Gloster Meteor developments - Meteor F.4, FR.5, T.7

The Meteor III was a substantial improvement over the Meteor I, but the basic design still had not reached its full potential. Wind-tunnel and flight tests demonstrated that the short nacelles of the Meteor III, which ended just behind the wing, contributed heavily to compressibility buffeting at high speed, and a new, longer nacelle was designed as a fix. The new nacelles increased the redline speed at altitude by 120 KPH (75 MPH), even without new powerplants. The last batch of Meteor IIIs that rolled off the production line featured the longer nacelles, and apparently some Meteor IIIs were retrofitted in the field with the new nacelles.

Engine development had continued in the meantime, and one Meteor III was built with Rolls-Royce Derwent 5 engines, the scaled-down version of the Nene, providing 15.6 kN (1,590 kgp / 3,500 lbf) thrust each. This aircraft first flew in July 1945, and became the prototype of the next Meteor variant, the "F.4" (Fighter Mark 4, the RAF having switched from Roman to Arabic numbers by that time, with the type having the company designation "G-41F").

Gloster Meteor Speed records

However, in Britain the end of the war was followed by a general assumption that nobody was going to be in the mood for more fighting any time soon, an idea that proved to be a complete delusion, and also by general physical and economic exhaustion. For the moment, there was no urgency to produce an updated Meteor variant. As a result, Gloster, under Air Ministry direction, continued to tweak the Meteor design without putting a new version into production. One F.4 prototype had its guns removed, gun ports faired over, and engines uprated for burst power to set a world speed record of 975 KPH (606 MPH) on 7 November 1945, with Group Captain H. Wilson at the controls.

On learning that the Americans were preparing for an assault on the world speed record with the Lockheed Shooting Star, the RAF reworked a few F.4 prototypes with a number of tweaks, most notably clipping the wings to reduce the span by 1.47 meters (4 feet 10 inches), and broke the Meteor's own world speed record on 7 September 1946, with Group Captain "Teddy" Donaldson clocked at 991 KPH (616 MPH). The aircraft was painted yellow and named either "Forever Amber" or "Yellow Peril". It is an interesting comment on the rate of progress in aircraft performance at that time that this was regarded as such an astonishing improvement in performance that many believed aircraft wouldn't get much faster any time soon.

The Meteor F.4 finally went into production in 1947. It featured the Derwent 5 engines and the clipped wings, a stronger airframe, a fully pressurized cockpit, lighter ailerons to improve maneuverability, and rudder trim adjustments to reduce snaking. The F.4 could also be fitted with a drop tank under each wing, and experiments were performed with carriage of underwing stores.

The clipped wings not only provided greater speed, they also improved the roll rate, though at the expense of a longer takeoff run and faster landing speed. They were also intended to reduce stress on the wings, following an accident when a Meteor broke up in the air after pulling out of a dive, killing a Gloster test pilot.

A total of 535 Meteor F.4s were built for the RAF, with 48 of that number second-sourced by Armstrong-Whitworth. The F.4 was also exported in large numbers. Gloster took an F.4 on a sales tour in 1947, painted red with white detailing. Although this aircraft was damaged beyond repair by a Belgian pilot early in the tour due to a landing gear malfunction, international sales were brisk.

100 were bought by Argentina in 1947, with the aircraft sent to the country as kits, which were then assembled by Gloster personnel. They saw action during political unrest in 1955, with at least two being lost, and remained in service into the early 1970s. 48 were bought by Belgium, 20 by Denmark, 12 by Egypt, and 38 by the Netherlands. The Dutch later obtained 27 used F.4s from the RAF, and the French obtained a pair of used F.4s for development work, one being used to test Atar engines.

As with the original Meteor prototypes, the Meteor F.4 was used as an engine test bed. Meteors were fitted axial-flow engines, including the MetroVic F.2/4 Beryl, the ancestor of the Armstrong-Siddeley Sapphire, and with Rolls-Royce RA.2 and RA.3 Avon engines. These engines were mounted in oversized nacelles, in much the same way as had the MetroVic F.2s tested with one of the original Meteor prototypes. Both the Beryl and Avon test aircraft demonstrated extraordinary rates of climb.

