United States. War Department

“ Dry thickener is extremely hygroscopic, that is, it absorbs moisture from the atmosphere very rapidly. For this reason, thickener is shipped in hermetically sealed tin cans containing the exact quantity of powder required for mixing with 20 gallons of fuel to prepare a 4.2 percent mixture. It is important that the gasoline or fuel oil and gasoline be measured out before the thickener container is opened. ”

“ FILLING BY BLOWING. Thickened fuel may be readily forced into the fuel tanks of flame throwers by the use of extremely low pressures of compressed air or nitrogen. Flame thrower fuel filling kit E6 or equivalent may be used. When equipment is available, filling by blowing is more efficient for filling large numbers of flame throwers with thickened fuel. Pouring or pumping are more time-consuming, depending on the consistency of the gel. The consistency may vary among batches even when the same proportion of thickener is used. ”

“ If compressed air is to be used, and if any grease, oil, or flame thrower fuel is detected by sense of smell or sight within pressure tank and valve assemblies or cylinders, return tanks or cylinders for cleaning to the appropriate third-echelon maintenance agency of Chemical Warfare Service. ”

“ While it does not billow around corners as does liquid fuel, thickened fuel strikes the target with force enough to ricochet inside. It clings to skin and clothing while burning. It also has excellent incendiary effects. The initial flame and smoke are less from thickened fuel than from liquid fuel, but the lower visibility, greater range, and much longer burning period of thickened fuel compensate for its smaller screening effect. Liquid fuels are easier to pour when filling than are thickened fuels. ”

“ Procedure. To fill fuel tanks:
(1) Remove both the filling and safety-head plugs.
(2) Inspect interior of tanks to see if clean and free from foreign matter. If not clean, flush with gasoline.
(3) Place end of fuel-filling hose in either one of the two fuel-tank plug holes, using a nipple as a spout.
(4) Start air compressor or pump, or open the valve on the cylinder of compressed air or nitrogen. Open regulator valve on filling line by turning handle slowly until gage shows 15 to 20 pounds pressure, but no more. ”

“ Detachable pressure tank and valve assemblies (par. 66.1) make possible the use of packboards for transporting pressure tanks, 5-gallon cans of fuel, wrenches, and additional ignition cylinders close to the front line of combat to troops using flame throwers. As packboards are not manufactured specifically for servicing flame throwers, standard quartermaster-issue packboards are used. Packboard transportation is practicable only with pourable fuel. (Pourable fuels include some thickened fuels and all liquid fuels.) ”

“ Equipment. An open-head 55-gallon or 42-gallon drum and an improvised wooden mixing paddle are used. The paddle should be approximately 5 feet long, 2 inches wide, and 1 inch thick. A metal paddle should not be provided because of the danger of striking a spark from the drum. Five-gallon cans may also be furnished for measuring and transferring ingredients. Clean, unrusted, steel storage drums should be at hand. They should be at least 16-gage to have sufficient strength to withstand the internal vapor pressure of the fuel. ”

“ When the weapon is fired at small openings in a bunker or pillbox, the firer and other members of the assault squad should not approach closer than 7 to 10 yards from the target.
b. Other effective ranges.
(1) Open fields of fire. When thickened gasoline is used, portable flame throwers may fire with considerable effect as far as 40 yards under normal conditions, depending on wind direction and wind speed. Under the same conditions, liquid fuel maybe effective at 20 yards. Results and accuracy are not as great as at point-blank range. ”

“ Do not permit flames, sparks, or ignition from the flame thrower or other source to touch hose.
j. Blowing out dust. Immediately before coupling an attachment to the pressure tank or cylinder valve, open it for an instant to blow out any dust or dirt. Never stand where gas or dirt may be blown into the eyes or face. If the valve is difficult to open, apply more force gradually. ”

“ One can of thickener to 20 U.S. gallons of gasoline, or gasoline and light fuel-oil mixture, gives good results. This is a 4.2 percent by weight mixture. Except in hot weather, a fuel mixture of less than 3 percent thickener requires such long stirring that its preparation is impractical. ”

“ In tropical theaters, a thickened blend of 50 percent gasoline and 50 percent light fuel oil has been reported to give favorable results. Storage qualities are not known, however. Another mixture which has been well recommended in field reports is 15 gallons of gasoline to 5 gallons of diesel fuel oil. Issue gasoline may be used, but locally procured gasolines which contain alcohol are not suitable.
b. Proportion of thickener to fuel. Less thickener is recommended than formerly. A low ratio of thickener gives a thickened fuel with many of the characteristics of liquid fuel. ”

“ If the target is located in jungle or thick underbrush without cleared fields of fire, the effective range of the flame thrower is reduced by as much as one half, depending on the nature and density of the vegetation. ”

