Nakajima Kikka jet interceptor

Imperial Japanese Navy Kikka ("Orange Blossom") - 1942-1945

© 2018 Bob Hackett
18 July 1942:
Leipheim, Bavaria, Germany. The third Me-262 prototype airframe becomes a true jet when it flies piloted by test pilot Fritz Wendel - almost nine months ahead of the British Gloster "Meteor's" first flight. Retracting the Me-262's conventional tail wheel gear causes its jet exhaust to deflect off the runway. The wing's turbulence negates the effects of the elevators and the first takeoff attempt has to be cut short.

On the second attempt, Wendel solves the problem by tapping the aircraft's brakes at takeoff speed, lifting the horizontal tail out of the wing's turbulence. The initial four prototypes are built with the conventional gear configuration. Changing to a tricycle arrangement—a permanently fixed undercarriage on the fifth prototype, with a definitive fully retractable nosewheel gear on the 6th and subsequent aircraft - corrects this problem.

The Japanese Air Attache in Berlin witnesses a number of flight tests when Germany begins flight trials of its first prototype of the Messerschmitt Me-262 Schwalbe (“Swallow”). The attaché sends enthusiastic reports to Tokyo about the Me-262's potential to defend Japan's homeland.

1943:
Test flights continue throughout the year, but the project is plagued by engine problems. The Junkers Jumo 004 engine is only marginally more reliable than the lower-thrust BMW 003. Airframe modifications are complete by 1942, but hampered by the lack of engines, serial production does not begin until 1944, and deliveries are low, with 28 Me-262s in June, 59 in July, but only 20 in August.

16 December 1943:
At 1100 (JST), Cdr (Rear Admiral, posthumously) Kinashi Takakazu's Type B1 submarine I-29 (coded Matsu(Pine) by the Japanese) departs Seletar Naval Base, Singapore for Nazi-occupied France.

Early 1944:
Berlin. The Japanese Air Attache is shown the Me-262 along with several other advanced German aircraft. He reports back to Tokyo on these new aircraft. The Imperial Naval Staff authorizes him to open negotiations to buy a production licence for the Me-262 and Me-163.

11 March-15 April 1944:
IJN submarine I-29 arrives safely at Lorient, France. During her stay, I-29 embarks 18 passengers (including four Germans) and takes on a Jumo 004B engine used on the Me-262 jet fighter and an HWK 509A-1 bi-fuel rocket motor used on the Me-163 Komet rocket interceptor. Documents for the two planes along with a complete Me-163 and other aircraft parts are also loaded onto I-29.

16 April 1944:
I-29 departs Lorient, escorted by seven M-class minesweepers. Technical Cdr Iwaya Eiichi carries blueprints of Messerschmitt Me-262 jet fighter and the Me-163 Komet rocket-propelled interceptor. I-29 journeys around Africa back to Japan.

19 April 1944:
Lechfeld Air Base, Bavaria. Erprobungskommando 262, the Luftwaffe evaluation squadron charged with service testing the revolutionary jet-propelled fighter, is formed as a test unit to introduce the Me-262 into service and to train a corps of pilots to fly it.

14 July 1944:
At 1030, I-29 arrives safely at Singapore. I-29's passengers, including Iwaya disembark with their plans and documents and proceed to Japan by air, but most of the German scientific cargo remains aboard.

22 July 1944:
At 0800, I-29 departs Singapore for Kure.

26 July 1944:
Luzon Strait. W entrance of Balintang Channel. About 1700, Cdr Alan B. Banister's SAWFISH (SS-276) sights I-29 running on the surface. Hs fires four torpedoes and gets three hits that sink I-29 almost immediately at 20-10N, 121-55E. Cdr Kinashi, Japan's leading submarine "Ace", is among the 105 crewmen and passengers KIA. He is honored by a rare two-rank promotion to Rear Admiral, posthumously.

The loss of the full scale German aircraft aboard I-29 slows the Japanese jet program greatly, but their blueprints, flown to Tokyo, arrive safely. They are used immediately to develop the Nakajima Kikka ("Orange Blossom") based on the Me-262 and the Mitsubishi J8MI Shusui ("Sword Stroke") based on the Me-163. Because the joint-service commission never made it Germany to observe production, the Nakajima team has to make some educated guesses during the design process in preparing the aircraft for production.

September 1944:
Tokyo. Reports on the progress of the Me-262 received from their air attaché in Berlin lead the Imperial Naval Staff to instruct Nakajima Hikoki K. K. to develop a twin-jet, single-seat, attack fighter similar in layout to the Me-262. Among the specifications for the design are requirements that it should achieve a maximum speed of 431 mph, a range of 127 miles with a 1100-lb bomb load, or 173 miles with a 551-lb bombload. The new fighter should be able to be built largely by unskilled labor, and the wings should be foldable to enable the aircraft to be hidden in caves and tunnels around Japan. Nakajima designers Kazuo Ohno and Kenichi Matsumura lay out an aircraft that bears a strong, but superficial, resemblance to the Me-262.

