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).
Tests to investigate persistent steering jiggling on Phantom II cars.
| Identifier | ExFiles\Box 28\5\ Scan063 | |
| Date | 1st August 1931 | |
| To R.{Sir Henry Royce} From Hs{Lord Ernest Hives - Chair}/Lid.{A. J. Lidsey} c. Sg.{Arthur F. Sidgreaves - MD} Wor.{Arthur Wormald - General Works Manager} C. E.{Mr Elliott - Chief Engineer} Da.{Bernard Day - Chassis Design} Ey. 8457 Hs{Lord Ernest Hives - Chair}/Lid{A. J. Lidsey}3/ADL1.8.31. x457. x7430. P.II. STEERING. We have lately carried out a number of tests to find out more about the conditions which are necessary to cause the persistent jiggling which is prevalent in some degree on the majority of P.II. cars. The car used for the tests was 20-EX which is fitted with low rating springs front and rear and has damper loads to suit viz. Front 110/110 lbs. (.055" and .032" dia. leaks in H.P. valve) Rear 115/90 lbs. (one .055" dia. leak in H.P. valve). The engine mounting is the sandwich feet type; we would have preferred diamond mounting but there was no car available with this latest modification. 20-EX was really chosen because the steering was a very good example of bad jiggling. Actually, the P.II steering is really very good for road shocks usually associated with running over very badly potholed roads; steering wheel movement from this cause is almost negligible. The objectionable feature is jiggling which takes place on roads which can be described as normal main roads at speeds above 40 M.P.H. The jiggling appears in some way associated with front end jellying - the same type of road produces it at the same speeds. Jiggling, which in a new car is generally very slight, becomes worse as the car becomes older and more used, evidently due to wear in the various steering connections reducing the damping friction. In order to reduce the personal element from the comparative tests to be carried out, a device was made to measure the integrated steering wheel movement due to jiggling and steering whilst the car was driven over the chosen test road. The device worked quite well and the results obtained from it agreed very well with personal opinions of comparative tests. | ||