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).
The specifications for a proposed harmonic damper, including its polar moment of inertia and natural frequency.
| Identifier | ExFiles\Box 181\M9\ img004 | |
| Date | 21th August 1931 | |
| ORIGINAL To E.{Mr Elliott - Chief Engineer} From Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls} Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls}1/MJ.21.8.31. r634. Herewith sketch of proposed harmonic damper. The polar moment of inertia is 13.8 lbs. in.2 or about one tenth of the effective interia of the crankshaft assembly. This was the greatest we could have without breaking the driving members. The strength of the springs is 7380 lbs/ft./rad. to give a natural frequency of the damper of 250 per sec. i.e. three impulses per revolution at 5000 R.P.M. as then theoretically the crankshaft undergoes no oscillation when disturbed by an oscillation of its natural frequency and has a maximum of movement when the disturbing frequency is about 20% above and below the critical frequency. Attached Hs.{Lord Ernest Hives - Chair}433. Hs{Lord Ernest Hives - Chair}/H.Grylls. | ||