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).
Series of graphs showing air pressure under the bonnet at various road speeds for Chassis 20 EX under different configurations.
| Identifier | ExFiles\Box 16\2\ Scan040 | |
| Date | 16th September 1931 | |
| CHASSIS 20 EX AIR PRESSURE UNDER BONNET (RECORDED BY U TUBES) STANDARD UNDERSHIELDS. RESULTS GIVEN ARE AVERAGE OF FOUR READINGS, TWO ON EACH SIDE OF ENGINE, HALF WAY BETWEEN BONNET SIDE HINGE & BOTTOM OF SIDE PANEL, ONE AT FRONT END & ONE AT REAR END OF ENGINE TOP GEAR PRESSURE UNDER BONNET (INCHES OF WATER) ROAD SPEED (M.P.H) LBS/SQ IN FLIP FLAP SHUTTERS (3 EACH SIDE) SHUTTERS OPEN -----------x SHUTTERS CLOSED ---------o RADIATOR FITTED WITH 6x7.5 MM MATRIX TUBES | ||