The Imperial Japanese Army Ki-115 Tsurugi (Saber)
Army Special Attack Aircraft
Allied code name: Ken
Translations performed by George and Kiri Elephtheriou
Special thanks to Harvey Low for technical verification

Notice that nothing new is written that hasn't been included in Rene J. Francillon's book, Japanese Aircraft of the Pacific War, (© 1970, ISBN 0-87021-313-X). Nevertheless, many people would like to know what mysterious and inconceivable things are written in the Japanese books.

From X-Planes, p.151:

NAKAJIMA SPECIAL ATTACKER TSURUGI (Saber) KI-115

Upper photo caption:

After the end of the war, one Ki-115 KO was transported to the U.S. for evaluation. A very simple design, with an easily recognizable outward appearance.

Text:

In purpose, this plane was the equivalent of Navy's Ohka for the Army, designed exclusively for Taiatari special attack. However, while the Ohka had the thrust of its rocket for final attack propulsion, the Tsurugi had a conventional radial engine installed which enabled it to make its own sorties from bases, which made a big strategic difference.

A completely expendable weapon in character, a very simple structural design was pursued in consideration (apart from mass production) to be produced in Japan's aviation cottage industry's town factories in the provinces. The outward appearance was quite linear, with a fuselage of thin steel, light alloy wings, and wooden tail. In the bottom of the fuselage, a large cavity accommodated a bomb of up to 800kg. Because the bomb was partially recessed within the belly, after take off, the landing gear could be jettisoned. The tail was fitted with a primitive fixed skid.

The first plane was finished on March 5th, 1945, only 45 days after the trial production order, and tests immediately began at the testing department. The army intended to use the plane in combat since the battle of Okinawa; but the Tsurugi had very poor handling, stability, and take-off and landing performance and could not be flown by anyone other than experienced pilots. The testing department concluded that it was a virtually useless design, but because the order had already been given to Nakajima to urgently mass-produce it, more than 100 were made; for the above-mentioned reasons, not even one participated in actual fighting until the end of the war.

Ki-115Ko Data:

Wing Span:

8.572m

Full Length:

8.55m

Full Height:

3.30m

Weight:

1,640kg

Fully Equipped:

2,630kg

Engine:

One Nakajima Type 2 (HA 115), air-cooled, 14 cylinder two-row radial 1,130hp

Max. Speed:

550 km/h

Flying Range:

1,200km

Armament:

Bomb either 250, 500, 800kg X 1

Crew:

One

Lower photo caption:

The top photo is the same plane with the light shining from the rear and to the right. A fixed flap was installed at the trailing edge of the wing for training, but during actual fighting sorties, was to be removed.

From Model Art #533, p.17:

NAKAJIMA SPECIAL ATTACKER TSURUGI (Saber) KI-115

Upper surface dark green or dark brown. Under surface gray.

An example of a camouflaged plane of the Nakajima Factory 1st Munitions Arsenal.

There were also planes with black anti-glare nose.

From Model Art #533, p.156:

4. SPECIAL ATTACKER

NAKAJIMA SPECIAL ATTACKER TSURUGI (Saber) KI-115

Top photo caption:

During the days around the end of the war, this Ki-115 KO was painted with dark green upper surfaces, gray under surfaces. Although it was camouflaged, the top of the nose was painted with anti-glare black (matte). The green paint extended back to the green surround around the fuselage's Hinomaru. Notice the main gear's pillar buffer (strut?) which indicates an improved type. To the left and back of this photo, unpainted planes are lined up.

Lower photo caption:

In this photo taken at Nakajima's Ohta factory, completed planes are gathered. Although the propellers are removed according to US forces orders, the rest of the planes are as they stand (in completed and factory-fresh condition).

The plane to the front has a finished camouflage, black anti-glare upper nose and (we understand) the width, the position and the size of the wing's Hinomaru. From the second plane, all other planes are not camouflaged except the 5th. The second plane is in just before the application of camouflage condition, with Hinomaru in all positions applied and fuselage's Hinomaru, with a hand-brushed green border around the white.

From Model Art #533, p.157:

August, 1945. Nakajima Ohta Factory.

This plane's basic painting is displayed in color at page 17 but many planes were left unpainted until the end of the war. Many of them were found lined up at the airfield adjacent to Nakajima's Ohta factory. These planes were found lacking a white Hinomaru surround with flat black anti-glare and dark brown spinner and propeller. But other planes that were to be camouflaged had white surrounds for all Hinomarus (including under wing) and sometimes had a green surround around the white surround.

From Japanese Secret Weapons of W.W.II, pp. 76-77:

On January 1945 the order for the development of the Ki-115 was given. Because of the deteriorating war condition, the installation of an air-cooled engine of the 800-1000hp class was requested.

There was no bomb release system.

105 planes were finished mainly at Ohta.

The Ki-115 Otsu was developed with improved pilot visibility; the pilot's seat was moved further to the front and wing area was increased. A HA 112 engine of 1500hp was to be installed to improve the performance, but none was finished by the end of the war.

With modified construction, the navy planned to use this plane, which would be named Tohka (wisteria).

NOTE: In X-Planes, p. 296, a passage mentions the Tohka. The text says that not even one was made but it was to be generally the same as the Tsurugi. Therefore, the photo is of a Tsurugi and is merely illustrating how the Tohka might have looked.

Page layout by Rob Graham.

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