Nakajima Ki-201 Karyu and "J9N/J9Y" Kikka

[windswords]

I read your previous version and it was well researched and presented. This is even better. Well done!

 

[QAZ]

'Kikka' could not become the mainstay of Japanese special attackers.

Compared to the 'Ōka' Model 43 Otsu, which was heading towards production at the end of the war, 'Kikka' was more expensive, required two Ne-20 motors instead of one, and more extensive pilot training due to being closer to an airplane. ('Ōka' Model 43 Otsu only needs basic glider training).

For these reasons, the production of 'Kikka' was only a bridge until 'Ōka' Model 43 Otsu reached major production, and the long-term production plans for 'Kikka' as a special attacker were cancelled by the end of the war.

Although it was Japan's first jet-plane, 'Kikka' was too much like a normal airplane to succeed in the flow of special attackers going unconventional.

Perhaps the fighter and recon models of 'Kikka' would have continued past 'Ouka' Model 43, had the war continued for that time.

 

[JC Carbonel]

That sounds most interesting.

JCC

 

[blackkite]

Hi! Animation. Enjoy.
https://www.youtube.com/watch?v=FIzHcQMSSkI&t=174s

 

[QAZ]

Japan's First Jet Plane [1/3]: The Unofficial Development of 'Kikka'

From June 19-20, 1944, a large scale air attack against the US Navy task force covering the invasion of Saipan Island ended in a devasta...

sensha-manual.blogspot.com

Hi, my first article on the development of 'Kikka'. This one is covering the time in which Kikka was unofficially developed as 'Prosperous Country Mk. 2 Weapon (興国二号兵器) by the orders of Vice Admiral Wada alone. As such it is not so picture heavy, because no actual figures of 'Kikka' during this time of early development exist.

Part 2 will cover official development from Jan-Aug 1945. Part 3 is to be variant development from May 1945.

 

[Airborne2001]

Kikka

This is my first time seeing many of these plans. Thank you for sharing.

 

[Justo Miranda]

Kikka

This is my first time seeing many of these plans. Thank you for sharing.

 

[HAEzu]

Hello, sorry to bring up this forum again... I want to ask about the purpose or role type of the Kikka. As the name of Nakajima "Kikka" didn't have something like a designation number like others like Navy Fighter and Interceptor, which means Kikka has the same role as Kugisho Ōka (I then don't know what MXY7 means) as "Special Attacker," or I can say intended as a "Kamikaze" role historically in our timeline. What I ask is: could Kikka be used as a Navy fighter or interceptor or not (this may be something I don't know about Kikka)?

Also, I'm interested in the name, which comes from Tzoli, "J9K".
Best regards,

 

[blackkite]

At the time of development, the Kikka was not equipped with a fixed machine gun, but was planned to carry a single 500 kg or 800 kg bomb under the fuselage, and to launch from land to conduct horizontal bombing and shallow dive bombing against enemy ships. According to one theory, skip bombing using a bomb called "Type 3 25-8 bomb or tentatively designated Type 4 50-8 bomb" was also planned (described in the draft request for the prototype Kikka project).

This aircraft is a attack aircraft intended for anti-ship attacks by bombing. It was not a aircraft designed exclusively for ramming attack from the beginning, like Ohka, but considering the name "flower（花）" that represents a ramming attack aircraft, and considering the war situation at the time, there is an opinion that there was no use other than to use it as a ramming attack aircraft.

In addition, the military wanted to preserve reciprocating engines, which require expensive and high production technology, and use them for air defense interceptors rather than using them for ramming attack aircraft, and if the technical aspects were overcome and mass production was achieved, jet engines, which were cheaper than reciprocating engines and easier to mass-produce, were considered to be the most suitable engines for ramming attack aircraft.

However, Susumu Watanabe, who was in charge of the engine rigging of the Kikka said, "The Kikka was not a ramming attack aircraft, but a attack aircraft that was premised on returning from the beginning," suggesting that the Kikka was not a ramming attack aircraft.

 

[HoHun]

Hi,

However, Susumu Watanabe, who was in charge of the engine rigging of the Kikka said, "The Kikka was not a ramming attack aircraft, but a attack aircraft that was premised on returning from the beginning," suggesting that the Kikka was not a ramming attack aircraft.

