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).
Dual-issue phenomenon in a car's fuel system: an air-lock caused by test piping and a low-speed jet blockage from grit after petrol failure.
| Identifier | ExFiles\Box 181\M11\ img041 | |
| Date | 25th June 1919 | |
| To E.H. from R.{Sir Henry Royce} Copy to Co. DN. ORIGINAL. RE RUNNING OF 7 CA. A mysterious phenomenon has occurred on this car which has been hard to locate, because it was double, viz,- (1) An air-lock due to the use of the piping to the small test tank, the surprise being that although there was enough head to feed this tank from the main tank, there was insufficient head to start the flow to the float chamber when an attempt was made to run direct after the small tank had emptied itself - [DIAGRAM] Diagram shows a fuel pipe system from a 'MAIN TANK' at the bottom left, looping up to a 'SMALL MEASURING TANK' at the top, and then down to a 'FLOAT-CHAMBER' on the right. Text on diagram: - Left of the main tank: Arrow pointing down labelled 'HEAD AGAINST FLOW THIS' and another arrow below it labelled 'PLUS THIS'. - Pointing to the loop top: 'SMALL MEASURING TANK'. - Pointing to the end container: 'FLOAT-CHAMBER'. - Right of the float chamber: An arrow pointing up labelled 'ENDEAVOUR TO AVOID THIS'. [/DIAGRAM] RECEIVED STAMP: 25 JUN 1919 The thick lines shew the double column against the flow, the thin line the part of the pipe with air or vapour in. You will remember that many months ago you got over this by increasing the main tank air pressure to considerably over 2 lbs., which did not shew itself because of a low reading pressure gauge, but was manifest owing to the needle valve being held open (through this pressure acting on the full diameter of its spindle, (since modified) causing flooding. (2) After a petrol failure, and when flow of petrol was again obtained, the rush into the float chamber stirred up particles of grit, which stopped the low speed jet. (Contd.) | ||