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).
Test results for 20 HP engine foot rubbers, showing load versus deflection.
| Identifier | ExFiles\Box 104\1\ scan0077 | |
| Date | 18th February 1930 guessed | |
| 20 HP. ENGINE FOOT RUBBERS. F.80057 SUPPLIED BY DUNLOP'S (12 OFF: NO1 TESTED). DRILLED .515 DIA. TO MAKE F.57075. DISTANCE PIECE 1.000" LONG: TESTED IN CUPS F.57078. LOAD | DEFLECTION. LB. | INS. ----------- ZERO | - 50 | .012 100 | .025 150 | .035 200 | .045 250 | .056 300 | .065 350 | .075 400 | .084 450 | .090 | ||