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).
On the performance and updated testing speeds for a Watford R.O.1 magneto following a customer complaint.
| Identifier | ExFiles\Box 47\4\ Scan106 | |
| Date | 3rd March 1925 | |
| To BY/HM.{Capt. W. Hallam - Head Repairs} from EFC. c. Wd.{Mr Wood/Mr Whitehead} X4118 EFC3/T3.3.25. X. 3551. WATFORD R.O.1 MAGNETO NO. 68602. EX CHASSIS GAK.77. J C.JACKSON. Reference your BY/HM{Capt. W. Hallam - Head Repairs}13/W28.1.25 and Wd{Mr Wood/Mr Whitehead}/Dn2/DH{D. Henderson - Showroom}13.2.25, we have now run this magneto, as suggested, on a chassis, and now agree that in a hot condition it has not been found quite up to scratch. Early on it was necessary to set the low speed sparking limits to rather high speed figures, because at that time the material of the magnets, as admitted by Messrs. Norths, was not quite correct. Now, however, these magnetos have very much improved in low speed sparking, as is evident from our observations on various machines. Accordingly we are re-issuing the low speed sparking speeds such that item (6) of our production specification of test now reads :- "Now connect up the high tension terminal to a "three point spark gap set at 4.5 mm. The slowest "speeds at which regular sparking will occur shall "be ascertained and shall not exceed :- for (a) Fully advanced position 325 r.p.m. and " (b) Central position 225 r.p.m. " (c) Fully retarded position 175 r.p.m. " these speeds replacing respectively 450, 300 and 275 r.p.m. With these new speeds this magneto does not pass our production test, whereas the other two complaint magnetos and all other R.O.1 magnetos which we have tested recently do so very easily. It therefore appears in this instance that the customer is justified in his complaint and that the magneto should be returned to Messrs. Norths for correction. We return the machine herewith. EFC. | ||