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 report comparing boiling temperatures for different types of bonnet ventilation at various speeds.
| Identifier | ExFiles\Box 29\3\ Scan314 | |
| Date | 19th June 1931 guessed | |
| Figures given Ats. temps. at which Car will boil if driven for sufficiently long at full throttle under the conditions named. C° | Type of Bonnet Ventilation | All Out | 45 M.P.H. | 30. M.P.H. | |---------------------------------------|---------|-----------|------------| | Vertical Louvres. | 44.5 | 37.5 | 36.5 | | Three ventilating shutters per side. | 41.5 | 33.00 | 32.5 | | No bonnet ventilation. | 38.0 | - | 27.5 | Tests on 19-EX. Rad. used. small Hexagon U.S.A. Hexagon .305 across Flats. Centre .255 dia. round 18 dents. Car weight. 48 cwt. Axle 11 X 41 Radiator dimensions 25.9 X 33.7. Radiator shutters fitted for all tests. Louvred Bonnet F.79291 Shutter Bonnet N.S.L 3232. | ||