RUINOUS SPEEDS.

Putaruru Press, Volume VI, Issue 232, 12 April 1928, Page 7

RUINOUS SPEEDS.

According to Professor A. M. Low, the well-known English automotive engineering authority, only about 2 per cent, of touring cars upon the road could stand “ all out ” 10 laps of Brooklands track without permanent damage. It is a well-known fact to the Brooklands habitue that the “ all out ” test of any car upon the track is one of the most severe ordeals imaginable. More than one sporting car enthusiast has seen the vanishing of his hopes, based upon a successful bench test of three or four hours, when confronted by three laps of Brooklands at maximum speed. It is at first sight difficult to realise why an engine should operate without trouble for two hours at its maximum power on the bench and prove totally incapable of more than 100 miles on the track. In all probability the reason is to be found in the additional load put upon every part of the car by vibration. The life of a new racing car is certainly short and sweet. The engine is prepared with the greatest care, strains are calculated most accurately, and at its final test upon the bench and on the track it is watched by experts at every point. So soon as the throttle is kept wide open for 20 or 30 miles it is more than likely that some unexpected weakness will come to light. It may be the engine itself, gearbox or even springs or axles.

Innumerable examples could be given of cars prepared by some of the greatest factories in the world and which have performed in a totally-different manner on the day of the race from the showing at their preliminary test. It is practically impossible to foretell which particular part of a car will be loaded to excess unless the entire vehicle is subjected to exactly the same degree of general vibration which it is likely to receive in the race. For this reason the importance of flexibility in operation is beginning to receive attention, cylinders becoming smaller and smaller, and designers are giving their entire attention to the eight-cylinder or even twelve-cylinder car for engine capacities, which at one time would have called for two or four cylinders at most.

A touring car on Brooklands track will seldom travel for more than three or four laps if the throttle is kept wide open, but momentary

“ ease ups ” may save the situation, and many ca'rs giving exemplary service in the hands of owner-drivers owe their longevity to the fact that the roads seldom permit of more than two miles being covered on end at maximum speed. It is commonly said that a car will be less damaged if driven by the accelerator pedal than on the hand throttle. The reason is quite evident : The engine is responsive to the movement of the driver’s foot and is constantly being momentarily throttled down. On the road the accelerator pedal is always moving and it is this fluctuation (Continued in Next Column)

which saves the ordinary touring engine from the continuous strain of driving with the throttle full open. The information gathered from these tests at Brooklands is of great value to the motor industry, and ultimately the motor owner reaps the benefit in the car he buys.