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).
Typed report page detailing tests and modifications on a carburetter to fix acceleration issues.
| Identifier | ExFiles\Box 42\3\ Scan028 | |
| Date | 11th November 1926 guessed | |
| contd :- -4- it as the throttle was closed but owing to space could not insert a larger slotted plug in the present carburetter. We therefore richened up the idler jet at the change over point and neglected the proportioning at low speeds to see if this rich mixture would carry us over the weak spot for acceleration. Exactly the same thing was found to happen - ie. the idler would cut out when the throttle was suddenly opened but would operate again a second or so later when the speed became steady. A very rich mixture however was found to be a slight improvement. OTHER ARRANGEMENTS. Finding that the idler cut out due to the sudden fall in suction on acceleration we thought perhaps a petrol capacity provided in the idler tube with the jet arranged at the top would be an advantage as it would allow petrol to drain back into the accelerator well when the suction fell and so tend to promote a rapid delivery at the sprayer. This was arranged as shewn on the appended print. Tests however shewed no benefit to be derived from this which we think is due to the slowness of the petrol draining back. The release hole for drainage is the jet and naturally this has to be of small size. All our tests seem to indicate that the trouble is mostly due to the capacity and distance between the petrol in the diffuser and the spray nozzle. Even with a high level we have to carry the fuel and emulsion a considerable distance contd :- | ||