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).
Radiator tests with a spring-fitted thermostat, comparing performance with an empty versus nearly full header tank.
| Identifier | ExFiles\Box 155\1\ scan0200 | |
| Date | 31th March 1936 | |
| (9) Radiator Tests Continued. 4. Spring was fitted in thermostat, and test continued with empty header tank at max. speed. Air 16°C. WATER IN ENGINE | WATER IN RADIATOR | DIFFERENCE | SHUTTER POSITION 71°C. | 65°C. | 6°C. | Closed. 75 | 70 | 5 | " 82 | 80 | 2 | " 88 | 85 | 3 | " Shutters begin to open | | | 95 | 87 | 8 | Half open. 91 | 85 | 6 | " " 88 | 80 | 8 | " " 88 | 80 | 8 | " " 88 | 80 | 8 | " " FLUCTUATING | | | 92/90/93 | 84 | 8 | " " 89 | 81 | 8 | " " Average 86°C. | 78.7°C | 6.3°C | 5. Last test was repeated with header tank nearly full. WATER IN ENGINE | WATER IN RADIATOR | DIFFERENCE | SHUTTER POSITION 83°C | 75°C | 8°C | Closed. 83 | 80 | 3 | " 89 | 85 | 4 | " Shutters begin to open | | | 93 | 87 | 6 | Half open 94 | 86 | 8 | & open. FLUCTUATING. | | | 90/93/92 | 85 | 7 | " " 85 | 78 | 7 | Half open. 85 | 76 | 9 | " " 86 | 80 | 6 | " " REFLUCTUATING. | | | 90/93/92 | 84 | 8 | " " 90 | 84 | 6 | " " 93 | 85 | 8 | " " 90 | 84 | 6 | " " Average 89°C | 82°C | 7°C. | | ||