The Mitsubishi T-2 / F-1 & Kawasaki T-4

v1.0.0 / 01 sep 03 / greg goebel / public domain

* In the late 1960s, Japan began to consider development of a tandem-seat supersonic jet trainer that could be adapted as a single-seat strike aircraft. Using the Anglo-French SEPECAT Jaguar trainer / strike aircraft as a model, Mitsubishi developed the "T-2" jet trainer and "F-1" strike aircraft.

The T-2 and F-1 were the first supersonic aircraft to be developed in Japan, and have given several decades of reliable service. In the 1980s, the T-2 was complemented by a subsonic trainer, the Kawasaki "T-4". This document gives a history of the T-2 / F-1 and T-4.



* In the mid-1960s, the Japanese Air Self-Defense Force (JASDF) began to search about for a new jet trainer, tentatively designated the "T-X". There was a belief that the modern Mach 2 fighters then being acquired and operated by the JASDF, including the Lockheed F-104J Starfighter and, eventually, the McDonnell F-4EJ Phantom, required a supersonic advanced trainer. The T-X was also seen as the basis for a single-seat strike aircraft, tentatively designated the "SF-X".

Supersonic jet trainers were something of a fad at the time. The US Air Force had already acquired the Northrop T-38 Talon supersonic trainer, and the Anglo-French SEPECAT Jaguar partly emerged from a perceived need for a supersonic trainer, though it would primarily end up being used as a strike fighter. Both the T-38 and the two-seat Jaguar were promoted by their respective nations as solutions to the Japanese training requirement, while the Northrop F-5, a complementary design to the T-38, and the single-seat Jaguar were promoted for the strike requirement. The JASDF was very interested in the Jaguar and the Japanese even negotiated to build it under license, but royalty issues and nationalism led the Japanese to decide to build their own design.

Fuji, Kawasaki, and Mitsubishi submitted proposals in early 1967, with the Mitsubishi design selected as the winner on 5 September 1967, with a formal contract issued for development of the "XT-2" on 30 March 1968. The design team was led by Dr. Kenji Ikeda, chief engineer of Mitsubishi. Fuji was to be a major subcontractor, and several other Japanese aviation firms obtained substantial subcontracts as well. It is unclear if this distribution of contracts was for any other reason other than to make sure that all the major Japanese aerospace firms got their share of the government pie.

A preliminary mockup was unveiled on 24 April 1968, and by the spring of 1969 the design had been finalized. The initial XT-2 prototype performed its first flight on 20 July 1971, with Kenshiro Endo and Mitsui Sato in the cockpit. It was followed by three more prototypes, for a total of four. It became the first aircraft of Japanese design to break Mach 1 in level flight.

The type entered JASDF service in 1975. 90 production T-2s were built, including 28 unarmed "T-2(Z)s", with the "Z" standing for "Zenkigata (early type)" and 62 armed "T-2(K)s", with the "K" standing for "Kokigata (late type)". Some sources translate these variants as "T-2A" and "T-2B" respectively. Two of the four prototypes were unarmed, two were armed. An additional two T-2(Z)s were built but modified for the S-FX / F-1 strike fighter program off the production line, as discussed in the next section. The last T-2 was delivered in 1988.

* Given that the Japanese requirements for the T-FX weren't so different from those that gave rise to the Jaguar, it wasn't too surprising that Mitsubishi engineers saw the Jaguar as something of a model for what they wanted to do. The T-2's configuration is clearly reminiscent of that of the two-seat Jaguar, with the two aircraft having the same overall configuration and some resemblance in details. In particular, the T-1 is also powered by two Rolls-Royce / Turbomeca Adour turbofans, the same powerplants used by the Jaguar, with the engines license-built by Ishikawajima-Harima Heavy Industries under the designation "TF40-IHI-801A".

However, the T-2 was also clearly not a copy of the Jaguar. The best way to describe the Jaguar's role in the T-2's design is as "inspirational". The two aircraft can be distinguished at a glance, with the T-2 having a more dartlike appearance, being noticeably longer and having a distinctly shorter wingspan than the Jaguar. The Japanese machine also has many detail differences -- for example, as the JASDF had no rough-field requirement, the T-2 has conventional single-wheeled landing gear and not the distinctive "farm tractor grade" landing gear of the Jaguar.

