly formed British Aircraft Corporation. It was then marketed as the BAC Lightning. The Lightning was the only all-British Mach 2 fighter aircraft and was the first aircraft capable of supercruise[citation needed]. The Lightning was used by the Royal Air Force (RAF) and the Royal Saudi Air Force (RSAF). Although it was the RAF's primary interceptor for more than two decades it was never required to attack another aircraft.
The Lightning is powered by two Rolls-Royce Avon turbojet engines in a unique staggered stacked installation in the fuselage. The Lightning was developed to intercept increasingly capable bomber aircraft (Tupolev Tu-16, Tupolev Tu-22, Tupolev Tu-95), and thus has exceptional rate of climb, ceiling, and speed; pilots have described flying it as "being saddled to a skyrocket".[1] This performance made the Lightning a 'fuel critical' aircraft meaning that its missions are dictated to a high degree by its limited range. Later developments provided greater range and speed along with aerial reconnaissance and ground-attack capability.
Following retirement in the late 1980s, many of the remaining aircraft became museum exhibits and, until 2010, 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.[2]

Contents

Development

Origins

The two P.1 research aircraft
 
The specification for the aircraft followed the cancellation of the Air Ministry's 1942 E.24/43 supersonic research aircraft specification which had resulted in the Miles M.52 programme.[3] W.E.W "Teddy" Petter, formerly chief designer at Westland Aircraft, was a keen early proponent of Britain's need to develop a supersonic fighter aircraft, and proved his point when trials between an RAF Gloster Meteor F.4 and an English Electric Canberra demonstrated that Britain's current air defenses would be entirely unable to intercept a bomber travelling at an altitude of 50,000 feet (15,000 m) and at a speed of Mach 0.85 (903 km/h). In 1947, Petter approached the Ministry of Supply with his proposal, in response Specification ER.103 was issued for a single research aircraft, which was to be capable of flight at Mach 1.5 (1,593 km/h) and 50,000 feet (15,000 m).[4]
It was apparent that the aircraft's wings would need to be highly swept in order for an aircraft to attain such a high speed, English Electric decided to adopt an angle of 60 degrees. In order to test the design of both the wing and the tailplane and to assess handling, Short Brothers were issued a contract to produce the Short SB5, a low-speed research aircraft. The SB5 was developed so that different wing sweep angles could be assumed by the single aircraft, an assortment of tailplanes and wings were supplied and could be installed in order for their flight performance to be evaluated. The Royal Aircraft Establishment was notably skeptical of Petter's swept wing concepts however, following the first flight of the SB.5 on 2 December 1952, the trials performed demonstrated the choice of a tailplane and a 60 degree wingsweep proved the design principles to be effective.[5]
Aerodynamic data produced from the SB.5 flights and wind tunnel testing helped shape the emerging ER103 design. In 1949, the Ministry of Supply had issued Specification F23/49, which expanded upon the scope of ER103 to include fighter-level maneuvering. On 1 April 1950, English Electric received a contract for two flying airframes, as well as one static airframe, designated P.1.. Following the resignation of Petter, F. W. Page took over as design team leader for the P.1.[6] From 1953 onwards, the first three prototype aircraft were hand-built at Salmesbury, these aircraft had been assigned the aircraft serials WG760, WG763, and WG765. In May 1954, WG760 and its support equipment were moved to RAF Boscombe Down for pre-flight ground taxi trials; on the morning of 4 August 1954, WG760, piloted by Roland Beamont, flew for the first time from Boscombe Down.[7] One week later, WG760 officially achieved supersonic flight for the first time, having exceeded the speed of sound during its third flight.[8] During its first flight, WG760 had unknowingly exceeded Mach 1 (1,225 km/h), due to position error the Mach meter only showed a maximum of Mach 0.95 (1,164 km/h), the occurrence was noticed during flight data analysis a few days later.[9]
While WG760 had proven the P.1 design to be viable, it was limited to Mach 1.51 (1,850 km/h) due to directional stability limits. On 9 June 1952, it had been decided that there would be a second phase of prototypes built to develop the aircraft towards achieving Mach 2.0 (2,450 km/h), these were designated P.1B while the initial three prototypes were retroactively reclassified as P.1A.[10] The P.1B featured extensive alterations to the forward fuselage and refinement to the inlet cone that regulated airflow into the engine inlet.[8] In May 1956, the P.1 received the Lightning name, which was said to have been partially selected to reflect the aircraft's supersonic capabilities.[11] On 25 November 1958, the P.1B became the first British aircraft to fly at Mach 2.[1] The prototypes were powered by un-reheated Armstrong Siddeley Sapphire turbojets as the selected Rolls-Royce Avon engines, which would power subsequent production aircraft, had fallen behind schedule due to their own development issues.[12] Due to the limited internal space of the fuselage the fuel capacity was relatively small, giving the prototypes an extremely limited endurance, and the narrow tyres housed in the thin wings would rapidly wear out.[13] Outwardly, the prototypes looked very much like the production series, they were distinguished by the rounded-triangular intakes, short fins and lacked operational equipment.[1]

