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).
Comparative tests of different bonnet types, recommending the four-shuttered bonnet as the new standard to prevent engine overheating.
| Identifier | ExFiles\Box 119\3\ scan0056 | |
| Date | 30th July 1914 | |
| 884 (180 H) (W.W. 529. 2-7-14) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 0670. From Exp. Dept. Copies to:- J.{Mr Johnson W.M.} R.{Sir Henry Royce} E.{Mr Elliott - Chief Engineer} Na.{Mr Nadin} Wor{Arthur Wormald - General Works Manager}/EH18/B30Z14. 30th July, 1914. Report on Bonnets with 4 Shutters. X.1085. Attached are comparative tests with (1) Plain bonnet (2) two shuttered bonnet (3) four shuttered bonnet (4) louvred bonnet. We recommend that the bonnet with four shutters is adopted as standard. With a shuttered bonnet we shall not loose any of the advantages of a plain bonnet, neither shall we have the disadvantages of the louvred bonnet, the shutters need only be used when it is found necessary, it is an improvement that we ought to take advantage of immediately. The improvement it makes is over the standard radiator and bonnet, it does not keep the water as cool as the large radiator and louvred bonnet, this was clearly demonstrated in Austria this year, 5BNA with standard size radiator and large fan and 4 shuttered bonnet, boiled badly on all the long hills, the other cars with large radiators and louvred bonnets did not. The fact that it is necessary for us with our present make of radiator to fit a larger one on cars we know are going to be used in hot climates is a great point in favour of fitting 4 shutters to the standard cars. The standard car should be capable of going anywhere. I think it should be known by all our customers how the car should be driven so as to avoid the water boiling when run- | ||