A 100 h.p. SIX-CYLINDER CHASSIS.
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Fuller Details of a Chassis of Clean Design Intended for Fast Motor Coach Work.,
I N our issue of December 6th last we were able to give some particulars of the new six-cylinder White chassis which has been produced for motor coach work, some preliminary details of the chassis having been sent to us by the director of engineering of the White Co., of Cleveland, Ohio. These particulars fully covered the engine, which We were, therefore, able to describe in detail, and we have now received from the company some interesting facts and photographs with regard to the chassis design as a whole. It will be remembered that the engine is six-cylindered, the bore of the cylinders being 4* ins. and the piston stroke 51 ins., the crankshaft being carried in seven bearings, and the intake and exhaust valves being placed in line and mounted in the detachable cylinder head, being operated through the medium of push rods and overhead rockers with a special farm of pivoted cam follower which reduces wear to a minimum. In order that all parts of the valve gear shall be well lubricated and that any side thrust from the rocker shall not be transmitted to the valve stem, which would cause valve-stem wear and leakage, each valve stem is cur
rounded by an inverted plunger cup, operating in a small cast-iron cylinder.
The exhaust valves arc of particular interest, because they are specially cooled by a salt mixture. This mixture occupies half the .hollow space in the valve stem and becomes molten at a low temperature. This molten salt is reciprocated within the hole in the valve stem by the motion of the valve 'itself and acts as a mechanical conveyor to take heat from the valve head and to distribute it through t.,he adequate water-cooled portion of the valve-stem guide.
In the caption below the sectioned illustration of the engine we now observe that the engine is referred to as being of 30 h.p. We are not now able to find any authority for that statement and, as a matter of fact, in the last letter we had from the White Co. the actual bp. of the engine is given as being well over 100 when driving all accessories, steel' as the generator, fan, water pump, etc.
The illustrations which appear in these pages show the general layout of the chassis, details of the springing, the axle and wheel mountings and the method of brake operation. Two photographs of the chassis show a frame of very deep section, sweeping down behind the engine to a low level, and with only a moderate wheel arch, the rear platform being at the same level as the frame at its midsection. The frame is stiffened by ample cross-membering, two of the cross-members, namely, the one behind the engine and the one immediately to the rear of the wheel arch, being tubular and of large diameter. There is a deep central cross-member which carries the housing for the central bearing supporting the forward end of the propeller 'shaft.
Being constructed for service in America, the vehicle has its steering column on the left-hand side, the brake lever being carried over to the driver's left and the gear lever being mounted slightly to the left of the centre line of the chassis.
The petrol tank is mounted on the right-hand side and is carried in a special cradle, which permits of ready removal when the body is in position. It has a capacity of about 40 American gallons, the fuel being delivered
to the engine by means of a tripleunit, electrically operated pump. The chassis is equipped with domed front wings and a twin-leaf bumper, whilst an apron bridges the space between the two front dumb-irons.
The clutch consists of three pressure plates (two, having through-cored passages for lightness and cool running, being of east-iron) and .two steel clutch discs, carrying friction _ material of the moulded type. These discs are slotted radially to prevent undue distortion under heat. Air is forced through the clutch in order to cool the friction surfaces. The gearbox is mounted in unit with the engine.
One of our illustrations shows the front-wheel brake mechanism with the cam, and the diaphragm housing of the Westinghouse compressed-air system. One side of the expander cam which operates the lower shoe is clearly shown in the illnstration. The cam on the opposite side is exactly the same and expands the upper shoe. The shoes are not lined with fabric material, being of the metalto-metal type, and they are described as "throw-aways," to be entirely replaced when worn. The brake-actuating camshaft is mounted at the front, in the case of front-wheel' brakes, and flexible piping passes from the diaphragm housing to ,a union on the side of the frame, as is clearly seen in the illustration showing the front-axle suspension. The latter photograph shows that, on the top of the spring, there are held in position by spring-plate clips two friction plates, which have been placed in position with initial tension. The effect of the employment of these friction plates is to damp out excessive rebound and to act similarly to the usual shock absorber.
Another illustration which we are able to produce in this issue shows part of a rear spring, together with the brake shoes, arching of the frame and the mounting of the Westinghouse brake-actuating mechanism on the axle easing, the shaft for operating the eipander cam being rear. The rear spring, it will be seen, has four auxiliary leaves and the spring is under full load with the progressive and main spring portions in contact. The spring shackles used are of a special design, the patentfor which is held by the White Co. Whilst effectively clamping the pins in position, this type of shackle is provided with means for adjustment in order to take care of side play with a positive clamping action. This shackle has been found to be very satisfactory, in service.
The design of this new White motor coach chassis seems to us to be particularly clean and practical. There is no mass of detail and there are no loose ends about it, everything being so located as to produce a clean 'and simple design.