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 memorandum discussing improvements for battery ignition, connecting rods, and crankshafts.
| Identifier | ExFiles\Box 181\M11\ img104 | |
| Date | 12th December 1918 | |
| To BY.DA.{Bernard Day - Chassis Design}& EH.from R.{Sir Henry Royce} -5- R7/G121218 Contd. (3) BATTERY IGNITION. The R.R. aero Jump spark coil is to be used in place of our present trembler. The existing distributor and low tension contact maker on the chassis should be retained but with a new cam giving 2/3 on contact and 1/3 off, so as to be less sensitive (in its timing) to the break adjustment. An extra condenser should be added close to the contact breaker and a non-inductive resistance or balance coil must be suitably incorporated in the system. The danger of leaving on the ignition switch and running down the starter battery was mentioned and Mr. Royce suggests using a lamp as both a non-inductive resistance and as a warning. (4) CONNECTING RODS. A design of connecting rod machined all over was standardised for the chassis engine on the one or two series which were being built in July 1914. The design of this rod should be gone over, and examined in comparison with the whole connecting rod experience gained during the War. It should be confirmed that the connecting rod flanges grow at the roots in a similar fashion to our aero rods. The fixings and material of the oil pipe should be modernised and the dimensions and type of connecting rod bolts criticised. (5) CRANKSHAFTS. The crankshaft at present being tested on 7CA is understood to have lighter drilled out crankpins and crankshaft webs, with outer ends milled to the semi-circular pattern used on the aero engines, and no balance weights. The design should be further improved by cutting off the crankshaft web inner ends to the semi-circular shape used on the "Condor" crank. The oil caps should be the aluminium spigotted type standard on aero work. (Contd.) | ||