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).
Tests conducted to investigate and resolve bonnet knocking issues.
| Identifier | ExFiles\Box 11\3\ 03-page378 | |
| Date | 1st July 1931 | |
| To Hs.{Lord Ernest Hives - Chair} From Hs{Lord Ernest Hives - Chair}/Les.{Ivan A. Leslie} Hotel de France, Chateauroux, Indre, France. 1.7.31. BONNET KNOCKS. For these tests the bonnet at any time did not emit knocks that were audible in the car. Therefore the amount of relative movement between the bonnet and the scuttle is considered proportional to bonnet knocks. The relative movement between the bonnet and the radiator is negligible owing to the central mounted radiator. The road so far used is a long straight, bad surface, where speeds up to 60 m.p.h. were maintained. The surface not being of the worst order, but one where slight improvement for bonnet movement are detectable. TEST I. (a) Radiator given .375" movement each way on its central mounting, measured at the top of the water connection to cylinder head. (b) .030" clearance between bonnet and radiator. (c) .070" clearance between bonnet and scuttle. (d) .312" clearance between bottom of the bonnet side and the bonnet strip. (e) Control springs each side of radiator central mounting set at 45 lbs load. (f) V.{VIENNA} stay tubes between rad. and dash. Result. The radiator set up several undamped periods in a vertical plain about its mounting which caused the bonnet to touch the scuttles at its maximum position. TEST II Control springs removed each side of central mounting. Result. No definite change from previous result although 10% improvement was estimated. TEST III. (a) Top water connection replaced by a larger rubber | ||