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).
The comparative bench tests of B.T.H. and Watford magnetos, focusing on noise, weight, and price.
| Identifier | WestWitteringFiles\N\2October1925-December1925\ Scan267 | |
| Date | 12th June 1925 | |
| R.R. 493A (50 H) (D.D. 31, 12-6-25) J.H.D. EXPERIMENTAL REPORT. Contd. -2- Expl. No. REF: ERM/TM.12.25. The following are the comparative results of bench tests of these two B.T.H. magnetos interspar with one of the latest standard Watford machines, incorporating the improved end location of sleeve for reduced noise. (1) Weight of the standard Watford magneto 13.4 lbs. B.T.H. Type RMG 11.5 " As regards the mechanical and electrical details of design of the B.T.H. magneto, the following is an extract from my assistant's report WB.{Mr Brazier/Mr Bell}59 :- "These magnetos are quite good machines both mechanically and electrically. They are fairly robust design, a special feature, in the bench at any rate, being the absence of abnormal noise of these magnetos as compared with Watford machines. The contact breaker is quieter in operation, so are the gears and sleeves, this quietness being attributed (a) To the design of the contact breaker rocker arm, which is apparently friction damped. (b) To the armature gear pinion which is made of fabroil material. and (c) To the fact of the sleeves being well enclosed in the main die casting incorporating the pole pieces. The distributor is of the jump spark pattern, incorporating the H.T. safety gap on the rotor. These magnetos are two lbs. lighter than the Watford, - a point worthy of note. From the results recorded below it will be seen that these magnetos are well designed, the utility performance showing up very well. As a matter of further interest, the price of these magnetos is quoted at £7. as compared with the Watford at £10.10.0." Contd. | ||