Mitsubishi J8M
Encyclopedia
The Mitsubishi
Mitsubishi
The Mitsubishi Group , Mitsubishi Group of Companies, or Mitsubishi Companies is a Japanese multinational conglomerate company that consists of a range of autonomous businesses which share the Mitsubishi brand, trademark and legacy...
J8M Shūsui (Japanese
Japanese language
is a language spoken by over 130 million people in Japan and in Japanese emigrant communities. It is a member of the Japonic language family, which has a number of proposed relationships with other languages, none of which has gained wide acceptance among historical linguists .Japanese is an...
: 三菱 J8M 秋水, literally "Autumn Water", used as a poetic term meaning "Sharp Sword" deriving from the swishing sound swords make) was a Japanese
Empire of Japan
The Empire of Japan is the name of the state of Japan that existed from the Meiji Restoration on 3 January 1868 to the enactment of the post-World War II Constitution of...
World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
rocket
Rocket engine
A rocket engine, or simply "rocket", is a jet engineRocket Propulsion Elements; 7th edition- chapter 1 that uses only propellant mass for forming its high speed propulsive jet. Rocket engines are reaction engines and obtain thrust in accordance with Newton's third law...
-powered interceptor aircraft
Interceptor aircraft
An interceptor aircraft is a type of fighter aircraft designed specifically to prevent missions of enemy aircraft, particularly bombers and reconnaissance aircraft. Interceptors generally rely on high speed and powerful armament in order to complete their mission as quickly as possible and set up...
closely based on the German
Nazi Germany
Nazi Germany , also known as the Third Reich , but officially called German Reich from 1933 to 1943 and Greater German Reich from 26 June 1943 onward, is the name commonly used to refer to the state of Germany from 1933 to 1945, when it was a totalitarian dictatorship ruled by...
Messerschmitt Me 163
Messerschmitt Me 163
The Messerschmitt Me 163 Komet, designed by Alexander Lippisch, was a German rocket-powered fighter aircraft. It is the only rocket-powered fighter aircraft ever to have been operational. Its design was revolutionary, and the Me 163 was capable of performance unrivaled at the time. Messerschmitt...
Komet.
Built as a joint project for both the Navy
Imperial Japanese Navy Air Service
The Imperial Japanese Navy Air Service was the air arm of the Imperial Japanese Navy during World War II, the organization was responsible for the operation of naval aircraft and the conduct of aerial warfare in the Pacific War.It was controlled by the Navy Staff of the Imperial Japanese Navy and...
and the Army Air Services
Imperial Japanese Army Air Service
The , was the land-based aviation force of the Imperial Japanese Army. As with the IJA itself, the IJAAF was developed along the lines of Imperial German Army Aviation so its primary mission was to provide tactical close air support for ground troops while maintaining a limited air interdiction...
, it was designated J8M (Navy) and Ki-200 (Army).
Design and development
The J8M1 was intended to be a licence-built copy of the Messerschmitt Me 163 Komet. Difficulties in shipping an example to Japan meant that the aircraft eventually had to be reverse-engineered from a flight operations manual and other limited documentation. A single prototype was tested before the end of World War II.The Japanese were quite aware of the results of the strategic bombing
Strategic bombing
Strategic bombing is a military strategy used in a total war with the goal of defeating an enemy nation-state by destroying its economic ability and public will to wage war rather than destroying its land or naval forces...
of Germany, and knew that the B-29 Superfortress
B-29 Superfortress
The B-29 Superfortress is a four-engine propeller-driven heavy bomber designed by Boeing that was flown primarily by the United States Air Forces in late-World War II and through the Korean War. The B-29 was one of the largest aircraft to see service during World War II...
would be bombing Japan and the resultant problems which would arise from trying to combat this. Japanese military attachés had become aware of the Komet during a visit to the Luftwaffe
Luftwaffe
Luftwaffe is a generic German term for an air force. It is also the official name for two of the four historic German air forces, the Wehrmacht air arm founded in 1935 and disbanded in 1946; and the current Bundeswehr air arm founded in 1956....
squadron evaluation aircraft centre Erprobungskommando 16. They negotiated the rights to licence-produce the aircraft and its Walter HWK 509A
Walter HWK 109-509
-See also:-Bibliography:*Jane's Fighting Aircraft of World War II. London. Studio Editions Ltd, 1989. ISBN 0-517-67964-7-External links:*...
rocket engine. The engine license alone cost the Japanese 20 million Reichsmarks.
