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).
Issues with the Phantom III carburettors, including accelerator pedal spring tension and float mechanism design.
Identifier | ExFiles\Box 93\2\ scan0096 | |
Date | 3rd October 1935 | |
Swdl.{Len H. Swindell} We should reply to this Rm{William Robotham - Chief Engineer} 7308 Hs.{Lord Ernest Hives - Chair} from E.{Mr Elliott - Chief Engineer} c. By.{R.W. Bailey - Chief Engineer} Hs{Lord Ernest Hives - Chair}/GWH.{George W. Hancock - Head Chateauroux} Da.{Bernard Day - Chassis Design} Hs{Lord Ernest Hives - Chair}/Swdl.{Len H. Swindell} E/Psn. re Phantom 3 Carburetters. With regard to the question of/springing of the accelerator pedal being too heavy with four throttle closing springs on the engine, there appears to me to be no reason why we should not reduce the spring on the accelerator pedal itself, either in force or rating, or both. This would leave the springing of the throttle valves at an adequate amount and yet allow the total springing to be reduced at a point where it would just comfortably carry the weight of the foot, which is our usual standard. At the same time it may be desirable to reduce the throttle springs a little, but we are investigating the whole question, and will very shortly instruct a modified springing. With regard to the question of the float mechanism on the reverse throttle carburetters, I cannot see any difference fundamentally with the old mechanism if the float is working at the same immersion, in other words, there are the same forces available for operating the mechanism since the weights of the pieces involved must have been readjusted to ensure that the float is not submerged any more than it used to be. The only difference might be sluggishness of operation affected by inertia of the moving parts, but this inertia should be no more than formerly. The real trouble seems to be reduced down to the fact that the float pressings are hardly thick enough to be practicable, and we are, therefore, looking into the matter to see what improvement can be made from this point of view. We should like an experiment made to tell us how far the needle should be opened on the existing carburetters for full throttle petrol delivery. This will give us a clue to the area necessary. We expect to be able to reduce the size of the | ||