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).
Torsional vibration tests performed on the B.80 No.2 engine, comparing different dampers.
| Identifier | ExFiles\Box 124\1\ scan0219 | |
| Date | 24th July 1939 | |
| 10414 1110 To By.{R.W. Bailey - Chief Engineer} from Rm{William Robotham - Chief Engineer}/JRS. c. Da.{Bernard Day - Chassis Design} c. Da{Bernard Day - Chassis Design}/Jnr.{Charles L. Jenner} c. Da{Bernard Day - Chassis Design}/Mes. Rm{William Robotham - Chief Engineer}/JRS.8/MH.{M. Huckerby}24.7.39. TORSIONAL VIBRATION TESTS ON B.80 No.2. These tests were designed to give full data on all dampers applied to the B.80 engine, and cover the Studebaker, Buick, Cadillac and the B.80 dampers. The Buick and B.80 dampers are of the harmonic type with flat springs forming the spring element. The torsional stiffness of these dampers can be varied by means of inter-changing springs of different thickness. In the Studebaker the springing is by means of rubber cone bushes and the flexibility is altered by using different sets of rubbers having different load - deflection characteristics. The inertia member is spring loaded onto a disc of friction material carried on the back plate. The Cadillac damper is of the rubber bonded type in which the whole of the energy dissipated is by hysteresis of the rubber insert. The spring constant of this damper is invariable. The tests were carried out on B.80 No.2 at maximum power conditions throughout, and the range covered was 1000 to 4500 r.p.m. The procedure for all except the Cadillac, is to tune the damper by adjusting the torsional flexibility for any particular moment of inertia. In the case of the Cadillac tuning must be accomplished by arranging the inertia to suit the spring constant of the damper. The results are given on the accompanying curves and their description follows. Fig.1 shows how the amplitude of oscillation varies for damper stiffness each side of the optimum setting for the B.80 damper and confirms previous results for this figure. For Fig.2 three different inertias were used on the B.80 damper, having moments of inertia of .017, .0332 and .0485 slug ft2. | ||