It would be interesting to know the amount of fuel carried by the aircraft, and the specific fuel consumption of the jet engines.

From the article linked here ...

https://www.secretprojects.co.uk/threads/nakajima-ki-201-karyu-and-j9n-j9y-kikka.5813/page-4#post-381760

... it seems that the TR10 engines gave 300 kgf each, but it seems the TR12 yielded a significantly higher sea-level speed and thus must have given noticably more thrust, but the value doesn't appear to be specified in the article.

Regards,

Henning (HoHun)

 

[blackkite]

Kikka　Performance
The following specifications were listed in "Aviation Fan Supplement Pacific War / Japan Navy Aircraft".

Type: Prototype
Primary mission: Coastal anti-ship attack (special attack)
Main Contract: Nakajima Aircraft
First flight August 7, 1945
Crew: 1 pilot
Length: 9.25m
Height: 3.05m
Breadth: 10.00m
Wing area: 13.21㎡
Dry weight 2,300kg
Maximum takeoff weight: 3,550kg (regular) / 4,312kg (overweight)
Fuel load: 725 liters (regular) / 1,450 liters (overload)
Engine: Ishikawajima Ne-20 Axial flow turbojet × 2 units
Thrust: 475 kg (4,655 Newtons)
Estimated maximum speed: 677 km/h (altitude 6,000 m) / 670 km/h (altitude 10,000 m)
Estimated service climb altitude 10,700m
Estimated maximum cruising range: 584 km (altitude 6,000 m) / 899 km (altitude 10,000 m)
Armament: 1 500 kg or 250 kg bomb ×

 

[blackkite]

Ne20's specific fuel consumption was 1.5 lb/(lbh).

BMW 003 : 1.4 lb/(lbh). (144kg/kNh)

Data from Turbojet History and Development 1930–1960 Volume 2

 

[blackkite]

Hi!

画像ギャラリー | 日本の空をジェット機が飛んだ日 戦闘機「橘花」初飛行-1945.8.7 | 乗りものニュース

77年前の8月7日、日本初のジェット航空機となる、戦闘機「橘花」が初飛行しました。

trafficnews.jp

ƒWƒFƒbƒg‚Ö‚Ì“¹‚Í‚¯‚킵‚©‚Á‚½

 

[blackkite]

Hi!

Nakajima Kikka (Orange Blossom)

Twin-engine, single-seat, all-metal monocoque construction; conventional layout with tricycle landing gear configuration.The Nakajima Kikka was the only World War II Japanese jet aircraft capable of taking off under its own power.

airandspace.si.edu

https://www.reddit.com/r/Planes/comments/j61cwg/the_only_surviving_nakajima_kikka_japans_first

View: https://www.reddit.com/r/Planes/comments/j61cwg/the_only_surviving_nakajima_kikka_japans_first/

https://upload.wikimedia.org/wikipedia/commons/b/b7/Nakajima_Kikka_%E2%80%93_NASM_Udvar_Hazy_Center.jpg

Blueprints > WW2 Airplanes > Nakajima > Nakajima Kikka Vs Me 262

www.the-blueprints.com

Log into Facebook

Log into Facebook to start sharing and connecting with your friends, family, and people you know.

www.facebook.com

 

[blackkite]

Hi! Almost same scale.

 

[blackkite]

Hi! Almost same scale.

 

[blackkite]

Nakajima KARYU2

Nakajima Ki-201 Fighter Attack Aircraft Karyu (former Japanese Army)
Top secret Ki-201 aircraft manual 1945
Nakajima Aircraft Co., Ltd. Ota Manufacturing Technology Division

Structure

1. Overview
The emergence of "turbine rocket" aircraft as a new weapon during the war has demonstrated its operational superiority due to its superior high speed and the suitability of the "turbine rocket" engine for mass production. This aircraft is a twin-engine single-seat land fighter and attack aircraft equipped with the "turbine rocket" Ne-230, and is a special weapon. It has a low-wing monoplane semi-tensioned hull stressed skin structure and uses a mixture of light alloy and steel.

2. Main wing

The center wing and outer wing are connected by bolts to the main spar support girder cap and longitudinal members. The angle of inclination is 3 degrees, and the wing-to-body joint is easily separable. The main spar support girder cap and the circular frame are connected by bolts to the side wall of the fuselage.

