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).
Testing the force required to operate radiator shutters and proposing geometry changes.
| Identifier | ExFiles\Box 15\1\ Scan184 | |
| Date | 24th December 1929 | |
| R.{Sir Henry Royce} FROM E.{Mr Elliott - Chief Engineer} C. to SG.{Arthur F. Sidgreaves - MD}HS.{Lord Ernest Hives - Chair}BY. X7350 E4/M24.12.29. X.3499. X.7250. X.5250. RADIATOR SHUTTERS. We have disconnected the manual control of the shutters on the 20HP. RR. at WW. and tested them with a spring balance to get an idea of the force required to operate them. The balance was hung on the bell crank immediately behind the top tank and the test thus included the two horizontal control links passing through the radiator. The figures observed were as follows :- TO CLOSE SHUTTERS. 8 to 9 lbs. at begining 12 to 14 lbs. to completely close. TO OPEN SHUTTERS. 5 to 6 lbs. approx. The shutters we then treated with paraffin progressively to find out where most of the friction occurred, and this appeared to be all in the top bearings where the controlling force is applied. The above figures all fell to about a half after the application of paraffin. There is a tension spring of .5 lbs. load on each extreme side shutter opposing closing. We are somewhat astonished at the magnitude of the force required to operate these shutters, but some of it is occasioned by the poor geometry of the operating links passing throughthe radiator tank. On our very early design of these shutters e.g. LeC.1910 the lever is arranged to swing equally 35° each side of the normal but on the present shutters the lever moves from 15° forward to 55° rearward, its leverage falling from .575 to .3. Unfortunately the latter figure obtains when the shutters are closing and the closing spring is at its weakest on the thermostatically operated scheme. We therefore propose to reinstate the original geometry on the thermostatic scheme which demands .125 more thickness on the radiator. The shutters only just clear the matrix when fully open and therefore cannot be moved mearer. The attached print of LeC. 2773. shews revision for slyphon tube construction. We do not quite like the amount of guide available for the bellows and are preparing alternatives as soon as we receive the required Fulton prints from Derby. LeC. 2773 shews tank 5.75 thick in error. We propose to ask for 5.625 instead of 5.5. | ||