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).
Mechanics, forces, and costs involved in operating radiator shutters.
| Identifier | ExFiles\Box 39\4\ Scan262 | |
| Date | 12th May 1932 | |
| X3499. Sg.{Arthur F. Sidgreaves - MD} From Hs{Lord Ernest Hives - Chair}/Ru. c. to Wor.{Arthur Wormald - General Works Manager} c. to E.{Mr Elliott - Chief Engineer} Hs{Lord Ernest Hives - Chair}/Ru.1/A.12. 5. 32. RADIATOR SHUTTERS. Ref. Sg.{Arthur F. Sidgreaves - MD}6/2.3.5.32. To ensure that the shutters close it would be necessary to employ a spring of about 15 lbs. load. The friction in the shutters under the worst conditions might be expected to be at least 10 lbs. Therefore the suction cylinder would have to exert a force of 25 lbs. Now almost all other suction operated devices such as brakes, clutch control etc are only used when the throttle is shut, and the depressions in the induction pipe then is as much as 10 lbs/sq.in. When the throttle is fully open at low speeds, however, the induction depression falls to .5 lbs/sq.in. or less, and this is why a suction wind-screen wiper even will not function under these conditions. However, climbing a hill at slow speed full throttle is exactly the condition under which it is most essential that the shutters should be fully open. To be certain of this, the area of piston operating these shutters would have to be at least 50 sq.in., or a cylinder of 8" dia., unless a somewhat complicated system of reduction leverage were incorporated when it might be possible to reduce it to 6" dia. In addition to this a thermostatic element would still have to be provided though admittedly this could possibly be changed to a bi-metal strip. The cost and unsightliness of a pipe from the induction pipe to the radiator is of minor importance but should be considered. The existing thermostat which we should hope to replace costs 25/-. | ||