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).
Utility test results for magnetos, detailing maximum gap measurements under various coil and primary circuit conditions.
| Identifier | ExFiles\Box 37\1\ scan 088 | |
| Date | 24th January 1919 | |
| RR 300 (f20B) (SF 349 24-1-19) MP 200552 88256 ROLLS-ROYCE LIMITED. INSTRUCTIONS. To Order No Customer's No. 2 Re: Utility Test of Magnetos (condt) doubtless do much better, if the safety gap were wider. Table of Results: Conditions | Max-gap. mms. Advanced | Centre | Retarded ------------------------------------------------------ of gap under test. Without coils shunted | 5.0 | 4.0 | 6.0 With 2 coils (sers) prims open | 5.0 | 4.0 | 4.5 " " 1 prim. closed | 4.75 | 4.25 | 4.75 " " both prims " | 4.25 | 4.25 | 5.25 " 1 coil, prim. open. | 4.5 | 4.5 | 4.75 " " " " closed. | 3.5 | 4.0 | 5.25 Signed: Francis J Allen This Sheet must be filed on completion of the work. | ||