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).
The bump test of an EAC.11 chassis, detailing its specifications and a summary of failures observed during the first 90 hours.
| Identifier | ExFiles\Box 119\2\ scan0226 | |
| Date | 12th December 1924 guessed | |
| BUMP TEST OF EAC.11. CHASSIS. SPECIFICATION OF CHASSIS. FRAME. EAC.11. Short wheelbase. Fitted with additional cross member at front of chassis. Fitted with top half of crankcase weighted with 800 lbs. Rear of frame fitted with a ballast box weighing approx. 1000 lbs. FRONT AXLE. EAC.11. Radius rods attached to bottom of axle, and anchored to a pillar attached to frame, so that they assume a position almost parallel to rear half of springs. FRONT SPRINGS. 45" symmetrical type. Shackled at front - anchored at rear. RADIATOR. EAC.11. Fitted with integral vertical shutters. Filled with water. STEERING GEAR. EAC.11. Straight side steering tube. CONDITIONS OF TEST. Bumping front axle. Drum = 105 r.p.m. Tyres = 65 lbs.sq.in. Cams = 2" lift, spaced at 180° (one cam per wheel). SUMMARY OF IMPORTANT FAILURES(excluding Road Springs) DURING FIRST 90 HOURS OF TEST. Running time hrs.mins. | Piece No. | Position on chassis. | DESCRIPTION. -------------------|-----------|----------------------|---------------------------------------------------------------------------------- 21 53 | G.2903 | Off | Diagonal stay of sphere anchorage broken at front end. 44 38 | G.2903 | Near | Diagonal stay of sphere anchorage broken at front end. 65 15 | F.2888 | Off | Flange of 4th. cross member (from front of chassis) cracked. 65 16 | F.2725 | Near | Flange of 3rd. cross member (from front of chassis) cracked. 73 55 | F.71432 | Near | Frame side member fractured immediately in front of base of front cross member. 73 55 | F.71431 | Off | Frame side member slightly cracked at base of front cross member. 73 55 | F.2888 | Near | Flange of 4th. cross member (from front of chassis) cracked. 73 55 | F.1328 | Near | Bracket of 5th. cross member (from front of chassis) cracked. 73 55 | F.1328 | Off | Bracket of 5th. cross member (from front of chassis) cracked. contd :- | ||