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).
Design and analysis of a modified throttle control spring for a 20 HP engine, including diagrams and performance graphs.
| Identifier | ExFiles\Box 66a\3\ scan0063 | |
| Date | 20th April 1925 | |
| PARTICULARS OF 20 HP SPRING 16 FULL WORKING COILS 4 TAPER COILS AT EACH END 18 SWG. (.048 DIA) FREE LENGTH = 1.550 LOAD WITH SPRING EXTENDED TO 3.125 TO BE 9 1/4 LBS. INITIAL LOAD WITH SPRING EXTENDED TO 2.250 TO BE 4. LBS. W x R1 = 9.25 X .201 = 1.86. STRESS = (40000 x 1.86) / 1.38 = 54,000 LBS/SQ IN (MAX) W x R1 = 4 X .201 = .804. STRESS = (40000 x .804) / 1.38 = 23,000 LBS/SQ IN (MIN) SPRING RATE = 5.7 LBS PER IN. INITIAL TORQUE = 3.4 IN. LBS FINAL TORQUE = 3.45 IN. LBS 20 HP THROTTLE CONTROL Top Graph: - Title: THROTTLE SPINDLE TORQUE & ROLLER TORQUE - Y-Axis Left: TORQUE IN. LBS. INS. - Y-Axis Right: TORQUE IN. LBS. INS. (ROLLER) - X-Axis: THROTTLE MOVEMENT IN DEGREES. Bottom Graph: - Title: DIAGRAM OF SPRING LOADING &c - Labels: THROTTLE VALVE FULL OPEN, THROTTLE VALVE CLOSED - Y-Axis Left: LOAD IN LBS. - Y-Axis Right: STRESS IN LBS. PER SQ. IN. - X-Axis: DEFLECTION IN INCHES PARTICULARS OF SPRING 30 FULL WORKING COILS AND 4 TAPER COILS AT EACH END. 17. SWG. (.056 DIA) FREE LENGTH 2.528 LOAD WITH SPRING EXTENDED TO 4.925 TO BE 12 LBS. INITIAL LOAD WITH SPRING EXTENDED TO 3.900 TO BE 6.9 LBS. W x R1 = 12 x .222 = 2.664. STRESS = (40000 x 2.664) / 1.38 = 77,000 LBS/SQ IN (MAX) W x R1 = 6.9 x .222 = 1.53. STRESS = (40000 x 1.53) / 1.38 = 44,300 LBS/SQ IN (MIN) SPRING RATE = 5. LBS PER IN. Annotations: - 2.250 - .700 INITIAL SET - .850 - .375 - 12 SWG (.104) - THROTTLE CLOSED - 78° - SCALE 1/1 - LINK .900 Crs - Stamp: ALTERED FROM, 20 APR 1925, DERBY. SCALE 2/1 AND 1/1. MODIFIED THROTTLE CONTROL SPRING SCHEME 630 | ||