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).
Test results for a large type Smith's Calorstat, detailing load requirements at various temperatures.
| Identifier | ExFiles\Box 39\4\ Scan175 | |
| Date | 2nd October 1930 | |
| X3499. SMITH'S CALORSTAT TESTS - LARGE TYPE. LOAD REQUIRED TO MAINTAIN SYLPHON IN NORMAL POSITION, (i.e. SHUTTERS FULLY CLOSED). TEMP °C | PULL LB | PUSH LB. 20 | 36¼ | — 30 | 33 | — 40 | 23 | — 50 | 11¼ | — 60 | — | 7½ 70 | — | 30½ 80 | — | 58½ 90 | — | 105½ LOAD REQUIRED TO MAINTAIN SYLPHON ON STOP (i.e. SHUTTERS FULLY OPENED). TEMP °C | PULL LB | PUSH LB. 20 | 54½ | — 30 | 49½ | — 40 | 38 | — 50 | 26¼ | — 60 | 11¼ | — 70 | — | 15½ 80 | — | 39½ 90 | — | 65½ | ||