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).
Comparison table of calculated stiffness, inertia, and critical speed for various engine components.
| Identifier | ExFiles\Box 85\5\ scan0013 | |
| Date | 22th June 1932 guessed | |
| Top Header Row: PEREGRINE | BENSPORT. | ALFA ROMEO. Second Header Row / Details: L.100043 | Lac.3097 | 2.5 journal 1.75 min. | 2.375 journal 2.0 min Row 'Calculated stiffness': 34500 | 43000 | 48000 | 52000 | 62000 Row 'Inertia': 1 unit | 1.05 | 1.05 | 1.15 Row 'Critical speed': 5400 | 5900 | 5200 with damper fitted, we consider the safe limit for this shaft is 5600 | 7300 | ||