A. Center wing

Stressed skin semi-tensioned shell structure with single girder structure. The left and right sides are integrated with a support girder. The girder is of the web plate type, the cap material is H.D.T. extrusion material, and the web plate uses SHD plate. The outer plate longitudinal members and ribs also use SHD plate. The center wing section is equipped with an inner gap lower wing and a leading edge "slat", and between the girders there is a main wheel landing gear that retracts into the inner fuselage, and a "turbine rocket" is attached to the underside of the outer wing of the same device via a vibration absorber. The wing thickness is constant at 13%.

B. Outer wing

It has two main and auxiliary spars, and the wing joint is a semi-tensioned shell type, but the structure near the aileron is pure tensioned shell. The structure and materials of the spars are the same as those of the center wing spars, but the spars are made of silicon manganese steel plate. The outer plate longitudinal members are made of SDH plate, and the ribs are all made of brazing plate or carbon steel plate. The outer wing is equipped with an outer gap lower wing, the tip of the aileron (ailile wing flap), and separate cell leading edge "slats" on the inside and outside. The wing thickness has changed from 13% to 9%, and a 2.5 degree twist lower wing is added.

3. Fuselage

The fuselage is made up of three sections, the front, middle and rear, and each section is connected to the others by numerous thin bolts. Each section is a stressed-skin semi-tensioned structure, and the cross-sectional shape is circular at the tip, but becomes a triangle shape above and behind the wheel well. It changes to an oblong shape near the vertical stabilizer. The maximum width is 1.8m.

A. Fore fuselage

For mounting the nose landing gear and gun, there are side walls for mounting the landing gear, a gun mounting beam and a floor, and gun magazine covers and landing gear wheel covers are also attached. The outer plate and main frame are made of SDH plate, but the frame, longerons, side walls, beams and floor are made of general reinforcement plate, and the main longerons are made of silicon manganese steel plate.

B. Center fuselage

There is a seat in the center, and two 200-liter main fuel tanks are stored in front and behind it, and a 600-liter auxiliary fuel tank is located behind the rear main fuel tank. The seat floor is supported by a central rib and uses a bracing plate. The main wheels are stored under the floor. SDH plates are used for the outer plate longitudinal members, circular frames, and side walls, and bracing plates are used for the firewall. SDH plates are used for the front and rear fuel tanks and the engine cock room cover. The seat windshield is a frame-type made of SDH plates, and the rear slides open and close.

C. Rear fuselage

The front of the rear fuselage stores radio and radio weapons, and has a work hole and ear fittings for attaching the tail. SDH plates are used for the outer panels and special frames, but reinforcement plates are used for general frames and silicon-manganese steel plates are used for the longitudinal members.

4. Elevator

A. Horizontal stabilizer
The left and right sides are integrated and have a two-spar stressed skin structure. The leading edge is covered. It is designed to be able to install an angle adjustment device. SDH plates are used for the outer skin web and longitudinal members, SDH extrusions are used for the girder cap, and bracing plates are used for the ribs except for the central rib.
Fh= 4.113 m2.

B. Elevator
The elevator is a metal fabric-covered structure for running, with a trim tab made of SDH plates. It also has a cast iron horn balance. Bracing plates or carbon steel plates are used for the leading edge skin, ribs, and girder, and SDH plates are used for the trailing edge ribs to reduce the weight. The rudder angle is 30 degrees up and 20 degrees down, and is 70% when changing the rudder angle at high speed.
Fe= 2×0.588 M2.
C. Vertical stabilizer
Two-spar stressed skin structure with covered leading edge. The material used is the same as the horizontal stabilizer. The mounting angle is zero degrees.
Fv= 2.018 M2.

D. Rudder
The same structure as the elevator and has a "trim tab." The rudder angle is 30 degrees on both sides and there is no device for changing the rudder angle at high speeds.
Fr= 1.056 M2.

5. Aileron

Metal wing fabric structure, leading edge skin, ribs and spar are made of reinforcing plate or carbon steel plate, trailing edge ribs are made of SDH plate. When landing, it works in conjunction with leading edge "slat" and acts as aileron "flap". Rudder angle is 20 degrees up and 25 degrees down. The rudder angle as aileron "flap" is 15 degrees.

