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).
Carburetter system design, comparing performance and proposing system rearrangements.
| Identifier | ExFiles\Box 7\4\ X 608 Carburetter-page02 | |
| Date | 26th September 1934 | |
| -2- Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}7/KW.26.9.34. Correcting for the compression ratio, changing from two carburetters directly on the induction pipe to one feeding from the block, dropped our output 6 H.P. or 7%. Measuring the restriction caused by the block we find this exactly accounts for the other 6 H.P. In other words, if we are not restricted by the distance between the two cylinders as on the 20/25 we can get exactly the same top H.P. passing the mixture through the block as we do with the Bentley carburation system. There is no doubt that for actual snap opening up there is a slight advantage in favour of two carburetters as close to the cylinders as possible, but the difficulties of getting such a system on the Wraith appear to us to be very considerable, especially with any of our existing types of expanding carburetter. The proposed system will necessitate some rearrangement of the present carburetter to get two throttles and chokes but we think it is well worth laying out to see what it involves. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||