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).
Performance graph showing the compression versus load for a Woodhead Special Spring D.
| Identifier | ExFiles\Box 42\3\ Scan208 | |
| Date | 10th August 1926 guessed | |
| WOODHEAD SPECIAL SPRING D.{John DeLooze - Company Secretary} 4 REBOUND LEAVES & CLIPS COMPRESSION - INCHES TOTAL SPRING LOAD LBS. REBOUND LEAVES GRADUAL LOADING " UNLOADING INTERNAL FRICTION APPROX = 25 LBS. | ||