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).
Comparative suspension tests for 40/50 HP models, comparing semi-elliptic and cantilever springs.
| Identifier | ExFiles\Box 16\7\ Scan023 | |
| Date | 11th November 1927 | |
| To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} c. to BJ. WoR.{Arthur Wormald - General Works Manager} c. to E.{Mr Elliott - Chief Engineer} DA.{Bernard Day - Chassis Design} c. to SY. OY. x7410 Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}1/LG2.11.27. +8440 EAC.7. & 40/50 HP. SUSPENSION TESTS. We have been carrying out careful comparative tests of semi elliptic and cantilever sprung 40/50 cars. A peculiarity of the semi-elliptic sprung cars is that for equal buffer clearance they require more damping to give equal stability and freedom from roll at high speeds. This is noticeable even on the 20 HP. (10-G-111) the car which is at present at WW., having over 60 lbs. load in both directions on the rear hydraulics, though the body has a low c. of g.{Mr Griffiths - Chief Accountant / Mr Gnapp} and it is a small car. Therefore we find that, having damped EAC.7. to permit of high app speed touring with comfort to the rear passengers, the riding at 20/30 m.p.h. is not so good as that of 8-EX a standard Phantom. We are more than ever convinced that good riding is largely a matter of weight distribution as we have never attained the riding quality of the 20 HP. car on a semi elliptic Phantom. Again one of the most difficult cars to spring is a shortish open touring car such as 12-EX. This type of car always has a most objectionable tendency to pitch which is very difficult to eliminate. A touring body with a large overhang on a short chassis however produces the reverse effect, 10-EX riding well over a large range of spring ratings. contd :- | ||