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).
Unsatisfactory performance of bolts on rubber engine feet and suggesting the use of tight-fitting tapered bolts.
| Identifier | ExFiles\Box 14\5\ Scan030 | |
| Date | 2nd December 1928 | |
| To E.{Mr Elliott - Chief Engineer} from Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} +7005 Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}3/LGl.2.12.28. c. to BY.{R.W. Bailey - Chief Engineer} c. to WOr.{Arthur Wormald - General Works Manager} RUBBER ENGINE FEET. X7005 ~~X8005~~ The bolts on these engine feet indicated in the attached sketch have never been very satisfactory. Their average life on the bump is something under 30 hrs. In addition, on examining those off 12-EX after 7000 miles we found that they had worn badly, so much so that the engine was moving about independently without utilising the rubber. We can improve the wearing qualities by hardening but hardly the life. We find however that if we make the bolts a tight fit, i.e. slightly taper with reamered holes, we do not seem to encounter any disadvantage while the bolts have run 100 hrs. without failure. We appreciate that the stress on the spring strips may go up because the frame has to 'breathe' to allow the foreshortening of these strips, but in practice this does not seem to affect the life of the strips or the frame. We therefore suggest that we should use tight fitting bolts in this position. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||