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).
The efficiency of an oil relay, detailing tests on expanding rings and the power required to operate controls.
| Identifier | ExFiles\Box 65\1\ scan0125 | |
| Date | 16th February 1926 guessed | |
| contd :- -4- on "Efficiency of Oil Relay"). It will be seen from these figures that so far rings substituted for the cup leather have not proved a success. A light ring under the cup leather to expand it, does not make any improvement with a new leather but with one that has become well worn produces an appreciable improvement. We therefore consider that the expanding ring is desirable to maintain the efficiency of the unit. The actual ring we are employing is very much lighter than the original expanding ring detailed and does not impede the movement of the piston in the cylinder to any appreciable extent. The power we have to rely on from the relay to manip-ulate the controls at 1000 engine r.p.m. - oil pressure14 lbs/sq. in. - under ordinary conditions is therefore only about 27 lbs. In extreme conditions it will fall as low as 20 lbs. The test we next undertook was to ascertain the power required to operate the controls. A standard magneto was procured and the friction on its sleeve adjusted to the plus limit of 3 lbs. at the ball end which is the standard load for product-ion. For a long time we have been endeavouring to get this load reduced, but it appears to be quite incompatible with the degree of silence required from the magneto. Unless there is a friction on the sleeve, the magneto is noisy. A good set of controls were then fitted up and by means of a spring balance attached to the relay cap in the manner indicated, the load required to advance the magneto and distributor was determined. This appears to be 26 lbs. whether the engine is stationary or running, | ||