Production

The first operational Lightning, designated the F.1, was designed as a point defence interceptor to defend mainland Britain from bomber attack. To best perform this intercept mission, emphasis was placed on rate-of-climb, acceleration, and speed, rather than range and combat endurance. It was equipped with two 30 mm ADEN cannon in front of the cockpit windscreen and an interchangeable fuselage weapons pack containing either an additional two ADEN cannon, 48 two-inch (51 mm) unguided air-to-air rockets, or two de Havilland Firestreak air-to-air missiles;[13] a heavy loadout optimized for damaging large aircraft, missile guidance and ranging, as well as search and track functions, mainly were provided via the Ferranti AI.23 onboard radar.[14]
The next two Lightning variants, the F.1A and F.2, were steady but relatively minor refinements of the design; the next variant, the F.3, was a major departure. The F.3 had higher thrust Rolls-Royce Avon 301R engines, a larger squared-off fin and strengthened inlet cone allowing a service clearance to Mach 2.0 (2,450 km/h) (the F.1, F.1A and F.2 were limited to Mach 1.7 (2,083 km/h)).[15] The A.I.23B radar and Red Top missile offered a forward hemisphere attack capability and deletion of the nose cannon. The new engines and fin made the F.3 the highest performance Lightning yet, but with an even higher fuel consumption and resulting shorter range. The next variant, the F.6, was already in development, but there was a need for an interim solution to partially address the F.3’s shortcomings, the F.3A.
Lightning F.3 in flight, 1983
 
The F.3A introduced two improvements: a new, non-jettisonable, 610-imperial-gallon (2,800 L) ventral fuel tank,[16] and a new, kinked, conically cambered wing leading edge, incorporating a slightly larger leading edge fuel tank, raising the total usable internal fuel to 716 imperial gallons (3,260 L). The conically cambered wing noticeably improved manoeuvrability, especially at higher altitudes, and the ventral tank nearly doubled available fuel. The increased fuel was very welcome, but the lack of cannon armament was felt to be a deficiency. It was thought that cannons were desirable to fire warning shots in the intercept mission.[17]
The F.6 was the ultimate Lightning version to see British service. Originally, it was nearly identical to the F.3A with the exception that it could carry two 260-imperial-gallon (1,200 L) ferry tanks on pylons over the wings. These tanks were jettisonable in an emergency, and gave the F.6 a substantially improved deployment capability. There remained one glaring shortcoming: the lack of cannon. This was finally rectified in the form of a modified ventral tank with two ADEN cannons mounted in the front. The addition of the cannons and their ammunition decreased the tank's fuel capacity from 610 to 535 imperial gallons (2,770 to 2,430 L), but the cannon made the F.6 a “real fighter” again.[16]
The final British Lightning was the F.2A. This was an F.2 upgraded with the cambered wing, the squared fin, and the 610 imperial gallons (2,800 L) ventral. The F.2A retained the A.I.23 and Firestreak missile, the nose cannon, and the earlier Avon 211R engines.[18] Although the F.2A lacked the thrust of the later Lightnings, it had the longest tactical range of all Lightning variants, and was used for low-altitude interception over West Germany.

