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).
Page 2 of a letter discussing fan performance charts, comparing a standard fan to one with adjustable blades.
| Identifier | ExFiles\Box 119\3\ scan0187 | |
| Date | 25th November 1931 guessed | |
| 2 The chart showing a normal fan clearly shows that performance above and below a certain number of revs. The strongly rising performance curve explains the overloading of fan-belt. The air volume drop is due to churning evident at high revs. The second chart gives details of performance of a fan on our principle, with adjustable blades. It goes without saying that any data furnished us regarding your fans will treated in strictest confidence and we assume that will accord us the same courtesy regarding our own. With compliments, Yours faithfully, [Signature] S Dow. Encl.2 Charts. [Watermark: ABERMILL BOND MADE IN GT BRITAIN] | ||