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).
Induction pipe design, carburettor performance, and fuel distribution issues, specifically mentioning the 10-EX and Phantom models.
| Identifier | WestWitteringFiles\R\2December1927-February1928\ Scan101 | |
| Date | 3rd January 1928 guessed | |
| contd :- -3- dimsnsions for the slot and projecting lip in the distributing pipe. From a production point of view the built up pipe is preferable and we think that more consistent results will be obtainable with this type due to the possibility of more accurate internal finishing. We have fitted a weir pipe to 10-EX from which we shall be able to get a better idea of the general distribution, other things being equal, such as power output etc., the criterion is the time which elapses before the driver can turn off the starter carburetter and get normal operation of the engine when starting from cold, also the low speed pulling capabilities of the car. We will report on this in due course. There seems every reason to suppose that the weir type pipe in conjunction with the proposed new design of expanding carburetter should make a good combination as it has always been our experience that a straight through vertical carb. was conducive to good distribution and not so dependent upon induction pipe design. Considering the general question of cold distribution on the Phantom we have found that most of the numerous induction systems with which we have experimented gave trouble chiefly at the siamesed port. Practically never have we been able to obtain the same mixture quality at two cylinders supplied by the common port. As a general rule it seemed that one of the siamesed inlets got a large share of the wet unevaporated fuel at the expense of its neighbour. This could no doubt be caused by the heavy unevaporated fuel tending to flow in more contd :- | ||