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).
Outlining five required improvements for the 'General' filter as standardised on the Wraith model.
| Identifier | ExFiles\Box 136\3\ scan0031 | |
| Date | 16th January 1939 | |
| 1139 To By.{R.W. Bailey - Chief Engineer} from Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} c. RHC.{R. H. Coverley - Production Engineer} c. Da{Bernard Day - Chassis Design}/McS. c. By/CS. "GENERAL" FILTER. Regarding the above filter which has been standardised on Wraith, we have taken up the following points with the makers who are going to comply with these criticisms. (a) Clamping down screw too long, to be reduced from 2.00 to 1.5". (b) Improved exterior enamel finish and consistent spot welding. (c) Bridge piece to be better finish nickel plated. (d) Transfer on lid{A. J. Lidsey} regarding changing the element to be black and white, not red lettering as at present. (e) Internal rust, inside to be cleaned and coated with non corrosive and non coloured cellulose similar to the coating on the actual filter element. Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} | ||