SPEED RECORD

Southland Times, Issue 22508, 16 February 1935, Page 9

SPEED RECORD

THE NEW BLUE BIRD.. j SOME INTERESTING FEATURES. Sir Malcolm Campbell (England), holder of the world’s land speed record of 272 miles an hour, has revealed some interesting features of his new Blue Bird with which he is to make a further attempt on the classic record this month at Daytona Beach (United States). The outstanding changes to be incorporated in the latest contender for the coveted record, are twin driving wheels, dual crown wheels and pinions, a new designed streamlined body and decelerating fins in place of four wheel brakes. Only the 12-cylinder 2600 horse-power Rolls-Royce aero engine, gear-box, and side members of the old Blue Bird were used in the construction of the machine, everything else being new. The adoption of twin Dunlop wheels and tyres should ensure two important gains, greater tractive adhesiqn with the smooth treaded covers and greater stability in holding the automobile bullet on a straight course, along the 10Jmiles stretch of hard beach at Daytona. Twin Wheels Favoured. Sir Malcolm Campbell and his designer had alternative designs to consider in regard to the important factor of efficient traction, among which were front wheel drive, four-wheel drive, a six-wheeler, or the orthodox single tyre type of rear wheel drive, but eventually all were ruled out in favour of twin wheels. These it is thought, owing to spreading the weight over four driving tyres (which will be run at a reduced pressure as compared with the single Dunlops carrying the same weight during the 1933 achievement at Daytona) will overcome the terrific wheel spin which lost Campbell many miles an hour when he raised his own record figures from 254 to 272 miles an hour. On that occasion, although the clocked speed averaged 272 miles an hour, the rev counter showed that the engine had turned over during sections of the mile run at the equivalent of 320 miles an hour, the difference representing an enormous loss of energy through failure of the wheels to retain a grip on the hard sand, although some hundredweights of lead were carried in the rear of the chassis with the object of improving traction. The use of twin wheels will increase the stability of the machine and the factor of safety. After nine months of wind-tunnel tests with models, a design has been selected which will materially lessen air-resistance as compared with the Blue Bird of 1933. The body on that machine was not ultra-efficient aerodynamically, it having a frontal area of 15 square feet or three feet more than the Golden Arrow with which Sir Henry Segrave recorded 231.4 at Daytona in 1929. Major Segrave, on that occasion, only had the benefit of 910 horse-power, whereas Campbell had 2600 horsepower, much of which went to waste through wheel spin. It is of interest to mention that the 3500 horse-power seaplane recently flown at a speed of 440 miles an hour over Lake Garda (Italy) by Lieutenant Agello has a frontal area of only about four square feet. The frontal area of Sir Malcolm Campbell’s new machine has not been disclosed, but no doubt every effort has been made to reduce to a minimum this most vital factor. The radiator has been merged into the front of the 1935 machine, so that it offers the minimum of resistance, in fact, actually less than 5 per cent., which is much less than in any previous ultra-speed racer driven by Sir Malcolm. Radiator Shutters. Provision has been made to shut off the rush of air into the radiator whilst the car flashes over the measured mile, by the use of shutters. This item alone will, it is thought, increase the Blue Bird’s speed by about 15 miles an hour. The shutter cannot be closed for more than 30 seconds, otherwise the water would rapidly boil away. A few years ago, when Major Segrave raised the record to 231 miles an hour, it was thought that the limit of tyre endurance carrying such a weight at such terrific speed had about been reached, but Dunlop technologists during the last five years have really progressed faster than the automotive designers and engineers, and have tyres ready for Sir Malcolm Campbell s forthcoming big effort, tested to stand up to a speed of just over 300 miles an hour or five miles a minute. The dual crown-wheels and pinions have been incorporated better to withstand the tremendous tooth-pressure on the gears. When the 1933 Blue Bird was taken down and examined after its epic achievement, it was found that the conventional single crownwheel and pinion had been badly stressed. Much interest will be focused on the use of decelerating fins instead of the orthodox brakes on the four wheels. In the past, it has been found that at speeds exceeding 200 miles an hour, brakes were practically useless in stopping a four ton machine until the speed had dropped to less than 100 miles an hour. Earlier application is dangerous and simply fuses the brakes. To stop the car when travelling at 300 miles an hour within one mile after passing the finishing banner would absorb 1350 horse power. Sir Malcolm Campbell will have about four miles in which to pull up, and unless the fin-Accelerators are highly efficient, he will need every yard of it, if this great driver (he is nearly 50 years of age) is to attain his ambition, the 300 mark.