Page:EB1922 - Volume 31.djvu/99

Rh this and the oil container were interposed a reducing valve (to reduce the storage pressure to a working pressure of 250 Ib. per sq. in.) and a pressure gauge. Each oil container, when filled about three- quarters full (as was the usual practice), held 25 gal. and weighed 180 Ib. filled. Ignition was at the nozzle by means of the electric device above mentioned. The range of this model was about 90 yd. actual throw. This apparatus, modified in details, was operated on one or two occasions in very unsuitable conditions during the battle of the Somme 1916, and was then rejected by G.H.Q. 1 But before experiment was abandoned two important alterations were made, (a) The valves between the separate containers were done away with, and the freer flow of oil thereby obtained enabled a " record " range of 134 yd. to be reached. (6) The " director tube " built into the parapet was replaced by a so-called " monitor," a lazy-tongs device carrying a short, universal-jointed, nozzle-tube, which was raised above the parapet only during firing, the whole Installation at other times being below ground in a dugout. Other improvements were made to facilitate assembly and taking down in trench conditions. On one occasion a complete " battery " of four containers and monitor was taken down, removed, reassembled, filled and fired in slightly less than 15 minutes by ten men. The container unit was also lightened.

French heavy flamethrowers were substantially of the same character as the British model just described, but simpler. They did not range quite so well. Storage pressure was somewhat higher, working pressure slightly lower than in the British engines. The unit container was shorter and wider, and of lower capacity; the " battery " usually consisted of three containers placed one behind the other and connected by coupling-pipes at an acute angle to a single collector-tube which carried the nozzle. As above mentioned nozzle ignition and ground ignition were both used.

The German Grof (grosser Flammenwerfer) was similar in capacity to the British " battery " type, but otherwise resembled the French.

A heavy flamethrower of an entirely different type was the Livens, designed by Capt. Livens, R.E. In this the containers were, so to speak, elongated until they took the form of a single long 9-inch pipe stowed horizontally in a deep dugout or gallery. In the pipe worked a floating piston which separated the gas and the oil posi- tively. Along this pipe, at intervals, were placed refilling tanks, so arranged that at the conclusion of each shoot the pipe-container could be refilled with oil very quickly by power supplied from the main reservoir of propellant gas. In the model here described three shoots could be made, each of 80 gal., in four minutes. The propellant gas, stored in the usual bottles, was admitted to a welded reservoir which was tested to 1, 800 Ib. per sq. inch. This equalizing reservoir gave a powerful and steady drive at the relatively high working pressure of 325 Ib. per sq. inch. At the end of the container pipe was a " monitor " or rising discharger, arranged on the principle of a hydraulic ram, worked by the oil itself. This rose through a hole in the roof of the dug-out, delivered its shot, and sank automatically when the oil which supported it was drained off below.

Portable Flamethrowers. These were used to a far greater extent in the World War than were the heavier types. In most cases the container with the gas bottle strapped to it was carried on the man's back, and the discharger tube with nozzle carried in his hand, the two being connected by the usual flexible pipe. The necessary lightness was obtained of course by the sacrifice of ranging power, both quantity of oil and working pressure being lower (3 gal., and 140-170 Ib. per sq. in. respectively in the French " Schilt " types).

The general principles were similar to those of the heavy flame- throwers, except in- the method of release. Whereas in the heavy types a single long-ranging shot of great power is fired in one blast, in the light type or at least in those light types designed after the requirement had been realized a succession of very short spurts is arranged for by a quick-acting trigger-valve of some sort. This enables the user to move hither and thither, driving back now one party of the enemy, now another, or clearing several dugouts in succession without reloading. In earlier French patterns ignition was by incendiary grenades after a shot of unignited oil, but the tactical usefulness of this weapon, even more than that of the heavy type, suffers by this limitation, and in all later French models nozzle- ignition is fitted. Of these the Schilt " No. 3 bis " may be taken as representative (fig. 3). Its outstanding characteristic is the power of delivering very many short shots without reloading. The " record " is no less than 103, but such a figure can only be obtained at the expense of range, and the usual practice was to use up one filling in about 8 or ip shots with a range of rather less than 30 metres. The ignition device js the " tubular magazine " mentioned earlier and burns for 8-9 minutes. The dimensions are: container 2 cm. thick, 55 cm. high and 20 cm. in diameter, tested to 427 Ib. per sq. in. with a capacity 3 gallons. The gas is at a storage pressure of 2,133 Ib.

1 The available sets were handed over to Russia, a company of escaped Russian prisoners of war being formed and trained in Eng- land to handle them. No use was apparently made either of the apparatus or the trained men, owing to the Revolution.

per sq. in., which a reducing valve converts to a working pressure 171 Ib. per sq. inch. The trigger valve has to be held down in operation and instantly springs up and closes the passage of oil if the operator is shot an important point, as experience had shown in the case of the earlier small flamethrowers, which emptied them'

FIG. 3.

selves in a single shot. A tap is also fitted, at the origin of the flexible tube, which is turned on in going into action. The flexible tube is about 2 ft. long, and f in. in bore, the nozzle pipe also 2 ft. long with an orifice of & inch. The total weight, full, is about 65 Ib. Fig. 3 shows the apparatus in action. Like all French flamethrowers it was designed by Capt. Schilt of the Paris sapeurs-pompiers, who also organized the special flamethrower companies named after him.

The original German light Flammenwerfer, known as Kleif, was a 3-gallon engine which presents no particular point of interest. It was replaced by a smaller weapon known as Wex, which had a capacity of 2 J gal. and was fitted for successive shots. Both " Kleif " and " Wex " were operated by two men, one carrying the container knapsack-fashion while the other carried the discharge pipe and moved about as required.

The early British types known as the Norris, or Norris-Menchen, were of much the same general design as the Schilts; the first emptied themselves at one shot, the later ones had trigger valves. Another type, invented by Lt. Lawrence, R.E., and originally designed to throw either poison-gas or flame or both, was, after modification to convert it into a flamethrower pure and simple, found to possess a much longer range, as well as a better balance of the elements of the design than any existing model. Its range was no less than 45 yd., and it was capable of maintaining that range for some 15 to 1 8 shots from a single filling of 3 gallons. Safety was ensured by the use of inert gas and by the fact that if the operator lost control all valves automatically closed. This type was under manufacture in Russia in 1917 at the time of the Revolution. Experiments were also made in England with smaller models, some of which were used in the Zeebrugge landing in 1918. Finally, a flame projector was designed but never actually used, which acted in the same way as a land mine, i.e. it was buried and left to itself, inert, till the enemy in his advance stumbled upon a tripwire which set the machine in operation.

Tactical Uses. Flamethrowers used in the World War were in all the three countries which employed them engineer weapons. In Great Britain those used on service were manned by a unit of the Special Brigade R.E. In France Capt. Schilt, the designer of the Schilt throwers in use, organized some seven companies of engineers known as compagnies Schilt for flamethrower work. In Germany it was the special province of a unit of pioneers which from small beginnings finally became the Guard Reserve Pio- neer regiment, and lent its weapons and its men to the " assault battalions " as required. These battalions generally included in their attack formations a number of portable " Kleifs " or " Wexs." The G.R.P.R. also found heavy machines (two-cou- pled) and personnel for shell-hole warfare and anti-tank defence.

In reviewing, even generally, their tactical work in the war, and estimating their future potentialities, it is obvious that a clear distinction must be drawn between the heavy and the light types. The intermediates were, and so far as can be seen will always be, an unnecessary type possessing the defects without the virtues of the others.

Too little use was made in the war of true heavy types, such as the British " battery " and " Livens," for any final judgment