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).
Results of air flow tests on an instrument under various configurations to identify restrictions.
| Identifier | ExFiles\Box 123\1\ scan0106 | |
| Date | 17th June 1936 guessed | |
| -2- Test No. 3. Air flow tests were then made with the complete instrument. Cold position 7.95 Hot Position 8.3 Cold position being the starting position when all the air has to pass over the heater coils, and hot position when all the air is passing to the instrument below the heater coils. The Thermostat and sleeve control was then removed leaving the heating coils and cover in position. Figure of merit 10.2. This showed ample area as the figure of merit is above that of the carburetter. Heater coils were then removed and the Thermostat was left in the cap. Figure of merit 10.6. Heater coils, Thermostat and sleeve were then removed leaving the cap in position, this being a test of the air cleaner entry. Figure of merit 10.70. From this series of tests it is obvious that the major restriction is caused by the temperature regulating sleeve. Tests were then made with edges of the regulator sleeve bevelled off which improved the flow to cold position 8.20 and hot position 8.40. A circular ring of metal forming a bead of 3/16" diameter was then soldered in to the top and bottom edges of the regulator sleeve which again improved the flow to hot position 9.8 and cold position 9.35. These rings made the regulator sleeve very much more solid and could be made of some anti-rattle material. Continuation No. S. SMITH & SONS (Motor Accessories) LTD., CRICKLEWOOD WORKS, LONDON, N.W.2. RP81 | ||