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).
Decision to revert to water heating for the throttle on 40/50 and EAC models.
| Identifier | ExFiles\Box 24\5\ Scan042 | |
| Date | 1st May 1925 | |
| 4766 To Hs.{Lord Ernest Hives - Chair} from R.{Sir Henry Royce} SECRET. R2/M.5.25. EAC. AND 40/50. THROTTLE HEATING. X. 8230 X. 3436 X. 766 E.{Mr Elliott - Chief Engineer} and I have come to the conclusion that we should be better off if we revert to water heating of the throttle both on the 40/50 and EAC. Our reason for this is that the success with the exhaust heating is not as great as we should have hoped, principally because of the necessity of using the choke valve in the exhaust pipe. This is proved for many reasons to be an undesirable fitting. Another reason is that after the spell of very bad petrol that was distributed directly after the war, which caused USA. and others to severely censor us, the petrol has so much improved that the requirements of a change in the induction system are much less considering that it cannot be done without some disadvantages. We do not think under normal conditions that there will be any reversion to the poor petrol because nine-tenths of the cars would not be satisfactory if they were supplied with such petrol. Moreover any low grade spirit is a source of trouble whatever method of heating of the induction system is provided because there would still be the problems of starting up when cold, and the necessary care of keeping the temperature very exact. We are therefore sending you the drawings of the modifications necessary to EAC. to test whether we can run equally satisfactorily with a water heated throttle. It will be remembered that this is the same conclusion the aeroplane people have arrived at, inasmuch as they find that the water heating of the throttle is sufficient for ordinary decent fuel, and that it is very desirable that the ingoing gas shall be heated as little as possible both for performance and detonations, and general engine temperature (oil and water). I do not wish to suggest that there is much difference except for the impracticability of the choke valve, but it is in the direction indicated. R.{Sir Henry Royce} | ||