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).
Bump test results for four special type Firth leaf springs.
| Identifier | ExFiles\Box 119\2\ scan0223 | |
| Date | 26th November 1924 | |
| BUMP TEST. RE. 40/50 FRONT SPRINGS. TEST OF FOUR SPECIAL TYPE FIRTH SPRINGS (F11980/1[?]) 1100 & 1150LBS. CONDITIONS: 2" CAMS SET AT 180°. DRUMS MAKE 105 R.P.M. TYRES AT 65 LBS/SQ" LOAD ON FRONT OF CHASSIS = 1000LBS. | SPRING DETAILS. | FRACTURE | POSITION OF LEAF | POSITION OF FRACTURE FROM CENTRE BOLT | APPROXIMATE RUNNING TIME | THICKNESS OF LEAF | BRINELL AT FRACTURE | |---|---|---|---|---|---|---| | Nº 019. NEAR SIDE 1100LBS. FLEXION: COMPRESSION = 2.0"; REBOUND = 2.5" | A | BOTTOM. | 2" TO REAR. | 22-44 | .182" | 363 | | | B | NEXT TO BOTTOM. | 3.5" TO REAR. | 27-44 | .205" | 388 | | | C | BOTTOM. | 1.5" TO FRONT. | 30-54 | .182" | 363 | | | D | 2ND (FROM TOP) | 4.25" TO REAR | 30-54 | .245" | 375 | | | E | 3RD (FROM TOP) | 2" TO REAR | 30-54 | .247" | 388 | | | F | TOP. | 5.25" TO REAR. | 30-54 | .290" | 363 | |---|---|---|---|---|---|---| | Nº 020. OFF SIDE 1150LBS. FLEXION: COMPRESSION = 1.9"; REBOUND = 2.5" | G | TOP | 2" TO REAR | 45-42 | .281" | 352 | | | H | 5TH (FROM TOP) | 1" TO REAR | 45-42 | .237" | 341 | | | J | BOTTOM | 1.5" TO REAR | 45-42 | .208" | 363 | |---|---|---|---|---|---|---| | Nº 022. NEAR SIDE 1100 LBS. FLEXION: COMPRESSION = 1.6"; REBOUND = 2.4" | K | 4TH (FROM TOP) | 7" TO REAR | 36-0 | .232" | 388 | | | L | 5TH (FROM TOP) | 7.5" TO FRONT | 42-30 | .240" | 388 | |---|---|---|---|---|---|---| | Nº 023. OFF SIDE 1150LBS. FLEXION: COMPRESSION = 1.5"; REBOUND = 2.5" | M | TOP. | 2" TO REAR | 32-57 | .282" | 363 | | | N | BOTTOM. | 1.25" TO REAR | 32-57 | .210" | 352 | | ||