Matters Assessed as Bottlenecks Concerning Navy Cutting-Edge Weapons


1. Concerning Maru-Dai

(A) No. 1

(I) Nothing in particular regarding the use of Ro-Gō Kō-Yaku.

(II) The engine using Ro-Gō Otsu-Yaku is Army-supervised.

(B) No. 2

The ‘turbine rocket’ is currently unfinished, as follows:

(I) Planned specifications and prototype manufacturing outline as per the separate sheet.
However, it will take about a month to know the actual progress.

(II) Model TR10
Planned as an auxiliary ‘rocket’, the former centrifugal supercharger impeller A increases the wind pressure to an extent depending on the speed of the aircraft, gasoline is sprayed in by injection valve D and combusted, producing a gas temperature of about 700 degrees Celsius which drives the exhaust ‘turbine’ B (the exhaust ‘turbine’ drives the impeller A), and is expelled from the rear jet nozzle generating a ‘rocket’ effect.

Currently undergoing countermeasures for the following faults that occurred during experiments:

(1) Cracking from the central part of the exhaust ‘turbine’ blades (material I-306) is presumed to be due to a two-node vibration of the blades.
Currently going under the implementation of countermeasures to increase the natural frequency by changing the blade shape and cross-section ratio, as well as changing the nozzle hole count and the critical revolution speed.
Furthermore, Model TR10 is currently being experimentally manufactured with an axial-flow compressor added to the single centrifugal impeller, which is the Model TR12.

(2) In the initial stage, combustion conditions were not good, but recently, due to research into the structure of the combustion chamber, it has greatly improved.

(3) Further research is being advanced on the automatic control of revolution speed and combustion temperature.

(III) Model TR30
Being designed as the Model TR12 enlarged and with a starter attached so it can be used for primary propulsion.
The design basis is generally identical to the Model TR10, and the blade vibration problem is currently under research as it is feared that it will occur in the same way.

(IV) Model TR140, Model TR230, and Model TR330 are imitations of the German BMW ‘rocket turbine’, and are being experimentally manufactured at Ishikawajima, Nakajima, and Mitsubishi respectively based on their independent designs (axial-flow compressor + exhaust ‘turbine’).

2. Concerning Kaiten

Small sonar equipment that works at high speed.
Research is being promoted as much as possible at the technical research institute, but a definite plan has not yet been reached.
The creation of a new weapon is requested that fulfills the objective of sonar without the restraints of the current system of hydrophones and echo ranging equipment.

3. Concerning SS

Small sonar (same as Kaiten).

4. Magnetic Detector for Aircraft

The current capability is terribly inadequate with a maximum direct range of 100 meters from submarines, and a revolutionary increase is urgently required.
(To be effective against degaussed submarines from an effective range of 300 meters or more)

5. Magnetic Depth Charge

(A) Inadequate performance

Maximum effective range: 8 meters

(B) Due to the mechanical complexity and large copper requirement it is unsuitable for mass production, and considering the current situation as described above, it is necessary to create a depth charge that automatically detonates in the vicinity (direct range 20 meters or more) of submerged enemy submarines, independent from the current system.

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