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).
Two faults observed with the EAC.11 engine's electrical starter unit.
| Identifier | ExFiles\Box 64\3\ scan0019 | |
| Date | 20th March 1924 | |
| R.R. 490A (BOH) (D.A. 652 20-3-24) J.H.D. EXPERIMENTAL REPORT. Expl. No. X8650 REF: Hs{Lord Ernest Hives - Chair}9/LG5.11.24. To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} c. to CJ. BJ. c. to E.{Mr Elliott - Chief Engineer} BY.{R.W. Bailey - Chief Engineer} c. to DA.{Bernard Day - Chassis Design} Wor.{Arthur Wormald - General Works Manager} SECRET. EAC.11. ELECTRICAL UNITS. X8650 (crossed out) X8780 We have an EAC.11. engine fitted up with the complete electrical units. The arrangement on the whole, is working very satisfactory. There are however, two points in connection with this which we think you will criticise :- 1. There is a very objectionable thump when the starter commences to turn the engine. This thump appears to be caused by the amount of free movement from when the contacts on the solenoid switch on the main current to when the pinion reaches the end of the thread. The actual engagement of the pinion is very silent but as soon as the main current is switched on, the motor races away free until the pinion reaches the end of the thread. It is at that point we get the bad thump. 2. When the engine is hot and the motor is turning the engine, the engine over-runs the motor after compression. We then get bad thumping caused by the motor pinion unwinding and then coming solid against the end of the thread. Hs.{Lord Ernest Hives - Chair} | ||