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).
Graph of make ratio versus speed curves for a standard contact breaker, comparing standard and stronger springs at various gap settings.
| Identifier | ExFiles\Box 61b\2\ scan0055 | |
| Date | 31th March 1927 | |
| X6118 MAKE RATIO NORMAL RUNNING SPEED 700 r.p.m. .010" GAP .018" GAP .026" GAP MAKE RATIO - SPEED CURVES OF R STANDARD CONTACT BREAKER WITH STANDARD AND INCREASED RATED SPRINGS. SPEED (r.p.m.) STD. SPRING (LOAD ON POINTS .91 LBS) STRONGER SPRING (LOAD ON POINTS 1.4 LBS) HEW 30-3-27 E.F.C. 31/3/27 | ||