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).
Internal memorandum requesting information and data on centrifugal type superchargers.
| Identifier | ExFiles\Box 140\4\ scan0260 | |
| Date | 15th March 1940 | |
| Leyland INTERNAL MEMORANDUM One subject only on each sheet Date 15.3.40. Dict. 14th. From H.Q. LEYLAND RESEARCH ENGINEER. To CHIEF ENGINEER. CE/SM/NH [Handwritten top left]: Attach to RR letter J.S. CENTRIFUGAL TYPE SUPERCHARGERS. ----------------------- The following is a list of the information which would be useful to us in connection with centrifugal type superchargers - Information required for a type to give approximately 350 cu.ft. free air at pressures of the order of 3 - 5 lbs. per sq.in. [Handwritten right: 27 lbs. (per min) i.e. 270 B.H.P. approx.] [Handwritten left margin]: R = 20/15 = 1.33 Gear sec.? Tip Speed? (1). Arrangement drawings of supercharger and drive. (2). Detail drawings of rotors, casings and pressure stage blading, if any. [Handwritten: Circle taken?] (3). What are the advantages, if any, of stationary pressure stage blading? Any test data comparing a simple rotor with volute type casing and rotor with casing containing pressure stage blading would be useful. [Handwritten left margin: none at the moment I think.] (4). What is the most desirable type of rotor? (a). Unshrouded rotor. [Handwritten left margin: Our type, side open, i.e...] (b). Completely shrouded rotor. (5). What is the most desirable blade shape? (a). Radial. [Handwritten left margin: Radial - easier to make.] (b). Curved. (6). Test results showing comparisons of (a). and (b). in (4). and (5). would be useful. [Handwritten right: No data on our own] (7). Test data giving relationship of F.A.D. cu.ft. per minute, and air delivery pressure in lbs. per square inch at different supercharger speeds up to 20,000 r.p.m. [Handwritten right: We could estimate this.] [Handwritten left margin]: 70% (8). Test data showing overall efficiency at conditions for (6). [Handwritten: Yes] Is a free wheel or inertia unloading device necessary in supercharger drive? [Handwritten: No] [Handwritten left margin: Yes, a stepper drive but not free wheel.] [Signature]: S Markland | ||