The T-2 is made mostly of aircraft aluminum alloys, though it features selective use of titanium. The high-mounted wings have a leading-edge sweep of 42.5 degrees and a 9 degree anhedral. The wings feature a noticeable "leading edge root extensions (LERXs)" and full span leading-edge flaps, with a "dogtooth" discontinuity on the outer edge of the span, though the dogtooth does not split the flap. There is a single 3/4ths-span flap in the back, unlike the split full-span double slotted flaps of the Jaguar, but the T-2 does use twin spoilers on each wing just forward of the flap for roll control, another element clearly derived from the Jaguar. There is a small fence mounted inboard on the top of the wing. There are no fuel tanks in the wings.

The tail assembly is conventional, featuring slab all-moving horizontal tailplanes with an anhedral of 15 degrees. The steep anhedral keeps the tailplanes out of the engine exhaust while allowing them to remain effective through the wing wash. Like the Jaguar, there is a fixed ventral fin under each exhaust, and a hydraulically-operated airbrake just forward of each ventral fin.

Each Adour engine provides 22.75A kN (2,320 kgp / 5,115) max dry thrust and 32.49 kgp (3,315 kgp / 7,305 lbf) afterburning thrust. The TF40-IHI-801As do not have the "part throttle reheat" feature added to Adour 102s as an engine-out safety feature, and the T-2 was never refitted with more powerful Adour engine variants, along the lines of the Adour 104 eventually refitted to British Jaguars, leaving the T-2 somewhat underpowered. The engine intakes have fixed rectangular geometry and fuselage splitter plates, plus a set of spring-loaded auxiliary inlets behind the intake lip for increased airflow in ground running. There are large service doors beneath the fuselage that provide excellent access to the engines for maintenance.

The T-2's landing gear all features single wheels, with the nose gear retracting backward and the main gear retracting forward into the fuselage, rotating 90 degrees to lie flat, another scheme that echoes the Jaguar. The nose gear is offset slightly to the right, with a small fixed vertical airfoil mounted in front of it to compensate for the extended nose gear's tendency to cause yaw. The landing gear features an antiskid control system. Also like the Jaguar, the T-2 has a runway arresting hook, in this case on the underside of the tail behind the engine exhausts, and a drag chute in the tailcone.

The aircrew sit in tandem, with the flight instructor sitting behind the student on a raised seat to give a good forward view. There is a windblast screen between the two cockpits. Of course, there are dual controls. The aircrew sit under separate clamshell canopies on Weber ES-7J zero-zero ejection seats, built by Daiseru. The seats feature specially modified canopy penetrators to ensure safe ejection even if the canopy isn't blown off. The seats also dispense a cloud of radar-reflecting "chaff" on ejection so that ground controllers will be able to spot where the ejection occurred and direct search and rescue teams to the proper area.

Standard equipment for the armed T-2(K) includes a Mitsubishi Electric J/AWG-11 search and ranging radar in the nose; a French Thomson-CSF head-up display (HUD), license-built by Mitsubishi Electric; a Lear-Siegler 501OBL automatic heading and reference system (AHRS); as well as a UHF radio, an IFF system, and a TACAN radio beacon navigation receiver system, all built in Japan. The J/AWG-11 is basically a member of the family of radars fitted to the US F-4 Phantom, in specific being very similar to the AN/AWG-11 fitted to the British Royal Navy Phantom FG.1. The unarmed T-2(Z) lacks the radar, though apparently its avionics kit is otherwise the same as that of the T-2(K).

   _____________________   _________________   _______________________
   spec                    metric              english
   _____________________   _________________   _______________________

   wingspan                7.88 meters         25 feet 10 inches
   wing area               21.17 sq_meters     227.88 sq_feet   
   length                  17.86 meters        58 feet 7 inches
   height                  4.39 meters         14 feet 5 inches

   empty weight            6,307 kilograms     13,905 pounds
   MTO weight              12,800 kilograms    28,219 pounds

   max speed at altitude   1,700 KPH           1,055 MPH / 920 KT
   service ceiling         15,240 meters       50,000 feet
   ferry range             2,595 kilometers    1,610 MI / 1,400 NMI
   _____________________   _________________   _______________________

The T-2(K) features built-in armament consisting of a General Electric M61 Vulcan 20-millimeter six-barreled Gatling-type cannon, license built in Japan as the JM61 and mounted on the left side of the fuselage, under the cockpit. The nose gear's offset, mentioned above, was to accommodate the cannon. The ammunition store is behind the rear cockpit. Of course, this weapon is not fitted to the T-2(Z). All T-2s have four underwing hardpoints, the inner two being "wet", and they can be fitted with wingtip launch rails for Sidewinder air to air missiles (AAMs).

