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).
Graph showing water flow through the bottom water pipe versus engine RPM for a 20/25 HP engine with a standard dropped radiator.
| Identifier | ExFiles\Box 149a\2\ scan0008 | |
| Date | 4th April 1932 guessed | |
| WATER FLOW THROUGH BOTTOM WATER PIPE (19 GIV) 20 25 HP. R.R STANDARD DROPPED RADIATOR WATER FLOW (GALLS/MIN) ENGINE R.P.M. 20 15 10 5 500 1000 1500 2000 2500 3000 | ||