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).
Progress report on the development and testing of a new blower, supercharger, and associated drive components.
| Identifier | ExFiles\Box 140\1\ scan0159 | |
| Date | 18th April 1935 | |
| -3- Hs{Lord Ernest Hives - Chair}/Smth.12/KW.18.4.35. Blower. We have replaced the Grahen rotor by an R.R. dural rotor, machined all over and of 50% greater tip width. The clearance between the rotor and its casing is now reduced to .018". As a result of these modifications we now get 5% more boost at 4500 r.p.m. with the same temperature rise, indicating a substantial improvement in blower efficiency. Attached are power curves comparing the two rotors. There are indications that the standard Bentley head is undervalued at high speeds when supercharged, and we shall try a head with larger inlet valves. We have under construction a supercharger embodying a diffuser which we shall soon be testing. In view of LR{Mr Ellor}'s American information there seems to be little doubt that we shall want a diffuser. Blower Drive. We are still using the original D.H.S. gears which have now worn very badly. We have increased the flexibility of the horizontal drive and have by this means reduced the gear rattles considerably. It is evident that we must aim at the maximum possible flexibility for the blower drive. Road Testing. We are now building up a supercharged unit for road tests. The arrangement will be the same as on S-12, with the blower on the exhaust side. We hope to have this running in the course of a week. Hs{Lord Ernest Hives - Chair}/Smth. | ||