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).
Technical memo detailing tests and issues with an aero engine boost regulator.
| Identifier | WestWitteringFiles\V\December1930-February1931\ Scan079 | |
| Date | 3rd January 1931 | |
| To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/ACL. c. to SG.{Arthur F. Sidgreaves - MD}. WOY. c. to RG.{Mr Rowledge} E.{Mr Elliott - Chief Engineer} c. to LR.{Mr Ellor} Hs{Lord Ernest Hives - Chair}/ACL.2/MJ.3.1.31. [Stamped] ORIGINAL [Handwritten] K4033 AERO ENGINE BOOST REGULATOR. Tests with the differential boost regulator are progressing quite well and being carried out on "F".S. No.105 engine. At first we were troubled with very slow and indefinite action which meant that when the hand throttle was varied the butterfly throttles would be relatively slow in assuming a stable position. The trouble was traced to friction at the aneroid caused by the balance spring rubbing against the tubular bronze spring case also to there not being sufficient movement of the bellows in the downward position. These points were remedied by carefully centralising the spring and reducing its free length by one coil. We should like modification to the bronze spring case or spring so as to allow more clearance and insure that the spring is centralised at the ends and does not rub the case. It is also very important that the sliding valve operates freely in its guide. After correction the regulator suffered from excessive hunting at certain throttle positions and we retested with the isolating cock disconnected from the piston operated mechanism. This resulted in the throttles becoming stable. It would appear that the inertia effect of the boost regulator piston when coupled with the slide valve action of the isolating valve was primarily responsible for the hunting. We next operated this isolating cock by a lever carried on the differential casing so that it was operated by the hand throttle movement. This eliminated the continued 'hunting' but with quick operation of the throttle there was a tendency to 'overshoot' and oscillation before the stable position was assumed. We are attempting to overcome this by using restriction jets in the pressure and suction passages on either side of the operating piston but leaving full bore passages to the aneroid. | ||