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).
Note detailing the specifications for a standard and an experimental spring for a 20HP spring drive.
| Identifier | ExFiles\Box 79\3\ scan0159 | |
| Date | 18th December 1923 | |
| Hs.{Lord Ernest Hives - Chair} re 20HP Spring drive The spring we have tried temporarily in place of standard, are standard springs E52491 drawn out .05" i.e. Std. spring .75" free - 6 1/2 coils - 15G wire - 14 3/8 lbs at .625" Exp. " .80" " - 6 1/2 " - 15G " - 20 lbs at .625" EP{G. Eric Platford - Chief Quality Engineer}/mm | ||