APO 925

9 Nov. 1945
Report No. 52

SUBJECT: Turbojets and Rocket Engines (JAF)

REFERENCE: Hdqtrs. AAF, “Air Staff Intelligence Requirements in the Far East” dated 25 July 1945. Section III A 18

Persons Interviewed:

Major Masahiko Zaitsu
Lt. Col. Kagemitsu Kadiamara

Interviewing Officer:

Robert L. Jackson, Major, AC

Brief of Material Discussed:

  1. Technical Lieutenant Colonel Kadimara was in the Japanese Regular Army. He spent eight years (1934-1942) in the Engine Testing Laboratory at Tachikawa and three years, (1942-1945), in the Technical Section of Air HQ in Tokyo. He is not a military pilot. He furnished information on the source of rocket fuels.
  2. Major Zaitsu was also of the Japanese Regular Army. He spent six years (1938-1944) with Engineer Units in China and Japan,. and one year (1944-1945) with Army Aviation Rocket Research, Matsumoto, Nagano Ken.
  3. The “Tokuro-20” was a rocket motor for the Shu sui, a plane similar to the German Me-163.

A. An account of the development of Tokuro-20 as written by Major Zaitsu is included in Appendix “A”.

B. Dimensions of Tokuro-20:

Length2523mm (99.5 in)
Width904mm (35.6 in)
Height654.5mm (25.76 in)
Weight (dry)156kg (344 lb)
Max. Thrust1500kg (3300 lb)
Max fuel consumption8kg/sec (17.6 lb/sec or 0.00534 lb/lb/sec

C. The fuels used were H₂O₂ (hydrogen peroxide), N₂H₄H₂O (hydrazine hydrate), and CH₃OH (methyl alcohol). There is also a solid catalyzer in the turbine combustion pot. The CH₃OH, N₂H₄H₂O, and water were mixed in one tank and the H₂O₂ was carried in another tank. The following fuel mixtures were tested: (the figures are weights)

N₂H₄H₂OCH₃OHH₂OCrude PetrolH₂O₂ (80%)

Mixture No. 2 was the most satisfactory. Mixture No. 4 was planned but never tested.

D. The N₂H₄H₂O was manufactured by Mitsubishi Kasei at Yamata, Kyushu. Lt. Col. Kadimara stated that this factory had not been bombed. The H₂O₂ (80%) was obtained from the Edogama Kogyo factory at Yamakita, Shizuoka.

E. Major Zaitsu stated that the experimental Tokuro-20 was built by the Mitsubishi Factory at Matsumoto without the aid of blueprints but from photographs and descriptions only. The mass production was to be done by two Mitsubishi subordinates, the Kyoto-Kosakukikai factory and the Washiro Seiki factory at Okazaki, Aichi-Ken, and by an arsenal subordinate to the Naval Technical Department at Hiro near Kure in Hiroshima-Ken. A total of twenty units were built. Major Zaitsu believes that there is an undamaged unit at Matsumoto and one at Hiro. The Mitsubishi Co. has blue prints and diagrams.

F. On the test of the Tokuro-20, holes were burned in the nozzle near the throat section, the inner wall of the combustion chamber buckled inward in spots, and cones broke off of injector spindles, Thecombustion chamber and nozzle were made of a Nickel-Cromium-Molydenum steel alloy. Major Zaitsu did not know the composition of the alloy.

G. The mixture of CH₃OH,N₂H₄H₂O and water was passed thru the cooling jacket under 27 atmospheres pressure. The combustion chamber pressure was 18 atmospheres.

H. It was planned to use two motors on Shu-sui No. 2. One motor was to have 1500 kg. (3300 lb.) thrust and the other 400 Kg.(883 lb.) thrust. Both motors were to be used for takeoff and high speed and the small motor was to be used for cruising. Both motors were to be supplied by the same fuel pump-turbine set but a control system had not been designed when the war ended.

  1. The Ne-130 was a turbojet engine based on the German Jumo 004 to be used in an airplane similar to the German Me-262. A description of the Ne-130 program was written by Major Zaitsu is included in Appendix “A”. Three units were built by the Ishikawajima Shibaura Turbine Factory and all three have been destroyed.
  2. The “Karo-10” was a pulse jet engine modeled after the German V-1 engine. The Karo-10 program is described by Major Zaitsu in Appendix “A”. The program was in the early stages of its development. Five units were built at the Sagami Army Arsenal, Sagami, Kanagama-Ken. Major Zaitsu states that the arsenal has not been destroyed.

The JAF jet propulsion program consisted entirely of copying German material with very little aid from the Germans. At the close of the war the JAF did not have a successful jet propelled airplane.

It is recommended that the Mitsubishi Company be contacted for further information regarding the Tokuro-20 and similar rocket motors.

Blueprints of the three units, Tokuro-20, Ne-130, and Karo-10, are on file in the Air Documents Division, Wright Field, Dayton, Ohio.

