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).
Spring and damper modifications and subsequent road tests on a car.
| Identifier | ExFiles\Box 101\2\ scan0171 | |
| Date | 14th November 1936 | |
| 500ad HOTEL DE FRANCE, CHATEAUROUX. Indre. France GWH{George W. Hancock - Head Chateauroux}/HFH{Hoppy F. Hamilton}/3/JAB. 14th November 1936 [Handwritten] Les - Please carry out these modifications on G.A.E. 20 and let me try the car. Rm{William Robotham - Chief Engineer} To. Rm.{William Robotham - Chief Engineer} c. GWH{George W. Hancock - Head Chateauroux} [crossed out] SPRINGING TESTS. 22. G.{Mr Griffiths - Chief Accountant / Mr Gnapp} V.{VIENNA} Tests on the above car were started after a new set of soft springs and a front roll-bar had been fitted in Paris. The chassis at the time was not fitted with frame tie-bars, and owing to the excessive amount of distortion taking place which made comparative tests difficult, a set of bars were forwarded to us and duly fitted. We checked over the tests which had been started before we took over. This constituted the removal of the .015" valve spring packing washers alternatively front and rear, but we were unable to detect any appreciable differences in the ride over 10-12 MPH. the hand control in maximum position, and only a very slight difference could be detected below this speed. We accordingly arrived at our ultimate damper settings in the following way:- Dampers were removed front and rear. All .015" washers were removed from behind the springs. The control system was disconnected. The aluminum washer behind the bellows guide cap was removed, allowing the cap to be screwed right up if required. By screwing up the cap, it was found possible to instantly adjust the initial load ranging from 40 lbs up to 100 lbs, when the dampers were in position. Each cap was calibrated so that by screwing up one flat or two flats a pre-determined setting could be obtained. To obtain a consistent set of readings with high damper loads, all readings were taken over a 14 second oscillation. One flat made approximately 10 lbs difference. By this method, the damping could be set hard or soft, the front being independent of the rear, at the same time knowing exactly what loads we were getting. Tests were run over the same road including two bad hump backs. Special note was taken as to braking, steering, back seat ride, and controlability on corners. Test 1) End caps were screwed hard up giving hard damping all round. The car gave a very similar ride to a Sport's car. | ||