The T-2 can carry a respectable, if not impressive, external load of up to 2,000 kilograms (4,400 pounds), including up to two 821 liter (217 US gallon) external tanks. Apparently pylons are usually only fitted for carriage of external tanks, and it is unlikely that the wingtip launch rails are often fitted to the unarmed T-2(Z).

* In service, the T-2 is painted standard training colors of overall light grey, with the unarmed T-2(Z)s distinguished by dayglo orange on the nose, LERXs, and the tips of the flight surfaces. A few T-2(K)s were provided to operational units flying the F-1 strike fighter, presumably for operational conversion, with these T-2s featuring a light green / dark green / tan camouflage pattern, as used on the F-1.

A number of T-2s, peaking at eight machines, was also used in the "aggressor" role, being painted in color schemes to simulate possible opponents, such as overall silver with a black-painted nose and other black patterns to make them resemble a MiG-21. They were eventually replaced in the aggressor role with the F-15DJ, whose superior performance made it a better aggressor. Apparently the safety record of the T-2 also played a part in their replacement. The type was said to have nasty spin characteristics, though little information on the T-2's handling has appeared in print.

Six T-2(K)s were used by the JASDF "Blue Impulse (Sengi Kenkyuhan)" flight demonstration team, with the aircraft painted in spiffy dark blue / light blue / white colors, fitted with a multicolor smoke generator, and flown in formation aerobatics to wow the crowds. The first performances of the Blue Impulse with the T-2 were flown in 1982. The Blue Impulse team traded in their T-2s for T-4s in 1995.

One T-2 was used as a experimental platform by the Japan Defense Agency (JDA), modified as the "T-2 Control Configured Vehicle (T-2CCV)". The aircraft was fitted with a fin under the nose, moving canard fins on the engine inlets, a triple-redundant digital fly-by-wire system, and the back seat was loaded up with test avionics. The T-2CCV performed its first flight on 9 August 1983, and performed a set of 138 test flights in 1984 through 1986. It was painted in spiffy red-white-black colors, with a red-on-white lightning bolt along the fuselage and "CCV" in big letters on the tail.



* As mentioned, the Japanese had planned to develop a single-seat strike fighter version of the T-2 under the SF-X program. A formal development contract for the "F-1" strike fighter was issued in 1973, and, as mentioned, two T-2s were taken from the production line to be converted into prototypes. These two machines were originally given the designation of "Special Spec T-2", then "T-2(FS)", and then "FS-T2 Kai", where "Kai" is short for "kaizen (modification)". The initial conversion performed performing its maiden flight on 3 June 1975. The type was ordered into production after a year's evaluation at the JASDF test center at Gifu, with the production F-1 performing its initial flight on 16 June 1977.

The F-1 is basically much like the armed T-2(K), with identical dimensions and almost identical performance, the only major visual difference being that the T-2's rear cockpit is faired over and acts as an avionics bay, with an access cover that hinges open to the left. The rules of the development program specified that minimal changes were to be made to the T-2 airframe to get the aircraft into service more quickly and at lower cost. The F-1 features the same TF40-IHI-801 engines; the same built-in JM61 Vulcan cannon; and features the four wing hardpoints and wingtip launch rails for Sidewinder AAMs. However, unlike the T-2, the F-1 has a centerline pylon, which is "wet" to allow carriage of a third external tank.

The F-1's avionics is a superset of the T-2's avionics. It differs in fit of a J/AWG-12 radar, instead of the J/AWG-11 of the T-2(K), with the J/AWG-12 similar to the AN/AWG-12 fitted to the British Royal Air Force Phantom FGR.2. The radar is backed up by a Mitsubishi Electric J/ASQ-1 fire control system (FCS), and the Lear-Siegler AHRS is augmented by a J/ASN-1 inertial navigation system, a license-built copy of the Ferranti 6TNJ-F unit. The F-1 also features a J/APR-3 radar homing and warning system (RHAWS), with a tubular antenna at the top of the tailfin, as well as a J/APN-44 radar altimeter system, a J/A24G-3 air data computer, and a strike camera system.

