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).
Battery support designs, comparing crossmember and cantilever types, and requesting vibration tests for 20HP and 25HP models.
| Identifier | WestWitteringFiles\V\October1930-February1931\ Scan098 | |
| Date | 20th November 1930 | |
| BY.{R.W. Bailey - Chief Engineer} / EFC. ) FROM DA{Bernard Day - Chassis Design}/EV.{Ivan Evernden - coachwork} Copy to SG.{Arthur F. Sidgreaves - MD} HS{Lord Ernest Hives - Chair}/RM.{William Robotham - Chief Engineer} re: BATTERIES. (1) P. 2. We are in great need of doing away with the crossmember for the support of the rear of the battery because it limits the depth of the cushions of low cars such as 26-EX. If we are to keep abreast of the times we must do all we can to make possible low cars with ample headroom over the seat, and really luxurious cushions. We agree that we must carry on with the crossmember at present but we want to discover why our cantilever caused the battery to fail after 17,000 miles, and if possible design a cantilever support that will be satisfactory. We do not believe that some sort of cantilever support is impossible for the following reasons: (1) We used such a support as standard on the 20HP. without batteries shewing distress. (2) EAC. 7. has had such a support. (3) Other firms use such supports very frequently. We would like HS{Lord Ernest Hives - Chair}/RM.{William Robotham - Chief Engineer} to make tests to say - (a) Has the cantilever a natural frequency of vibration which is set up as a period at any particular car or engine speed? (b) Does the shock damper which is twisting the frame at this point affect the case in question? (c) What is the frequency and amplitude of the vibration, as one can see that a rubber support could be used at the rear like the proposed 25HP. engine foot? (d) If the box is suspended as on the new design for the 25HP. with the control at the front, and only one point of suspension at the rear, does this affect the case? It will be recollected that the old 20HP. had a single point at the cantilever? Will HS{Lord Ernest Hives - Chair}/RM.{William Robotham - Chief Engineer} please test a support as set out for the new 25HP. (2) 25HP. We were under the impression that in a memo. from EFC. we read that you have had a battery on test for some thousands of miles with the new internal features and in the old original moulded experimental case. In order to test the sheet metal carriage on 18-G-4. an ordinary wooden battery can be fitted with a lid{A. J. Lidsey} and used like we did on the first P. 2. (18-EX.) We wish you to test the cantilever support even if not on 18-G-4. as we have reason to believe it will be satisfactory, as the original 20HP. had such a support. (1) | ||