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).
Crashing engagements in the Maybach vacuum-controlled change gear and a proposed interlock solution.
| Identifier | WestWitteringFiles\V\March1931-September1931\ Scan050 | |
| Date | 14th March 1931 | |
| HS{Lord Ernest Hives - Chair}/RM.{William Robotham - Chief Engineer} FROM DA{Bernard Day - Chassis Design}/HDY{William Hardy} C. to R.{Sir Henry Royce} SG.{Arthur F. Sidgreaves - MD} E.{Mr Elliott - Chief Engineer} BY.{R.W. Bailey - Chief Engineer} [Text crossed out] [Stamped] ORIGINAL MAYBACH CHANGE GEAR. VACUUM CONTROL. DA{Bernard Day - Chassis Design}/HDY{William Hardy}1/M14.3.31. [Handwritten] X2200 [Handwritten] X525. You are no doubt aware that with the vacuum controlled Maybach jaws it is still possible to obtain crashing engagements, although compared with the hand controlled scheme the chances of this happening are few. We are thinking particularly of a change from top to 3rd. in which, for some reason or the other, 3rd. was not engaged - i.e. the engine was not accelerated, but slowed to idling speed, and then top gear was re-engaged. This, it will be seen, will result in a crashing engagement, and if done at high speed will no doubt smash something. We should like to know whether you found any evidence that the Maybach Co. have had to consider this possibility. The remedy appears to be to provide an interlock which prevents further operation of the control until the jaws are engaged. DA{Bernard Day - Chassis Design}/HDY.{William Hardy} | ||