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).
Comparison of test results between fabric and serrated magneto drives for the 40/50 chassis.
| Identifier | ExFiles\Box 172\3\ img033 | |
| Date | 27th September 1920 | |
| To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} CJ. Rn.{Mr Robinson} E.{Mr Elliott - Chief Engineer} Sa. By.{R.W. Bailey - Chief Engineer} NEW MAGNETO DRIVES. We have now had considerable experience with both the fabric magneto drive and the serrated magneto drives for the present 40/50 chassis. We have had three sets of the serrated drives running.- No.1 set has completed 11,000 miles. No.2 " " " 8,000 " No.3 " " run 70 hours on the test bed engine. We have also had three sets of the fabric drives running.- No.1 set has completed 13,000 miles. No.2 " " " 5,000 " No.3 " " 40 hours running on the test bed engine. From the results of our tests we prefer the serrated drive to the fabric drive. We have also consulted the Works and Tool Draughtsmen and they are of the opinion that they would sooner make the serrated drive than the drive using the fabric. The advantage we have found in the serrated drives are as follows:- They give the minimum amount of trouble to fit together. On the engine we have not had the least trouble with them nor can we detect any signs of wear after 11,000 miles. They are excellent as regards being oil retaining and for excluding dust and dirt. The serrated drive also has the advantage that, if found necessary, a magneto brake could be fitted. We have found on our tests that as long as the magneto drive (Contd). | ||