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).
Design modifications for Bentley instrument patches and associated components.
| Identifier | ExFiles\Box 62\2\ scan0197 | |
| Date | 4th May 1933 | |
| x6135' To-WOR.{Arthur Wormald - General Works Manager} from E.{Mr Elliott - Chief Engineer} c. Sg.{Arthur F. Sidgreaves - MD} Hs.{Lord Ernest Hives - Chair} By.{R.W. Bailey - Chief Engineer} Hs{Lord Ernest Hives - Chair}/Wst. (Strikethrough) EV.{Ivan Evernden - coachwork} By/RD. E.2/HP.4.5.33. re Bentley Instrument Patches. In connection with the instrument equipment for the third Bentley, there are one or two points which have arisen showing that certain modifications are desirable to the design of the patches. With regard to the group containing the speedometer, tachometer and clock, it is found that the bevel edge on the glass is not likely to be supplied to very accurate limits. This matter has been taken up with the suppliers, and at the same time a dimension is being added with agreed limits to the important diameter on the glass face. It was considered also desirable to reduce the diameters of the holes through the mounts in front of the glasses, to increase the overlap by 50%, so as to provide greater latitude for variation. These remarks also apply to the central patch containing the smaller instruments. As mentioned in another report the angle of the bevel of the glass should also be fixed to give the best results as regards illumination, and this angle may be different on the large instruments from what is required on the small ones. In connection with the central patch, EV.{Ivan Evernden - coachwork} has raised a point that this patch is more dependent on the instrument board being correct thickness than are our previous RR.patches, as any discrepancy will result in leakage of light between the mounts and the faces of the instrument glasses and switchbox, and that as it has now been decided for the Bentley chassis to be broadcasted to coachbuilders to the same extent as RR. chassis, this discrepancy is likely to lead to a lot of trouble in obtaining a satisfactory mounting for the patch. The same remarks also apply to the shape of the hole to be cut in the instrument board for the patch framing. | ||