LAND SPEED RECORD

Poverty Bay Herald, Volume LXII, Issue 18610, 22 January 1935, Page 11

LAND SPEED RECORD

300 M.P.H. ATTEMPT CAMPBELL’S BLUE BIRD Sir Malcolm Campbell (England), holder oil the world's land speed record of 272 m.p.h.. has at lust lifted the curtain and revealed some interesting features of his new Blue Bird, with which he, is to make, a further attempt on the classic record about February 18 at Daytona Beach (U.S.A.). The outstanding changes to lie 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 inis in place of four-wheel brakes. Only the 12-cylinder 2600 h.j). Rolls-Boyce aero engine, gearbox, and side members of the old Blue Bird are being used in the construction of the machine, everything else being new, The adoption of the twill Dunlop wheels and tyres should ensure two important- gains, viz., greater tractive adhesion with the smooth treaded covers and greater stability in holding the automobile bullet on a straight course along the lOi miles stretch of hard beach at Daytona.

Campbell and his designer had alternative designs to consider in regard to the important factor nl 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 favor of twin wheels. These, it is thought, owing to spreading the weight over four driving tyres (which will hi run at- a. reduced pressure as compared with the single. Dunlaps carrying the same weight- during the. 1933 achievement iit Daytona) will overcome the terrific wheel spin which lost Campbell many m.p.h. when he raised his own record figures from 254 to 272 m.p.h. On that occasion, although the clocked speed averaged 272 m.p.h., the "revv counter showed that the engine had turned over during sections ol' the mile run at the equivalent of 320 m.p.h., the difference representing an enormous loss of energy through failure of the wheels to retain a grip on the hard sand, despite of the fact that some cwts. of lead wero carried in tlu; rear of the chassis with the object of improving traction. The use of twin wheels will increase tlnstability of machine and the factor ol safety. ' STREAMLINED BODY As regards the new streamlined body, after nine mouths’ wiml-tunnel tests with models, a design has been selected which will materially lessen air-resistance as compared with the Blue Bird ol 1933. The body on that machine was not, ultraefficient aero-dynamicallv, it having a frontal area of 15 sq. It-, or 3ft. more than the Golden Arrow, with which, the late Sir Henry Segrave recorded 231.4 at Dnvtona in 1929.

Segrave, on that occasion, only had vhe heuclit of 919 b.h.p.. whereas Campbell had 25C0 b.h.p., much of which went to waste through wheel spin. It. is ol interest to mention that the 3500 1 h.p. seaplane recently flown at a speed of 440 m.p.h. over Lake Garda (Italy) by Lieut. Agelle lias a frontal area of only about four square leet. The frontal area of Campbell’s new machine lias 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 Campbell. Provision is being made to shut olf the rush of air into the radiator whilst the car flashes over the measured mile ny the use of shutters. This item alone will, it- is thought, increase the Blue Bird’s speed by about 15 m.p.h. The shutter cannot he closed for more than 30 seconds, otherwise the water would rapidly boil away.

TYRE ENDURANCE A few years back when Segrave raised the record to 231 m.p.h. it was though that, the limit of tyre endurance carrying such a weight at such terrific speed had about been reached, but Dunlop technologists during, 'the last live years havcj really progressed faster than the auto motive designers and engineers, and havij lyres ready for Campbell’s forthcoming big effort, tested to stand up lo a speet of just over 7>oo m.p.h., or 5 miles a minute.

The dual crown-wheels and pinion.' have been incorporated to better withstand tlie tremendous tooth-pressure ol the gears. When in 1933 Blue Bird was taken down and examined after its epic achievement, it was found that the conventional single crown wheel and pinion bad been badly stressed.

Needless to say, much interest will be focussed oil the use of decelerating tins instead of the orthodox brakes on the four wheels. . In the past-, it has been found that at speeds exceeding 200 m.p.h brakes were practically useless - ill stop ping a 4-ton machine until the speed hae dropped to under ICO m.p.h. Earliei application is dangerous and simply fuses the brakes. To stop the car when travelling at 300 m.p.h. within one mill after passing the finishing banner would absorb 1350 h.p. Campbell will have about four miles in which to pull up and unless the iiti-decelerntors are highly efficient, he will need every yard of it if this great driver (he is close on 5( years of age) is to attain his ambition, the “ZOO” mark.