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).
Friction and other losses in the Mk. Hall-Scott servo.
| Identifier | WestWitteringFiles\L\2April1924-June1924\ Scan123 | |
| Date | 4th April 1924 | |
| R.R. 403A (40 H) (SL 42 12-7-28). J.H., D.{John DeLooze - Company Secretary} EXPERIMENTAL REPORT. Expl. No. 9910 REF: Hs{Lord Ernest Hives - Chair}/ACL/LG14.4.24 FRICTION AND OTHER LOSSES IN MK.{R. E. B. Meade-King} HALL-SCOTT SERVO. The tests were divided into three main sections :- (1) Determining of the actual coefficient of friction for the plates used and the apparent distortion of the plate. (2) Overall mechanical efficiency of servo - not including the losses due to friction of the driving dogs. (3) Friction losses due to the driving dogs. No. 1. The actual co-efficient of friction for the servo plates was determined by uniformly loading the plate - to prevent possibility of distortion - and finding the effort necessary to maintain the plate rotating. The frictional force was assumed to act at the mean radius of 3". (b) The apparent co-efficient of friction was similarly determined but by applying the load to the central shaft carrying the operating thread. The smaller value of µ obtained with the higher press-ures in test (b) indicates the decreasing of the mean press-ure radius through plate distortion. No. 2. For the purpose of obtaining the overall mechanical efficiency of the servo - not including the losses due to friction in the driving dogs - the dogs of the one plate were removed, consequently tor-que was obtained from one plate only. There was no appreciable difference in the torque output when taken with increasing and decreasing loads. The mechanical efficiency given was taken on the basis that the co-efficient of friction at the plate was .26. The fall of the efficiency with the increase of load rather points to distortion taking place in the mechanism. No. 3. The torque output was taken with the standard arrgmt. of plates in order to determine the loss due to the driving dogs with increasing pressures. The loss was arrived at as follows :- Twice the servo-torque given by one plate should be obtained from the two plates with no loss to the driving dogs. contd:- | ||