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).
Letter from Cadillac Motor Car Company providing experience and feedback on synchromesh transmissions.
| Identifier | ExFiles\Box 170\2\ img067 | |
| Date | 25th May 1932 | |
| Copy for R.H.C. FILE CADILLAC MOTOR CAR COMPANY DETROIT, MICHIGAN CADILLAC AND LaSALLE MOTOR CARS May 25, 1932. Mr. W. A.{Mr Adams} Robotham, Rolls Royce, Limited, Derby, England. Dear Rm{William Robotham - Chief Engineer}: Will try to catch up with your recent correspondence on transmissions. (1) Letter of April 23rd to Kingston Forbes. Beringer writes:- "Re. R.{Sir Henry Royce} R.{Sir Henry Royce} Synchromesh. "Cone angle checks with our experience with this type of synchronizer (10°). Large cones lack rigidity and could never be made round within satisfactory tolerance." "Satisfactory oil not thicker than A-150 in summer and A-90 to A-100 in winter. I prefer 110 for summer. Running clearance of .003 on diameter of 3.625 is minimum for cones grooved as we do them. Best cam angle varies for every job." "Pull off spring of our yoke type synchronizer has tension amounting to approximately 15% of application force. Cones bearing slightly heavy on big end separate easier when synchronizer load is removed." "Cadillac drum assembly normalized after pressing bronze into stamping. Ageing bronze, after turning may help. Various alloys grow after turning." The principal thing seems to be a "super-gauge" accuracy in the cones, together with ageing and normalizing of the cone assembly. We did find that, without this, the bedding altered with temperature. (2) Letter of May 5th. Thompson's original designs contemplated synchromesh on all forward speeds. The other was adopted as a reasonable simplification. The actual use for a 1st speed synchronizer is very slight. [Handwritten note in left margin]: This is our practice to normalize after Rough machining but we do not also after finish turning. See our ref letter of... [Stamp]: RECEIVED 27 JUN 1932 | ||