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).
Technical memo comparing rear springing and load calculations for the EAC. 7 and Phantom models.
| Identifier | WestWitteringFiles\Q\July1927-September1927\ Scan091 | |
| Date | 3rd September 1927 | |
| HS.{Lord Ernest Hives - Chair}) FROM DA.{Bernard Day - Chassis Design} ORIGINAL DA{Bernard Day - Chassis Design}1/M3.9.27. EAC.7. REAR SPRINGING. X7410 (struck through) Y8410 With reference to the question, raised by HS.{Lord Ernest Hives - Chair} while here, of the apparently heavy rear springs needed on EAC. 7. compared with an equivalent Phantom, it is pointed out that what may be called the "nominal" load of the springs has not the same meaning in the two cases. On the Phantom the nominal load is that after a deflection of 3", but on the actual car the springs are deflected through 4 1/8" under "full load". On EAC. 7 the nominal load is that after a deflection of 8.25", that is, the equivalent of the full load in the Phantom. If there were a car of each type precisely similar as to full rear load, and a 2200 lb. spring were found satisfactory on the Phantom, it is evident that an 1100 lb. EAC. 7. spring would be too light for that car. The spring required would be 2200 X 8.25 / 6 X 2 = 1510 lbs. On EAC. 7. as made however, there has been a redistribution of weight as regards front and back, so that in spite of the 1400 lbs. springs now fitted, it is possible the car is lightly sprung compared with an equivalent Phantom. DA.{Bernard Day - Chassis Design} | ||