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).
Analysis of petrol supply issues to the carburettor, detailing flow rate reductions caused by various obstructions.
| Identifier | ExFiles\Box 65a\3\ scan0162 | |
| Date | 7th November 1923 | |
| To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/Rn.{Mr Robinson} c.c. EG. c.c. WOR.{Arthur Wormald - General Works Manager} E.{Mr Elliott - Chief Engineer} c.c. Ds. BY.{R.W. Bailey - Chief Engineer} X 777 o Hs{Lord Ernest Hives - Chair}/Bm2/AD7.11.23. for sketch see orig. X7080 X7770 PETROL SUPPLY TO CARBURETTOR. We have only just sufficient petrol supply in the float chamber to keep the car running all out. The fault in most cases is not in the Autovac being unable to draw sufficient petrol from the rear tank, though we have had experience of defective autovacs. It is that the gravity head of petrol from the Autovac to the float chamber is insufficient to supply the required quantity of petrol through the intervening obstructions, i.e. pipe, filter, needle valve. We have analysed the obstructions which bring us down from a free flow with a plain open ended 5/16" pipe of 131 pts/hr. to a delivery through the needle valve into the float chamber of only 75 pts/hr. Building up from the plain pipe we get the following deliveries. State of Supply Delivery Pts/Hr. (1) Plain 5/16" pipe from autovac to float chamber level. 131 pts/hr. (2) Empty filter head coupled up in system. 110 pts/hr. (3) Filtering element inserted in filter head. 104.2 pts/hr. (4) Banjo head fixed to end of pipe (delivery c) 97.5 pts/hr. | ||