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).
Examination and testing report on a Splitdorf Magneto Type SS No. 31545 from a Curtiss Aero Engine.
| Identifier | WestWitteringFiles\R\2December1927-February1928\ Scan089 | |
| Date | 22th December 1927 | |
| WC.56. 22.12.27. SPLITDORF MAGNETO TYPE SS.{S. Smith}No.31545. OFF CURTISS AERO ENGINE. We have had an opportunity of examining and testing the above and we give below a few points of design observed on this magneto as follows :- (1) Weight 14.625 lbs. -1¼ lighter than BTH. SC12/7 magneto. (2) Contact breaker. The design of this unit is very original. A bakelite cam rotating rubs direct on to a channel section contact lever spring with a small coil spring directly behind the contact points. The contact points which look like tungsten are shielded from any oil, etc. thrown off the cam, the lubrication of which is provided by an oiled felt pad connected to the contact lever in such a way as to touch the cam when the lever lifts at break. (3) Condenser. This is housed behind the distributor as near to the points as possible. (4) Distributor. This is of the jump spark pattern and is designed very inaccessibly, it being necessary to unscrew and remove the rotor to move the screws which secure the H.T. wires. A plain bearing is used for the bakelite distributor gear wheel, the H.T. supply brush coming up through the centre without any provision for protecting it from the oil etc. of the bearing. With regard to the H.T. wire securing screws mentioned above, there does not appear to be any precaution taken to prevent these working loose and fouling the rotor. (5) Armature and magnetic circuit. As far as we can gather from observation this machine is a pure inductor, the armature being located inside the arch of the horse shoe magnet. This magneto has been tested to our general specification for a 300 magneto and passes it completely with a considerable margin, one feature being the phenomenal low speed performance. This extraordinary performance may have been obtained by the use of a horse shoe cobalt steel magnet. EFC/H.E.West. | ||