Export and further developments

The F.53, otherwise known as the Export Lightning, developed as a private venture by BAC; while the Lightning had originated as an interception aircraft, this version was to have a multirole capability for quickly interchanging between interception, reconnaissance, and ground-attack duties.[19] The F.53 was based on the F.6 airframe and avionics, including the large ventral fuel tank, cambered wing and overwing pylons for drop tanks of the F.6, but incorporated an additional pair of hardpoints under the outer wing. These hardpoints could be fitted with pylons for air-to-ground weaponry, including two 1,000 lb (450 kg) bombs or four SNEB rocket pods each carrying 18 68 mm rockets. A gun pack carrying two ADEN cannons and 120 rounds each could replace the forward part of the ventral fuel tank.[20][nb 1] Alternative, interchangeable packs in the forward fuselage carried two Firestreak missiles, two Red Top missiles, twin retractable launchers for 44× 2-inch (50 mm) rockets, or a reconnaissance pod fitted with five 70 mm Type 360 Vinten cameras.[22]
BAC also proposed clearing the overwing hardpoints for carriage of weapons as well as drop tanks, with additional Matra JL-100 combined rocket and fuel pods (each containing 18 SNEB 68 mm (2.7 in) rockets and 227 litres (50 imp gal) of fuel) or 1,000 pounds (450 kg) bombs being possible options. This could give a maximum ground attack weapons load for a developed export Lightning of six 1,000 pounds (450 kg) bombs or 44 × 2 in (51 mm) rockets and 144 × 68 mm rockets.[23][24] The T.55 was the export two-seat variant; unlike the RAF two-seaters, the T.55 was equipped for combat duties. The T.55 had a very similar fuselage to the T.5, while also using the wing and large ventral tank of the F.6.[25] The Export Lightning had all of the capability of the RAF's own Lightnings: exceptional climb rate, agile manoeuvering, and a hard-hitting punch. Unfortunately, the Export Lightning also retained the difficulty of maintenance, and serviceability rates suffered. The F.53 was generally well regarded by its pilots, and its adaptation to multiple roles showed the skill of its designers.[26]
In 1963, BAC Warton was working on the preliminary design of a two-seat Lightning development with a variable-geometry wing, based on the Lightning T.5. In addition to the variable-sweep wing, which was to sweepback between 25 degrees and 60 degrees, the proposed design featured an extended ventral pack for greater fuel capacity, an enlarged dorsal fin fairing, an arrestor hook, and a revised inward-retracting undercarriage. The aircraft was designed to be compatible with the Royal Navy's existing aircraft carriers carrier-based aircraft, the VG Lightning concept was revised into a land-based interceptor intended for the RAF the following year.[27] Various alternative engines to the Avon were suggested, such as the newer Rolls-Royce Spey engine; it is also likely that the VG Lightning would have adopted a solid nose (by moving the air inlet to the sides or to upper fuselage) to install a larger, more capable radar.[28]

Design

Overview

The Lightning had several unique and distinctive design features, the principal of these being the twin engine arrangement, a notched delta wing, and a low-mounted tailplane. The vertically stacked, longitudinally staggered engines was the solution devised by Petter to the conflicting requirements of minimizing frontal area, providing undisturbed engine airflow across a wide speed range, and packaging two engines to provide sufficient thrust to meet performance goals. The unusual over/under configuration allowed for the thrust of two engines, with the drag equivalent to only 1.5 engines mounted side-by-side, a reduction in drag of 25% over more conventional twin engine installations.[29] The engines were fed by a single nose inlet (with inlet cone), with the flow split vertically aft of the cockpit, and the nozzles tightly stacked, effectively tucking one engine behind the cockpit. The result was a low frontal area, an efficient inlet, and excellent single-engine handling with no problems of asymmetrical thrust. But, due to the proximity of the engines, a catastrophic failure of one engine is likely also to damage the other engine. If desired, an engine could be shut down in flight and the remaining engine run in a more efficient power regime for increased range or endurance;[30][31] although this was rarely done operationally due to the risk of loss of hydraulic power in the event of engine failure.[32]
Lightning F.6 XS904 after a high speed taxi run at 2012 Cold War Jets Day, Bruntingthorpe
 