The agreement was for Germany to provide the following by spring 1944:
- Complete blueprints of the Me 163B Komet and the HWK 509A engine.
- One complete Komet; two sets of sub-assemblies and components.
- Three complete HWK 509A engines.
- Inform Japan of any improvements and developments of the Komet.
- Allow the Japanese to study the manufacturing processes for both the Komet and the engine.
- Allow the Japanese to study Luftwaffe operational procedures for the Komet.
The broken-down aircraft and engine were sent to Kobe
Kobe
, pronounced , is the fifth-largest city in Japan and is the capital city of Hyōgo Prefecture on the southern side of the main island of Honshū, approximately west of Osaka...
, Japan in early 1944. It is probable that the airframe was on the Japanese submarine RO-501 (ex-U-1224), which left Kiel
Kiel
Kiel is the capital and most populous city in the northern German state of Schleswig-Holstein, with a population of 238,049 .Kiel is approximately north of Hamburg. Due to its geographic location in the north of Germany, the southeast of the Jutland peninsula, and the southwestern shore of the...
, Germany on 30 March 1944 and was sunk in the mid-Atlantic on 13 May 1944 by the hunter-killer group based on the escort carrier . Plans and engines were on the Japanese submarine I-29
Japanese submarine I-29
I-29, code-named Matsu , was a B1 type submarine of the Imperial Japanese Navy used during World War II on two secret missions with Germany, during one of which she was sunk.-Type B Submarines:...
, which left Lorient
Lorient
Lorient, or L'Orient, is a commune and a seaport in the Morbihan department in Brittany in north-western France.-History:At the beginning of the 17th century, merchants who were trading with India had established warehouses in Port-Louis...
, France on 16 April 1944 and arrived in Singapore
Singapore
Singapore , officially the Republic of Singapore, is a Southeast Asian city-state off the southern tip of the Malay Peninsula, north of the equator. An island country made up of 63 islands, it is separated from Malaysia by the Straits of Johor to its north and from Indonesia's Riau Islands by the...
on 14 July 1944, later sunk by the submarine
Submarine
A submarine is a watercraft capable of independent operation below the surface of the water. It differs from a submersible, which has more limited underwater capability...
on 26 July 1944, near the Philippines
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
, after leaving Singapore.
The Japanese decided to attempt to copy the Me 163 using a basic instructional manual on the Komet in the hands of naval mission member Commander Eiichi Iwaya who had travelled to Singapore in the I-29 and flown on to Japan when the submarine docked.
From its inception, the project was a joint Imperial Japanese Army Air Service
Imperial Japanese Army Air Service
The , was the land-based aviation force of the Imperial Japanese Army. As with the IJA itself, the IJAAF was developed along the lines of Imperial German Army Aviation so its primary mission was to provide tactical close air support for ground troops while maintaining a limited air interdiction...
(JAAF)/Imperial Japanese Navy Air Service
Imperial Japanese Navy Air Service
The Imperial Japanese Navy Air Service was the air arm of the Imperial Japanese Navy during World War II, the organization was responsible for the operation of naval aircraft and the conduct of aerial warfare in the Pacific War.It was controlled by the Navy Staff of the Imperial Japanese Navy and...
(JNAF) venture. The JAAF wanted a new design to be drawn up. The JNAF, on the other hand, felt the design should mimic the German Komet because it had already proven to be a stable aerodynamic body. It was the JNAF which won and issued the 19-shi specification in July 1944 for the design of the rocket-powered defence fighter. The contract went to Mitsubishi Jukogyo KK, which would produce both the JNAF version the J8M1 Shūsui and the JAAF version Ki-200.
The project was headed by Mijiro Takahashi. The JAAF, however decided to undertake their own design to meet the 19-shi specifications, working at their Rikugun Kokugijitsu Kenkyujo (JAAF Aerotechnical Institute) in secret.
