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 the cooling performance of a 40/50 model against a Hispano Suiza at an average speed of 35 mph.
| Identifier | ExFiles\Box 38\2\ Scan215 | |
| Date | 25th August 1924 | |
| COMPARATIVE COOLING TESTS Rolls Royce & HISPANO SUIZA. AVERAGE SPEED 35 M.P.H. RADIATOR TEMPERATURES MILES RR 40/50 STANDARD OUTWARD TRIP " " NO BONNET RETURN TRIP HISPANO SUIZA STANDARD OUTWARD TRIP " " " NO BONNET RETURN TRIP R.P. Ballon 25.8.24 | ||