Production aircraft were powered by various models of the Rolls-Royce Avon engine. This power-plant was initially rated as capable of generating 11,250 lbf (50.0 kN) of dry thrust, but when employing the four-stage afterburner this increased to a maximum thrust of 14,430 lbf (64.2 kN). Later models of the Avon would feature, in addition to increased thrust, a full-variable reheat arrangement.[33] In flight, the engines would often reach 600 °C in temperature; a special heat-reflecting paint containing gold was used to protect the aircraft's structure. Under optimum conditions, a well-equipped maintenance facility would take four hours to perform an engine change so specialised ground test rigs were developed to speed up maintenance and remove the need to perform a full ground run of the engine after some maintenance tasks.[34] The stacked engine configuration complicated maintenance work, and the leakage of fluid from the upper engine was a recurring fire hazard.[13] The fire risk was reduced, but not eliminated, following remedial work during development.[35]
The fuselage was tightly packed, leaving no room for fuel tankage or main landing gear. While the notched delta wing lacked the volume of a standard delta wing, each wing contained a fairly conventional three-section main fuel tank and leading-edge tank, holding 312 imp gal (1,420 L);[nb 2] the wing flaps also each contained a 33 imp gal (150 L) fuel tank and an additional 5 imp gal (23 L) was contained in a fuel recuperator, bringing the aircraft's total internal fuel capacity to 700 imp gal (3,200 L). The main landing gear was sandwiched outboard of the main tanks and aft of the leading edge tanks, with the flap fuel tanks behind.[14] The long main gear legs retracted towards the wingtip, necessitating an exceptionally thin main tyre inflated to the high pressure of 330–350 psi (23–24 bar; 2,300–2,400 kPa).[36]
The Lightning featured a conformal ventral store to house either a fuel tank or a rocket engine. The rocket engine, a Napier Double Scorpion motor, also contained a reserve of 200 imp gal (910 L) of high-test peroxide (HTP) to drive the rocket’s turbopump and act as an oxidizer; fuel would have been drawn from the aircraft internal tankage. The rocket engine was intended at an early stage in the Lightning’s development to boost performance should non-afterburning (reheated) engines be fitted; the subsequent basic performance with reheated Avons was deemed sufficient and the rocket engine option was cancelled in 1958.[13] The ventral store was routinely used as an extra fuel tank, holding 247 imp gal (1,120 L) of usable fuel.[14] On later variants of the Lightning, a ventral weapons pack could be installed to equip the aircraft alternatively with different armaments, including missiles, rockets, and cannons.[37]

Avionics and systems

Underside of a Lightning F.3 with undercarriage deployed, 23 June 1979
 
Early versions of the Lightning were equipped with the Ferranti-developed AI.23 monopulse radar, which was contained right at the front of the fuselage within an inlet cone at the centre of the engine intake. Radar information was displayed on an early head-up display and managed by onboard computers.[38] The AI.23, an immediate predecessor of the AI.24 Foxhunter, supported several operational modes, which included autonomous search, automatic target tracking, and ranging for all weapons; the pilot attack sight provided gyroscopically-derived lead angle and backup stadiametric ranging for gun firing.[14] The radar and gunsight were collectively designated the AIRPASS: Airborne Interception Radar and Pilot Attack Sight System. The radar would be successively upgraded with the introduction of more capable Lightning variants, such as to provide guidance for the Red Top missile.[39]
The cockpit of the Lightning was designed to meet the RAF's OR946 specification for tactical air navigation technology, and thus featured an integrated flight instrument display arrangement, an Elliott Bros (London) Ltd[40] auto-pilot, a master reference gyroscopic reader, an auto-attack system, and an instrument landing system.[41] Despite initial scepticism of the aircraft's centralised detection and warning system, the system proved its merits during the development program and was subsequently redeveloped for greater reliability.[42] Communications included UHF and VHF radios and a datalink.[43] Unlike the previous generation of aircraft which used gaseous oxygen for lifesupport, the Lightning would employ liquid oxygen-based apparatus for the pilot; cockpit pressurisation and conditioning would be maintained through tappings from the engine compressors.[44]
Electricity was provided via a bleed air-driven turbine housed in the rear fuselage, which in turn drove an AC alternator and DC generator; the approach was considered unusual at the time due to most aircraft using driveshaft-driven generators/alternators for electrical energy. A 28V DC battery provided emergency backup power. Aviation author Kev Darling stated of the Lightning: "Never before had a fighter been so dependent upon electronics".[45] Each engine was equipped with a pair of hydraulic pumps, one of which would provide pressure for the flight-control systems and the other, pressure for the undercarriage, flaps, and airbrakes; switchable hydraulic circuits were used for redundancy in the event of a leak or other failure. A combination of Dunlop Maxaret[32] anti-skid brakes on the main wheels and an Irvin Air Chute[46] braking parachute slowed the aircraft during landing; a tailhook was also fitted.[47] Accumulators on the wheel brakes performed as backups to the hydraulics, providing minimal braking.[48] A stopped engine could also be 'windmilled' to generate hydraulic power during flight.[40]
Towards the end of its service, the Lightning was increasingly outclassed by newer fighters, mainly due to the avionics and armaments being obsolete. The radar had a limited range and no track while scanning capability, and it could detect targets only in a fairly narrow (40 degree) arc. While an automatic collision course attack system was developed and successfully demonstrated by English Electric, it was not adopted due to cost concerns.[49][50] Plans were mooted to supplement or replace the obsolete Red Top and Firestreak missiles with modern AIM-9L Sidewinder missiles to help rectify some of the obsolescence, but these ambitions were never realised due to lack of funding.[49][51] An alternative to the modernization of existing aircraft would have been the development of more advanced variants; a proposed Variable-sweep wing Lightning would have likely involved the adoption of a new powerplant and radar and was believed by BAC to significantly increase performance, but ultimately was not pursued.[28]