“ While the above test firing is proceeding, check for leaks at all joints and connections on the tank group. The pressure system should be checked by painting the joints with soap-and-water solution and by looking for bubbles which indicate leaks. For replacement of parts where pressure leaks, see Paragraph 66. Fuel leaks may be seen without soap and water. For repair of fuel leaks, see Paragraph 75 e. The nozzle should be observed by removing the ignition shield. Nozzle leaks are corrected by cleaning, adjusting needle (Par 75 d) , or by regrinding. ”

“ One man then stirs the fuel vigorously. Another takes a can of thickener, splits it with a machete, bayonet, or ax, and pours it immediately into the fuel. Any large lumps of powder are broken by hand before the powder is added to the fuel. When mixing 40 gallons at a time, the two cans of thickener should be opened and added to the fuel in rapid succession. If the contents of the first can are permitted to gel before adding the second can, it will be difficult to obtain a uniform mix. ”

“ Thin fuel has shorter range; it is largely consumed in the air before it reaches usual effective ranges. Where the climate is torrid, less gasoline or other thinning agents should be used in a fuel blend than normally. (Pars 34 through 36)
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44. COLD. Cold weather reduces total heat produced at target but seldom enough to seriously lower value of a firing mission. Incendiary effects may be decreased because materiel is less flammable when cold. The weapon may be used at temperatures as low as minus 20 degrees Fahrenheit. To improve ignition, use more gasoline in fuel than normally. ”

“ The threads in the fuel-valve body will be damaged by frequent screwing and unscrewing of the hose because the body is a lightweight aluminum casting. Fuel hose is replaced as a unit and is not disassembled in the second echelon. To disconnect from tank group, see Paragraph 70 b.
c. Installation of fuel-hose assembly.
(1) To install in tank group, see Paragraph 70 c.
(2) To install in gun, apply anti-seize compound (from service kit) lightly to threads and screw hose in fuel-valve body by hand. Use wrench only enough to make a secure connection.
d. Maintenance of fuel-hose assembly. ”

“ If no additional shots are to be fired before refilling and recharging, open pressure-tank valve by turning handle counterclockwise. Point the gun away from personnel and blow out the remaining fuel and pressure, if any, from the fuel tanks by squeezing the valve lever and grip safety until there is no further discharge. ”

“ Ignition shield, a cylindrical, thin-metal tube with a conical front end. The shield guides the flame and protects the firer. Eight holes around the base of the cone provide an air intake for burning the fuel. The base of the shield is threaded, and it screws onto the ignition-head body. ”

“ Unused motor lubricating oil can be employed in place of crankcase drainings, but usually it will be unavailable for flame-thrower use.
b. Preparation of ingredients. Before mixing blends, the following steps should be taken:
(1) Gasoline, diesel oils, and fuel oils. These fuel materials should be allowed to stand quietly for at least 30 minutes to permit any small quantity of water present to settle to the bottom. When transferring the fuel to another container, remove the fuel carefully so that no water is remixed with it. ”

“ Areas where paint has worn off should be touched up with fresh paint. The weapon should be stored in a dry place. Moisture must not be allowed to enter fuel, ingredients of fuel, or containers of ignition cylinders.
42. DUST AND MUD. Keep all possible dust, earth, and mud out of the flame thrower; particles may interfere with the operation of spring case, valves, bearings, and pressure regulator. Store weapons and auxiliary equipment in closed chests and boxes when not in use. ”

“ After charging, and as few hours as possible before a mission, use an 0-3,000-pound gage furnished in service kit to test pressure. (Fig 32) To install gage, unscrew check-valve cap and screw gage in check-valve body. If pressure has fallen below that to which the tank was charged (Par 32) , a leak is indicated. Remove gage, replace check-valve cap, and check for leaks at joints between pressure tank and valve and between tank valve and check valve. (A wrench should be used to tighten cap on check-valve body so as to avoid producing an additional leak.) Large leaks can be felt or heard. ”

“ Thin fuels are * * * reaching the target. For this reason, liquid fuels should contain the lowest proportion of gasoline and the highest proportion of heavier fuels that permit easy ignition. In hot climates, * * * of great importance. The gasoline used can be any U. S. grade of motor fuel or aviation gasoline. ”

“ A loose tank group can cause discomfort or injury when the wearer changes positions while on a mission. Check presence and condition of the two pins and two cotter pins which hold shoulder straps to steel support. Check fasteners.
52. BEFORE-OPERATION SERVICE OF GUN GROUP. The following services are to be performed before filling, charging, and loading with pressure, fuel, and ignition cylinder:
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a. Hose nipple, tank end. Examine to be sure nipple is clean and not badly nicked. If badly nicked, the nipple may not make a tight seal at the tank coupling. A leak and loss of pressure may result. ”

“ To keep fuel in good condition, drums for shipping and storing must be clean, moistureproof, dry, strong, and unrusted, but not galvanized. They must be kept tightly closed and should be laid on their sides so that rain water will not collect around the bungs. ”