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 bonnets and radiators.
| Identifier | WestWitteringFiles\V\October1930-February1931\ Scan032 | |
| Date | 25th October 1930 | |
| TO HS.{Lord Ernest Hives - Chair} FROM EV.{Ivan Evernden - coachwork} COPY TO W. E.{Mr Elliott - Chief Engineer} BONNETS. ETC. 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 W.W. (a) We can reduce the number of rivets on the bonnet by increasing the spacing 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) Rivetting is the only means that we know of for fixing hinges and other fittings to aluminium. The Daimler Co. conceal all of their hinges by using a double thickness bonnet, and by open- 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 .028ins. would weigh about the same. It would be poss- 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 them 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 for T.2. in connection with 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 elimin- ate the four rivets at the base of the filler by the use of pins which could be filed off. (h) A quickly detachable filler cap has been suggested. We have one for the petrol tank on N.2.Series, but that design would not be suitable for the radiator. | ||