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).
Report page detailing carburetter experiments, including pressure restoration and power curve comparisons.
| Identifier | ExFiles\Box 13\3\ 03-page114 | |
| Date | 21th October 1929 guessed | |
| -3- standpipe for an ordinary jet made from the diffuser tube of an "F" engine carburetter. No emulsion air was admitted and the fuel was sprayed from holes in the top of the tube. The free choke area, allowing for the space occupied by the central jet, was 1.40 sq. in. A power curve taken with this arrangement is appended and it will be seen that the power output equals that of the R.E. C.H. although the choke area is about 8% smaller. Very good pressure restoration is obtained, the choke depression being 3.8" Hg. while the manifold depression is only 1.95" Hg. This experiment indicates that when the mixture is discharged from a number of holes in the walls of the choke the steady flow of air through the venture is affected and does not give such a good pressure restoration ratio as when the mixture is discharged at the centre of the choke. A further test was tried with small tubes fitting in the choke spray holes so as to direct the mixture into thecentre of the choke. Various numbers of tubes were tested and of various lengths, but the results were not so good as when the plain spray holes were employed. Looking again at the power curve of the expanding carburetter compared with the R.E. C.H. and the Standard Phantom carburetter, we see that the former gives a substantial increase over the latter. When looking at these power curves we must remember they are taken on the | ||