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).
Brief description of the action, adjustment, and limitations of the New Phantom carburetter.
| Identifier | WestWitteringFiles\N\2October1925-December1925\ Scan186 | |
| Date | 26th November 1925 | |
| Expl.report. Expl:No. Ref. Hs{Lord Ernest Hives - Chair}/ACL/LG26.11.25 A BRIEF DESCRIPTION OF THE ACTION, ADJUSTMENT AND LIMITATIONS OF THE NEW PHANTOMCodename for PHANTOM I CARB. WITH METHOD OF RECTIFYING TROUBLES POSSIBLE TO ENCOUNTER. In order to understand more clearly how the various factors affect the action of the New PhantomCodename for PHANTOM I carburetter and what degree of perfection we may expect, it is as well to give a brief description of the fundamental principle upon which it works. It is of the variable suction type, i.e., with fixed throats and jets - in which compensation is obtained by means of an auxiliary air valve. The characteristic of a simple jet in a choke is that as the rate of flow of air through the choke increases, the petrol flow through the jet increases at a greater rate, which results in a non-proportional mixture. To compensate for this the New PhantomCodename for PHANTOM I carburetter employs an auxiliary air valve operated by the engine suction and it is so proportioned that the amount of extra air admitted normally compensates for the increased petrol flow. Without extra air, the richening of the mixture is more marked when the velocity of air passed the jet is only a little more than what is necessary to feed the petrol. One of the chief causes of this inequality of mixture is that in practice the petrol cannot be allowed to stand at a level equal to the height of the jet. This does not account for all the extra air needed because viscosity and contd :- | ||