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).
Springing specifications and load calculations for the New Phantom and 20 HP models.
| Identifier | ExFiles\Box 67a\1\ scan0069 | |
| Date | 25th January 1926 | |
| NEW PHANTOMCodename for PHANTOM I SPRINGING FIXED LOADS CHASSIS WT 4000 LBS UNSPRUNG WT FRONT. AXLE WHEELS & TOTAL WT. OF THE SPRINGS. TOTAL WT. 460 LBS. REAR. AXLE WHEELS & NONE OF THE WT. OF THE SPRINGS. TOTAL WT. 610 LBS. 100 LBS. SPARES. 1/3 ON FRONT 2/3 ON REAR. 2 SPARE WHEELS. TAKEN AS 75 LBS. EACH. 2/3 ON FRONT 1/3 ON REAR. ALLOWANCE FOR CHAUFFEUR & TORQUE ON O.S. CHASSIS. FRONT SPRINGS 50 LBS. REAR SPRING 100 LBS. (LUGGAGE) SPRINGS TABLE (FIXED LOADS): FRONT REAR NEAR OFF NEAR OFF 1060 1060 940 940 230 230 305 305 Subtotal: 830 830 635 635 16 16 33 33 50 50 25 25 50 100 Total: 896 946 693 793 VARIABLE LOADS. TOTAL FIXED UNSPRUNG WT. ON THE 40/50 ALL VARIABLE LOADS, WHETHER PASS BODY OR LUGGAGE ARE ALLOWED FOR IN FULL. BODY. TOTAL WT. W LBS. 30% ON FRONT 70% ON REAR. TOTAL WT. SPRUNG FOR PASSENGERS. No. OF PASS N. EACH PASS IS CONSIDERED AS WEIGHING 154 LBS. 30% ON FRONT. 70% ON REAR. LUGGAGE. TOTAL WT. P LBS. 30% ON FRONT 70% ON REAR. (Table shows Wx30 / 200 for all four spring positions). ALLOWANCES. TO TOTALS. 50 LBS. TAKEN OFF EACH FRONT SPRING. RS{Sir Henry Royce's Secretary} INSTRUCTIONS. REAR SPRING LOAD MULTIPLIED BY 1.5 BEING CANTILEVER. THE REAR SPRING LOAD SHOULD BE DOUBLED TO GIVE CORRECT SPRING LOADING REQ'S. ACTUALLY THE CAR IS SPRUNG FOR 75% OF LOAD ONLY (RS{Sir Henry Royce's Secretary} INSTRUCTIONS). 100 LBS. SUBTRACTED FROM EACH REAR SPRING. FURTHER SUGGESTION TO IMPROVE SPRINGING ON TOP OF BOW PROPOSED BY 'R'. THE RATING OF THE FRONT SPRINGS FOR ANY LOAD IS INCREASED 12 1/2 %. COMPARED WITH CHASSIS PRIOR TO F.W.B. TYPE. (Table shows: TOTAL -50 for front springs, x 1.5 for rear springs, -100 for rear springs, RATING INCREASED 12 1/2% for front springs). SPECIAL BODIES COUPÉS & 2 SEATERS DISTRIBUTION OF BODY WT. 40% FRONT 60% REAR. ALTERATIONS FOR ABROAD. AMERICA. AS ABOVE. FRANCE. ADD 100 LBS. TO EACH REAR SPRING. AUSTRALIA. ADD 20% TO REAR. SPAIN. MAKE FRONT SPRINGS 3 1/2 % STRONGER. -------------------------------------------------------------------------------- 20 H.P. SPRINGING FIXED CHASSIS WTS. LESS UNSPRUNG WT. FRONT 305 LBS. REAR 485 LBS. INCLUDE TYRES, PETROL, OIL BTY & FILLED WITH WATER. 1 SPARE WHEEL ON REAR. SPARES, TOOLS, ETC. SPRINGS TABLE (FIXED LOADS): FRONT REAR N.S. O.S. N.S. O.S. 500 500 375 375 35 35 10 10 15 15 Total: 510 510 425 425 VARIABLES BODY WT. W. 75% ON REAR 25% ON FRONT. HALF OF PASS WT ONLY SPRUNG FOR. No. OF PASS N. WT. OF PASS. PER PASS 154 LBS. 75% ON REAR. 25% FRONT. LUGGAGE IS ALWAYS ALLOWED FOR AS BEING ALL ON THE REAR AXLE & BEING A VARIABLE LOAD. 50% IS TAKEN. WT. OF LUGGAGE P LBS. SPARE WHEEL ON SIDE. 50 LBS. ALLOWED ON SPRINGS. THIS IS TO KEEP FRONT SPRINGS UP A BIT. (Table shows calculations: .125W, .125(77N), 50 for front; .375W, .375(77N), P/4 for rear). ALLOWANCES. ALLOWANCE FOR FRONT BRAKES BEING FITTED TO THE 20 H.P. 25% STIFFER FRONT SPRINGS. (Table shows: 25% STIFFER for front springs). ALTERATIONS FOR ABROAD CONTINENT. ADD 10% TO REAR SPRINGS. AUSTRALIA & SPAIN. 20% STIFFER REAR SPRINGS. EXCEPTIONAL BODIES. THE WT. OF COUPÉS & 2 SEATERS IS TAKEN AS BEING 40% ON FRONT 60% ON REAR. STAMP: ROLLS-ROYCE LIMITED, PRINT ROOM, 25 JAN 1926, DERBY. | ||