Climb

Main article: Rate of climb
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).[36][nb 3] 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 4] If climbing further, pilots would accelerate to supersonic speed at the tropopause before resuming the climb.[16][36] A Lightning flying at optimum climb profile would reach 36,000 ft (11,000 m) in under three minutes.[36]
Lightning in flight at the Ysterplaat Airshow, Cape Town, September 2006
 
The official ceiling of the Lightning was kept secret; low security RAF documents would often state in excess of 60,000 ft (18,000 m). In September 1962, 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.[52][53][54] 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 eighteen 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.[55]
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".[56] 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".[57]
Brian 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.[58]

Speed

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.[14][59] 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”.[15][16][18][60] 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;[61] 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.[36] 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 5] Imposed Mach limits during missile launches protected stability;[nb 6] later Lightning variants had a larger vertical fin, giving a greater stability margin at high speed.[26]
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[clarification needed]. Around the Design Mach speed, the oblique shock was positioned just in front of the inlet lip and efficiently compressed the air without spillage. When travelling beyond the Design Mach, the oblique shock would become supercritical, supersonic airflow entering 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 interfere with the AI 23’s radar emissions. The shock cone would be 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 would be similar to those at Sea Level and 650 knots (1,200 km/h) indicated airspeed,[nb 7] but if the speed was increased to Mach 2.0 (2,136 km/h) at 36,000 feet (11,000 m), the shock cone would be exposed to higher temperatures[nb 8] 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.[26]
The small-fin variants could exceed Mach 1.7,[nb 9] 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,[36][61][64] 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 10]

Other flying

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.[65]

Operational history

Royal Air Force

A Royal Air Force Lightning F.1A at Yeovilton, 8 September 1973
 
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.[66][67] 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 Leader John "Johnny" Howe at Coltishall from 11 July 1960.[68]
While performance achieved was excellent, both the aircraft's radar and missiles had proved to be effective and pilots were reporting that the Lightning was easy to fly, in the first few months of operation, the aircraft's serviceability was extremely poor. This was due to both the complexity of the Lightning's 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.[66][69] In spite of these issues, within six months of the Lightning having entered service, 74 Squadron was able to achieve 100 flying hours per aircraft.[70]
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.[71] Deliveries of the slightly improved Lightning F.1A, with improved avionics and provision for an air-to-air refuelling probe, allowed two more squadrons, 54 and 111 Squadron, both based at RAF Wattisham to convert to the Lightning in 1960–1961.[66] The Lightning F.1 would only be ordered in limited numbers and serve for a short time, regardless 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.[72]

