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).
Table showing the effect on petrol level of larger floats and needle valves combined with various float leverages.
| Identifier | WestWitteringFiles\S\March1928-May1928\ Scan107 | |
| Date | 13th April 1928 | |
| TABLE SHEWING EFFECT ON PETROL LEVEL OF LARGER FLOATS & NEEDLE VALVE COMBINED WITH VARIOUS FLOAT LEVERAGES. FLOATS. FLOATS. MADE .250 WIDER THAN STD. THIS WILL INCREASE: @ TOTAL VOLUME TO *11.124 cu. ins. @ SECTIONAL AREA AT CENTRE TO *5.487 sq. ins. NO ALTERATIONS ARE MADE TO ANY OTHER DIMENSION. * ONE FLOAT ONLY. NEEDLE VALVE. BORE OF ORIFICE MADE .3437 DIA. WITH AN .031 RAD. AT SEATING. AREA AT SEATING WILL BE .0976 sq. ins. NEEDLE VALVE LIFT REQ'D = .150 in. WITH THE ABOVE ALTERATIONS & THE EFFECTIVE WEIGHT OF FLOAT ASSEMBLY ADJUSTED SO THAT THE PETROL LEVEL IS AT FLOAT CENTRE WHEN FED FROM 6 FT. HEAD. TABLE: LEVERAGE RATIO OF FLOAT MOVEMENT / NEEDLE VALVE MOVEMENT Columns (Leverage Ratio): 3.0, 3.25, 3.50, 3.75, 4.0, 4.25, 4.50, 4.75, 5.0 Row 1 - Variation in Petrol Level, 18 ins TO 12 ft. HEAD.: .373, .344, .320, .298", .280, .263, .249, .236, .224" Row 2 - Necessary Fall of Floats to Give .150 Needle Lift.: .450, .487", .525", .562", .600, .637", .675", .712", .750" | ||