NEW MOTOR RECORD.

Shannon News, 15 March 1929, Page 4

NEW MOTOR RECORD.

NEARLY FOUR MILES A MINUTE BY SEGRATP3. NEW YORK, March 11. At Daytona Beach, Major Segravo, the British driver, set a new world's automobile \ record of 231.36246 miles per hour. '. * THE GOLDEN ARROW'' SUCCESSFUL. 900 H.P. ENGINES. Major H. O. D. Segrave's car. was specially constructed for him and from its shape was aptly named "The Goldden Arrow." The previous speed record Avas 207.5526 miles an hour. The Golden Arrow has been designed especially to resist the wind force and in it Major Segrave hoped to reach the stupendous speed of four miles per minute. More About The Car Design. "The Golden Arrow."—lt is a name .which fits the car exactly suggesting an Instrument 'fashioned for a straight .flight,at speed, with slim wind-cutting lines and strength withal. In these record-breaking cars the reduction.of wind resistance is all-import-ant, and some idea of the success which has been achieved in the. design of the "Golden Arrow" is obtained from the fact that the frontal area of the ear is only 12 square feet, or the equivalent of an.oblong measuring 3ft by 4ft. There is many a 12 h.p. light car with a frontal area double as great and yet 'this "Golden Arrow" carries a 900 h.p. engine and, of course, transmission and other components commensurate in size ;with the big power unit. Output, 900 H.P. The Napier engine which is being employed develops 900 b.h.p. at 3,400 r.p.m., and his huge output is conveyed through a multi-plate clutch and a three-foriward-speed gearbox; in order to prevent slip powerful springs have > had to be employed in the former to place a total load of over tons on the plates, pressing them together. This.necessitated the design of a special control mechanism, without which the driver would have been unable to control the clutch against springs of ithis strength. The gear ratios selected are: Top, 1.475 to 1; second, 2.195 to 1; and first, 4.47 to 1, and the theoretical speeds corresponding to , the engine speed at which maximum'(power is developed arc 246 m.p.h., 166 m.p.h., and 81 m.p.h. respectively. Imagine the average/driver being called' upon to handle a car which will exceed 160 m.p.h. before it is necessary .to change up from second 'to top gear! The tyre size, incidentally, is 37in by 7in, these components being specially constructed to withstand the terrific centrifugal and driving forces produced in an attempt of this kind; the maximum speed of the wheels will be, about 2,300 r.p.m. A great many painstaking experiments in a wind tunnel have been made on a scale model of the car, not .only to ascertain the exact wind resistance, which of course, had to be known before proceeding with the design, but also to find out whether the car would be sufficiently stable from the aero-dynamical point of view. Then again, a perfectly streamlined, body tends to be highly unstable, so that the slightest deviation from a straight course makes the car wholly uncontrollable.

The energy stored up in a car weighing 2\ tons and moving at four miles per minute runs into millions of footpounds and must all be dissipated in the form of heat when bringing the car to rest after the measured mile has been covered; furthermore, there is only a limited space in which to pull 6p. Consequently, the design of the rakes is as important as that of any other component. Drums of large diameter are fitted to each of the four wheels with in-ternal-expanding shoes operated by a pedal assisted by a Dewandre suction operated servo cylinder. An interesting point ia that there is no compensating gear of any kind in the system. Some idea of the -work that will be thrown on the brakes can be obtained from the fact that at a rough estimate this car would run a distance of about live miles after closing the throt--Ide, despite the retarding effect of air resistance, were no brakes employed. Petrol and Oil Tanks. The petrql tank is fitted in the bodywork immediately behind the driver, air pressure being employed to maintain the feed to the carburetters. An oil tank is fitted alongside the engines, which is lubricated on the dry samp principle but there is no special provision for cooling the oil. ' The general dimensions arc interesting, particularly the height, which is only 3ft 9in. The wheel-base and track are similar to those of a large private ear, being 13ft 4in and oft respectively, but the overall length is —26 ft—becauset —because of the use of a long projecting tail. ' The Maximum width is 6ft 4in, but, of course, the actual width of the body is very much less than this. A minimum ground clearance of fin. i'3 allowed in the design.