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).
Main leaf test data for 20 HP front and rear springs, including camber and load ratings.
| Identifier | WestWitteringFiles\W\May1931-August1931\ Scan007 | |
| Date | 6th May 1931 guessed | |
| FILES. Sent to R.{Sir Henry Royce} and Da.{Bernard Day - Chassis Design} only. F.56511. 20 HP. FRONT SPRING MAIN LEAF TEST. Free Camber of Main Leaf without plates = 3.000" Free Camber of Main Leaf with plates = 2.712" } Set .112 Free Camber of Main Leaf with plates = 2.600" } After Test Free Camber of Main Leaf without plates = 2.875" } Free Camber of Complete Spring = 4.525" With Plates Load lb Camber ins 0 2.712 42 2.0 87 1.0 137 0 190 -1.0 210 -1.375 244 -2.0 Spring Length Flat 38" stress approaching 145,000 lbs/sq.in. F.57192. 20 HP. REAR SPRING MAIN LEAF TEST. Free Camber of Complete Spring = 6.1" Free Camber of Main Leaf = 4.525" } Set .350" Free Camber of Main Leaf after plate test = 4.175" } Main Leaf Rating Without Plates Load lb Camber ins 53 +2.0 83 +1.0 109 0 143 -1.050 173 -2.0 With Plates Load lb Camber ins 87 +1.0 123 0 161 -1.0 205 -2.0 Spring Length Flat 56" Stress approaching 100,000 lbs/sq.in. Plates referred to are spring clip plates. Tested with shackle at correct angle in each case. | ||