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).
Test report on a modified straight through vertical carburetter for the Phantom engine.
| Identifier | WestWitteringFiles\S\March1928-May1928\ Scan133 | |
| Date | 25th April 1928 | |
| To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/ACL. c. to BJ. Wor.{Arthur Wormald - General Works Manager} c. to E.{Mr Elliott - Chief Engineer} DA.{Bernard Day - Chassis Design} c. to BY.{R.W. Bailey - Chief Engineer} ORIGINAL Hs{Lord Ernest Hives - Chair}/ACL1/LG25.4.28. PHANTOM STRAIGHT THROUGH VERTICAL CARBURETTER. [Handwritten] X8080 (crossed out) X7080 Built in X-numbers We have made some tests with a modified straight through - Eagle type - carburetter on the Phantom in conjunction with the weir induction pipe with the object of determining a suitable choke area and throttle area to give max. power output. The carburetter and induction pipe arrangement used for these tests is shewn in the appended print. In the first test a large choke 1.800 dia; giving a free area past the diffuser of 2.238 sq.ins., was used and the power output obtained is shewn on appended curves. It will be observed that the depression at the smallest section of the choke is only very little more than the depression in the induction manifold - the induction manifold depression being 2.05 ins.Hg. and the choke depression 2.4 ins.Hg. A smaller choke was next tested which had a dia. of 1.53 ins. and a free area of 1.532 sq.ins. The power output was very nearly the same and the induction pipe depression only slightly more but there was a considerable increase in the choke depression which was desired and indicated a good restoration of pressure energy. It would appear that these proportions of choke and throttle would be very suitable for good power output on the Phantom and on the appended curves will be seen the appreciable increase in power over the std. chassis carb., amounting to 8.5 HP. or 8% at 2500 r.p.m. contd :- | ||