MOTORING WORLD

Manawatu Standard, Volume LIX, Issue 69, 18 February 1939, Page 6

MOTORING WORLD

NOTES. More than half the motor vehicles sold in Canada last year were used ones. Oil ail average there were 1.91 used vehicles sold lor every new model. Tests by mechanics for renewal of warrants of fitness have shown a. high proportion of cars to have un-evenly-adjusted brakes. Apart from increasing the hazard of driving on wet roads, this fault also results in uneven tyro wear, and is therefore one to be rectified as soon as possible.

Construction of roads for fast motor traffic is now being pushed forward in Russia. One of the first to be constructed is that from Moscow to Minsk, which is alvcady open from Minsk to Smolensk, and between Moscow and Golitsin. Some 25 miles of the road have still to bo constructed, But it is expected that it will be open throughout its whole length of 434 miles early in the present year. NEW MORRIS TEN. The new Morris Ten was recently exhibited at motor shows in England and already a number of these cars have made their appearance in New Zealand. One’s first impression is that it is a completely new car. This view is correct, for the 1939 model is an entirely new design, not only in external details but mechanically, too. A new overhead-valve engine is used, coupled with a four-speed gearbox with synchro-mesh on second, third, and top. This unit, the makers say, gives an extremely lively performance and actually results in better petrolconsumption figures. Vibration is completely eliminated by engine design and the floating rubber engine suspension system. A new system of springing is incorporated. The engineers responsible for the design of the car express themselves as highly pleased after testing it in a strenuous 2200 mile run through Asia Minor and Europe. During this trip the car was deliberately taken over the worst of roads, including stony tracks and desert routes where motor-cars are seldom eeen. The way the car behaved proved, to tho satisfaction of the drivers, that it would give exceptional riding comfort in any part of tho world. The. whole body is scientifically sound insulated. Ventilation, also, has received special attention, and the makers claim that all passengers may enjoy fresh .air without draughts. The front seats rest on floating springs and are shaped to provide maximum support and relaxation. The back seat is 51 inches across at the elbows and is designed to give support to the knees, a welcome factor on a long journey. Other interesting features of tlie interior arc a parcel shelf running tlic full width of tho ear under the instrument panel; an electric clock; concealer] ash-trays; well-less floors; and upholstery to tone, with the bodycolour. Luggage is taken care of in a large compartment, which has an opening at the rear. Immediately under this is another compartment where the spare wheel is housed. BETTER BRAKES. IMPROVEMENTS IN DESIGN. A very gratifying feature of the recent Earl’s Court motor exhibition in London was the improvement which had been made to car braking systems. In the last two or three years designers have possibly paid more attention to brakes than to any other part of the car. It has been realised that the higher operating speeds and the more congested traffic of to-day demand a much greater efficiency from the brakes than even those of recent car models have supplied. A. well-known manufacturer ef hydraulic brakes showed at Earl’s Court three important improvements produced because of known minor faults in previous brake design. Two of these were inspired by the difficulty that has been experienced in distributing tlie braking pressure equally over the full area of the brake linings. With the average arrangement of the shoes within a drum, the forward rotation of the drum tends to wrap the leading shoe into closer contact with the drum and force the trailing shoe awav from it, so that the hulk of the work is taken by the leading shoe. This ts berause both shoes are hinged together at the bottom and expanded at the top. IMPROVED CONTACT. With one new design produced by this manufacturer, the shoes are slotted at their bottom ends and fit over a squared peg on the hinge so that, to a limited extent, they can slide angularly on this peg. It is . arranged in such a fashion that application of the brakes makes the shoes move slightly within the drum so that they come into far better contact with the drums than, did shoes of earlier design. Far more efficient even than this, hut naturally more expensive, is a design in which there arc actually two leading shoes. The front shoe is arranged in the normal manner, hinged at the bottom and forced against the drum by a hydraulic cylinder from the top. The after shoe, however, is hinged at the top and has its own operating cylinder at the bottom. Therefore, both arc in effect leading shoes and have precisely the same efficiency, because both are subjected to the self-wrapping tendency. Because tin’s brake, for obvious reasons, is not very effective when the car is in reverse, it is only used in the front wheels, and already has been employed for some' months with great success in a number of racing cars and in at least one well-known high-priced m odel.

In tho hack drums a system of braking is employed which has the shoos arranged in the usual fashion, but with a rather unusual method of oneration. The hydraulic cylinder is placed horizontally outside the drum and operates the brakes by a wedge. Tlirough the centre of this cylinder to the wedge runs a roc] which is connected hv mechanical means with the hand brake lever. Tn most countries, licensing regulations insist on a mechanically-operated hand brake, hut with the usual hydraulic system, that is rather hard to arrange without undesirable complication. The system just described overcomes that problem simply and effie’ontl v.

HYDRAULIC AND MECHANICAL. Another manufacturer shows a combination of hydraulic and mechanical operation. There is, in tho usual fashion, a master hydraulic cylindor connected by pipe lines with individual front wheel cylinders. Tho roar wheels, however, are connected with the master cylinder by an arrangement of straightforward rods. Should tho hydraulio system fail, a little more pressure on the brake pedal will transfer all the force directly to the mechanical linkage running to tho back wheels. Therefore, although tho front brakes have been lost, a quite efficient mechanical back braking system remains.

XJjo same firm. has produced an ar-

rangement by which the two shoes in a brake drum exert an even pressure on the drum when the brakes are applied over their entiro surfaces. Usually, of course, tho greatest pressure is applied at the ends expanded and tho least at the hinged ends. This new system really converts both shoes into loading shoes, but with this advantage, that tho brakes are equally effective whether the car is going forward or backward.

.As the manufacturers whose products have just been described, together with one other whoso system remains unaltered, supply brakes for about 90 per cent, of tho makes of car in production, these new developments are very important and their advantages will be enjoyed by motorists as the new model cars arrive.

Almost the only cars which do not use these systems arc some very high priced ones and one or two which, because of unorthodox transmission arrangements, must also have special brakes.