Japanese rocket-powered interceptor
The
Mitsubishi J8M
Sh?sui
(
Japanese
: 三菱 J8M 秋水, literally "Autumn Water", used as a poetic term meaning "Sharp Sword" deriving from the swishing sound of a sword) is a
Japanese
World War II
rocket
-powered
interceptor aircraft
closely based on the
German
Messerschmitt Me 163 Komet
. Built as a joint project for both the
Navy
and the
Army Air Services
, it was designated
J8M
(Navy) and
Ki-200
(Army).
Design and development
[
edit
]
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 aware of the results of the
strategic bombing
of Germany, and knew that the
B-29 Superfortress
would be bombing Japan and the resultant problems which would arise from trying to combat this. Japanese military attaches had become aware of the
Komet
during a visit to the
Bad Zwischenahn
airfield of
Erprobungskommando
16
, the
Luftwaffe
evaluation squadron charged with service test of the revolutionary rocket-propelled interceptor. They negotiated the rights to licence-produce the aircraft and its
Walter HWK 509A
rocket engine. The engine licence alone cost the Japanese 20 million
Reichsmarks
(equivalent to 81 million 2021 euros).
[2]
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
, Japan in early 1944. It is probable that the airframe was on the Japanese submarine
RO-501
(ex-
U-1224
), which left
Kiel
, 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
USS
Bogue
. Plans and engines were on the Japanese submarine
I-29
, which left
Lorient
, France on 16 April 1944 and arrived in
Singapore
on 14 July 1944, later sunk by the
submarine
USS
Sawfish
on 26 July 1944, near the
Philippines
, 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
(JAAF)/
Imperial Japanese Navy Air Service
(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
Sh?sui
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
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 of 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
Sh?ka
(秋火, "Autumn Fire") which would be powered by a 2 kN (450 lb
f
) thrust Tsu-11 ducted-fan engine. The war, however, ended before this model could be built.
Mitsubishi and partners
Nissan
and
Fuji
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 400 kg (880 lb) lighter, the aircraft having a
plywood
main
spar
and wooden vertical tail. The designers had also dispensed with the armoured glass in the
cockpit
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
(with a rate of fire of 450 rounds per minute and a muzzle velocity of 920 m/s (3,000 ft/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 750 m/s (2,500 ft/s). The Ho-105 was the lighter of the two and both offered a higher velocity than the
MK 108 cannon
of the Me 163 (whose muzzle velocity was 520 m/s (1,700 ft/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.
[3]
The engine used the German propellants of
T-Stoff
oxidizer and
C-Stoff
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 and
Maeda
. Seven of the operational version (J8M1/Ki-200) were built by
Mitsubishi
.
Operational history
[
edit
]
On 8 January 1945, one of the two J8M1 prototypes was towed aloft, water ballast added in place of the
fuel tank
and rocket engine to test its
aerodynamics
. The test flights confirmed the design.
Training
courses for JAAF and JNAF pilots began on the Ku-53
glider
, 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,
[4]
with
Lieutenant 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 400 m (1,300 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.
[5]
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
. Requests to continue flight testing were denied pending the modification of the
fuel pumps
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 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
Sh?sui-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
by British submarine
HMS
Venturer
in February 1945.
As with many other Japanese fighter types combating air raids over Japan, the Ki-200 was considered for use in
ramming
attacks against B-29s. The envisioned mission profile was to make one or two firing passes and then, with the remaining energy, conduct a ramming attack. Any fuel left on board would most likely detonate, increasing the effectiveness of the attack, but also meaning the pilot had little chance of survival. Nevertheless, the cost was deemed to be worth it and plans were being drawn up to form a "Hagakure-Tai" (Special Attack Unit), similar to the German
Sonderkommando Elbe
, when the war ended.
Variants
[
edit
]
- Ki-200
- An interceptor variant for the IJAAS, almost identical to the IJNAS J8M
- J8M1
- J8M2
Sh?sui
Model 21(?)
- Long-range version for Navy, identical to J8M1, but armament reduced to a single 30 mm (1.18 in) cannon.
