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).
Radiator filler cap design issues and proposed modifications for the Wraith and other models.
| Identifier | ExFiles\Box 9\3\ 03-page053 | |
| Date | 1st October 1937 | |
| WRAITH (AND ULTIMATELY P.III AND P.II) RADIATOR FILLER CAPS. We are not satisfied with the filler cap on Wraith radiator, the following being the criticisms - (1) It is necessary to tighten same with a spanner, and is even then difficult to make entirely leak proof. We think it should be possible to tighten the cap sufficiently by hand. (2) The joint washer is a loose one and can easily drop off and get lost. (3) The cap tends to seize in position and is extremely difficult to unscrew. In order to get over these difficulties, we have considered - (a) A knurled cap. (b) A rubber or copper asbestos washer and have requested a cap incorporating these modifications. However, after further thought, and after trying out a copper asbestos washer, we do not think it will be very easy to get a washer which is sufficiently soft to make a joint by screwing cap up by hand, and which is yet hard enough to avoid squeezing out permanently, under the action of heat and pressure. We therefore, wish to try the idea shown on attached sketch. This is derived from the domestic hot water bottle stopper. For experimental purposes the pieces can be machined, but our ultimate aim would be to mould the cap in some plastic such as bakelite and roll the thread in a tube for the housing. To By/NS.{Norman Scott} from RM{William Robotham - Chief Engineer}/Std. c. ps. f 640 RM{William Robotham - Chief Engineer}/Std.4/HP.5/10.37. | ||