A NEW 3-TONNER OF SIMPLE LAYOUT
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QUITE extensive developments are taking place at the Luton works of Cornmer Cars, Ltd. In addition to the introduction of an entirely new 3-tonner, several other important improvements are being made to other models, and plans are afoot for completing the range of light delivery chassis. An aggressive export policy is being pursued, and there is now a practically standardized overseas edition of the Raider 30-cwt, machine, which has proved so successful in this country.
The new GL3 model displaces the G3 3-tonner, from which it is entirely different except as' regards the engine; the weight is less, the design is far more up to date, the frame height is lower and the engine and varbox form a unit with quite a new system of suspension in the frame. In spite of the improved design, it has been found possible to reduce the chassis price to 1550, or 160 less than the old G3 type.
In some respects, the chassis layout resembles that of the G2 2i-tonner and, although it is a heavier job, the unladen weight has been satisfactorily kept down. The GL3 chassis is made in one wheelbase length, namely, 13 ft. 6 ins., and has a frame height (laden) of 2 ft. 2 ins. Although the driver sits behind the engine, a length of no less than 16 ft. 6 ins, is available from the dashboard to the end of the frame. The front track is 5 ft. 6 ins., and the rear track, between the twin India 32-in. by 6-in, reinforced tyres, is 5 ft.
The new frame has a maximum section of 6 ins, by 2 ins, by i in., and its longitudinals are parallel, being 2 ft. 81 ins. apart. The frame is only slightly arched over the rear axle, but it gives quite as low a floor height as the present 2i-tonner, the rear springs
being mounted above instead of below the axle. As a matter of fact, this gives a better resistance to rolling tendency.
The engine is the company's well-known four-cylindered side-valve unit of 105 mm. bore and 140 mm. stroke ; it develops a maximum of 70 b.h.p. at n32 a crankshaft speed of 2,500 r.p.m.
The power unit embodies several improvements over the earlier model. It has a Solex self-starting up-draught carburetter, and coil ignition is fitted as standard, although a magneto is available, if preferred. In place of the rigid three-point mounting, the engine now has a trunnion rear mounting in large rubber blocks, also a single rubber-mounted front trunnion. The rear supports are cleverly arranged in that, as the metal shell is drawn up to the frame member in order to compress the rubber, it rides up a wedge, so lifting the engine. The rear mounting of the engine does not serve to brace the frame, there being a heavy bridge-type cast crossmember at this point.
The rear end of the crankcase has been modified to take a bellhousing for a unit-type clutch and gearbox mounting. The gearbox resembles that employed in the 2itonner, having a silent third-speed gear, and the gears are made of special high-grade case-hardened steel. The electric starter is bolted to the rear face of the clutch housing —actually, an extension of the gearbox casting—in which position it is more accessible than at the front. A short jointed shaft extends to a self-aligning ball centre bearing, suspended from the tubular crossmember, and the final propeller shaft, which is a Spicer unit with a sliding front joint, drives through a spiral-bevel gear, with four-pinion differential, the fully floating shafts of the rear axle. These are contained in a banjo-type case, which is made strong by reinforcement tubes. Steel disc wheels are fitted.
The springs, which are of new design, are mounted above the axles and shackled at the rear, and are arranged so as to be straight when under full load. The front springs are 3 ft. 4 ins, long and 21 ins, wide, whilst the rear springs are 4 ft. 6 ins, long and 3i ins. wide.
The brake gear follows the principles adopted for the Raider and Centaur chassis. In place of the transmission brake on the old 3tanner, Bendix Duo Servo brakes act on all four wheels, the front drums being of 14 ins, diameter, and the rear drums of 16 ins, diameter, whilst all shoes are 2i ins. wide.
This single set of powerful brakes has two independent means for operation, being coupled up to a stout cross-member mounted amidships. Either the hand-lever or the pedal will actuate this cross-member, slotted links being fitted to prevent interference between hand and foot operation. As •a safety measure, a cross-shaft support bearing is arranged between the hand-brake and foot-brake levers, thus complying with regulations.