- J8M3
Sh?sui
Model 22 (
Rikugun Ki-202 Sh?sui-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-11
thermojet engine.
Operators
[
edit
]
-
Japan
Survivors
[
edit
]
In November 1945, two aircraft were taken from
Yokosuka
to the
United States
for evaluation aboard
USS
Barnes
. FE-300/T2-300 (USA ident) (Japanese ident 403) is now exhibited at the
Planes of Fame Museum
in
Chino, California
.
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 Self Defense Force base near
Gifu
until 1999, when it was restored and completed by Mitsubishi for display in the company's internal Komaki Plant Museum.
[6]
Gallery
[
edit
]
Comparative Specifications
[
edit
]
Specifications
[7]
|
|
J8M1
|
J8M2
|
Ki-200
|
Manufacturer:
|
Mitsubishi Jukogyo K.K
|
Type:
|
Interceptor
|
Crew:
|
1
|
Span:
|
9.50 m (31 ft)
|
|
9.47 m (31 ft)
|
Length:
|
6.03 m (20 ft)
|
|
5.88 m (19 ft)
|
Height:
|
2.68 m (9 ft)
|
|
2.68 m (9 ft)
|
Wing area:
|
17.72 m
2
(191 sq ft)
|
|
17.69 m
2
(190 sq ft)
|
Wing loading:
|
219.22 kg/m
2
(44.9 lb/ft
2
)
|
219.70 kg/m
2
(45 lb/ft
2
)
|
|
Empty weight:
|
1,445 kg (3,186 lb)
|
1,510 kg (3,329 lb)
|
1,505 kg (3,318 lb)
|
Loaded:
|
3,000 kg (6,614 lb)
|
3,650 kg (8,047 lb)
|
Maximum:
|
3,870 kg (8,532 lb)
|
3,900 kg (8,598 lb)
|
3,870 kg (8,532 lb)
|
Useful load:
|
1,545 kg (3,406 lb)
|
2,140 kg (4,718 lb)
|
|
Fuel capacity:
|
T-Stoff
= 1,181 L (260 imp gal)
C-Stoff
= 522 L (115 imp gal)
|
Armament
|
Gun:
|
2x
Type 5 30mm autocannon
|
2x
Type 5 30mm autocannon
|
2x
Ho-155 30mm autocannon
or 2x
Ho-5 20mm autocannon
|
Capacity:
|
53 rounds per gun
|
Performance
|
Powerplant:
|
One Toku-Ro.2 (KR10) bi-fuel rocket motor developing 1,500 kg (3,307 lb) of thrust
|
Liquid-propellant:
|
T-Stoff
= 80%
Hydrogen Peroxide
+ 20%
Oxyquinoline
and
Pyrophosphates
C-Stoff
= 30%
Hydrazine Hydrate
+ 70%
Methanol
,
Water
and
Potassium
-
Copper
Cyanides
|
Max speed:
|
900 km/h (559 mph) at 10,000 m (32,808 ft)
|
Cruise speed:
|
699 km/h (434 mph)
|
|
351 km/h (218 mph)
|
Landing speed:
|
150 km/h (93 mph)
|
|
|
Range:
|
3 min 06 seconds
of powered flight
|
|
2 min 30 seconds
of powered flight
|
Max range:
|
5 min 30 seconds
of powered flight
|
|
7 min
of powered flight
|
Climb:
|
2,000 m (6,562 ft)
in 40 seconds
4,000 m (13,123 ft)
in 2 minutes 08 seconds
8,000 m (26,247 ft)
in 3 minutes 08 seconds
10,000 m (32,808 ft)
in 3 minutes 50 seconds
|
|
10,000 m (32,808 ft)
in 3 minutes 40 seconds
|
Rate of climb:
|
43.47 m/s (8,557 ft/min)
|
|
45.45 m/s (8,947 ft/min)
|
Ceiling:
|
12,000 m (39,370 ft)
|
See also
[
edit
]
Related development
Related lists
Notes
[
edit
]
Bibliography
[
edit
]
- Butler, Phil.