6. Lowered wing

Gap lowered wing consists of both inner and outer lowered wings. The inner lowered wing is between the fuselage and "rocket", the outer lowered wing is between the wing joint and the aileron. It is operated hydraulically, and the inner and outer left and right are linked, and the operating angle is 20 degrees during takeoff and 40 degrees during landing. Although it is a single girder stressed skin structure, the upper surface of the rear of the spar is covered with fabric. SDH plates are used for the leading edge outer plate and girders, but reinforcement plates are used elsewhere.

7. Landing Gear

Uses a nosewheel type.

A. Main Landing Gear

The main landing gear is mainly made of silicon manganese steel and is attached via the landing gear mounting material and auxiliary girder of the center wing. It is operated hydraulically and retracts with a "link" and the wheels are stored inside the inner fuselage. It has an air hydraulic shock absorber and the "wheel" inner diameter is 200 mm. The wheels are 950 x 320 mm at 5 atmospheres. It has landing gear struts and wheel covers and is made of SDH.

B. Nose Landing Gear

The nose landing gear is also mainly made of silicon manganese steel and is attached to the nose fuselage landing gear mounting wall. It has an air hydraulic shock absorber and the "wheel" inner diameter is 80 mm and the stroke is 250 mm. The wheels are 600 x 175 mm at 4 atmospheres. The operation is hydraulically linked to the main landing gear, the wheels retract toward the rear, and the landing gear and wheel covers are made of SDH plates. There is also a hydraulic vibration absorber and an emergency lowering device.

8. Installation and Covering of the "Turbine Rocket"

The "Rocket" is attached to the metal fittings attached to the leading edge of the center wing and the small ribs between the girders by means of shock absorbing "rubbers" and "bolts". The cover is made of three parts, front, middle, and rear, and uses SDH plates. The front cover is double-walled, with the inner wall forming the "diffuser" wall, and a 50L lubricant tank and lubricant cooler are stored between the inner and outer walls. There is also an inspection cover on the upper side. This corresponds to the maintenance and inspection of the "Rocket" accessories. The middle cover is fastened with "turnbuckles" from the left and right parts and is free from the main wing body. The main part corresponds to the axial flow blower and the combustion chamber. The rear cover is also free from the main wing body from the left and right parts. The main part corresponds to the air flow control valve and the ejection part

Aircraft equipment

1. Armament

Two 20mm and two 30mm machine guns are mounted on the upper front fuselage, with magazines on the side walls where the landing gear is attached. They are located under the floor between the fuselage walls. All empty cartridges and ammunition are stored.

The 20mm machine gun is located on the upper inside and carries 2 x 200 rounds of ammunition, and the 30mm machine gun is located on the lower outside and carries 2 x 120 rounds of ammunition.
Loading is hydraulic, firing is electric, and all guns are loaded and fired simultaneously.

2. Bombing equipment

A suspension beam attached to the underside of the fuselage can be equipped with one 500- or 800-barrel bomb. The suspension beam is easily attached and detached, and the bomb is dropped manually.

3. Bulletproof equipment

70mm bulletproof glass is used for the forward fixed windshield, 8mm bulletproof steel plate is installed in front of the seat, 12mm at the head, and 8mm at the back. Each fuel tank is covered with 10mm bulletproof rubber, and the main fuel tank room is equipped with a fire extinguishing fluid device.

4. Communications and radio weapons

The radio is stored in the rear fuselage, just behind the fuselage, the Taki-15 friendly or enemy locator is installed behind the seat, and the Taki-13 altitude indicator is installed in the rear fuselage near the radio.

5. Oxygen equipment

Two 3.3L oxygen bombs are installed in the front fuselage, and three oxygen generators are installed near the rear fuselage access hole.

6. Auxiliary explosive rocket device

Two 1000-kilometer thrust explosive "rockets" are attached to the left and right underside of the fuselage for takeoff.

<Data provided by Fuji Heavy Industries Ltd.>

The above is the "Ki-201 Aircraft Manual" I found. Rather than being a technical explanation, the discussion of alternative metal materials is prominent and thought-provoking, especially since they were struggling with special light metals such as duralumin. The entire text is handwritten in katakana, and there are many unfamiliar kanji characters. By the way, tin plate = tinplate, round frame = enkamachi, cartridge case = yakkyo, 粍 = mm, 瓩 = kg, 立 = liter, etc. (I wonder if it's still the same today?). Also, the word "jet" is not used, and oxygen cylinders are expressed in English as "bomb".