With the loss of the I-29, Nakajima's engineers only have the few documents flown from Singapore along with the memories of a few officers who had seen the Me-262. Even with this limited amount of information, Nakajima starts work on the Kikka. Several changes are made to the original Me-262 design making it simpler and easier for manufacture including using more readily available materials such as wood. One major change is the addition of folding wings to enable the aircraft to be concealed more easily. At first, it is planned to fit the Kikka with the Ishikawajima Tsu-11, a crude thermojet style of jet engine - little more than a ducted fan with an afterburner - originally designed for use on the MXY7 Ohka kamikaze plane.

Instead, Ishikawajima starts development of new jet engines specificity for use in the Kikka called the Ne-10 (TR-10) centrifugal-flow turbojet, and the Ne-12, which adds a four-stage axial compressor to the front of the Ne-10. Tests of this powerplant soon reveal that it will not produce anywhere near the power required to propel the aircraft, so the project is stalled. It is decided to produce a new axial flow turbojet based a reverse engineered version of the German BMW 003. Development of the engine is troublesome. The Ishikawajima engineers have only a few photographs and a cut-away drawing to work from. Even with this limited amount of information they are able to produce a usable engine, the Ishikawajima Ne-20.

Mid-1945:
The Kikka project is making progress once again, but it reflects the deteriorating war situation. Compared to the German Me-262, the Japanese Kikka's airframe is noticeably smaller and more conventional in design, with straight (rather than swept) wings and tail surfaces. The triangular fuselage cross section, characteristic of the German design, is less pronounced, due to smaller fuel tanks. The main landing gear of the Kikka is taken from the A6M "Zeke" and the nose wheel from the tail of a Yokosuka P1Y Ginga ("Milky Way") bomber.

30 June 1945:
The first prototype commences ground tests at the Nakajima factory. In July, it is dismantled and delivered to Kisarazu Naval Airfield where it is re-assembled and prepared for flight testing.

Kisarazu Naval Airfield - Ground crews ready prototype Kikka for flight test.

6 August 1945:
Colonel (later BrigGen) Paul Tibbets' Boeing B-29 Superfortress heavy bomber "Enola Gay" drops "Little Boy", the first atomic bomb, on Hiroshima, Japan. The explosion wipes out 90 percent of the city and immediately kills about 80,000 people; tens of thousands more later die of radiation exposure.

7 August 1945:
LtCdr Takaoka Susumu pilots the Kikka's first 20-minute test flight. The aircraft performs well, the only concern being the length of the takeoff run.

9 August 1945:
Major (later MajGen, MA NatlGuard) Charles W. Sweeney's B-29 "Bockscar" drops "Fat Man", the second atomic bomb, on Nagasaki killing between 80,000 and 100,000 people.

11 August 1945:
For the Kikka's second test flight, rocket assisted take off (RATO) units are fitted to the aircraft. The pilot is uneasy about the angle at which the rocket tubes are set. With no time to correct this, it is decided to simply reduce thrust of the rockets from 800 kg to only 400 kg. Four seconds into take off the RATO is actuated. It immediately jolts the aircraft back onto its tail leaving the pilot with no effective tail control. After its nine-second burning time, the RATO runs out, the nose comes down and the nose wheel contacts the runway resulting in a sudden deceleration. Since both engines are functioning normally, the pilot opts to abort take off. While he fights to brake the aircraft and perform a ground loop, the Kikka runs over a drainage ditch which catches its tricycle landing gear and tears it off. The aircraft continues to skid forward and stops short of the water's edge.

15 August 1945:
Before the Kikka can be repaired, the Emperor and Japan unconditionally surrender. All work on the Kikka ceases. At this time, the second prototype is near completion and Nakajima has 23 more airframes under construction.

 
Aircraft under construction at Nakajima plant, 1945 - foreground-Kikka
jets, background-G8N Renzan heavy bombers. 		  Kikka beneath B-29 "Enola Gay" at Stephen F. Udvar-Hazy Center,
Chantilly, VA.

Authors Notes:
[1] The Kikka is often identified as the Nakajima J9N1, or occasionally J9Y, which is incorrect. Like other Japanese aircraft intended for use in suicide missions, it received only a name.

[2] Although the Kikka resembled the Me-262 in layout and shape, the Japanese jet was considerably smaller and slower. For example, the Kikka's wingspan was 32' 10" while the Me-262's was 41' 6" and the Kikka's length was just 26' 8" vs. the Me-262's 34' 9". Fully loaded, the Kikka’s maximum speed was 432 mph vs. the fully loaded Me-262's maximum speed of 540 mph.

-Bob Hackett

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