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).
Carburettor performance and cold start tests for the SS chassis.
| Identifier | ExFiles\Box 13\3\ 03-page086 | |
| Date | 2nd February 1929 | |
| HS.{Lord Ernest Hives - Chair} E.{Mr Elliott - Chief Engineer} from R.{Sir Henry Royce} c. to Mr. Fuller. OY. c. to SG.{Arthur F. Sidgreaves - MD} BY.{R.W. Bailey - Chief Engineer} DA.{Bernard Day - Chassis Design} C. c. to PN.{Mr Northey} CWB. SS.{S. Smith} CHASSIS. CARBURATION AND STARTING FROM COLD. I am extremely pleased that your tests shew that the above is satisfactory when subjected to severe cold. We had hoped that the induction modification would enable us to avoid the exhaust heating and its disadvantages. It is altogether better also to keep the carb. away from the exhaust system. Although it is not excessively cold here, sometimes just freezing outside garage, and therefore not a good test, we find the car can be started up and driven away at once with good running full throttle from slow engine revs - quite an improvement on present Phantom or 20 HP. We have repeatedly confirmed that the SS.{S. Smith} does not bang in the exhaust, cutout open or closed (throttle closed by governor.) I cannot suggest why except perhaps no petrol in induction pipe and running conditions much better; with throttle completely closing car luffs up well without brakes and saves petrol for when it is wanted. Your tests shew our carburetter (RR. expanding) to be much more economical - for running conditions this may have several bearings on average road conditions : (1) Reliable pulling up at all speeds and throttle openings. (2) Carboning up. (3) Condition of plugs. (4) Cyl. lubrication. We cannot have double carbs. but we can do better than others with one. This is intended for your Solex remarks. I want you to continue testing our single throat expanding carbs. I have several ideas for making this simpler, but want to settle upon the principle. There are no reasons why an expanding carb. should be low in power; quite the opposite because it can be of ample size. I think pumps and squirts are wrong in principle and only very approximately meet the requirements. R.{Sir Henry Royce} | ||