Many of Nakajima's documents from before the war were a mix of katakana French and English, but this book is written in Japanese (kanji) for a considerable part. In any case, while the Navy's "Tachibana" was designed to clearly express the characteristics of a special attack aircraft, the "Ki-201 Karyu" was designed with a clear idea of being a complete fighter-attack aircraft, so I felt a sense of relief.

 

[blackkite]

Specification.
The numbers in this table are hard to read, but they look something like this:
Wing width: 13.7m
Total length: 11.5m
Total height: 4.05m
Wing area: 25 m2
Aspect ratio: 7.5
Aileron area: 2.06 m2
Vertical tail area: 3.07 m2
Horizontal tail area: 5.218 m2
Touch down angle: 13 degrees
Wheel spacing: 2.7m

 

[blackkite]

The Ne-230 is a turbojet engine developed by Hitachi starting in 1944. Two prototypes were produced, and development was terminated when the war ended after performance testing.

Overview
From the end of 1942, the Army, under the leadership of the Second Army Aviation Technical Research Institute (hereafter referred to as the Second Army Aviation Technical Research Institute), was developing jet engines, including the Ne-101 motorjet and Ne-201 turboprop for main engines proposed by the Tokyo Imperial University Aviation Research Institute, the Ne-0 ramjet for basic research proposed by Hayashi Sadasuke, who was seconded from Kawasaki Aircraft to the Second Army Aviation Technical Research Institute as a contract engineer, and the Ne-1, Ne-2 motorjet, and Ne-3, Ne-4 turbojet for auxiliary engines.

However, engine development was difficult, and in July 1944, an order was issued to halt development of the auxiliary engines as technical documents were expected to be obtained from Germany due to the submarine operation to Germany. At this time, construction of the Ne-101 had already been halted at the end of June, the Ne-201 prototype was completed (but not yet tested), the Ne-1 parts were half-completed, the Ne-2 drawings had not yet begun, the Ne-3 and Ne-4 were in ground operation, and only the Ne-0 for basic research had reached flight test status.

Furthermore, with the Navy cooperating with the Army, orders were placed with private companies to develop turbojet engines for the main engines, and the Ne-230 was ordered from Hitachi.

The first unit was completed in March 1945, and performance tests were conducted at a test site set up at the Takahagi Plant and completed in May. The second unit was also completed, but the war ended during performance tests.

In June 2015, three stainless steel parts were discovered on the International Christian University (ICU) campus, which was the former site of the Nakajima Aircraft Mitaka Research Center, and investigation revealed that they were likely parts from the Ne-230.

Specifications
Diameter: 780 mm
Weight: 900 kg
Compressor
Type: Axial
Number of stages: 7
Compression ratio: 2.86
Turbine
Number of stages: 1
Turbine inlet temperature: 800°C
Rotation speed: 9,000 rpm
Air intake: 18.6 kg/s
Thrust: 885 kg

 

[blackkite]

Hi!

 

[HoHun]

Hi,

Thanks a lot, that's great stuff!

I hope you don't mind a few terminology suggestions, in the spirit of continuous improvement:

The angle of inclination is 3 degrees, and the wing-to-body joint is easily separable.

This would normally be called "angle of incidence", I believe.

The center wing section is equipped with an inner gap lower wing

The "gap lower wing" probably is a "slotted flap".

The outer wing is equipped with an outer gap lower wing

Again, the "gap lower wing" probably is a "slotted flap".

2.5 degree twist lower wing

If the "lower wing" is a "flap" here too, I'm not sure how to interprete the "2.5 degree twist", except of course that if the wing has "twist" (usually called "wash-out"), the flap would have to conform with that in order to preserve the airfoil shape when retracted.

The rudder angle as aileron "flap" is 15 degrees.

The aileron droops by 15 degrees when flaps are lowered.

Gap lowered wing consists of both inner and outer lowered wings.

The slotted flap consists of an inboard and and an outboard flap.

axial flow blower

Axial compressor.

Quite a fascinating find, thanks a lot for the translation!

Regards,

Henning (HoHun)

 

[blackkite]

Thanks a lot. You are absolutely right.