War Prizes: An Illustrated Survey of German, Italian and Japanese Aircraft Brought to Allied Countries During and After the Second World War
. Leicestershire, UK: Midland, 1994.
ISBN
0-904597-86-5
.
- Dyer, Edward M. III.
Japanese Secret Projects: Experimental Aircraft of the IJA and IJN 1939-1945.
Hinckley, UK: Midland Publishing, 2009.
ISBN
978-1-85780-317-4
.
- Ethell, Jeffrey L.
Komet: The Messerschmitt 163
. London: Ian Allan, 1978.
ISBN
0-7110-0827-2
. (This book shows U-852 or U-68 being used to carry the Me 163.)
- Francillon, Ph.D., Rene J.
Japanese Aircraft of the Pacific War
. London: Putnam & Company, 1970 (2nd edition 1979).
ISBN
0-370-30251-6
.
- Green, William (1971).
Rocket Fighter (Ballantine's Illustrated History of World War II, Weapons Book No. 20)
. New York: Ballantine Books, Inc.
ISBN
0-345-02163-0
.
.
- Green, William.
War Planes of the Second World War: Fighters, Volume Three
. London: Macdonald, 1961.
ISBN
0-356-01447-9
.
- Yamashita, Takeo (ed).
秋水」と日本陸海軍ジェット、ロケット機
. Tokyo: Model Art Co., 1998.
- Yamazaki, Akio (January?February 2005). "Tail of the Tiger: Japan's 'Shushi' Interceptor".
Air Enthusiast
. No. 115. pp. 36?41.
ISSN
0143-5450
.
External links
[
edit
]
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Company designations
| |
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Imperial Japanese Army
early designations
| |
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Imperial Japanese Army
short designations
| |
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Imperial Japanese Navy
short designations
| Carrier fighters
| |
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Carrier Torpedo Bombers
| |
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Reconnaissance aircraft
| |
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Carrier dive bombers
| |
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Observation seaplanes
| |
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Land-based Attack Bombers
| |
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Interceptors
| |
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Transports
| |
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Trainers
| |
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Patrol Aircraft
| |
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World War II Allied
reporting names
| |
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Japanese Self-Defense
Force designations
| |
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Company divisions
| |
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|
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Fighters (A)
| |
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Torpedo bombers (B)
| |
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Shipboard reconnaissance (C)
| |
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Dive bombers (D)
| |
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Reconnaissance seaplanes (E)
| |
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Observation seaplanes (F)
| |
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Land-based bombers (G)
| |
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Flying Boats (H)
| |
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Land-based Fighters (J)
| |
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Trainers (K)
| |
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Transports (L)
| |
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Special-purpose (M)
1
| |
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Floatplane fighters (N)
| |
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Land-based bombers (P)
| |
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Patrol (Q)
| |
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Land-based reconnaissance (R)
| |
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Night fighters (S)
| |
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1
X as second letter is for experimental aircraft or imported technology demonstrators not intended for service,
2
Hyphenated trailing letter (-J, -K, -L, -N or -S) denotes design modified for secondary role,
3
Possibly incorrect designation, but used in many sources
|
|
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Fighters
| Naval fighters
1
| |
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Land-based fighters
2
| |
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Nightfighters
3
| |
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Jet/rocket fighters
| |
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|
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Heavy bombers
4
| |
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Bombers
5
| |
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Patrol
6
| |
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Reconnaissance
7
| |
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Trainers
8
| |
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Transports
9
| |
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Miscellaneous
10
| |
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Special-purpose aircraft
11
| |
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With some exceptions for rockets, jets and repurposed aircraft, names chosen were for: 1. Winds, 2. Lightning, 3. Nighttime lights, 4. Mountains, 5. Stars/constellations, 6. Seas, 7. Clouds, 8. Plants, 9. Skies, 10. Landscapes, and 11. Flowers. Published translations disagree, and many are simplified, especially for plants, where the Japanese referred to a specific variety and the common translations only to the broader type.
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Fighters
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Bombers
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Transports
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Reconnaissance
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Trainers
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Special Attackers
| |
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