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).
Trials log for a speed indicator tester.
| Identifier | ExFiles\Box 33\5\ Scan078 | |
| Date | 18th March 1926 | |
| X1807 TRIALS OF SPEED INDICATOR TESTER. & Date. | Approx. time period. | Time under 10 mins. for 3000 counter revs. (secs). | % Fast. | Frequency. --- | --- | --- | --- | --- 25.2.26. | 10.45 to 10.55 | -1.6 | -.27 | 49.9 25.2.26. | 12.22 to 12.32 | -.8 | -.13 | 49.9 " | 1.35 to 1.45 | +4.5 | +.75 | 50.4 " | 1.52 to 1.62 | +3.4 | +.57 | 50.3 " | 2.27 to 2.37 | + 4.0 | +.66 | 50.3 " | 2.55 to 3.5 | + 1.8 | +.30 | 50.15 " | 3.23 to 3.33 | + 3.2 | +.53 | 50.3 " | 3.37 to 3.47 | + 4.0 | +.66 | 50.3 " | 3.48 to 3.58 | + 3.6 | +.60 | 50.3 " | 4.15 to 4.25 | + 2.7 | +.45 | 50.2 5.3.26. | 9.47 to 9.57 | +.60 | +.10 | 50.0 5.3.26. | 10.5 to 10.15 | + 3.2 | +.53 | 50.3 " | 10.17 to 10.27 | + 2.5 | +.42 | 50.2 " | 10.42 to 10.52 | + 3.7 | +.62 | 50.3 " | 11.15 to 11.25 | + 2.8 | +.47 | 50.2 " | 11.41 to 11.51 | + 2.1 | +.35 | 50.2 " | 12.25 to 12.35 | + .5 | +.083 | 50.0 " | 1.3 to 1.13 | + 1.6 | +.27 | 50.1 " | 1.25 to 1.35 | + 2.3 | +.38 | 50.2 " | 2.15 to 2.25 | Correct | Correct | 50.0 18.3.26. | ||