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).
Tabular analysis of brake linkage efficiency for direct pedal and servo-assisted systems.
| Identifier | WestWitteringFiles\T\2January1929-June1929\ Scan186 | |
| Date | 19th April 1929 | |
| EFFICIENCY OF BRAKE LINKAGE SS{S. Smith} ① DIRECT PEDAL LINKAGE FROM PEDAL TO REAR BRAKE COUNTERSHAFT LBS/FT TORQUE AT ONE CAMSHAFT FOR PEDAL LOAD P = 1/2 [ (16.65 x 1.375 x 2.00 x 1.875 x 2.85 x 3.750 x 4) / (6.25 x 1.725 x 2.00 x 4.00 x 1.85 x 12) ] = .475 P | PEDAL PUSH P | THEORETICAL TORQUE AT CAMSHAFT .475 P | OBSERVED TORQUE ORIGINAL SHAFT SUPPORT | EFFICIENCY ORIGINAL SHAFT SUPPORT | OBSERVED TORQUE IMPROVED SHAFT SUPPORT | FINAL DIRECT BRAKING EFFICIENCY | |---|---|---|---|---|---| | 100 | 47.5 | 25 | 52.5% | 26 | 55% | | 125 | 59.2 | 31 | 52.5 | 32.4 | 55 | | 150 | 71.2 | 40 | 56.3 | 46 | 64.5 | | 175 | 83.0 | 44.5 | 53.5 | 55 | 66.2 | | 200 | 95.0 | 46.5 | 49.0 | 62 | 65.1 | ② EFFICIENCY OF SERVO BRAKING FROM SWINGING ARM TO THE REAR BRAKE CAMSHAFT. LBS/FT TORQUE AT ONE CAMSHAFT FOR PULL P = 1/2 [ (21 x 2.125 x 2.85 x 3.75 x 4) / (8.5 x 2.00 x 4 x 1.85 x 12) ] = .63 P | EQUIVALENT PEDAL PRESSURE FOR PULL P AT SERVO * | PULL P AT SERVO | THEORETICAL TORQUE AT REAR CAMSHAFT .63 P | OBSERVED TORQUE ORIGINAL SHAFT SUPPORT | EFFICIENCY ORIGINAL SHAFT SUPPORT | OBSERVED TORQUE IMPROVED SHAFT SUPPORT | FINAL IMPROVED BRAKING EFFICIENCY | |---|---|---|---|---|---|---| | 67.3 | 49.3 | 31.0 | 22.5 | 72.5% | 25.0 | 80% | | 84.5 | 61.9 | 39.0 | 26.0 | 66.5 | 31.5 | 80.5% | | 100.0 | 74.0 | 46.6 | 30.5 | 65.0 | 38.0 | 81.5% | | 118.0 | 86.5 | 54.5 | 34.0 | 63.0 | 45.0 | 83.5% | | 150.0 | 100.0 | 63.0 | 38.0 | 60.0 | 53.0 | 84.0% | | 200.0 | 123.0 | 77.5 | 42.5 | 55.0 | 62.0 | 80.0% | ③ EFFICIENCY OF SERVO BRAKING FROM SWINGING ARM TO THE FRONT BRAKE CAM SHAFT. LBS/FT TORQUE AT ONE CAMSHAFT FOR PULL P = 1/2 [ (21 x 1.75 x 3.15 x 4.5) / (8.5 x 1.75 x 3.25 x 12) ] = .65 P | EQUIVALENT PEDAL PRESSURE FOR PULL P AT SERVO * | PULL P AT SERVO | THEORETICAL TORQUE AT FRONT CAMSHAFT .65 P | OBSERVED TORQUE FRONT CAMSHAFT | LINKAGE EFFICIENCY % | |---|---|---|---|---| | 67.0 | 49.3 | 32.0 | 30.0 | 93.5% | | 84.5 | 61.9 | 40.2 | 37.0 | 92.0 | | 100.0 | 74.0 | 48.0 | 43.5 | 90.5 | | 118.0 | 86.5 | 56.2 | 50.5 | 89.5 | | 150.0 | 100.0 | 65.0 | 56.5 | 87.0 | | 200.0 | 123.0 | 80.0 | 68.0 | 85.0 | * THIS PEDAL PRESSURE IS ARRIVED AT BY ALLOWING FOR LINKAGE LOSS BETWEEN THE PEDAL AND THE SERVO AND USING ACTUAL MEASURED SERVO EFFICIENCIES. Stamp: ROLLS-ROYCE LIMITED, PRINT ROOM, 19 APR 1929, DERBY | ||