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).
The fit and stress issues of the overhanging bonnet on the 20/25 HP and Phantom II models.
| Identifier | ExFiles\Box 102\6\ scan0140 | |
| Date | 18th March 1932 | |
| Copy. Bs.{A J. Barnes - Assistant Manager} HS.{Lord Ernest Hives - Chair} Mx.{John H Maddocks - Chief Proving Officer} c. AEM. c. EP.{G. Eric Platford - Chief Quality Engineer} c. D/BP. x5260. x7260. BY.1/G.18. 3. 32. RE: FIT OF OVERHANGING BONNET. 20/25 HP. and P.II. Referring to Bs.{A J. Barnes - Assistant Manager}17/H.10.3.32, Mx.{John H Maddocks - Chief Proving Officer}17/T.11.3.32., and Mx.{John H Maddocks - Chief Proving Officer}13/T.12.3.32., it certainly appears definite that the opening of the bonnet by pushing the bonnet completely back and allowing the upper half on one side to be supported by the upper half across the other side of the hinge introduces forces which although we utilise a stop carried on a reinforcement, with the stop located a good distance from the hinge, with the object of reducing the stress, that the stress is still too high. This bonnet is going out of production, and has been replaced by the concealed hinge type of bonnet, the required stiffness being supposed to be attanied by the increase of the gauge, so that the thickness is now .104 on the 40/50 whereas before it was .080. We think that in view of what has happened that it is desirable for Hs.{Lord Ernest Hives - Chair} to put tests in hand to demonstrate that the concealed hinge type of bonnet does not take a permanent set when open and resting upon the upper half in the normal way. In regard to the question of charge, I do not think that we should give way to Messrs. Barkers on this point, the reasonable thing was for Barkers to inform us of the trouble, which would have enabled us to put a reinforcing piece into the bonnet and overcome the trouble on future chassis, as well as the particular onw which was giving the trouble. It would create a precedent to make a payment on a matter of this kind, and I think we should do our best to avoid being pushed into such a decision. By.{R.W. Bailey - Chief Engineer} | ||