At the 1st Naval Air Technical Arsenal in Yokosuka, in association with Mitsubishi and Yokosuka Arsenal, work began to adapt the Walter HWK 509A engine to Japanese manufacturing capabilities and techniques. This was also where efforts were underway to produce a glider version of the J8M to provide handling data. While working on this glider, the MXY8 Akigusa (秋草, "Autumn Grass"), Mitsubishi completed a mock-up of the J8M1 in September 1944.
Both the JAAF and JNAF approved its design and construction and a prototype
Prototype
A prototype is an early sample or model built to test a concept or process or to act as a thing to be replicated or learned from.The word prototype derives from the Greek πρωτότυπον , "primitive form", neutral of πρωτότυπος , "original, primitive", from πρῶτος , "first" and τύπος ,...
was built. In December 1944, the MXY8 was completed and, on 8 December 1944, at the Hyakurigahara Airfield, Lieutenant-Commander Toyohiko Inuzuka took the controls of the MXY8. Once in the air, Inuzuka found the MXY8 almost perfectly emulated the handling characteristics of the Komet. Two additional MXY8 gliders were constructed in the naval yard at Yokosuka, one being delivered to the Rikugun Kokugijitsu Kenkyujo (JAAF Aerotechnical Institute) at Tachikawa for evaluation. The JNAF initiated the construction another prototype, production designation Ku-13. This was to use water ballast to simulate the weight of an operational J8M complete with engine and weapons. This variant was to be built by Maeda Aircraft Institute, while the JAAF version was to be constructed by Yokoi Koku KK (Yoki Aircraft Co). The JNAF also proposed a more advanced trainer, designated the MXY9 Shūka (秋火, "Autumn Fire") which would be powered by a 441 lbf (2 kN) thrust Tsu-11 ducted-fan engine. The war, however, ended before this model could be built.
Mitsubishi and partners Nissan and Fuji
Fuji
-People:* Mr. Fuji, ring name of wrestling and manager Harry Fujiwara* Keiko Fuji, a Japanese singer of the 1960s and 1970s, and mother of Hikaru Utada* Sumiko Fuji, a Japanese actressFictional characters* Fuji , a character in the Stormwatch series...
proceeded with development of the airframe and Yokosuka Arsenal was adapting the engine for Japanese production, designated the Ro.2. The Japanese succeeded in producing prototypes that outwardly looked very much similar to the Komet. The J8M1 had a wet weight that was 900 lb (408.2 kg) lighter, the aircraft having a plywood
Plywood
Plywood is a type of manufactured timber made from thin sheets of wood veneer. It is one of the most widely used wood products. It is flexible, inexpensive, workable, re-usable, and can usually be locally manufactured...
main spar
Spar (aviation)
In a fixed-wing aircraft, the spar is often the main structural member of the wing, running spanwise at right angles to the fuselage. The spar carries flight loads and the weight of the wings whilst on the ground...
and wooden vertical tail. The designers had also dispensed with the armoured glass in the cockpit
Cockpit
A cockpit or flight deck is the area, usually near the front of an aircraft, from which a pilot controls the aircraft. Most modern cockpits are enclosed, except on some small aircraft, and cockpits on large airliners are also physically separated from the cabin...
and the aircraft carried less ammunition and slightly less fuel.
The Ki-200 and the J8M1 differed only in minor items, but the most obvious difference was the JAAF's Ki-200 was armed with two 30 mm (1.18 in) Type 5 cannon
Type 5 cannon
The Type 5 was a Japanese Navy autocannon used near the end of World War II. It was an indigenous design with better performance than Oerlikon-derived Type 2 or Browning-derived Ho-155, although it was considerably heavier...
(with a rate of fire of 450 rounds per minute and a muzzle velocity of 2350 ft/s (716.3 m/s), while the J8M1 was armed with two 30 mm (1.18 in) Ho-105 cannon (rate of fire 400 rounds per minute, muzzle velocity 2460 ft/s (749.8 m/s). The Ho-105 was the lighter of the two and both offered a higher velocity than the MK 108 cannon
MK 108 cannon
The MK 108 was a 30 mm caliber autocannon manufactured in Germany during World War II by Rheinmetall-Borsig for use in aircraft.-Development:...
of the Me 163 (whose muzzle velocity was 1705 ft/s (519.7 m/s).
