Rumblings, October 1959

The 1960 Coronation Safari

The organisers of the 1960 Coronation Safari, now rechristened the Eighth East African Safari, to be run on April 15-18th, have decided to alter the method of classification of entries. This step has been taken with some reluctance, but it has been considered necessary in view of the international status of the event, and their desire for it to be considered as qualifying for the World Rally Championship.

Entries for the Safari have now been divided into two separate categories:

(1) Normal Series Production Touring Cars.

(2) Normal and Improved Series Production Grand Touring Cars.

Classification will be by engine capacity, the Normal Series Production Touring Cars to be classed as detailed below:

Class A: Below or equal to 750 c.c.

Class B: Above 750 c.c. and below or equal to 1,000 c.c.

Class C: Above 1,000 c.c. and below or equal to 1,300 c.c.

Class D: Above 1,300 c.c. and below or equal to 2,000 c.c.

Class E: Above 2,000 c.c.

Grand Touring Cars may be of any capacity.

The latter will be eligible for certain trophies but not for the outright winner of the Safari nor for cash prizes. There will be great interest, however, to see what these cars can do in competition with the Normal Series Production Touring Cars.

In previous years the entries have been classified according to price range, a method unique in international rallies. Whilst this has been abandoned, it is the intention to preserve continuity and the original character of the event by quoting the Nairobi prices in the programme for the benefit of the East African public. The route of the Safari and the control procedure will remain essentially the same as in 1959, although it has been found necessary to increase entry fees from £20 to £40 per car.

*

Rover Range Cut

In order to simplify their production programme Rovers have dropped the “60,” “75,” “90,” and “105” models and replaced them with the “80” and the “100,” which have the merit of looking like Rovers, whereas the 3-litre is a complete breakaway from the traditional outline of these famous luxury cars. These two new models retain the same basic body shell as used on last years’ range, the “80” using a four-cylinder engine and the “100” a short-stroke 2.6-litre version of the six-cylinder engine used in the “3-litre.”

The engine used in the “80” has a capacity of 2¼-litres and is a direct development of the petrol engine used in the Land-Rover. This engine develops 77 b.h.p. at 4,250 r.p.m., using a compression-ratio of only 7 to 1, and incorporates Rover roller-type tappets. The roller which follows the cam runs in a lead tin-plated bronze shoe which in turn slides in a cast iron tappet guide. In this way high valve lifts are obtained with a minimum of wear on the cams and from our experience the tappets seem remarkably quiet.

Bringing the “80” and “100” into line with the 3-litre model, Rovers are fitting them with Girling type 18 disc brakes on the front wheels in connection with 11 by 2½ in. leading and trailing shoe drum brakes at the rear. The braking system is vacuum-servo-assisted. The other major change is that the Laycock de Normanville overdrive is fitted as standard equipment. This Rover installation operates on top gear only and is brought into use by a steering column mounted switch which can be operated without moving the hand from the wheel. The car can be returned to direct drive by a kick-down switch under the accelerator pedal.

The engine of the “100” has a bore and stroke of 77.3 by 92.075 mm., and a capacity of 2,625 c.c. It has the familiar Rover overhead-inlet valves and inclined side exhaust valves in connection with an aluminium cylinder head. The crankshaft has seven copper-lead-lined steel shell main bearings and is fitted with a harmonic vibration damper. In this short-stroke form the engine develops 104 b.h.p. at 4,750 r.p.m. and its maximum torque of 138 lb. ft. at 1,500 r.p.m.

Apart from the engine, brake and overdrive changes, the cars remain very similar to the previous models, a fact we were able to confirm in the lanes around Warwick recently. An extra leaf has been added to the rear springs and the suspension has been stiffened slightly all round making these heavy saloons surprisingly roll free. They prefer to be cornered with the power on, as the Dunlop or Avon tyres squeal somewhat if the car is cornered with a trailing throttle. The braking is much improved with the Girling discs, although the front wheels can be locked if too much pressure is applied.

These new Rovers retain their traditional silence and air of quality and the useful features such as reserve fuel tank, reversing light, adjustable front seats for height and rake as well as fore-and-aft movement, vanity mirrors, interior tool kits, gaitered rear springs, and only four chassis greasing points are retained. The prices are as follows “80” £1,365 7s. 6d., “100” £1,538 4s. 2d., “3-litre” £1,715 5s. 10d. Automatic transmission model £1,864 0s.10d. All these prices include purchase tax. But what a pity the economical Rover 60, a real quality car of low petrol thirst has joined the “out of production” school.

*

And Now – Renault “Aerostable” Suspension

Because of the light weight of the Renault Dauphine it proved difficult in the past to find a type of suspension that was satisfactory both when the car carried a driver only, and when the car was fully laden. The difference in weight between these two conditions could be as much as 600 lb., nearly half the weight of the car. To obviate the suspension being too hard when carrying only a driver, and too soft when carrying four people and luggage, was the problem Renault engineers faced. It was necessary to find the best spring oscillation period and maintain this under all load conditions. Because the period of oscillation depends on both the flexibility of the springs and the weight of the vehicle, it was necessary to find a type of suspension in which the flexibility of the springs would decrease in inverse ratio to the increase in load. The answer was found in the “Aerostable” system.

The “Aerostable” system consists of normal all-round independent suspension — coil springs and hydraulic telescopic shock-absorbers — to which is added an extra suspension system. The coil springs have been softened (front wheel deflection 72 mm. per 100 kg. instead of 32 mm., rear 41 mm. instead of 17). Thus when the driver only is in the car, the ride is more comfortable. When the load is increased, the supplementary suspension comes into play. Rubber buffers of special design are used at the front. On the rear, sealed rubber air-filled cushions are fitted above each half axle. These cushions are filled with air at normal atmospheric pressure. Below each cushion, mounted on the half axle, is a metal dome. Thus the dome compresses the air cushion when additional weight is applied.

The flexibility of the air suspension decreases rapidly as the load is increased. The rubber buffers on the front suspension have the same characteristics.

The flexibility curve is such that the frequency of the suspension is kept within very narrow limits, regardless of load conditions. Consequently, whatever the load in the car, there is no lessening of comfort.

Road-holding of the car is also said to be improved. When empty, cars with “Aerostable” suspension are the same height off the ground as cars with the old-type suspension. The weight of the driver alone is sufficient to flex the suspension. This means that cars with “Aerostable” suspension are lower to the ground when moving. 

Road-holding of the car is improved by two factors. First, the car has a lower centre of gravity. Secondly, the positive camber of the wheels is lessened. Furthermore, with the “rapid return” characteristics of this type of suspension mean it is claimed that on uneven surfaces the wheels are always in contact with the ground. The following advantages are claimed over and above the increased comfort and improved road-holding:

(a) Simplicity.

(b) No maintenance.

(c) At rest the air cushions are not stressed.

(d) Constant performance in use. (The air, heated by compression is immediately cooled by de-compression.)

(e) Silent in operation.

( f) Safety: in the unlikely event of an air cushion needing replacement, the metal springs are sufficient to carry a loaded car without discomfort.

(g) Cheap and simple replacement. (The rubber of which the cushions are made is not affected by oil.)

(h) Tests have proved the system suitable at all speeds, loads, air temperatures and road surfaces.

The “Aerostable” system is installed in all Renault Dauphines, Dauphine-Gordinis and Florides.