In 1954, one of these same Meteors received a highly unusual engine fit, consisting of Nene engines with thrust deflectors on the bottom of the of the engine nacelles, intended to lower takeoff and landing speed. This engine fit demanded extensive modifications to the aircraft, with nacelles extended forward of the wings, clipped wings replaced by the old full-span wings, and replacement of the F.4 tail structure with the revised and lengthened tail structure of the Meteor F.8, of which more is said in the following section. Results were promising, but the scheme was regarded as too complicated. "Vectored thrust" systems would have to wait for a decade or so to become respectable.

Another interesting engine test bed was a Meteor FR.9 that was modified in 1955 to test the Rolls-Bristol RB.108 lift engine, a stubby turbojet designed to be fitted vertically into an aircraft to provide additional lift for short takeoffs and landings. The FR.9 was modified with a single RB.108 in the fuselage; the fit was intended strictly for engine test purposes and the configuration was never considered for operational service.

Other experimental engine fits included French Atar axial-flow engines, mentioned earlier, and afterburning versions of the Derwent Mark 5 and Mark 8. Meteor F.4s were also used to evaluate in-flight refueling schemes, which were never implemented in production Meteors, and Martin Baker ejection-seat trials, which led to standard fit of such seats in the later Meteor F.8.

Over 90 F.4s were modified by Flight Refueling LTD beginning in 1954 as target drones. The conversions were given the designation of "Meteor U.15", and featured airframe reinforcement; jettisonable wingtip camera pods for scoring, which were recovered by parachute and had a radio beacon; and an infrared flare system, with triple-flare launchers under each engine nacelle. They were radio-controlled, but still could be flown by a pilot. The cannon were of course removed. The U.15s served with both Britain and Australia. The were mostly used for missile trials and the like, since they were too expensive to be considered particularly expendable.

Several other Gloster Meteor variants were derived from the F.4. The experimental "FR.5" (Fighter-Reconnaissance Mark 5, or "G-41H") variant first flew on 13 July 1949. This aircraft featured two cameras in the rear fuselage for on-track imaging, and a single camera in the nose for oblique imaging that could be repositioned by ground crews to shoot through one of three windows. Unfortunately, the first flight of the FR.5 was also its last. It broke up in the air during a low-level high-speed pass, killing the test pilot. However, the concept was not abandoned and would be revived later.

The Meteor "F.6 (G-41J)" never got off the drawing board. Some sources claim it was a swept-wing variant, others claim it incorporated features that would go into the F.8. However, the two-seat "T.7" (Trainer Mark 7, or "G-43") variant did go into production, and served usefully with the RAF and other air services for many years. It featured a tandem two-seat cockpit with an antique-appearing "greenhouse" or "frame" canopy. Since the Meteor was often the first jet operated by the air arms that purchased the type, orders often included a few T.7s for conversion training. 650 T.7s were built.

Gloster Meteor F.8

As improved jet fighters began to emerge in the years following the war, Gloster decided to perform a significant redesign of the F.4 to keep it up to date, while retaining as much of the manufacturing tooling of the F.4 as possible. The result was the "Meteor F.8 (G-41K)". The first prototype was a modified F.4, followed by a true prototype that flew on 12 October 1948. Initial deliveries to the RAF were in August 1949.

The F.8 featured a fuselage stretch of 76 centimeters (30 inches), intended to shift the aircraft's center of gravity and eliminate the dead weight of ballast that had accumulated in earlier marks, which had reached a total of about 450 kilograms (1,000 pounds) in the F.4. Evaluation of the stretched fuselage in the initial prototype gave positive results, except that as ammunition was expended the aircraft became tail-heavy and unstable around the pitch axis. However, by an odd stroke of luck, Gloster had developed a single-engine jet fighter designated the "G.42" that hadn't entered production, and fitting the tail of the G.42 to the modified F.4 cleared up the stability problem.

Given the modular design of the Gloster Meteor , fitting the new tail proved simple. It also made the new variant distinctively different from its predecessors. While the tailfin of earlier Meteors was elliptical, resembling an asymmetric guitar pick, the new tailfin had straight edges.

