Nakajima Kikka

Japan's interest in jets increased in the month of September 1944, when the Japanese air Attache in Berlin sent a large number of detailed reports on the German Me262 program. Japanese Navy ordered Nakajima company to design a bomber similar but with more modest requirements (speed, load, etc. ..) as the Japanese industrial capacity was not prepared for it. The Nakajima Kikka was designed by Kazuo Ohno and Kenichi Matsumura.

The Kikka first design studies envisaged the use of 440 lb. thrust TSU-11 units which were based on the Campini principles and employed the Hitachi Hatsukaze (Fresh wind) piston engine to drive a ducted fan compressor.

However, at an early design stage the Tsu-11 was dropped in favour of the Ne-10 (TR-10) centrifugal-flow turbojet, and the NE-12 (TR-12), which added a four-stage axial compressor to the front of the Ne-10.

The first mock-up of the Kikka was inspected by Naval Officials on January 28, 1945, but estimated performance with the NE-12 turbo jet was uninspiring, and it was decided to make a further power plant change, supplanting the NE-12 with the more powerful NE-20.

Ishikawajima NE-20 fitted on Kikka No1

First flight

The prototype commenced ground tests at the Nakajima factory on 20th may 1945, and on 25th june the first Kikka was completed.

The following month it was dismantled and delivered to Kisarazu Naval Air base where it was re-assembled and prepared for flight testing. Ground tests continued on this airfield until 13th July.

On the 7th August 1945, Lieutenant Commander Susumu Takaoka made the first flight, with a duration of 11 minutes. His take-off run of 2,380 ft. took 25 seconds at an all-up weight of 6,945 lb. Wind speed was 23 ft.per second. He landed in 3,280 ft.

A ceremonial official "initial" test flight was made on 11th August, four days later. For this flight, rocket assisted take off (RATO) units were fitted to the aircraft. However, because their alignment had been miscalculated, The acceleration was so heavy that the nose of the aircraft came up, the tail went down and skidded along the runway.

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.

Technical characteristics

type
Single-seat twin-jet attack bomber, of all-metal construction with fabric-covered tail surfaces.

Accommodation
Pilot in enclosed cockpit.

Powerplant
Two Ne-20 axial-flow turbojets, rated at 1,047-lb. of static thrust.

Dimensions, weights, and performance

Wingspan.........	32	ft.	9 11/16	in.
Length	26	ft.	7 7/8	in.
Height	9	ft.	8 5/32	in.
Wing area	142.083	sq. ft.
Empty weight	5,071	lb.
Loaded weight,	7,716	lb.
Maximum weight	8,995	lb.
Wing loading	54.3	lb./sq. ft.
Power loading	3.7	lb./lb. s. t.

Estimated Performances
maximum speed	387	mph	at sea level
maximum speed	433	mph	at 32,810 ft.
climb to 32,810 ft.	26	minutes
service ceiling	39,370	ft.

Kikka No1

On this Photo, you can see the RATO rockets used for lift-off.

Kikka No2

Kikka No2 in the Navy Base of Patuxent River, Maryland. 1946

More detailed view with a focus on NE-20 jet engine

Unassembled Kikka in Nakajima's factory.

The second prototype was almost ready for its own first flight when the war ended on August 15. Between 18 and 25 more airframes were under construction.
Some of these were two-seat trainers.

Under completion. Any information, comments or correction are welcome!!!

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22.08.2012