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).
To Mr Hives discussing magneto test results, defects in American Bosch magnetos, and proposed modifications.
| Identifier | ExFiles\Box 49\5\ Scan228 | |
| Date | 4th May 1921 | |
| Oyll-G4521. -3- May 4, 1921. Mr Hives The first curve which I give you above is from an actual test taken this morning on the magneto we are sending on 4-EX. It was taken this morning after 2 hours run at 2500 r.p.m. and is therefore reliable. The speeds given are magneto speeds, not engine revs. The high speed limit for regular sparking on 5 mm. gaps is 4500 r.p.m. full advance. I may add that the only defects we have to complain of so far on American Bosch magnetos are the noise of the contact breaker, for which they are going to provide a thicker cover, and the fact that the platinum point in the rocker came loose in 24-PE (Demonstrator) after about 2000 miles. To overcome this we are having the makers rivet over the ends of the contact point screws thus: [Hand-drawn diagram of a riveted contact point screw] OY. The one ZR.6 machine that we have left (not the one put through our tests) is an E.d.18 with an N.B armature. C A.P. R.R. 238A.(100 T) S.B.S. 286. 10-12-20 G 2247 | ||