Nakajima J9Y

infobox Aircraft
name = J9Y Kikka
type = Attack aircraft
manufacturer = Nakajima



caption =
designer =
first flight = 7 August 1945
introduced =
retired = 15 August 1945
status = Prototype
primary user = IJN Air Service
more users =
produced =
number built = 2
unit cost =
variants with their own articles =

The nihongo|Nakajima Kikka|中島 橘花|"Orange Blossom"| was Japan's first jet-powered aircraft. It was developed late in World War II and the first prototype had only flown once before the end of the conflict. It also called as nihongo|Kōkoku Nigō Heiki|皇国二号兵器|"Imperial Weapon No.2"|.

Design and development

After the Japanese military attaché in Germany witnessed trials of the Messerschmitt Me 262 in 1944, the Imperial Japanese Navy issued a request to Nakajima to develop a similar aircraft to be used as a fast attack bomber. Among the specifications for the design were the requirements that it should be able to be built largely by unskilled labour, and that the wings should be foldable. This latter feature was to enable the aircraft to be hidden in caves and tunnels around Japan as the Navy began to prepare for the defence of the home islands. Nakajima designers Kazuo Ohno and Kenichi Matsumura laid out an aircraft that bore a strong but superficial resemblance to the Me 262.

The Kikka was designed in preliminary form to use the Tsu-11, a very crude thermojet style of jet engine that was little more than a ducted fan with an afterburner. Subsequent designs were planned around the Ne-10 (TR-10) centrifugal-flow turbojet, and the Ne-12, which added a four-stage axial compressor to the front of the Ne-10. Tests of this powerplant soon revealed that it would not produce anywhere near the power required to propel the aircraft, and the project was temporarily stalled. It was then decided to produce a new axial-flow turbojet based on the German BMW 003. Development was troublesome, based on little more than photographs and a cut-away drawing, but a suitable unit, the Ishikawajima Ne-20, was finally built. By Summer 1945, the Kikka project was making progress once again and at this stage, reflecting the deteriorating war situation, the Navy changed the role of the aircraft to "special attacker", the term reserved for kamikaze weapons.

Compared to the Me-262, the Kikka airframe was noticeably smaller and more conventional in design, with straight (rather than swept) wings and tail surfaces. The triangular cross-section characteristic of the German design was less pronounced, due to smaller fuel tanks. The main landing gear of the Kikka were taken from the Mitsubishi Zero and the nose wheel from the tail of a Yokosuka P1Y bomber.

Operational history

The first prototype commenced ground tests at the Nakajima factory on 30 June 1945. The following month it was dismantled and delivered to Kisarazu Naval Airfield where it was re-assembled and prepared for flight testing. The first flight took place on 7 August 1945, with Lt Cdr Susumu Takaoka at the controls. The aircraft performed well during a 20 minute test flight, with the only concern being the length of the takeoff run. For the second test flight, four days later, rocket assisted take off (RATO) units were fitted to the aircraft. However, because their alignment had been miscalculated, the pilot mistakenly believed that they had not fired and thus shut off the main engines to abort takeoff. As a result the aircraft did not take off at all and was damaged when it ran off the end of the runway. Before it could be repaired Japan had surrendered and the war was over.

At this point the second prototype was close to completion, and between 18 and 25 more airframes were under construction. One of these was a two-seat trainer. Other follow-on versions proposed had included a reconnaissance aircraft, and a fighter armed with two 30 mm cannons. These were expected to be powered by more advanced developments of the Ne-20, designated Ne-130 and Ne-330.

Postwar

After the war, a Kikka was taken to the United States, for analysis, to the Patuxent River Naval Air Base, Maryland. It is now housed in the National Air and Space Museum. This aircraft is very incomplete and is believed to have been patched together from a variety of semi-completed airframes.

Two Ne-20 jet engines had been taken to the US and sent for analysis to the Chrysler Corporation in 1946. This was only revealed in 2005 by W.I. Chapman, who was in charge of the project at the time. A working engine was assembled with the parts of the two Ne-20s, and extensively tested for 11 hours and 46 minutes. A report was issued on 7 April 1947, titled "Japanese NE-20 turbo jet engine. Construction and performance". The document is now on display at the Tokyo National Science Museum.

