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 comparing the temperature rise of different car heaters over time on model 1-R-1.
| Identifier | ExFiles\Box 137\3\ scan0259 | |
| Date | 3rd February 1941 | |
| Fig 1 COMPARATIVE TESTS CARRIED OUT ON HEATERS ON 1-R-1. RISE OF TEMPERATURE AT N.S. DOOR PILLAR IS SHEWN BELOW 1. HADEES HEATER WITH LONG SHIELD 2. HADEES HEATER WITH SHORT SHIELD 3. HADEES HEATER WITHOUT SHIELD 4. A.C. HEATER TEMPERATURE ABOVE OUTSIDE AIR IN DEGREES CENTIGRADE TIME FROM START OF TEST IN MINUTES Rui/Cem 3-2-41 | ||