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).
Comparison and bumper test of American front road springs versus standard springs for the Phantom model.
| Identifier | WestWitteringFiles\Q\2-July1927-September1927\ 107 | |
| Date | 13th September 1927 | |
| To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/AJL. c. to BJ. Wor.{Arthur Wormald - General Works Manager} c. to E.{Mr Elliott - Chief Engineer} DA.{Bernard Day - Chassis Design} c. to CY. BY.{R.W. Bailey - Chief Engineer} ORIGINAL Hs{Lord Ernest Hives - Chair}/AJL1/LG13.9.27. PHANTOM. AMERICAN FRONT ROAD SPRINGS. X.3900 X4429 We have received a pair of American front road springs as fitted to Phantom cars. The springs compare with our standard springs as follows :- (Std.)Firths springs. | American springs. Loading. | 1100 & 1150 lbs. | 1100 & 1150 lbs. No. of leaves. | 11 | 14 Initial camber. | 2.60 | 3.312 Thickness of top leaf. | .285" | .285" Weight of spring. | 38 lbs. | 38 lbs. N.B. Both springs (1100 and 1150 lbs.) have the same number of leaves, thickness of top plate and weight. The American springs have been tested on the bumper test as follows :- 33 X 6.75" tyres at 60 lbs/sq.in. pressure. Hartford shock dampers on front axle set at 20 lbs. Drum r.p.m. 105. Bump cams 1 1/4" high. The N.S. American spring (1100 lbs.) ran for 33 1/4 hrs. under these conditions when the top leaf broke 6" from the rear shackle. The O.S. spring (1150 lbs.) ran for 45 1/4 hrs. when the 2nd. leaf from the top broke between the second clip and the centre bolt and also the 3rd. leaf was found broken between the 1st. and 2nd. spring clips. contd :- | ||