Normal distribution


Prepared by: Robert L. Jackson, Major, AC

Approved by: F. O. Carroll
Brig. Gen., USA

Appendix “A”


  1. The use:
    A rocket for the “Shu-sui” similar to “Me-163”.
  2. The essential particulars of function:
Total length2523mm (99.5 in)
Total width904mm (35.6 in)
Total height654.5mm (25.76 in)
Total weight156kg (344 lb)
Max. Thrust1500kg (3300 lb)
Max fuel consumption8kg/sec (17.6 lb/sec or 0.00534 lb/lb/sec
FuelH₂O₂, N₂H₄H₂O, CH₃OH
  1. Research process:
    Based on the informations concerning “Me-163”, obtained in the summer of 1944, we proceeded with the study, and on August 1st started designing. As soon as the apparatus of the pump was completed on October, we began to test its functions. The design of the front impeller of the pump was difficult: we could not get satisfactory results, and the function in the high altitudes was very poor. However, as the result of several experiments made at the Hiro Navy Factory, we succeeded in making a pump which satisfied the required function at the altitude of 10,000 m. We also completed making of other parts one after another, and made the function test of each. As continuance of experimentation became difficult after Nagoya was bombarded on Dec. 13th, we moved to the 1st. Navy Technical Factory at Yokosuka, and we began a synthetic operation testing from Dec. 31st. With the progress of the synthetic test it was found various parts needed revision and these were revised one after another. What troubled us most was the pump, because as the result of making a main impeller large the number of the use revolution 14,500 rpm. and the number of the critical revolution 16,600 became as close that even the slightly excessive revolution bended the shaft of the pump.

    Two remedies were adopted: One was to enlarge the diameter of shaft and to shorten the internal of bearings, and the other was to support it on three points. The latter method was given up in the first part of May, because H₂O₂ intruding into the middle bearing and grease of the bearing produced a reactionary explosion. Since April, the experimentation, factory stopped production on account of bombardment, so we were compelled to rely upon the mass production factory, but we did not success. Testing became extremely inefficient on account of the shortage of test goods. In May, the Army section moved to Matsumoto with the Mitsubishi while the Navy section moved to Yamakiro.

    The test problem was that of the damage on the injection nozzle and the partial melting of the combustion chamber. The maximum time of continual revolution was three minutes. The major accident often occurred, various remedies were planed but before their results were confirmed, the war came to an end. In spite of so little indurability and dependability, under the urgent pressure of the critical situation we were obliged to make the first test flight on July at Yokosuka Navy airport. Due to an obstacle in the body, the engine stopped immediately after taking to flight, and made forced landing and the plane was seriously damaged and the pilot was killed.


  1. The use:
    A turbo-jet for an airplane similar to Me-262.
  2. The essential particulars of function:
Typeaxial blower type turbojet
Total length3850mm
Max. diameter767mm
Max. static thrust900kg (on the ground)
Fuel consumption1350kg/hr
Blower is seven stage
Turbine is one stage. Its output 4390 Hp
Temp. of gas before the turbine nozzle 750° C.
  1. Research process:
    Based on the informations about Jumo 004 obtained in the summer of 1944, we started designing from the end of December, and ordered to manufacture for trial to the Ishikawazima Shibaura Turbine Factory. The jet number One was to be completed at the end of March, but its completion was delayed to the end of May on account of bombardment. The trial was made at Tachikawa. The wings of the second and the rest stages were broken to pieces at that trial, for the uppermost blower wing damaged and scattered, when we revolved it as far as 8000 rpm. The cause was hair cruck occurred in making wings. The jet No. 2 was completed in the first part of July, and put to the test at Matumoto. We tested it favourably as far as 9000 rpm. Though the accurate data could not be obtained on account of imperfection of the measurement equipment, the function as the design was displayed on the whole. Then after auxiliary machines and the other defective parts were corrected we began operating again, and as the blower wing was damaged by a strange object coming from the opposite direction, the jet was sent to the factory for repair. At the time Jet No. 3 had been already completed and we were to test it immediately, But as the Turumi factory was bombarded on Aug. 2nd, the jet No. 3 and the rest were all destroyed and accordingly, there was no jet available at the time left. Then the war closed.


  1. The use unfixed.
  2. The essential particulars of function:
Total lengt4080mm
Max. diameter583mm
Max. static thrust320kg (on the ground)
Fuel consumption4.5 lt/kg-hr (CH₅OH)
  1. Research process:
    Refering to the informations concerning to V-1 of Germany the Mitsubishi had chiefly studied the suction valve by small-sized rocket from the first of 1945. In July 30th, or soon as we completed a blower in the Army laboratory at Matumoto, we began to test it, As the German informations obtained were very insufficient, we studied mainly the shape of the valve and lenght of combustion chamber, and as the result could have the function mentioned above. Gasoline for automobiles, CH₃OH and CH₅OH were used as fuel, and then crude petroleum was to be used for testing. Endurance of the valve was in the extent that one hours continual revolution occurred no obstacle, and moreover we expect it to be increased.

    The starting method, the fuel supplying apparatus, the supporting method and the vibration absorber were not decided yet, because they concerned to the tactical use. As uses of this rocket, those like V-1’s in Germany could not be allowed by the Japanese industrial power at that time, which needed much perfect arrangement of the stability apparatus and the others, and besides concerning to the tactics there was no proper objectives. Then as we were thinking the engine to be used for the Kamikaze plane as a remedy of the shortage of gasoline engines, the war came to an end.

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