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 the S.U. Carburetter Co. regarding weakness issues with the H.V.5 type carburetter upon acceleration.
| Identifier | ExFiles\Box 31\4\ Scan084 | |
| Date | 10th September 1931 | |
| 81487 Expl. Dept. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}7/MJ. September 10th.1931. The S.U. Carburetter Co., East Works, Bordesley Green Road, Adderley Park, BIRMINGHAM. For the attention of Mr. Skinner. Dear Mr. Skinner, On all the needles that we have for the H.V.5 type of carburetter, there is a tendency to weakness when the throttle is suddenly opened from the fully closed position at 30/40 M.P.H. The needle with which we have obtained the best results is the W.0.2 run slightly off the fully weak position to give us a range of mixture control in both directions. We attach herewith a throttle metering curve of this needle. with no.2 Piston When accelerating in the manner specified, the piston shoots momentarily to the top of the stroke. We imagine the defect complained of might be altered by increasing the mixture strength under full throttle, high speed, conditions. In any case, you will probably know the modification to the needle most likely to overcome the difficulty, and we should be obliged if you could let us have one or two needles to try representative of your best recommendations on the subject. We find the lighter piston to require altogether different mixture needles to the standard Cont'd.......... | ||