The F-1's primary role is antishipping attack, with its traditional configuration including carriage of two drop tanks, two ASM-1 antishipping missiles, and (if needed) one AIM-9L Sidewinder AAM on each wingtip launch rail for self-defense. The ASM-1 is a solid-fuel missile with an active radar seeker. The Japanese are very sensitive about the defensive nature of their armed forces and the ASM-1 is formally described as an "anti-landing craft" missile, though of course it could be used against almost any floating target. The F-1 is cued to targets for the ASM-1 by other platforms, such as Japanese Maritime Self-Defense Force Lockheed P-3C Orions, since the J/AWG-12 radar has limited range.

The F-1 can also carry 70 millimeter and 125 millimeter unguided rocket pods, as well as "iron" bombs and cluster bombs, with a maximum external load of up to 2,720 kilograms (6,000 pounds). Apparently the F-1 also can carry infrared-guided bombs, an interesting Japanese munition that looks very much like a laser-guided bomb but is designed to autonomously home in on maritime targets from their heat signature.

* The F-1 entered operational service with the JASDF in April 1978. A total of 160 were planned, but budget cuts meant that only 77 production machines were actually built, with the last delivered in March 1987. There was talk of an "RT-2" reconnaissance variant of the F-1, but the JASDF settled on the RF-4EJ Phantom instead. The standard color scheme for the F-1 is light green / dark green / tan camouflage, similar to standard USAF camouflage used over Vietnam, but with somewhat different color shades. Various other color schemes, such as a two-tone sea gray camouflage for maritime operations, were also evaluated, but not formally adopted.

The F-1 fleet was upgraded to an improved J/AWG-12 radar beginning in 1982, and in the mid-1990s the ASM-1 missile gave way to its much improved ASM-2 derivative, featuring turbojet propulsion to provide longer range and a much smarter imaging infrared (IIR) seeker system. A service-life extension program (SLEP) was also begun in the mid-1990s, with the effort increasing the F-1's airframe life from 3,500 to 4,000 hours. The Japanese have recently fielded an improved Sidewinder follow-on of local design, the "AAM-3", but the elderly F-1 is not being qualified to carry it.

The F-1 is an attractive aircraft and has proven serviceable, certainly superior to the JASDF combat aircraft it replaced, but foreign observers comment that in terms of published warload, performance, and range figures, it is not particularly impressive. The F-1 is now being replaced by the much more formidable Mitsubishi F-2A, an advanced derivative of the Lockheed Martin F-16, developed in Japan. Delays in the F-2 program led to the F-1 SLEP effort.

The T-2 has already been replaced in the advanced training role by the Kawasaki T-4, discussed below, and will be replaced in conversion training by the F-2B, the two-seat version of the F-2A. Both the T-2 and F-1 will likely be out of service by 2005. Neither ever fired a shot in anger, and that probably suits the Japanese just fine.



* The Mitsubishi T-2 trainer had not really been intended to perform the intermediate flight training role for the JASDF, which continued to be handled through the 1970s by the venerable Lockheed T-33 and the Fuji T-1, which was a subsonic tandem-seat aircraft modeled on the F-86 Sabre. By the late 1970s, both the T-33 and T-1 were clearly elderly and in need of a replacement, and the Japan Defense Agency requested designs from Fuji and Kawasaki for a new subsonic trainer.

In 1981, the JDA selected the Kawasaki "KA-851" design, produced by an engineering team under Kohki Isozaki, over the Fuji "FT-20", leading to a contract for two nonflying static-test airframes and four flying prototypes. As with the T-2, subcontracts were distributed over the pool of major Japanese aerospace firms. Detail design was complete by the end of 1983 and prototype construction began in the spring of 1984, leading to first flight of the initial "XT-4" prototype on 29 July 1985. The first production "T-4" was delivered to the JASDF in 1988.

* The T-4 is a conservative design, with such a strong general resemblance to the Dassault-Dornier Alpha Jet that it is hard to believe that Kawasaki engineers didn't see the Alpha Jet as a model for what they wanted to do. However, even if that was the case, as with the T-2 and the Jaguar the T-4 is by no means a copy of the Alpha Jet, and the two machines can be told apart at a glance. The T-4 has a substantially more muscular appearance than the wasplike Alpha Jet.

The T-4 is mostly made of aircraft aluminum alloys, with some control surfaces made of carbon-fiber / epoxy composite, plus very selective use of titanium. It has high-mounted swept wings, with a supercritical airfoil section and a leading-edge dogtooth; a conventional swept tail assembly; tricycle landing gear; twin engines, one mounted in a pod along each side of the fuselage; and a tandem-seat cockpit with dual controls.

