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).
Spring stiffness and buffer clearance for continental chassis to prevent 'crashing'.
| Identifier | ExFiles\Box 19\1\ Scan210 | |
| Date | 16th June 1932 | |
| -2- Hs{Lord Ernest Hives - Chair}/Bn.{W.O. Bentley / Mr Barrington}1/MA.16.6.32.Cont'd.{John DeLooze - Company Secretary} In view of the fact that "Hartfords" were fitted to continental chassis, this margin was thought to be sufficient. Apparently it is not and we therefore recommend that in selecting the poundage of the existing stiffer type stock of springs, an increase should be made to increase the buffer clearance to 3¼" with the car fully loaded. This gives immunity from "crashing" as follows :- Standard. Stiffer. Rate 164lbs/1" 237lbs/1" Deflection from normal riding to "crashing" 4¾" 4.430 Increase in "static" load to produce this result. 790 lbs 1050 lbs i.e. the stiffer spring used for continental work should with 3¼" buffer clearance require 30% more load to cause it to crash. Since practice shows we have insufficient margin, we recommend the stiffer type continental spring specification should be amended as follows :- New spec. Old spec. Free Camber 3.750" 3.060 Loaded " .440" Neg. 1.130 Neg. Buffer Clearance Normal 3.21" 2.530" We agree that it may be wise to work to a + limit from this figure. We should be interested to know what was the measured buffer clearance of the cars whose springs the Repair had to change. Hs{Lord Ernest Hives - Chair}/Rn.{Mr Robinson} | ||