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).
Summarizing tests on an aluminium hot spot's efficiency compared to cast iron.
| Identifier | WestWitteringFiles\K\November1923\ Scan58 | |
| Date | 16th November 1923 | |
| R.R. 493A (40 H) (EL 42 12-7-23). J.H., D.{John DeLooze - Company Secretary} EXPERIMENTAL REPORT. Expl. No. REF: Hs{Lord Ernest Hives - Chair}/ACL1/1.C161123 under the same conditions gave only .2 pts/hr. By increasing the heat supply to the aluminium no precipitation took place - under the same conditions the cast iron would give an average of .8 pts/hr. SUMMARY OF TESTS :- The aluminium hot spot proved to be the most efficient of the different types tested, both as regards to evaporation of fuel and the rapidity with which it heated up on starting the engine from cold. In starting from cold, owing to the rich mixture necessary - especially if the starting carburetter is kept in use for long - wet fuel drains into the boiler and a certain amount of the heat supplied to the hot-spot is taken in evap- orating this fuel in the boiler and reducing the amount available for supplying the latent heat of the petrol spray leaving the carburetter. Hence a long period is necessary for the hot-spot to heat up before the engine can be 'opened up' without 'missing'. It would probably be an advantage not to incorporate the 'boiler' with the hot-spot but to use a separate heat supply for this purpose. Increase of heat to the hot-spot is accompanied by a fall in power. Hs{Lord Ernest Hives - Chair}/ACL. | ||