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).
Modified Autovac suction elbow designed to solve uneven engine running.
| Identifier | WestWitteringFiles\N\July1925-September1925\ Scan68 | |
| Date | 13th August 1925 | |
| R.R. 493A (50 H) (D.D. 31, 12-6-25) J.H.D. EXPERIMENTAL REPORT. ORIGINAL Expl. No. REF: Hs{Lord Ernest Hives - Chair}/AIL/LG13.8.25. C To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} c. to CJ. BJ. c. to RG.{Mr Rowledge} R.{Sir Henry Royce} c. to DA.{Bernard Day - Chassis Design} BY.{R.W. Bailey - Chief Engineer} c. to Wor.{Arthur Wormald - General Works Manager} x3579 AUTOVAC. MODIFIED SUCTION ELBOW* TO INDUCTION PIPE PISTON AIR FROM AUTOVAC. The sketch shows an alternative suction elbow supplied to us by Autovac Ltd., in response to our complaints re. variation of engine speed at almost closed throttle when the Autovac is functioning. We have found that the uneven engine running is caused by a sudden 'richening up' of the induction pipe mixture every time the Autovac functions. What it amounts to is that the Autovac is acting as a surface carburetter. Each time the Autovac suction valve opens in response to the float toggle mechanism, air is drawn into the induction pipe from the Autovac, carrying with it sufficient petrol vapour to upset the even running of the engine. The above modified suction elbow is designed contd :- | ||