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).
Quoting Mr. Hives' report on the comparison between shuttered and louvred bonnets.
| Identifier | ExFiles\Box 119\3\ scan0026 | |
| Date | 21th January 1914 | |
| Re Shuttered Bonnets. X.1085. Na{Mr Nadin}/s. WOR{Arthur Wormald - General Works Manager}/Mcr2/021114. 21/1/14. In reply to your memo Na{Mr Nadin}/S16/LG14114, we give below Mr. Hives report:- "We have no results of any comparative tests taken with the shuttered bonnet and the louvred. We made a test yesterday but we could not appreciate the difference with the shutters open or closed, it is not much use taking temperature tests when the weather is cold. For appearance, I favour the shuttered bonnet, also it has the advantage that in cold weather the shutter can be closed, but in view of the fact that every summer we get complaints of cars boiling, I consider it would be dangerous to alter what we have proved to be very good, until we have tested the shuttered bonnet under the worst condition. I suggest that colonial cars still have the louvred bonnet but that the plain bonnets might be made with shutters in right away." p. Wor.{Arthur Wormald - General Works Manager} | ||