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).
Vehicle specifications and spring failure test results.
| Identifier | ExFiles\Box 119\2\ scan0242 | |
| Date | 23th March 1925 | |
| R.R. 493A (50n) (D.B. 175 25-9-24) J.H.D. EXPERIMENTAL REPORT. Expl. No. REF. Hs{Lord Ernest Hives - Chair}/RB{R. Bowen}/LG23.3.25. SPECIFICATION. Rear springs - standard - 950 lbs. Front Springs - special Firths - 650 lbs. Frame standard. Radiator standard. 'B' type steering column. 'D' type dash brackets. Cross steering tube and fittings standard. Rear axle - standard. Front axle - standard. Weight on front of chassis approx. 500 lbs. Ballast box as for 40/50 bump tests. 2" cams at 180º - Drum revs. 105. ---------- SPRING FAILURES - Firths special 650lbs. F.55336. | Hours run. | Position of Spring. | Fracture. | Thickness. | Brinell. | Ref.No. | |------------|---------------------|-------------------|------------|----------|---------| | 12.28 | N/S | Top 1" to rear | .233 | 363 | S.1. | | 19.12 | O/S | Top 1" to front | .240 | 363 | S.2. | | 14.30 | N/S | Top 1" to rear | .236 | 363 | S.3. | | 10.40 | N/S | Top 1½" to rear | .236 | 363 | S.4. | | 18.28 | O/S | Top 1½" to rear | .236 | 401 | S.5. | AVERAGE LIFE OF SPRING = 14¾ hrs. contd :- | ||