The Toko Ro.2 (KR10) rocket motor did not offer the same thrust rating as the original, and Mitsubishi calculated that the lighter weight of the J8M1 would not offset this. Performance would not be as good as that of the Komet, but was still substantial.
The engine still used the German propellants of T-Stoff
T-Stoff
T-Stoff was the oxidizer part of a bipropellant rocket fuel combination used in Germany during World War II. It is a stabilized high test peroxide...
oxidizer and C-Stoff
C-Stoff
C-Stoff was a reductant used in bipropellant rocket fuels developed by Hellmuth Walter Kommanditgesellschaft in Germany during World War 2...
fuel (hydrogen peroxide/methanol-hydrazine), known in Japan as Ko and Otsu respectively.
A total of 60 of the training version (Ku-13, Ki-13, MXY-8, MXY-9) were produced by Yokosuka, Yokoi
Yokoi
Yokoi is a common Japanese surname. It may refer to:*Gunpei Yokoi, designer of the Game Boy and other Nintendo products;*Hirotaka Yokoi, professional mixed martial arts fighter;*Shoichi Yokoi, soldier and celebrity;*Shonan Yokoi, political reformer;...
and Maeda
Maeda
Maeda is a Japanese surname. An archaic romanization includes Mayeda. It can refer to:-Maeda clan:One of the traditional Japanese clans and prominent family during the Sengoku period of Japanese history:...
. Seven of the operational version (J8M1/Ki-200) were built by Mitsubishi
Mitsubishi
The Mitsubishi Group , Mitsubishi Group of Companies, or Mitsubishi Companies is a Japanese multinational conglomerate company that consists of a range of autonomous businesses which share the Mitsubishi brand, trademark and legacy...
.
Operational history
In 8 January 1945, one of the two J8M1 prototypes was towed aloft, water ballast added in place of the fuel tank
Fuel tank
A fuel tank is safe container for flammable fluids. Though any storage tank for fuel may be so called, the term is typically applied to part of an engine system in which the fuel is stored and propelled or released into an engine...
and rocket engine to test its aerodynamics
Aerodynamics
Aerodynamics is a branch of dynamics concerned with studying the motion of air, particularly when it interacts with a moving object. Aerodynamics is a subfield of fluid dynamics and gas dynamics, with much theory shared between them. Aerodynamics is often used synonymously with gas dynamics, with...
. The test flights confirmed the design. Training
Flight training
Flight training is a course of study used when learning to pilot an aircraft. The overall purpose of primary and intermediate flight training is the acquisition and honing of basic airmanship skills....
courses for JAAF and JNAF pilots began on the Ku-53 glider
Military glider
Military gliders have been used by the military of various countries for carrying troops and heavy equipment to a combat zone, mainly during the Second World War. These engineless aircraft were towed into the air and most of the way to their target by military transport planes, e.g...
, which shared a similar configuration to the J8M1. The 312th Naval Air Group was selected to operate the first J8M1. Mitsubishi, Fuji Hikoki, and Nissan Jidosha all had tooling for mass production well into the advanced stages, ready to produce both the J8M1 and the J8M2 variant, which differed from the J8M1 in sacrificing one of the Type 5 cannon for a small increase in fuel capacity. The first J8M1 prototype to be equipped with the Toko Ro.2 (KR10) was ready in June 1945. They were then transferred from the Nagoya plant to Yokoku for final checks before powered flight testing, after final glide tests with the engine installed.
The J8M took to the air for its first powered flight on 7 July 1945, with Lieutenant Commander
Lieutenant Commander
Lieutenant Commander is a commissioned officer rank in many navies. The rank is superior to a lieutenant and subordinate to a commander...
Toyohiko Inuzuka at the controls; after his "sharp start" rocket-powered takeoff, Inuzuka successfully jettisoned the dolly upon becoming airborne and began to gain speed, climbing skywards at a 45° angle. At an altitude of 396 m (1,299.2 ft), the engine stopped abruptly and the J8M1 stalled. Inuzuka managed to glide the aircraft back, but clipped a small building at the edge of the airfield while trying to land, causing the aircraft to burst into flames. Inuzuka died the next day. While Mitsubishi and naval technicians sought to find the cause of the accident, all future flights were grounded. The engine cutout had occurred because the angle of climb, coupled with the fuel tanks being half-filled for this first flight, caused a shifting of the fuel, which in turn caused an auto cutout device to activate because of an air lock in the fuel line
Fuel line
A fuel line is a hose used to bring fuel from one point in a vehicle to another or from a storage tank to a vehicle. It is commonly made of reinforced rubber to prevent splitting and kinking....