Nine Lightning F.1s of No.74 Squadron display at the 1961 SBAC show, Farnborough
 
An improved variant, the F.2 first flew on 11 July 1961[73] 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.[74] More F.2s were produced than there were available squadron slots, thus later production aircraft were typically stored for years before being used operationally; a number of Lightning F.2s would be undergo conversion to become F.2A aircraft, which featured some of the improvements made upon the more advanced F.6 model.[75]
The "next generation" Lightning F.3, with more powerful engines and the ability to use the new Red-Top missile (although at the cost of losing the little-used 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.[76] On 16 June 1962, the F.3 was first flown.[77] The F.3 variant would have a short operational life and be withdrawn from service early due to the combined factors of defence cutbacks and the introduction of the more-capable Lightning F.6 model, of which a small number of F.3s were converted into prior to delivery.[78]
The Lightning F.6 was a far-more capable and longer-range version of the F.3; it initially lacked cannon, but in subsequent years installable gun packs were made available.[79] While a handful of F.3s were upgraded to the F.6 standard, the majority Lightning F.3s were not rebuilt to the F.6 standards, author Kev Darling suggests that decreasing British overseas defence commitments had led to those aircraft instead being prematurely withdrawn.[78] The introduction of the F.6, along with the preceding F.3, allowed the RAF to progressively reequip squadrons operating other interceptor aircraft such as the Gloster Javelin and retire these types during the mid-1960s.[80]
"Suddenly the telephone would ring and it would be one of the radar controllers from around the UK ordering you to scramble immediately. And so you would run to the aeroplane, jump in. They [Soviet aircraft] were just monitoring, listening, recording everything that went on. So you would get up alongside and normally they would wave, quite often there would be a little white face at every window. They knew we were there just to watch them. One I intercepted when he violated the airspace and I was trying to get him to land but it was scary. He just wanted to get out of there, he was out of Dodge as fast as he could go, he didn't want to mix it with me."
RAF Lightning pilot John Ward[81]
The English Electric Lightning is credited with a single kill in 1972, a British Harrier pilot had ejected from his aircraft following apparent engine failure; however, the pilotless aircraft unintentionally maintained flight and was heading towards the East German border, to avoid a diplomatic incident the Harrier was shot down.[82] 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.[56]
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.[83] 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.[84] 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.
Fighter Command/Strike Command
The main Lightning role was the air defence of the United Kingdom and was operated at first as part of Fighter Command and then from 1968 with No. 11 Group of Strike Command. At the formation of Strike Command nine Lightning squadrons were operational in the United Kingdom.[85]
Far East Air Force
In 1967 No. 74 Squadron was moved to RAF Tengah, Singapore to take over the air defence role from the Gloster Javelin equipped 60 Squadron.[86] The squadron was disbanded in 1971 following the withdrawal of British forces from Singapore.
Near East Air Force
The Royal Air Force had detached Lightnings to RAF Akrotiri, Cyprus to support the Near East Air Force and in 1967 No. 56 Squadron RAF moved from RAF Wattisham with the Lightning F.3 to provide a permanent air defence force, it converted to the F.6 in 1971 and returned to the United Kingdom in 1975.
Royal Air Force Germany
In the early 1960s No. 19 Squadron and No. 92 Squadron with Lightning F.2s, moved from RAF Leconfield to RAF Gütersloh in West Germany as part of Royal Air Force Germany and operated in the low-level air defence role until disbanded in 1977 when the role was taken over by the Phantom FGR2.

Middle East

Saudi Air Force T.55 at RAF Coltishall, in use by No. 226 Operational Conversion Unit for training Saudi pilots, 1968
 
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 United States 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.[25][87]
In order to provide an urgent counter to the air incursions, with Saudi towns close to 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 11]), six Hawker Hunters, two air defence radars and a number of Thunderbird surface-to-air missiles.[25][87] The "Magic Carpet" Lightnings were delivered to Saudi Arabia in July 1966, with an additional F.52 being delivered in May 1967 to replace a Lightning lost in an accident. 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.[21][87]
Although the first F.53s had been handed over to the RSAF in December 1967, 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.[89] 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.[88][90]

Kuwait Air Force Lightning F.53 in 1969. Note both underwing and overwing SNEB pods
 
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.[90][91] 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.[92]
Up to 1982, the 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.[93][94] 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.[93] While BAe offered the ex-Saudi Lightnings to Austria and Nigeria, no sales were made, and the aircraft were eventually disposed of to museums.[90][95]
Kuwait also 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.[96] 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.[97] The Kuwaiti Lightnings did not have a long service career; after unsuccessfully trying to sell them to Egypt in 1973, Kuwait replaced its last Lightnings with Dassault Mirage F1s in 1977.[98] The remaining aircraft were stored at Kuwait International Airport, many were subsequently destroyed during the Invasion of Kuwait by Iraq in August 1990.[99]

Variants

Lightning T.4 at Farnborough Airshow, England, in 1964
 
 
A USAF Sikorsky HH-53C helicopter of the 67th Aerospace Rescue and Recovery Squadron lifts a Lightning at RAF Woodbridge, Suffolk, 18 December 1987
 
