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).
Design and effectiveness of a louvered bonnet compared to shutters.
| Identifier | ExFiles\Box 22\1\ Scan273 | |
| Date | 1st September 1925 | |
| To Hs.{Lord Ernest Hives - Chair} from DA.{Bernard Day - Chassis Design} 4214 DA{Bernard Day - Chassis Design}12/M23. 9.25. LOUVRED BONNET X. 8260 X.4214 The louvres following on the lines of the Hispano which we saw on the bonnet of 7-EX, were a considerable improvement on the previous louvres. Mr. Royce would like to try some of approximately this pitch, but which are half bent inwards, and half bent outwards. It is understood however that louvres are not appreciably more effective than shutters when the latter are opened, the only advantage from a cooling point of view being that they are always open. As however they accentuate noise and fumes from the engine, andhave no advantage from a cooling point of view over the shutters, it is to be recommended that they should never be used where it can possibly be avoided. [Diagram of louver profile] DA.{Bernard Day - Chassis Design} | ||