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 plotting under bonnet pressures in inches of water against speed in miles per hour.
| Identifier | ExFiles\Box 87\1\ scan0184 | |
| Date | 20th June 1935 | |
| SHEET 7 UNDER BONNET PRESSURES - 3 - S - 1 PRESSURE TAKEN AT POINT CLOSE AGAINST DASH, ON CENTRE LINE OF ENGINE & BEHIND THE CARBURETTERS. O WITH FRONT LOUVRES TAKING IN AIR. X '' '' REJECTING AIR. TEMPERATURES AIR | UNDER BONNET | WATER 25° | 50° | 84° 26° | 50° | 82° Y-AXIS: INCHES OF WATER X-AXIS: MILES PER HOUR | ||