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).
Technical comparison of spring flexibility and specifications for Rolls-Royce, Lanchester, and Delaunay Belleville cars.
| Identifier | ExFiles\Box 80\2\ scan0003 | |
| Date | 8th April 1913 | |
| Contd. -2- AW/EH2/C8.4.13. FLEXIBILITY. To measure the flexibility we have taken records of the lbs increase in load for every 1" of movement of the springs. Springs actually on the cars, average lbs. increase in load for 1" movement. Rolls-Royce Lanchester Delaunay Belleville. Front. Rear. Front rear. Front rear. Rear Cross sprin Off side. 250 148 250 178 310 375 475 Near side. 270 144 255 178 320 360 Further particulars of springs. Front springs. Rolls-Royce. Lanchester. Delaunay Belleville OFF & NEAR. OFF - NEAR OFF - NEAR Length. 4' 2" 42" 39" 39" 40" 40" No. of leaves. 11 11 5 5 8 8 Width of leaves. 2" 2" 1.625" 1.625" 2.125" 2.125" Thickness of leaves. .25" top 2&3 the rest gradually get thinner bottom on .187. | .5 .5 The two bottom leaves taper to .375 where they rear of the axle. | .312 .312 Taper leaves like R.R. shortest leaf is .25 thick. LBS LOAD AT NORMAL CAMBER. 870 lbs. 811 lbs. 780 750 1100 1050 | ||