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).
Investigation into a petrol flow deficiency with the new Phantom petrol tank filter and the proposed modification to resolve it.
| Identifier | WestWitteringFiles\Q\December1926-January1927\ 130 | |
| Date | 31th January 1927 | |
| To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/AJL. c. to BJ. Wor.{Arthur Wormald - General Works Manager} c. to RG.{Mr Rowledge} E.{Mr Elliott - Chief Engineer} c. to BY.{R.W. Bailey - Chief Engineer} DA.{Bernard Day - Chassis Design} Hs{Lord Ernest Hives - Chair}/AJLL/LG31.1.27. PHANTOM - PETROL TANK FILTER. (8190 Complaints have been received from the Production Test Dept; to the effect that cars fitted with the latest type petrol tank filter with the reserve tap incorporated, run out of petrol on the standard dynamometer test under conditions where the old type filter gave satisfactory results - i.e., the Autovac will not deliver the same amount of petrol through the new type filter as through the old type under the same conditions. Investigations we have carried out indicate that the difference in delivery through the two types of filter is 12.6%. One of the new type filters has been run on 12-EX 20,000 miles mostly in France with no indication of any defect; it was not until the dynamometer test was run that the deficiency was indicated. The filter tap as originally designed, had the holes 'A' and 'B' .1875" diameter. We find that the reduction in petrol delivery is due to restriction at these points. Although the tap will pass ample petrol under gravity for all engine requirements, it restricts the flow when the Autovac is delivering the petrol. It is necessary to open out all the holes 'A', 'B' and 'C' to .3125" dia. in order to obtain the same flow as with the old type filter under the same conditions. This alteration is impracticable on existing taps as the 'off' position of the tap is unobtainable owing to increasing the size of the conta | ||