That Front Suspension



That Front Suspension

The point of my letter, as Mr. Ballamy is, of course, fully aware, was that I, not he, was responsible for correcting the geometry on the Allard divided axle front suspension in the period 1950-54 when I was Chief Draughtsman and Chassis Designer of that Company. He concedes this by saying I “came to the right conclusion”. However, to answer his many points in as objective a manner as possible: I did do a considerable amount of homework on the subject and was fully aware that he had “sold” divided axle front suspension units to Allards in the immediate pre-war period. This was in any case common Ithowledge among enthusiasts and was confirmed (in detail) by Sidney Allard [Correct spelling: Sydney Allard] when I joined the Company. I can’t quite understand how Mr. Ballamy misconstrued my letter to the extent that he gained the impression that “I regarded the arrangement as original for 30 years”. I only claimed it to be a logical arrangement, and it is after all a relatively simple system. It would seem that Mn. Ballamy did not do las homework otherwise he would have known that divided axle front suspension was tried. and discarded. before 1914 by several designers because of the phenomenon known as gyroscopic

precessional torque. In an effort to overcome this problem an American Co. who went into production in 1935 with a divided axle system. arranged the axle beams to “pass each other” to pivots on the opposite chassis side rails. This was a heavy expensive arrangement and was still not free of “gyroscopic kick” to it was abandoned after a few months in favour of an SLA scheme. This precessional torque problem is the limitation I was “hinting at” not the relatively simple geometrical arrangements.

There was not a great deal of written matter on suspension in the immediate post-war period and divided axle and front suspension got only the briefest mention, if at all.

The only material written by Mr. Bellamy that I subsequently came across was publicity matter for the LMB conversion units for the “Pop” of the period.

It was because of this paucity of properly considered material that I wrote the articles on the subject which were published in the Auto Engineer for January 1954 and June 1955.

Mr. Bellamy is right atmut one thing however, Cohn Chapman and myself were at school before the war — but it didn’t take at 30 years to realise that the divided axle front suspension system is not on as a serious suspension system thr any vehicle except possibly “mud-plugging buggies” and the like, a subject with which Mr. Bellamy is no doubt familiar. Sevenoaks D. R. HUME