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"Japanese Flame-Thrower" from Tactical and Technical Trends

The following U.S. military intelligence report on the Japanese portable flame-thrower in WWII was originally published in Tactical and Technical Trends, No. 18, Feb. 11, 1943.

[DISCLAIMER: The following text is taken from the U.S. War Department publication Tactical and Technical Trends. As with all wartime intelligence information, data may be incomplete or inaccurate. No attempt has been made to update or correct the text. Any views or opinions expressed do not necessarily represent those of the website.]


A Japanese portable flame-thrower, captured by American forces in Bataan, is described below. The weapon is of excellent design and construction, although considerably heavier than the corresponding American type. The valve of the gun is awkward to operate. The mechanism for positive ignition is a distinct advantage. A desirable feature is that the flame-thrower operator can operate the valve of the pressure cylinder, but the Japanese method of doing this by means of a flexible shaft is considered undesirable as the shaft is heavy and easily kinked.

a. Pressure Tank

The pressure tank (capacity, 350 cubic inches) is 6 inches in diameter and has an over-all length (with valve) of 16 inches (see accompanying sketch). It has welded joints and is of light construction. To work properly it should have an initial pressure of 300 to 400 pounds per square inch. It is fitted with small couplings to secure it to the two fuel tanks. In the aperture at the top is fitted a handwheel-operated needle valve. Copper tubing connects the pressure tank to the left-hand fuel tank. The pressure tank is filled with compressed nitrogen.

b. Fuel Tanks

The two fuel tanks are of the same diameter as the pressure tank, but being taller have 25 percent greater capacity. The tanks are connected by two welded tubes, one near the top and the other near the bottom. These act as pressure and fuel channels and as joints. As mentioned above, the left-hand tank is joined to the pressure tank by copper tubing. This tubing is connected to a needle valve of which the operating handwheel is on a flexible shaft 1 foot long and coming over the shoulder of the operator. The right-hand tank is fitted on top with a 1-inch filling cap. About two-thirds of the way down its right side is the hose connection. An interior tube insures emptying the tanks. The lower connecting tube or channel allows the fuel in the left tank to empty out. The upper channel insures an equal pressure on both tanks regardless of the position of the tanks or the amount of fuel remaining in each.

[Japanese Flame Thrower]

c. Connecting Rubber Hose

The hose which connects the nozzle to the fuel tanks is made of 1 1/2-inch reinforced fabricated rubber tubing. It is 45 inches long and has brass fittings on both ends.

d. Fuel Nozzle and Ignition Mechanism

The fuel nozzle and ignition mechanism has an over-all length of 47 inches. At the hose end, the tube is 1 inch in diameter and tapers down at the nozzle end (where it passes through the ignition mechanism) to one-quarter of an inch. The ignition mechanism depends on the firing of a .43-caliber blank cartridge into the stream of fuel. The nozzle, fitted in a 2 1/2-inch by 5-inch cylinder, contains the firing mechanism. Within the perimeter of the cylinder are ten .43-caliber holes to hold the blank cartridges. The cylinder revolves on a cam operated on each stroke of the firing handle. The firing handle is on the handle end of the nozzle, and is connected to the firing mechanism by a metal shaft. When the firing handle is turned, it performs a two-fold function. It fires the blank cartridge under the firing pin, and at the same time closes off the fuel by shutting off the valve in the handle. This prevents the flame from reaching the tanks in case of a flare-back.

e. Operation

The leather straps which enable the apparatus to be strapped on the operator are fixed to the two connecting tubes of the fuel tanks. The tanks are filled with coal tar, thinned down with hydro-carbons, and then a filled pressure tank is attached. The operator opens the pressure-tank valve, thus putting pressure on the fuel-tank valve. The apparatus is strapped on with the fuel-tank valve handwheel and shaft carried over the left shoulder, and the hose and nozzle under the right arm. The operator releases the fuel by turning the handwheel of the fuel valve. The stream of fuel is played on the target, and then the firing handle is turned, firing one cartridge which ignites the fuel. It is estimated that the flame-thrower has a range of about 30 yards. It is capable of firing a continuous jet of fuel for 10 to 12 seconds.

*Prepared in the office of the Chief of Chemical Warfare Service.


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