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).
Letter to Zenith Carburettor Co. Ltd. regarding design issues and failures with carburettor components.
| Identifier | ExFiles\Box 122\2\ scan0314 | |
| Date | 12th January 1938 | |
| The Zenith Carburettor Co.Ltd., -2- Rm{William Robotham - Chief Engineer}/GR.{George Ratcliffe}10/JH.12.1.38. the steel screws being counterbored slightly at the end for swaging. We would prefer this rather than the wedged open slot because of the risk of a fractured portion of the screw entering the engine. However, you will no doubt be kind enough to let us know if the swaging can be carried out. May we draw your attention to the leather pistons which you are supplying on the special lever carburettors. Two of the piston rods have unfortunately been sheered off during adjustments. We are returning one sample and would point out that the section at which the fracture has occured is only .060" dia. We would also like to have the bush 1.350" in length instead of 1.300" as this would cover a gap left at the top. With regard to the idle system; the first carburettors were not spot faced for the metering screwspring and the metering screws would not weaken off sufficiently. The holes required tapping deeper and the threads eased. This allows the screws to become more central. It is essential for control that they are concentric. We would very much like to have the Phantom III details of manufacture to be applied to these carburettors at this point. Will you kindly check up on all these details, the piston rod in particular, and let the writer have the results. Please find enclosed the broken piston and rod. Yours faithfully, FOR ROLLS-ROYCE LTD. | ||