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).
Report comparing ignition system components, including contact pressures and a diagram of an 'umbrella' rotor.
| Identifier | WestWitteringFiles\Q\January1927-March1927\ 41 | |
| Date | 18th January 1927 guessed | |
| (2) pedestal while the moving contact is carried on an extension of the sheet metal arm with rather inadequate side flanges. On the other hand the Remy contact screw is mounted on a comparatively flexible sheet metal earthed tongue while the moving contact extension has decided side flanges giving it stiffness. PRESSURE OF CONTACTS. This again does not seem of much significance. By very rough spring balance measurements the following appear to be the pressures - Bosch - 2 lbs. Remy - 1 lb. RR.20HP. - 1.5 lbs. It is interesting to note that there is no timing adjustment on the Bosch L.T. cam, the minor adjustment being obtained by rotating the whole unit relative to the control lever, which lever is provided with a split boss. The major adjustment is obtained by means of the gear wheel teeth. It is over 5 years since we saw this Bosch ignition unit with governor, and while remaining the same in principle it has been modified in detail in respect to a number of interesting points which we will deal with later when we have more time. There is one point however which may be of immediate interest. The rotor is formed in the shape of a complete disc. This umbrella rotor looks more like a scheme than an accident, made with the object of keeping up a circulation of pure air around the make and break, any gas formed at the H.T. points being carried away without mixing into the air below. E.{Mr Elliott - Chief Engineer} | ||