The "Sea Lightning" concept
English Electric P.1A
Single-seat supersonic research aircraft, two prototypes built and one static test airframe.
English Electric P.1B
Single-seat operational prototypes to meet Specification F23/49, three prototypes built, further 20 development aircraft ordered in February 1954. Type was officially named 'Lightning' in October 1958.
Lightning F.1
Development batch aircraft, single-seat fighters delivered from 1959, a total of 19 built (and one static test airframe). Nose-mounted twin 30 mm ADEN cannon, two Firestreak missiles, VHF Radio and Ferranti AI-23 "AIRPASS" radar.
Lightning F.1A
Single-seat fighter, delivered in 1961. Featured Avon 210R engines, an inflight refuelling probe and UHF Radio; a total of 28 built.
Lightning F.2
Single-seat fighter (an improved variant of the F.1), delivered in 1962. A total of 44 built with 31 later modified to F.2A standard, five later modified to F.52 for export to Saudi Arabia.
Lightning F.2A
Single-seat fighter (F.2s upgraded to near F.6 standard); featuring Avon 211R engines, retained ADEN cannon and Firestreak (replaceable Firestreak pack swappable with ADEN Cannon Pack for a total of four ADEN Cannon), arrestor hook and enlarged Ventral Tank for two hours flight endurance. A total of 31 converted from F.2.
Lightning F.3
Single-seat fighter with upgraded AI-23B radar, Avon 301R engines, new Red Top missiles, enlarged and clipped tailfin due to aerodynamics of carriage of Red Top, and deletion of ADEN cannon. A total of 70 built (at least nine were converted to F.6 standard).
Lightning F.3A
Single-seat fighter with extended range of 800 miles due to large ventral tank and new cambered wings. A total of 16 built, known also as an F.3 Interim version or F.6 Interim Version, 15 later modified to F.6 standard.
Lightning T.4
Two-seat side-by-side training version, based on the F.1A; two prototypes and 20 production built, two aircraft later converted to T.5 prototypes, two aircraft later converted to T.54.
Lightning T.5
Two-seat side-by-side training version, based on the F.3; 22 production aircraft built. One former RAF aircraft later converted to T.55 for Saudi Arabia.
Lightning F.6
Single-seat fighter (an improved longer-range variant of the F.3). It featured new wings with better efficiency and subsonic performance, overwing fuel tanks and a larger ventral fuel tank, reintroduction of 30 mm cannon (initially no cannon but later in the forward part of the ventral pack rather than in the nose), use of Red Top missiles. A total of 39 built (also nine converted from F.3 and 15 from F.3A).
Lightning F.7
Proposed single-seat interceptor featuring variable geometry wings, extended fuselage, relocated undercarriage, underwing hardpoints, cheek-mounted intakes, new radar and use of the Sparrow/Skyflash AAMs. Never built.[100]
Lightning F.52
Slightly modified ex-RAF F.2 single-seat fighters for export to Saudi Arabia (five converted).
Lightning F.53
Export version of the F.6 with pylons for bombs or unguided rocket pods, 44 × 2 in (50 mm), total of 46 built and one converted from F.6 (12 F.53Ks for the Kuwaiti Air Force, 34 F.53s for the Royal Saudi Arabian Air Force, one aircraft crashed before delivery).
Lightning T.54
Ex-RAF T.4 two-seat trainers supplied to Saudi Arabia (two converted).
Lightning T.55
Two-seat side-by-side training aircraft (export version of the T.5), eight built (six T.55s for the Royal Saudi Arabian Air Force, two T.55Ks for the Kuwaiti Air Force and one converted from T.5 that crashed before delivery).
Sea Lightning FAW.1
Proposed two-seat Royal Navy Fleet Air Arm carrier capable variant with variable-geometry wing; not built.[28]

Specifications (Lightning F.6)

BAC Lightning F Mk.6 silhouette no insignia.svg
External images
Cockpit of a Lightning F.53
Typical ejection seat of a Lightning T.4/5
Display of weapon load-out of a Lightning
Multiple Lightnings lined up on the ground
Data from Pilots Notes and Operating Data Manual for Lightning F.6 (unless otherwise noted)[16][36]
General characteristics
Performance
Armament
  • Guns: 2× 30 mm (1.18 in) ADEN cannon
  • Hardpoints: 2× under-fuselage for mounting air-to-air missiles, 2x overwing pylon stations for 260 gal ferry tanks  and provisions to carry combinations of:
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