Variants

Nakajima Aircraft Company developed some variants of these aircraft:

Jet Interceptor model

Estimated data about this development:

Proposed developments: (equivalents to Me 262 A-1a fighter type)

*Nakajima "Kikka" Turbojet Interceptor Basic version

*Length : 11.50 m
*Wing Span : 13.70 m
*Height : 4.05 m
*Wing Area : 25.0 m²
*All-Up Weight : 7,000 kg
*Empty Weight : 4,500 kg
*Engine : 2 x Ishikawajima Ne-130 Turbojet, 908 kgf (8.90 kN) or Nakajima Ne-230 *Turbojet, 885 kgf (8.68 kN)
*Max Speed : 852 km/h (Ne-130), 812 km/h (Ne-230)
*Range : 980 km
*Service Ceiling : 12,000+ m
*Crew : 1
*Armament: (only interceptor variant)
*30 mm Ho155-II Machine Gun x 2 or 20 mm Ho5 Machine Gun x 2 (for Navy)

*- if the regular version, equal to Nakajima Ki-201 "Karyuu" Army Interceptor jet fighter

Jet interceptor modifications

There is only incomplete information on this variant. There were three projects in development for a Kikka Interceptor in May 1945.

First and second projects were essentially similar:
*Specification
**Crew : 1
**Length : 9.25 m
**Wing span : 10.00 m
**Height : 3.05 m
**Wing area : 13.21 m²
**Weight
***Fully laded: 4,152 kg
***Empty : 3,920 kg
**Powerplant: 2 x Ishikawajima Ne20-Kai Turbojet, 618 kgf (6.06 kN)
with 2 x "Type 4" 1-Go Model 20 Rocket (800 kg thrust) for RATO
*Armament : 30mm Type 5 Machine Gun x 1
*Performance
**Max Speed : 700 km/h at altitude of 6,000 m
**Max Range : 609 km at altitude of 6,000 m
**Service Ceiling : 12,100 m

The third project had modified flaps and a different "extended" wing data as above but:
**Wing area : 14.52 m²
**Maximum speed : 685 km/h at altitude of 6,000 m
**Maximum range : 594 km at altitude of 6,000 m
**Service ceiling : 12,300 m

Jet Fighter/Bomber model

Estimated data about this development:

Proposed developments (equivalent to Me 262 A-2a fighter/bomber type)

*Nakajima "Kikka" Turbojet Fighter/Bomber version

*Length : 11.50 m
*Wing Span : 13.70 m
*Height : 4.05 m
*Wing Area : 25.0 m²
*All-Up Weight : 7,000 kg
*Empty Weight : 4,500 kg
*Engine : 2 x Ishikawajima Ne-130 Turbojet, 908 kgf (8.90 kN) or Nakajima Ne-230 *Turbojet, 885 kgf (8.68 kN)
*Max Speed : 852 km/h (Ne-130), 812 km/h (Ne-230)
*Range : 980 km
*Service Ceiling : 12,000+ m
*Crew : 1
*Armament : (only fighter bomber variant)
*2 x 30 mm Ho-155-II cannons, or 2 x 20 mm Ho-5 cannons (for Navy)
*single 500 kg or 800 kg bomb

Jet Trainer model

A tandem two seat trainer version was proposed to be equivalent to the Me 262 B-1a trainer, called the Nakajima "Kikka" Turbojet Operative Trainer
*Specification
**Crew: 2
**Length : 9.25 m
**Wing span : 10.00 m
**Height: 3.05 m
**Wing Area : 13.21 m²
**All-Up Weight : 4,009 kg
**Powerplant : 2 x Ishikawajima Ne20-kai Turbojet, 618 kgf (6.06 kN)
with 2 Type4 1-Go Model 20 Rocket of 800 kg each
*Performance
**Max Speed : 722 km/h (Altitude: 6,000 m)
**Max Range : 667 km (Altitude: 6,000 m)

