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).
Wheel self-centering and an analysis of 8-in-line engines with comparisons to Cadillac designs.
| Identifier | ExFiles\Box 173\1\ img311 | |
| Date | 12th February 1934 | |
| -8- (J) We had an argument about self-centering. I believe so much out of centre point as 2" is bound to give excessive centering with 8° king pin angle transverse lean, and even with the 3½° transverse they are using the out of centre is the major force in the straightening out. We can confirm by having wheels spoked to give rims which will cover the practical usable range. I think Cadillacs are tied up with their small wheels and large drums. 8 IN LINE ENGINES. As you know, Cadillacs are producing their first eight in line 5 bearing in the new La{L. A. Archer} Salle. I could get little information re critical speed, percentage balance of the shaft, etc. as the Research people of G.M. do the shaft and hand it to Cadillacs who have not yet taken torsion diagrams etc. However, they state that with a double carburetter, one choke feeding inner four and one the outer four cyls., four port induction system, they can get excellent distribution. They have done a lot of work on distribution and I propose to bring their latest pipe back with me. They are already getting better power out of the 8 in line than the V.8. I have the power curves. I went over the torsional vibration diagrams of their 12 and 16 with them, diagrams taken with the Summers indicator (much like we used) no crank damper being fitted. The 16, which is 5 bearing, has the 8 per rev. at 1600 r.p.m. The 12, which is 4 bearing and has a peculiar balance scheme which gives 85% balance of the centre pins but not equal reduction of load on all bearings, has the 12 per rev. at 2700, the amplitude in either case appears to be about the same and is taken care of with the rubbered centred damper. G.M. Research say that if the amplitude of any torsional exceeds 1° they have difficulty in damping it out. Cadillacs are not altogether satisfied with the rubber centred damper, as they say it has insufficient hysterisis loss to be really effective. A man in General Electrics has recently stumbled on the fact that you can replace the rubber with Micarta (That strange Bakerlite material that looks as if it is composed of old rags) and get much better results. Cadillacs have only been trying | ||