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).
The replacement of the piston throttle valve with a butterfly valve for the 20 HP model.
| Identifier | ExFiles\Box 50\3\ Scan104 | |
| Date | 10th November 1920 | |
| -2- Contd. With this arrangement we abandon the use of the piston throttle valve and use instead a butterfly valve. This is as much the same as we have arranged on the new small 20 H.P. model. Immediately after the butterfly throttle valve an exhaust heated jacket is used and continued nearly right across the top of the cylinders. We send you a sketch of this arrangement, which we hope will be tested in Derby in the course of the next few days. Should it prove superior to the present, of which we think there is little doubt, we believe this modification is the one you would like to adopt for cars about to be manufactured, and if it shows marked improvement on that in which the design of present type of throttle is heated by exhaust gas, then we should suppose that it might be worth while to make this more extensive alteration on existing cars. [Faint inverted watermark: 1804 MADE IN GREAT BRITAIN] [Faint inverted footer: K.R. 235A (100) 7/33. H.{Arthur M. Hanbury - Head Complaints} & S.(L) 762. 10-11-20. G 1947] | ||