Another important change in the F.8 was, of course, still further uprated engines in the form of Derwent 8 engines with 16 kN (1,633 kgp / 3,600 lbf) thrust each. Other changes included structural strengthening, a Martin Baker ejection seat as evaluated earlier on the F.4, and a revised "blown" cockpit canopy that provided improved pilot visibility. The F.8 could carry two 450 kilogram (1,000 pound) bombs or sixteen rocket projectiles.

The Meteor F.8 was the mainstay of RAF Fighter Command between 1950 and 1955, though it was increasingly outmatched by newer swept-wing fighters developed during this period, such as the US North American F-86 Sabre and the Soviet MiG-15. It was eventually replaced in RAF squadron service by the Hawker Hunter.

Although the Meteor may have been obsolescent in the 1950s, it served with distinction with the Royal Australian Air Force (RAAF) during the Korean War in the ground-attack role. The RAAF began receiving Meteor F.8s at the end of 1949, most of which were modified to carry a radio compass, with the antenna in a small dome on the aircraft's spine. The RAAF received 93 ex-RAF Meteor F.8s for combat service in Korea from 1951 through 1953, plus nine T.7s for operational conversion.

The F.8 was used for escort duties at first, with the aircraft's initial combat mission taking place on 29 July. A month later the Meteors mixed it up with MiG-15s and got the worst of it, with one Meteor lost and the pilot taken prisoner, and two others badly damaged. The Meteor seemed to be no match for the MiG-15, though Australian pilots protested that they might have done much better had they been trained for air-to-air combat instead of ground support, but by the end of 1951 the Meteor had been relegated to the ground-support role.

This was dangerous work, all the more so because a Meteor had to be held smooth and level on its firing run for its gyro-stabilized gunsight to be accurate, making the aircraft vulnerable to ground fire. 32 were lost in action. Despite the aircraft's general inferiority to the MiG-15, the Australians were able to score at least three "kills" against the Soviet fighter with the Meteor, with Flight Sergeant George Hale claiming two of the kills in his F.8, named "Halestorm". After the war, the F.8s were sent home to Australia, to be replaced by Commonwealth CA-27 Sabres in the mid-1950s.

A total of 1,183 F.8s were built in all by Gloster and Armstrong-Whitworth, with 23 ex-RAF aircraft supplied to Belgium, 60 new-build aircraft to Brazil, 20 new-build aircraft to Denmark, 12 ex-RAF aircraft to Egypt, 11 new-build aircraft to Israel, 5 ex-RAF aircraft to the Netherlands, and 12 new-build and 7 ex-RAF aircraft to Syria.

Fokker built 150 F.8s for the Dutch and 150 F.8s for the Belgians. Avions Fairey built 30 from kits supplied by Fokker and 37 from kits supplied by Gloster, with these aircraft going into Dutch service.

Two reconnaissance variants of the F.8 were also built. The "FR.9" (Fighter Reconnaissance 9, or "G-41L") retained the four 20 millimeter Hispano cannon, but had an extended nose to accommodate a camera that could be oriented on the ground to shoot through one of three windows. It could also carry an external tank under each wing and an external tank under the belly.

A total of 126 FR.9s were built and went into RAF service in the low-altitude reconnaissance role, with 12 of these aircraft later passed on to Ecuador, 7 passed on to Israel, and two passed on to Syria. RAF Meteor PR.9s saw extensive use in the 1956 Suez intervention, and Middle Eastern Meteors of various types saw intermittent combat through the 1950s.

The "PR.10 (G-41M)" was intended for the high-altitude reconnaissance role. It not only had the older long-span wing, it also had the older elliptical Meteor F.4 tail. Armament was deleted, and it was fitted both with a camera in the nose as with the FR.9 and wth two cameras in the rear fuselage for along-track imaging. The RAF received 59 PR.10s. None were exported.

The RAF also operated reconnaissance Meteors during security operations in Kenya, Aden, Cyprus, and Malaya through the 1950s.

