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).
Specifications for an outer spring for a Wraith III with reduced outside diameter as sent in by E.S.C.
| Identifier | ExFiles\Box 9\5\ 05-page228 | |
| Date | 4th November 1938 guessed | |
| Outer Spring for Wraith III as sent in by E.S.C. With reduced outside diameter. -------------------------------------------- Wire diameter. | 0.662" Mean diameter of coils. | 3.893" No. of effective coils. | 5 5/8 Normal load. | 2002 lbs. Normal deflection. | 2.300" Free length. | 8.355" Maximum load. | 2870 lbs. Maximum stress uncorrected. | 98,100 lb/in2 Maximum stress corrected. | 123,000 lbs/in2 Maximum deflection. | 3.295" Rate per inch. | 871 lbs. Outside diameter is 4.555" Room available for packing is approx. 0.400" Inside diameter is 3.231" | ||