Brake adjustment is effected by altering the shoe fulcrum according to the ordinary Bendix system. Interference with the brakes, due to spring flexing, is eliminated by the adoption of enclosed flexible cables for the final stage of brake-power transmission.
Bishop cam-type steering gear is being fitted to the new chassis, and it has a slightly self-centring action. The driver's daily work is simplified by mounting the throttle, ignition, dip-and-switch, horn and starting controls on the centre of the steering column, the horn and starter sharing a common button.
The instrument board is mounted on the steel dash, and incorporates a petrol gauge, oil-pressure gauge, speedometer, ammeter, light and ignition switches, selfstarting carburetter control, etc.
Tecalemit grouped oil lubrication is provided for all chassis parts, the pipe to the centre steady bearing, however, taking grease.. The fuel tank is suspended from outriggers at the near side of the frame, and the running-boards are supported on angle-iron crossmembers, which, as they extend right across the chassis, are very strong. The batteries are accessibly mounted on the off-side running-board, in which position they are protected by the cab door.
Improvements have been made to both chassis and body of the 4-tonner, the latest type being designated G1.4. In spite of this, the price has been reduced by £30, the normal-control model costing £695, or £40 extra with four-wheel brakes, whilst the forward control model costs £720, or £760 with four-wheel brakes.
Rubber engine mountings, as described in regard to the 3-tonner, are fitted. Incidentally, a point concerning this interesting mounting is that, by undoing four nuts on each rear trunnion arm, and detaching the front cast cross-member, the engine may easily be removed forward.
The patent type of gearbox, as in the G4 model, Is retained, but it has been moved back 1 ft. in the frame to allow for the more flexible engine support. and the result of this has been to allow the handbrake and gear levers to be placed farther back, so that the off-side cab doorway is now particularly free from obstruction.
The transmission brake of the earlier 4-tonner also is retained, and is foot operated, unless four-wheel• brakes are specified. In this case a Dewandre vacuum servo is fitted, and the transmission brake is then handoperated.
Engine improvements, as in the 3-tanner, are incorporated, including the Solex self-starting carburetter and coil ignition; also the controls are grouped on the centre of the steering column, and the instrument board, running-board mounting, fuel tank, etc., follow the arrangement of the GU.
Apart from the improvements affecting the interior of the cab, the cab itself has been redesigned, and the vehicle may be said to be one of the most handsome British goods carriers on the market. The cab has en eddy-free front and, as an extra, a sliding roof may be fitted.
The particularly smart appearance of this new 4-tonner really results from a happy blending of cab and bonnet lines. The radiator is uncommonly deep and of handsome outline, and the frame is sufficiently low to permit of a cab being fitted which has a low appearance in spite of the fact that it has all-round generous dimensions. The result of this, together with the rounded cab quarters and the window arrangement, Is to give the whole vehicle rather a majestic bearing. Drivers will appreciate the convenience of the controls, whilst the opening roof would appear to be an extra well worth specifying.
To complete the lower end of its range, Commer Cars, Ltd., is now introducing a 15-cwt. van, based on the Hillman van recently road-tested by us. The Commer vehicle, however, is superior as regards engine power, engine suspension, frame details and bodywork. The chassis price is £190, and the complete van sells at £230. In addition, we understand that the company will shortly introduce two other models in the lightdelivery class.
The Raider 30-cwt. chassis is meeting with a good demand from overseas, and a standardized overseas type is now available. This has a fully floating rear axle with over-mounted springs, bigger tyres (8,25-in. by 20-in., although tyres up to 9.00-in. section *May be specified), heavier headlamp bracket and stronger bumper, air cleaner, cowled radiator, heavier front axle, steering gear and connections, stronger runningboard supports, side spare-wheel mounting, towing hooks front and rear, and other improvements.
B34 In connection with the suspension, the Newton horizontal-type hydraulic recoil dampers, described elsewhere in this issue, are fitted to the rear axle. The final-drive ratio is 6,57 to 1; as against 6 to 1 for home service. Some of the machines are being equipped with Still-tube radiators, especially those used by the Royal Air Force under arduous conditions of tropical service.
The Commer range, it will be seen, is becoming a most comprehensive one, from the points of view of both home and overseas commercial-motor users.