. Requests to continue flight testing were denied pending the modification of the fuel pump
Fuel pump
A fuel pump is a frequently essential component on a car or other internal combustion engined device. Many engines do not require any fuel pump at all, requiring only gravity to feed fuel from the fuel tank through a line or hose to the engine...
s in the aircraft. The sixth and seventh prototypes were to be fitted with the modified Ro.2 engine.
Full scale production readiness was almost at hand and in fact, component construction was already underway. Flight testing was to resume, despite another explosion of the fuel mixture during a ground test days after the crash, in late August 1945 and the J8M2 design was finalized. But on 15 August 1945, the war ended for the Japanese and all work on the J8M ceased. The end of the war also spelled the end of the JAAF's Ki-202 Shūsui-Kai (Modified Shusui), whose design had begun in secret months before. The Ki-202 was to offer improved flight endurance over the Ki-200 and was slated to be the priority fighter for the JAAF in 1946, but no metal was cut before Japan's surrender.
Germany tried to send another Komet in U-864, but the submarine was sunk near Bergen
Bergen
Bergen is the second largest city in Norway with a population of as of , . Bergen is the administrative centre of Hordaland county. Greater Bergen or Bergen Metropolitan Area as defined by Statistics Norway, has a population of as of , ....
by British submarine in February 1945.
Variants
J8M1J8M2 Shūsui Model 21(?)
- Long-range version for Navy, identical to J8M1, but armament reduced to a single 30 mm (1.18 in) cannon.
J8M3 Shūsui Model 22 (Ki-202 Shūsui-kai)
- Long-range version for Army and Navy, with fuselage and wingspan lengthened to 7.10 m (23 ft 3 in) and 9.75 m (32 ft 0 in) respectively. Powered by 19.6 kN (4,410 lbf) Tokuro-3, projected maximum speed 900 km/h (560 mph).
Yokosuka MXY-8 "Akigusa" (Yokoi Ku-13)
- Training glider using J8M airframe for Navy and Army.
Yokosuka MXY-9 "Shuka"
- Training version using J8M airframe, powered by Tsu-11Tsu-11The Tsu-11 was a primitive, motorjet-style jet engine produced in small numbers in Japan in the closing stages of World War II. It was principally designed to propel the Japanese Ohka flying bomb, a kamikaze weapon....
thermojet engine.
Operators
- Imperial Japanese Army Air ServiceImperial Japanese Army Air ServiceThe , was the land-based aviation force of the Imperial Japanese Army. As with the IJA itself, the IJAAF was developed along the lines of Imperial German Army Aviation so its primary mission was to provide tactical close air support for ground troops while maintaining a limited air interdiction...
- Imperial Japanese Navy Air ServiceImperial Japanese Navy Air ServiceThe Imperial Japanese Navy Air Service was the air arm of the Imperial Japanese Navy during World War II, the organization was responsible for the operation of naval aircraft and the conduct of aerial warfare in the Pacific War.It was controlled by the Navy Staff of the Imperial Japanese Navy and...
Survivors
In November 1945, two aircraft were taken from Yokosuka to the United StatesUnited States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
for evaluation aboard USS Barnes. FE-300/T2-300 (USA ident) (Japanese ident 403) is now exhibited in the Planes of Fame Museum. The other was at NAS Glenview in October 1946 (identity unknown), but was scrapped.
In the 1960s, a nearly complete (but badly damaged) fuselage was discovered in a cave in Japan. This was on display at a Japanese Air Force Base near Gifu
Gifu, Gifu
is a city located in the south-central portion of Gifu Prefecture, Japan, and serves as the prefectural capital. The city has played an important role in Japan's history because of its location in the middle of the country. During the Sengoku period, various warlords, including Oda Nobunaga, used...
until 1999, when it was restored and completed by Mitsubishi for display in the company's internal Komaki Plant Museum.