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).
Comparison table for 'Light' and 'Heavy' oils, detailing specific gravity, viscosity at various temperatures, and cold starting times.
| Identifier | ExFiles\Box 145\3\ scan0246 | |
| Date | 31th May 1937 guessed | |
| LIGHT HEAVY (Probably marketed (Probably marketed as "Single" Shell) as "Triple" Shell) Sp.{Mr Spinney} Gravity 0.878 0.890 Viscosity Minus 1°C 995 centipoises 3,900 centipoises 70°F 845 secs. Red. I 2,400 secs. Red. I 140°F 125 " " " 261 " " " 200°F 55 " " " 84 " " " Starting time after 16 Starting time after 16 hrs. cold chamber at hrs. cold chamber at minus 1°C - instantaneous. minus 1°C - 13 seconds. NOTE Starting time is not time to first fire but time to attain continuous running. | ||