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).
With a sketch detailing the specifications for a heating tube, including dimensions and material requirements.
| Identifier | ExFiles\Box 36\3\ scan 111 | |
| Date | 18th July 1917 | |
| R.R. 238 A (770 H) (S.D. 444 9-5-17) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 1966. X.3039 COPY Laboratory. 18th July 1917. Mr: Clark. On looking down the tube it should appear 900°C on inside surface and give that pyrometic reading. Perhaps they do not wish to supply wire - if so would they make us one as per sketch (variations of 1/8" on dimensions are not important), and also another 12" long with 1 1/2" hole instead of 1 1/4". (We prefer the resistance wire close to the interior hole.) The same amount of wire and thickness of wall could be employed in each case. Above is about dimension of our heating coils the wire is shown in two layers & this however, is not important, 3 or 4 could, I think, be used without trouble so long as there is no possibility of short circuit. We have had made the coils with nickel or other wire in the past, we want Nichrome to increase lasting. (Sgd) HCH. Text on sketch: about 3" 1 1/4" 8" Resis. wire | ||