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).
Table showing examples of calculated critical speeds for various engines.
| Identifier | ExFiles\Box 6\1\ 01-page138 | |
| Date | 29th January 1926 | |
| TITLE: EXAMPLES OF CALCULATED CRITICAL SPEEDS REFERENCE/DATE: Jan. 29/AA{D. Abbot-Anderson}/26 OTHER REFERENCE: MISC 4 | ENGINE. | ASSETT STIFFNESS WESTS No | I OF FLYWHEEL | I OF R.END 6xN^2 | I OF SPRINGS @ CRANK HUB 6xN^2 | [Col 6] | Σe (Σ OF EQUIV I @ CRANK HUB) | Σf (I OF FLYWHEEL) | CALC. FREQ. | CALC. PERIOD RPM | OBSERVED PERIOD RPM | % | |----------------------------------------------------|---------------------------|---------------|------------------|--------------------------------|---------|-----------------------------|--------------------|-------------|------------------|---------------------|----------| | I-G-I | 14,750 | .01403 | .00528 | .00539 | - | .008161 | .4871 | 215 | 4310 | 3850 | ?% | | STD. 20 H.P. | 16,350 | .01623 | .02779 | .0247/10 | .00584 | .01854 | - | 164.5 | 3296 | 3300 | 0 | | 20 H.P. WITH BATT. FOR C.H.S. LOCKED SOLID TO NOSE | - | - | - | .02212 | - | .03190 | - | 116.5 | 2330 | 2450 | 5% LOW | | STD PHANTOM. | 45,000 | .06738 | .01023 | .01616 | .01237 | .05089 | 1.584 | 152.8 | 3056 | 3250 | 6% LOW | | LORRAINE-DIETRICH | 29,800 | .04322 | .01058 | .00587 | .00144 | .02131 | .3767 | 188.2 | 3764 | 3750~ | 0 | | STATZ - 8. LANCAIA FROM CALC. FIGURES | 56,400 | .03864 (CALC) | .00176 (CALC) | .01088 | - | .02417 | - | 237.1 | 3670 | 3800 | 6% LOW | | ||