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).
Performance graph with handwritten test result calculations.
| Identifier | ExFiles\Box 54\1\ Scan337 | |
| Date | 20th September 1927 | |
| 20-9-27 157 S.A. 75 a.h. 100 lbs Average amperes = 6.22 Hours = 8.75 Ampere hours = 54.4 .544 1.80w. EVERETT EDGCUMBE LONDON | ||