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).
Performance graph for a Clayton Dewandre interior car heater, showing temperature rise over time from a cold start.
| Identifier | ExFiles\Box 137\1\ scan0125 | |
| Date | 2nd June 1932 guessed | |
| CLAYTON DEWANDRE INTERIOR CAR HEATER ON 20EX (WARMING UP FROM COLD) ENGINE WATER TEMP RISE ENGINE SPEED CONSTANT AT 500 R.P.M. RISE OF TEMP. IN INTERIOR OF CAR TEMP °C AIR TEMP AT START TIME FROM START (MINS.) HEATER MOTOR RUNNING AT FULL SPEED HALF SPEED | ||