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 cars, focusing on the differences between semi-elliptic and cantilever sprung systems.
| Identifier | WestWitteringFiles\R\2October1927-November-1927\ 71 | |
| Date | 2nd 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 RE. E.{Mr Elliott - Chief Engineer} c. to DA.{Bernard Day - Chassis Design} BY.{R.W. Bailey - Chief Engineer}✓ c. to OY. Hs{Lord Ernest Hives - Chair}/Rml/LG2.11.27. ORIGINAL X8440 X7416 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 W.W., 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 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 std. 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 [strikethrough] well over a large range ofspring ratings. contd :- | ||