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).
Relocation of the Wraith thermometer bulb and a proposed solution to prevent shorting.
| Identifier | ExFiles\Box 175\5\ img023 | |
| Date | 11th March 1938 | |
| To By.{R.W. Bailey - Chief Engineer} from Rm{William Robotham - Chief Engineer}/Std. c. By/RD. c. By/CS. 6003 Rm{William Robotham - Chief Engineer}/Std.3/AP.11.3.38 WRAITH THERMOMETER BULB POSITION It will be recollected that we requested that on Wraith and B.III. the thermometer bulb should be moved to the front of the cylinder head in order to obtain an accurate temperature reading - this has now been instructed for Production. At the time of the request the Delco-Remy ignition distributor was also instructed for Production - with this distributor there is ample clearance between the distributor and the thermometer capillary. Since that time, however, the R.R. distributor has been standardised for Wraith and also raised 0.5" to facilitate machining operations. This means that the only way in which the thermometer bulb can be retained in the front position is by raising it or by bending the capillary so that it rises fairly sharply between the distributor terminals before curving back towards the dash. In this position there is a possibility of the leads from the distributor touching the capillary and perhaps wearing with consequent shorting. We think that this bulb position could be used if a rubber insulating sleeve were fixed on the first three inches of capillary adjacent to the bulb - this would prevent both chafing and any possibility of shorting. We do not see any other method of retaining this front position of the thermometer bulb other than raising the bulb - this will mean a pattern modification. If you agree with this proposal, will you please detail and instruct both the necessary rubber sleeve (which would be fitted by Messrs Smiths) and also an arrangement showing the correct bending and fastening of thermometer capillary - alternatively will you instruct the necessary casting modification etc. Rm{William Robotham - Chief Engineer}/Std. | ||