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 critical air temperatures for spring-tensioned vs positively-tensioned fan belts at 62 MPH without bonnet ventilation.
| Identifier | ExFiles\Box 92\2\ scan0081 | |
| Date | 25th June 1930 guessed | |
| GRAPH V.{VIENNA} 19 E.X. 62 M.P.H. NO BONNET VENTILATION. COMPARISON OF SPRING TENSIONED FAN AND FAN BELT TENSIONED POSITIVELY CRITICAL ATS TEMP. 40°C 30°C 20°C 10°C 40.5 SPRING TENSIONED 44.5 BELT TIGHTENED. CHOC à BLOC. | ||