Jet Special Attacker (Kamikaze) models

This was a proposed "Special Attack Project" existing only in plan form as the Nakajima "Kikka" Prototype Turbojet Special Attacker (or "Type 20 Special Attacker "Kikka")

*Crew : 1
*Length : 9.25 m
*Wing Span : 10.00 m
*Height : 3.05 m
*Wing Area : 13.21 m²
*All-Up Weight : 3,550 kg
*Empty Weight : 2,300 kg
*Engine : 2 x Ishikawajima Ne20 Turbojet, 475 kgf (4.66 kN)
with two Type4 1-Go Model20 Rockets of 800 kg
*Max Speed : 677 km/h (Altitude: 6,000 m)
*Max Range : 584 km (Altitude: 6,000 m)
*Service Ceiling : 10,700 m
*Armament: single 500 kg "or" 250 kg bomb "or" 2x 20mm Cannons

There was also a modified version of the design to be launched from a 200 m long catpult, the "Nakajima "Kikka-kai" Prototype Turbojet Special Attacker". This differed in having a projected total weight of 4,080 kg and a maximum speed of 687 km/h at 6,000 m.

Operators (Planned)

;JPN
*Imperial Japanese Navy Air Service

pecifications ( )

aircraft specifications

plane or copter?=plane
jet or prop?=jet

ref=

crew=1
capacity=
payload main=
payload alt=
length main= 8.13 m
length alt=26 ft 8 in
span main=10.00 m
span alt=32 ft 10 in
height main=2.95 m
height alt=9' 9"
area main= 13.2 m²
area alt= 142ft²
airfoil=
empty weight main= 2,300 kg
empty weight alt= 5,071 lb
loaded weight main= 3,507 kg
loaded weight alt= 7,716 lb
useful load main=
useful load alt=
max takeoff weight main= 4,088 kg
max takeoff weight alt= 8,995 lb
more general=

engine (jet)= Ne-20
type of jet=turbojets
number of jets=2
thrust main= 9.4 kN
thrust alt= 2,094 lbf
thrust original=
afterburning thrust main=
afterburning thrust alt=
engine (prop)=1
type of prop=
number of props=1
power main=
power alt=
power original=

max speed main= 695 km/h
max speed alt= 433 mph
cruise speed main=
cruise speed alt=
stall speed main=
stall speed alt=
never exceed speed main=
never exceed speed alt=
range main= 937 km
range alt=586 miles
ceiling main= 12,303 m
ceiling alt= 39,370 ft
climb rate main= 387 m/min
climb rate alt= 1,237 ft/min
loading main=
loading alt=
thrust/weight=
power/mass main=
power/mass alt=
more performance=

armament=Guns:4 × 20mm Ho-5 cannonBombs:1 × 250 kg, 500 kg, or 1,000 kg bombs

avionics=

ee also

aircontent
related=Nakajima Ki-201

similar aircraft=
*Messerschmitt Me 262
*Heinkel He 280
*Gloster E.28/39
*Gloster Meteor
*Bell P-59A
*Sukhoi Su-9

see also=
*List of World War II jet aircraft

References

Notes

Bibliography

* Francillon, Réne J. "Japanese Aircraft of the Pacific War". London: Putnam & Company Ltd., 1970 (2nd edition 1979). ISBN 0-370-30251-6.
* Mikesh, Robert C. "Kikka, Monogram Close-Up 19". Bolyston, Massachusetts: Monogram Aviation Publications, 1979. ISBN 0-914144-19-7.
* Unknown Author "Famous Aircraft of the World no.76: Japanese Army Experimental Fighters (1)". Japan: Bunrin-Do, August 1976.
* Yamashita, Takeo, ed.「秋水」と日本陸海軍ジェット、ロケット機. Tokyo: Model Art Co. Ltd., 1998.

External links

* [http://j-aircraft.org/xplanes/hikoki_files/kikka.html "The Nakajima Kikka" entry at the "Hikoki: 1946" website]
* [http://www.nasm.si.edu/research/aero/aircraft/nakakikka.htm Smithsonian NASM page on their Nakajima Kikka]