The F.8 proved popular as a test and trials aircraft. F.8s were used to test airborne radar for the Fireflash missile, midair refueling schemes, and engine fits. A heavily modified F.8 experimentally fitted with Armstrong-Siddeley Sapphire 2 engines set a world climb-rate record in August 1951. One test rig was fitted with the Armstrong-Siddeley Screamer rocket engine, fitted under the fuselage. Another was fitted with Rolls-Royce Soar mini-jet engines on the wingtips, while retaining its Derwents, making it the only four-engine Meteor.

One of the oddest test fits was built by Armstrong-Whitworth, and involved adding a second cockpit to a longer nose. This additional cockpit was intended to accommodate a pilot lying in a prone position on his stomach, in the belief that this posture might provide greater tolerance to gee forces. This testbed was first flown in February 1954, but the idea didn't pan out.

Martin Baker used three odd hybrids of T.7s with F.8 tails for ejection seat trials. They were informally given the designation "Meteor T.7 1/2". They provided many decades of fine and reliable service for Martin Baker, and at last notice were still in use.

Gloster also modified an F.8 into a specialized close-support configuration, with wingtip tanks and belly stores pylons. This aircraft was known as the "Reaper" or "G.44", and could carry 24 rockets or up to four 450 kilogram (1,000 pound) bombs.

A small number of F.8s were converted to a simple target tug configuration and redesignated "Meteor F(TT).8". The only modification was fit of a target towing lug under the fuselage, allowing the aircraft to pull a target banner along. A number of T.7s and F.8s in foreign service were also used as target tugs in this fashion. In addition, some F.8s were put into service as advanced single-seat trainers, apparently with some small modifications, and designated unofficially as "Meteor T.8".

Following the use of Meteor F.4s converted to the U.15 target drone configuration, about 250 Meteor F.8s were converted to "U.16" target drones by Flight Refueling LTD, beginning in 1956. The last conversion was apparently in 1975. The Australians received similar conversions with some minor differences in equipment kit as the "U.21".

The U.16 / U.21 conversion was broadly similar to the U.15 conversion, with airframe reinforcement, wingtip camera pods, radio control while retaining piloted capability, and no cannons. However, the U.16 had a characteristic modified extended nose, the camera pods were slenderer, and it is unclear if it had flare dispensers. These machines remained in service into the 1990s, and a few may be flying yet.

Armstrong-Whitworth NF.11 Through NF.14

In January 1947, the Air Ministry issued the specification F.44/46 for a two-seat, twin-jet-engine, night / all-weather fighter to replace the de Havilland Mosquito. A number of companies responded to the request, but none of their proposals met the requirement. Since there was still a need for a night fighter, Gloster suggested stretching the T.7 by 1.5 meters (five feet) to accommodate airborne-intercept (AI) radar in the nose. This was intended as an interim solution until the Gloster Javelin , then in development, was ready for service.

The proposal was accepted under the specification "F.24/48", but Gloster, having brought up the suggestion, was forced to admit that the company didn't have the resources to produce the machine. However, Armstrong-Whitworth, another member of the Hawker-Siddeley industrial group along with Gloster, had second-sourced the Meteor, and in 1949 Armstrong-Whitworth was given ownership of the project.

The first Meteor "NF.11" (Night Fighter Mark 11) or "G/47" prototype, a modified T.7, began flight tests in October 1949. The first true NF.11 prototype flew on 31 May 1950. The NF.11 retained the Derwent 8 engines of the F.8, but the four cannon were transferred from the nose to the wings, the wings were lengthened back to the original Meteor I span, and the longer nose accommodated AI.10 (US SCR-720) radar and a pressurized tandem cockpit. The cockpit featured a T.7 greenhouse canopy and a radar operator / navigator in the back seat.

The first production NF.11, with a proper Meteor F.8 tail, flew on 13 November 1950, and 307 production NF.11s were built. The Danes bought 11, the Belgians obtained 24 ex-RAF aircraft, somewhat surprisingly the French bought 41 used RAF NF.11s, and a single example was sent to Australia.

