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).
Test report page comparing oscillation and wobble characteristics between an EAC.V11 and a Hispano car.
| Identifier | ExFiles\Box 22\1\ Scan285 | |
| Date | 14th June 1927 guessed | |
| contd :- -3- (A) | (B) Periodic time for oscillation. | Equivalent road speed wobble in step. | Periodic time for oscillation. | Equivalent road speed wobble in step. EAC.V11. | .224 secs. | 26.8 MPH. | .568 secs. | 10.9 MPH. HISPANO. | .244 " | 24.6 " | .506 " | 12 " It is therefore clear that neither the frame periodicity nor the rear springs and frame periodicity is anywhere near the frequency of our high speed wobbles. On the other hand, though the Hispano frame is weaker in torsion than the EAC.7, it is singularly difficult to make this car wobble dangerously with its standard strong front springs and a heavy damper loading. We attribute this fact to the stiff rear springs employed and the high damping loads that can be produced at the rear with the double Hartfords fitted. It will be noted that the Hispano car is stiffer about the rear springs than EAC.7, though this is only deduced from the periodicity; we shall carry out another deflection test with the rear springs unclamped to eliminate the M.I. of the two bodies. Summarising the conclusions we have come to as a result of these tests - we have :- (1) The daoption of the aluminium engine may have a slight tendency to affect the steering adversely at high speeds, but this should not be noticeable as long as we can obtain satisfactory results with the present front shock damper settings. contd:- | ||