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).
Specification sheet detailing spring loads and calculations for the New Phantom and 20 HP models.
| Identifier | ExFiles\Box 71\2\ scan0121 | |
| Date | 23th 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). 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. 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 REQD. 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. 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. NEW PHANTOMCodename for PHANTOM I TABLE DATA: SPRINGS FRONT (NEAR | OFF), REAR (NEAR | OFF) Row 1: 1060 | 1060 | 940 | 940 Row 2: 230 | 230 | | Row 3: | | 305 | 305 Total: 830 | 830 | 635 | 635 Row 4: 16 | 16 | 33 | 33 Row 5: 50 | 50 | 25 | 25 Row 6: 50 | | 100 | Total: 896 | 946 | 693 | 793 Row 7: Wx30/200 | Wx30/200 | Wx30/200 | Wx30/200 Row 8: TOTAL -50 | TOTAL -50 | TOTAL | TOTAL Row 9: | | x 1.5 | x 1.5 Row 10: | | -100 | -100 Row 11: RATING INCREASED 12 1/2% | RATING INCREASED 12 1/2% | | 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. 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. ALLOWANCES ALLOWANCE FOR FRONT BRAKES BEING FITTED TO THE 20 H.P. 25% STIFFER 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. 20 H.P. TABLE DATA: SPRINGS FRONT (N.S. | O.S.), REAR (N.S. | O.S.) Row 1: 500 | 500 | 375 | 375 Row 2: | | 35 | 35 Row 3: 10 | 10 | 15 | 15 Total: 510 | 510 | 425 | 425 Row 4: .125W | .125W | .375W | .375W Row 5: .125(77N) | .125(77N) | .375(77N) | .375(77N) Row 6: | | P/4 | P/4 Row 7: 50 | 50 | | Total: TOTAL | TOTAL | TOTAL | TOTAL Row 8: 25% STIFFER | 25% STIFFER | | STAMPED TEXT: ROLLS-ROYCE LIMITED PRINT ROOM 23 JAN. 1926 DERBY. | ||