From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Front suspension rating calculations, leverage ratios, and spring ratings.
| Identifier | ExFiles\Box 154a\2\ scan0277 | |
| Date | 16th April 1940 | |
| Rm{William Robotham - Chief Engineer}/Clapham 1305 File To Oy. (America) c. to Rm.{William Robotham - Chief Engineer} c. to Ev.{Ivan Evernden - coachwork} Please note & return Ev{Ivan Evernden - coachwork}/DB.{Donald Bastow - Suspensions}10/JH.16.4.40. Vm noted Clm{D. D. Clapham} Front Suspension Rating. I have seen your Oy.1/DS/FEB.21.40. and hasten to remove the misapprehension noted in (2) of that. The figures given by Rm{William Robotham - Chief Engineer}/Clm.{D. D. Clapham} were based on out of date information and the true story as far as we know it today is given in my memo. DA{Bernard Day - Chassis Design}/DB.{Donald Bastow - Suspensions}10/G.30.3.39. of which I am sending a copy together with copies of the prints of PD.404. I should not like you to think that any pearls of wisdom you have dropped have fallen on stony ground (!) or even, as in "Omer Khayyam", that they went out at that same ear by which they entered in". In the linkage which will eventually be that used on the rationalised range, the leverage ratio becomes 1.76 instead of 1.724, and this slightly alters the relation of spring and wheel ratings. You will see that for the spring of which particulars were sent to you, the actual rating at the wheel is (297 x .323) + 23 = 119 lb.in. so that your guess of 115 lb/in. is not so far out. If you feel that our story is still very incomplete. I will endeavour to borrow the Henry Fuels booklet from Maurice Platt - could you say whether you think this would be a good idea in any case? You will see that we are rather in the dark because we have no means at all of checking our actual coil spring ratings. If we ever get an instrument for doing this our remainder method of finding spring bending effect can be checked over and probably corrected. D.Bastow. | ||