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).
Modified air inlet for a 20 HP car, detailing noise issues and providing a horsepower comparison with the standard part.
| Identifier | ExFiles\Box 172\1\ img059 | |
| Date | 29th April 1914 | |
| R.R. 493a (20H) (D.A. 652 20-3-24) J.E.D. EXPERIMENTAL REPORT Expl. No. REF. Hs{Lord Ernest Hives - Chair}/TMW/LG29.4.14. MODIFIED AIR INLET - 20 HP CAR. We recommend that Air Inlet No. E.53197 be made standard. At present, without an intake a slight roar combined with a distinct whining note is heard at 35 m.p.h. and increases to a maximum at 42 m.p.h., when it disappears to re-appear at 52 to 56 m.p.h. The present standard Intake considerably amplifies the noises to an objectionable degree. The Intake above has been evolved from the original Lec. design of silenced carburetter to reduce the noises emanating from the carburetter without any of the disadvantages, such as - Loss of HP., hissing, whistling, mixture interference and being flooded with oil from crankcase vent. Below is a HP. comparison taken on a test production engine between the std. and modified Intakes from which it will be seen that a slight improvement at high speeds in favour of the latter is shown :- HP. R.P.M. Std. Modified. 500 10 10 1000 22.5 22.5 1500 31.5 31.7 2000 41.75 42.5 2500 47.5 48.25 3000 47.8 49 [STAMP: RECEIVED 10 APR 1934] Hs{Lord Ernest Hives - Chair}/TMW. | ||