The Works Of Messrs. Schneider And Co.

FIELD CARRIAGES WITH COMPRESSIBLE TRAILS. 287 fired, are compressée!, and cause the trail for the moment to deerease in length. The india-rubber rings then relax, and run out the gun again. The bottom of the lower cylinder is made with a circular groove, the centre of which is practically on a vertical line drawn from the centre point of the axle. The trail-spade consists of a steel blade that bears against a horizontal trail-plate. The top surface of the latter is made with a ridge tbat fits in the circular groove in the lower cylinder, in which it can slide freely the slide being limited by catches at both ends. With this arrangement, when the spade has been placed in a hollow, or when it has penetrated the ground automatically after firing the first round, the carriage can be shifted over small angl.es to the right or to the left ; the lateral training of the gun can thus be corrected, when only a slight skifting is necessary, without extracting the spade. In this first type, the axle was independent of the carriage, the following arrangement being adoptée! : it was fitted with two saddle-plates opposite the soleplates of the brackets; tliese plates were provided at one end with india-rubber buffers, the other end bearing against angles rivetted to the brackets. When the gun was fired, the brackets, by recoiling, drew back the axle and the wheels, 75-Millimetre Gun with Elastic Trail and Gas Bi’ake. by pressing down the Intermediate buffers. At the same time, the trail cylinders telescoped and compressée! the sei of india-rubber rings. The trail-spade penetrated the ground more or less deeply, accorcling to the hardness of the soil ; it formed the required bearing point to limit reçoit, and caused the carriage to run out again by the relaxing of the india-rubber rings. In some experiments the rings were replacée! by metallic springs. It will be seen that almost the whole of the system recoilecl within the limit allowed by the compression of the elastic column, the vis-viva of recoil being greatly reduced. The results obtained with the first trials of this type were very interesting ; the carriage still recoiled and rose when fired, but to a lesser degree ; this evil was, in fact, so much reduced that it appeared likely, by improving the varions parts, a much greater stabiJity would be obtained than with any of the preceding systems. Numerous other trials were made ; among others, some with the gas check at the muzzle, already described. With this appliance, recoil was lessened ; but its disadvantages as regards inconvenience to the gunners still existed, and it was finally abandoned. The type which was tried with the gas check at the muzzle is shown in Fig. 919 ; from this it will be seen that the trail bad been lengthened. 75-Millimetre (2.952-In.) Gun, Long Type, on Car- riage with Compressible and Hydro-Pneumatic Recoil- ing Trail (Fig. 920, and Fig following are particulars of the 921, Plate gun: OLV.).—The Weight of gun... ,, carriage ,, projectile ... Muzzle velocity Energy of projectile ... 360 kg. 770 kg. 5.2 kg. 590 m. 92 t.-m. 793 1b. 1697 1b. lli 1b. 1936 ft. 306 foot-t<>ns The trials which had been made with the first types of carriages with elastic trail, proved the new system to be one of great promise ; they also showed that by increasing the length of action of the two parts of the trail, the stability of the system was also increased. It inay be mentioned here that all the trials we refer to were carried out in the proving grounds belonging to Messrs. Schneider and Co., with the Help of the most perfect measuring and recording instruments, such as crusher gauges, velocimeters. Chronograph s, &c., with which every action caused by firing was duly analysed ; all parts that were found to work unsatisfactorily were, of course, modified immediately. These trials showed that the working conditions of the 75-Millimetre Gun with Hydro-Pneumatic Trail Brake. carriage would be further improved if the elastic parts first employed, and which acted simply as buffers, were replaced by a hydraulic brake device, which would con- stantly offer a résistance direetly proportioned to the energy of recoil. If this were obtained, it would check the rising of the gun, and prevent its deviation. A first example of this type of carriage was therefore experimented upon. It consistée] mainly of the carriage proper, the trail-spade, and the hydro-pneumat.ic recoil trail. The carriage was formed of two principal parts : one, of cast steel, was a cylindrical tube carrying in front two vertical brackets, in which the gun trunnions are fitted. The tube was closed in front by a cover, in the centre of which was a passage, through which compressée! air was introduced in the recuperator ; this was closed by a valve. The carriage formed, with the gun, the axle and the wheels, the movable part which recoiled and ran out again. The second part was the trail, which remained fixed during firing; it consistée! of a forged-steel tube, which contained the hydro-pneumatic arrangement for checking recoil. It was provided in front with an outside gun- metal lining, which facilitated the sliding of the two parts during recoil and return, the sliding action being, moreover, controlled by lateral guides. A gland, through which ran the tube for the introduction of compressée! air,