Pat Driscoll at the 750 Club
Last month the 750 Club persuaded Pat Driscoll, the famous Austin racing driver, to attend a meeting of theirs, and Pat, in turn, invited the 750-ites to fire questions at him. The meeting wanted to know a lot about aluminium heads but Driscoll said the Austin designer did not hold with them — he used to motor sedately about in an Austin Twelve —although later they vastly improved Austin performance, for example on the Ten, and Pat was getting excellent results from an aluminium-sprayed head on his wife's Morris Eight. He had not had much experience, either, of unblown Austin Sevens except for the Le Mans "Grasshopper" type cars, which merely had to finish the first year in order to qualify for the next race, and so had a maximum of only about 88 m.p.h. "A good 'Nippy' could see them off," said Pat, and, pressed for confirmation, stated that one which they had as a hack lapped at 72 m.p.h. with a maximum of 77 m.p.h. [1931 was mentioned and possibly Pat meant an "Ulster" - Ed.] Ultimately the s.v. engine was blown at 20lb./sq. in. pressure with a compression ratio of about 7 1/2 to 1, and ran up to 10,500 r.p.m. The twin-cam engine was stressed for 14,000 r.p.m. but development was never completed and it was normally run at about 8,500 r.p.m. When war came all the spares for these cars were destroyed but the cars exist. When Lt.-Col. Waite became interested in golf he lost interest in motor-racing and Murray Jamieson — a splendid designer — got the sack. He had had independent rear suspension in mind for the twin-cam car but Austin's never encouraged him to press on very fast with such work. The special front axle he evolved gave excellent results and was copied by Bugatti — if they could have hidden the special joint they would have done so, but it had to be clear of the radiator, etc. and was visible on the near side. Two needle-roller bearings were used in this axle, about 5 in. apart. Driscoll said he had only once broken a crankshaft, but that he used specially light rods based on those used in Norton motorcycles, which probably helped. The early "dutch clog" cars were most uncomfortable for long-legged drivers, especially as the scuttle petrol tank chafed the thighs and the battery for the coil ignition dug into one's right leg. Later vertical magnetos were used, so the battery could be removed — incidentally, the lap speed went up by several m.p.h. Glycol cooling was used on the later s.v. cars and about 28 studs held the head down. Ballamy asked whether the design of Austin Seven stub-axles and steering pivots had worried Driscoll. "No," said Pat, "I never thought about them." Pressed as to whether the axles of the racing cars were changed frequently, Pat again said they never gave any trouble. Ballamy explained that he broke two stub-axles after a Brooklands-dice, but Boddy thought the divided L.M.B. axle probably put more strain on the steering pivots and stub-axles than the normal beam axle, which Lowrey rather confirmed. Driscoll said he could never understand why the Q-type M.G., which gave the same b.h.p. as the Austin, was slower. Asked whether it wasn't rather startling to follow an R-type M.G. in a race, Pat said not when Doreen Evans was driving, for she was a very good driver. Most M.G. drivers seemed so wild, however! Roddy asked how "Bira" appeared to like the s.v. car and was told he seemed quite at home in it but that Prince Chula expected him to beat Driscoll's lap record on his first outing, which he couldn't do, especially as the car wasn't then in 100% tune. Asked about the speed of the twin-cam car Pat recalled doing 122 m.p.h. along the straight at Brooklands. Ballamy said he had taken ciné films of the s.v. car cornering at the Fork and noticed it took a wide sweep and Driscoll said this was necessary as otherwise it tended to slide. In long races the cars ran better with half-empty tanks. Birkett queried whether controlled differentials had ever been used and although the question was not fully answered, Driscoll did tell us that a solid rear axle had been experimented with but that the car then became uncontrollable on sharp corners. The twin-cam car was not only noticeably more comfortable than the older cars but handled really magnificently and could be cornered as fast in the wet as in the dry.