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).
Letter detailing test requirements and modifications for a car, focusing on a boom at 40 MPH, swan neck vibration, and shock absorbers.
| Identifier | ExFiles\Box 5a\2\ 02-page312 | |
| Date | 27th November 1930 | |
| J5840 G.W.Hancock, Esq., Hotel de France, Chateauroux, Indre, FRANCE. To GWH.{George W. Hancock - Head Chateauroux} From Hs{Lord Ernest Hives - Chair}/RM.{William Robotham - Chief Engineer} Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}, 2/WJ. 27.11.30. 18-G4. The thing that worries us most is the boom on this car at 40 M.P.H. Anything you can tell us about the boom, would be most useful. We should like to know if the new rubber fan belt has any effect on this particular feature. We should also like to know whether the exhaust can have any bearing on it. R.{Sir Henry Royce} suggests that on his car he has found that the swan neck has a period which creates a bad boom which he can partially cure by wiring the two extremities of the bend together. You may possibly be able to find some better compromise of setting between the rear engine feet and torque reaction dampers. We should like you to get the car in the best possible condition before you start the mileage, as it is not a question of doing tests in the minimum of time so much as learning what we can to overcome the troubles which exist on this type of body which we are trying to sell every day. We were not convinced that the rattle which we heard at 40 m.p.h. was the servo gears and should like your confirmation on this point. The half-charge scheme dynamo has been turned down by Sg.{Arthur F. Sidgreaves - MD} on his car and we are going to send you out an alteration which will make the thing work reasonably well at low speeds. We should like you to alter the clearances of the air vent ball valve on your shock absorbers and see whether you do get improved damping. We can, by alteration to the shape of the air vent, restrict the lift of the ball and yet maintain the full efficiency of the shock absorber. Wor.{Arthur Wormald - General Works Manager} is very anxious that you should complete your | ||