The wings have a sweep of 27.5 degrees, an anhedral of 7 degrees, and feature ailerons for roll control and double slotted flaps. The horizontal tailplanes are all-moving, and also have an anhedral of 7 degrees. There is an airbrake on each side of the rear fuselage. Flight controls are hydraulic, and hydraulic systems are dual redundant.

The landing gear assemblies all feature single wheels, with the nose gear retracting forwards and the main gear retracting forward and into the fuselage. The landing gear features an antiskid braking system. The twin engines are Ishikawajima-Harima F3-IHI-30 turbofans, of completely Japanese design, with a maximum takeoff thrust of 16.28 kN (1,660 kgp / 3,660 lbf).

The instructor and cadet both sit on UPCO / Stencel SIIS-3 zero-zero ejection seats, with the instructor's seat in the rear raised 27 centimeters (10.6 inches) to give a good forward view. The cockpit is pressurized, with a one-piece canopy that provides excellent visibility and hinges open to the right. The cockpit layout is analog but features a Kaiser head-up display (HUD). Standard avionics includes a VHF/UHF radio; a TACAN beacon navigation system; VOR / ILS landing aids; a ring-laser gyro AHRS; and video and flight-data recorders.

   _____________________   _________________   _______________________
   spec                    metric              english
   _____________________   _________________   _______________________

   wingspan                9.94 meters         32 feet 7.5 inches
   wing area               21.0 sq_meters      226.05 sq_feet   
   length                  13.0 meters         42 feet 8 inches
   height                  4.60 meters         15 feet 1.35 inches

   empty weight            3,790 kilograms     8,536 pounds
   MTO weight              7,500 kilograms     16,534 pounds

   max speed at sea level  1,040 KPH           645 MPH / 560 KT
   service ceiling         15,240 meters       50,000 feet
   range (internal fuel)   1,300 kilometers    805 MI / 700 NMI
   _____________________   _________________   _______________________

The T-4 can be fitted with a stores pylon under each wing and under the fuselage centerline. The wing pylons are wet and can be used to carry 450 liter (119 US gallon) external tanks. Other external stores include a centerline target winch for the target tug role; an air-sampling pod for detection of fallout or other atmospheric pollutants; jammer or chaff pods for electronic warfare training; and a baggage pod for use in the liason role. The aircraft also includes a baggage compartment in the center fuselage.

The T-4 does not have a built-in cannon, but it can in principle carry a centerline cannon pod or other weapons and munitions, allowing it to be used for armament training. It is unclear if it ever has been qualified for weapons carriage.

* The T-4 is regarded as strong, agile, and pleasant to fly, while being cheap to operate. T-4s flying in the training role are painted overall gray with dayglo orange on the tips of the flight surfaces. Some of the few given to operational squadrons, which use them for keeping up flight hours and as hacks, have apparently been painted in camouflage colors to match the combat aircraft they share the flight line with.

As mentioned, the Blue Impulse team re-equipped with the T-4 in 1995, with their six machines painted in spiffy blue-and-white colors and fitted with a smoke generator system. The Blue Impulse T-4s also have a stronger canopy, presumably to deal with bird strikes and other low-level hazards; a ground-proximity warning system; and a few other modifications for their aerobatic display role. While not as fast as the T-2, the T-4 is much more agile and much cheaper to operate. Unfortunately, two of the Blue Impulse T-4s hit a mountain during low-visibility conditions on 4 July 2000, with three aircrew killed. The team performed with only four aircraft through 2001 and into 2002, though they were back up to six by the beginning of 2003.

A total of 208 production T-4s have been built. The JASDF has no further requirement for new T-4s at present. Upgrades are in planning, including fit of at least some T-4s with a modern "glass cockpit" to provide training for the F-2, and a full authority digital engine control (FADEC) for the F3-IHI-30 turbofans.



* I originally wanted to write up the T-2 / F-1 as part of a document on the Jaguar, since the two types have something of a familial relationship, but the Jaguar writeup turned out to be surprisingly complicated, and I would have had to split it into two parts to add the T-2 / F-1. It made as much sense to just build two separate documents.

Having done that, I decided to add the Kawasaki T-4, since I was interested in it and couldn't think of any better place to put a writeup on that aircraft. As usual, I ended up doing about twice as much work as I planned. I'm obsessive. I admit it.

* Sources include:

* Revision history:

    v1.0.0 / 01 sep 03 / gvg