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).
Chart showing the heat output of an S.2 car heater in relation to air flow.
| Identifier | ExFiles\Box 137\1\ scan0230 | |
| Date | 22th December 1936 guessed | |
| CHART SHOWING THE HEAT OUTPUT OF AN S.2 CAR HEATER TO AIR FLOW CONSTANT WATER FLOW = 2 GALLONS/MIN. WATTAGE TAKEN AT 12 VOLTS = 10 (APPROX) CX{Major Len W. Cox - Advertising Manager}/94 (L.452/C4) Vertical Axis: B.T.US / HOUR / 100° TEMP. DIFF. Horizontal Axis: AIR FLOW CUB. FT/MIN. Graph line point: 12 VOLTS | ||