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).
Potential improvements to the Phantom carburettor using a diffuser type jet.
| Identifier | ExFiles\Box 13\3\ 03-page066 | |
| Date | 21th January 1929 | |
| To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/ACL. c. to BJ. SE. c. to Wcr. E.{Mr Elliott - Chief Engineer} c. to DA.{Bernard Day - Chassis Design} BY.{R.W. Bailey - Chief Engineer} PHANTOM CARBURETTER. It has occurred to us that we might effect an improvement in the acceleration, distribution and a slight gain in power from the Phantom carburetter by employing a diffuser type jet in the high speed choke. This scheme was suggested a considerable time ago by Mr. Royce, but at that time we tested it out simply by substituting the diffuser jet for the standard plain jet in the high speed choke and had trouble with the metering. In an attempt to correct this we worked on the diffuser air holes and the air ports in the air valve but at that time were unable to make a satisfactory combination. The other trouble was that of loss of power as we reduced the air ports in an attempt to compensate the mixture. We have now had much more experience from aero engines in regulating the metering and accelerating characteristics of the diffuser type jet and think it would be worth while to revive this scheme in the light of our recent experience. In the first place it would appear that we should not require the air ports in the air valve as the diffuser correctly proportioned would be self-compensating. With these ports deleted the high speed choke would therefore be made correspondingly larger so that the full power depression would not be greater, but if possible less, than obtained at present. contd :- | ||