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 comparing flow rates between a standard filter and a modified filter under two different conditions.
| Identifier | ExFiles\Box 65a\3\ scan0166 | |
| Date | 1st November 1929 | |
| Hs{Lord Ernest Hives - Chair}/Sm2/ADL.11.29 contd. -4- | Standard filter | Modified filter Flow from banjo condition (4) | 97.5 pts/hr. | 110 pts/hr. Flow through needle valve condition (7) | 75 pts/hr. | 78.7 pts/hr. Hs{Lord Ernest Hives - Chair}/Sm. | ||