The Maudslay Gold Medallist.
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A Vehicle Remarkable for its Speed and the Accessibility a its Parts.
In our issue of last week, we were able to give an illustrated description of one of the vehicles which gained a gold medal in the class for vehicles constructed to carry a three-ton load; we now take pleasure in giving a few particulars of the Maudslay wagon, to which vehicle was awarded the other gold medal allotted to class E.
This wagon, which bore the number E4o, was also awarded a diploma by the War Office authorities on account of the accessibility of the component Paris of the engine. To such an extent has accessibility dominated the design of the engine, that it is possible to take oat any one connecting rod, with its piston and rings, without disturbing either crankcase, crankshaft, or cylinder : the provision of very large inspection doors in the sides of the crankcase, and the disposition of the camshaft, which latter part is mounted directly over the cylinders, and central with the engine, are the chief features that render this make of engine the most accessible one with which we are acquainted. This company has persistently adhered to the same design of engine since its first entry into the motor industry ; all weak points have been eliminated as they presented themselves, and the result has been the evolution of an engine tnat is accepted by users and engineers-in-charge alike, with evident satisfaction. The ease with which the pistons And connecting-rods can be taken out was a point which greatly impressed all those who examined the chassis : we believe that it is possible to take off one of the crankcase covers, uncouple a connecting-rod, and withdraw the latter (with its piston), in a matter of eight or ten minutes. The piston may be taken out from either side of the engine, and it will be noted that there are removable covers at each side of the crankcase. Having uncoupled one of the big-ends of the connecting„rods, a piston may be
withdrawn from the cylinder, and from the crankcase, without any awkward (lodging of parts " round corners.'' In the lower part of each piston there are two, half-round notches, cut at diametrically opposite points; these are pro vided in order to allow of the connecting-rods' being pulled over to a much greater angle than would otherwise be Possible, while withdrawing the pistons. These notches in the pistons are clearly shown in our illustration which shows a longitudinal section through the cylinders and camshaft, and again in the cross-sectional view of the engine. The cylinders, it will be observed, are cast in pairs and they have exceptionally large water-jacket covers. This point in their design should ensure perfectlysound castings, because of the freedom with which all gases may escape from the mould, and they have a further advantage in the fact that cleaning is rendered quite easy. We have heard of cases in which cylinder water-jackets have become so choked with dirt that cooling became practically impossible, and the design of the cylinders was such that the dirt could not be washed Out.
The engine is rated as a 3o-46h.p. and is capable of developing 30h.p. at 750 r.p.m., or 4oh.p. at i,000 rpm. The bore of the cylinders and the stroke of the pistons are each 5 inches. The valves are placed directly in the heads of the cylinders, and they are operated by a hinged and universally-jointed camshaft, which is driven, by skewgearing, frOrn the forward end of the crankshaft. When the camshaft is hinged over to one side, any, or all, Of the valves, together with their seatings, may he removed for grinding or for replacement. All the valves are
strictly interchangeable. As already mentioned, the crankcase is provided with large inspection doors, and, when I hese are opened, every working part within the chamber, including the five crankshaft bearings, may be adjusted with ease. The design of the connecting-rods is rather a good one and it ensures proper lubrication of the gudgeon-pins without depending on splash from the crankcase. They are of tubular form, with large bearings at top and bottom, and the big-ea caps are secured by four bolts, instead of the weaker two. A gear-drwen,rotary pump supplies oil, under pressure, through the hollow crankshaft to the main bearings, the big-ends of the connectingrods, and from thence, through the tubular portions of the latter parts., to the gudgeon-pins. The carburetter is of the usual float-feed, non-automatic type, but it is so designed that the air inlet, the supply of the mixture to the engine, and the opening of the
petrol jet, may all be varied in unison, by means of one lever, which will give the correct proportions to secure the best result for power and fuel consumption at all speeds of the engine. This hand lever is situated above the steering wheel.
High-tension, magneto ignition is fitted as a standard, and the magneto is mounted on the dashboard in full view of the driver ; it is driven by a short, universal shaft and bevel-gearingfrom the camshaft. High tension, battery and coil ignition can be fitted if required ; in that case the distributor would be mounted on the after end of the camshaft, in place of the magneto The cooling of the cylinders is well provided for in the extra-large, tubular radiator, the appearance of which is so
distinctive. In this cooler, the tank portion is an aluminium casting, and the tubes are connected thereto by flexible connections which greatly obviate the chance of leaky joints. The cooling is further assisted by a fan of about 20 inches in diameter.
The power of the engine is transmitted through a simple, leather-faced, cone clutch to the four-speed and reverse gear box. In the design of this
unit, as is the case with the engine, accessibility has been the dominating consideration. It is one of the few oommercial-motor gear-boxes in which plain bearings are successfully employed.
As may be seen from our illustration on this page : fine points have been avoided ; there is sufficient clearance between adjacent moving parts ; the cross-sections of all the wheels have not been pared down to such an extent that excessive warping of the gears results; and only as many parts are contained within the box as are absolutely necessary. All the gear-changes are effected by one lever with a gatechange. The condition of the hardened. steelgears in the gear-box of El.° was not so good as that of some of the other competing vehicles, but it must be borne in mind that this chassis had been engaged on demonstration work for about three months previous to the commencement of the trials, using, throughout that time, the same set of gears which was finally presented to the view of the judges for inspection.' The differential gear, with its bevel drive, is contained within the same casing as the change-speed gear. The differential shafts are articulated, and they are provided with Oldham coup hogs. The outer ends of the differential-countershaft are supported from the side channels by means of stout brackets from which, also, the hanging levers which carry the pedal brakeblocks are pivoted. The final drive from the countershaft is through Morse silent side-chains to the back wheels.
Two independent sets of brakes are fitted : one of these is operated by a foot-lever which causes two, metal blocks to be brought into frictional contact with two brake drums on the outer ends of the countershaft ; the other set of two drums is of similar design, but has much greater dimensions. The latter set is fitted on the rear wheels, and is applied by a hand lever. Both sets of brakes are of the loco. pattern, a type which possesses the merits of simplicity of design, fewness. of parts, and low cost for the renewal of the wearing parts. To these advantages we might add facility for easy and quick renewals, a point of no mean importance.
Throughout the whole vehicle, the design is such as to ensure great strength for all the parts, great rigidity where needed, as in the frame, whilst other parts, such as springs and wheels, give sufficient resilience to ensure easy riding.