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).
Criticisms and potential improvements for vehicle bonnets and radiators.
| Identifier | ExFiles\Box 15\1\ Scan422 | |
| Date | 25th October 1930 | |
| X7250 TO HS.{Lord Ernest Hives - Chair} FROM EV.{Ivan Evernden - coachwork} EV{Ivan Evernden - coachwork}1/25.10.30. COPY TO BY.{R.W. Bailey - Chief Engineer} E.{Mr Elliott - Chief Engineer} BONNETS. ETC. X.5250. X.7260. X.5260. X.7250. We have received various criticisms of our bonnets and radiators. This memo is an attempt to summarise the situation as we see it so that if possible HS.{Lord Ernest Hives - Chair} may bring Works information to WW. (a) We can reduce the number of rivets on the bonnet by increasing the spacings, and avoiding double rows. We would be glad if Derby would go over the design and make a suggestion on these lines. (b) We have tried to use countersunk rivets in the past. The trouble is with the paint cracking around the head, due to slight movements during the expansion and contraction of the bonnet. Can Works suggest a means of overcoming this? Coachbuilders say they know of none. (c) Riveting is the only means that we know of for fixing hinges and other fittings to aluminium. The Daimler Co. conceal all of their rivets by using a double thickness bonnet, and by opening it in such a way that no hinges are needed. The first feature is also of value as it is used to keep the outer bonnet panel cool and so avoid the discolouration of the paint. We are carefully examining such a bonnet at the first opportunity and will discuss the whole design with "R". (d) A steel bonnet of a third the thickness of the present alum. one say .028 ins. would weigh about the same. It would be possible to avoid the use of rivets, but such a bonnet would sound tinny, and would be noisy. The coachbuilders say they would have endless trouble with it rusting. Steel bonnets are used on all cheap cars and American cars, but in the case of mass production the bonnet is chemically treated and baked to a high temperature and then immediately enamelled and baked. (e) The side hinge could be illiminated, that is concealed, and we believe Derby have made such a bonnet for a special order. If so we would like to be sent a copy of the design. (f) The top hinge can only be made concealed as on the Humber Snipe if it is agreed that the bonnet need not completely open as ours does at present. This does not matter on a small car as the top of the engine is well away from the top of the bonnet, but in our case it would almost mean the removal of the bonnet to adjust the tappets. (g) A larger and more squat filler was designed for both cars and sent to Derby in July 1928. Examples of it will be seen on 25EX. and 18-G-4, a still later design as been since sent on P. 2. in connection with the loss of water, which is even bigger in diameter still. Would Derby please send SG.{Arthur F. Sidgreaves - MD} copies of N. sch. 2669. 2670. and Le.C.2817. We would be glad if Derby would tell us whether they could eliminate the four rivets at the base of the filler by the use of pins which could be filed off. | ||