The NF.11 was followed by the "NF.13" and "NF.12", in that order, with the reversal of the numeric sequence apparently due to the fact that the NF.13 revision was started later than the NF.12 but, being a more modest upgrade, was completed sooner. All the Meteor night fighter variants retained the "G.47" company designation.

In fact, the NF.13 was largely identical to the NF.11, except that it had a radio compass, cockpit cooling ducts, and other changes for tropical operation, and larger intakes to improve air mass flow to the engines, resulting in 45 kilograms (100 pounds) more thrust. The first NF.13 flew on 23 December 1952, and 40 were built.

The NF.12 featured Derwent 9 engines with 16.9 kN (1,725 kgp / 3,800 lbf) thrust each, and the nose lengthened by 43 centimeters (17 inches) to accommodate improved American Westinghouse AN/APS-21 radar. The top half of the tailfin was enlarged to compensate for the longer nose, giving the tailfin a slightly crooked appearance.

The first NF.12 flew on 21 April 1953, with 100 being built. France obtained two for test purposes, and six each ex-RAF aircraft were provided to Egypt, Syria, and Israel.

The "NF.14" was generally similar to the NF.12, but featured a "blown" clear-vision canopy to provide a much-improved view compared to the old framed canopy; improved US AN/APQ-43 radar and an even longer nose; yaw dampers to control "snaking"; and other lesser changes. 100 NF.14s were manufactured, and were the last Meteors built, with the very last of the breed delivered on 26 May 1955. The Meteor night fighters remained in front-line RAF service until 1961. The total number of Meteor night-fighters built by Armstrong-Whitworth was 547.

Some of the NF.14s were later converted to "NF(T).14" navigation trainers. Others were modified as target tugs, with a windmill-powered winch mounted inboard of the right engine, and were designated "TT.20". The TT.20s remained in service with the RAF at least into the 1970s.

A total of almost 4,000 Meteors was built in all, and the type served with ten air forces. The following table gives Meteor variants and their production quantities. The quantities tend to be somewhat difficult to pin down precisely since it is unclear in many cases whether prototype builds are counted as part of the total, but should be in the ballpark.

Footnote: The Gloster G.42 (E.1/44)

Gloster's single-engine jet fighter, the G.42, is worthwhile to discuss briefly here since its design, or at least the design of its tail, contributed to the development of the Meteor F.8 and later Meteor marks.

The G.42 was designed in response to the Air Ministry E.1/44 specification issued in early 1944, and Gloster was selected to build four prototypes. With the slowdown in aviation work after the end of the war, the first prototype wasn't completed until July 1947. This aircraft never flew, since it was involved in a traffic accident while being road-transported and was written off. It was probably a good thing that a machine with such extraordinary bad luck never got off the ground.

The second prototype was completed and first flew on 9 March 1948. It was of undistinguished appearance, of all-metal construction, a straight mid-mounted wing, engine inlets on the fuselage just in front of the wings, and tricycle landing gear. It was to be armed with four Hispano 20 millimeter cannon under the nose, with the capability of carrying a 450 kilogram (1,000 pound) bomb under each wing, or a total of eight rockets.

It was powered by a single Rolls-Royce Nene turbojet with 22.3 kN (2,270 kg / 6,000 lb) thrust. Wingspan was 11 meters (36 feet), length was 11.6 meters (38 feet), empty weight was 3.750 kilograms (8,260 pounds), and loaded weight was 5,200 kilograms (11,470 pounds).

A third prototype, with a modified tail, was built and flew in 1949, and a swept-wing version was considered under Air Ministry specification E.23/46, but by this time it was obvious the E.1/44 was no winner, and the fourth prototype was never built. The only legacy of the E.1/44 was its tail, which survived in the Meteor F.8.

The Meteor is noteworthy for its historical significance as the first Allied jet fighter to see service, as well as for its long service with the RAF and many other countries. To be sure, it was obsolete by the 1950s and only remained in production and service while nothing better was available, but this was no fault of the design itself. It was a first-generation jet that continued to serve well into the era of second-generation jets that built on its experience. The Meteor itself still remained simple, clean, and appealing, as were many of the first-generation jets.

Author: Greg Goebel