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).
Weakness in the Phantom semi-expanding carburetter and the specifications for a spring to fix it.
| Identifier | ExFiles\Box 19\1\ Scan234 | |
| Date | 17th October 1932 | |
| X7120. X7080 E.{Mr Elliott - Chief Engineer} from Hs{Lord Ernest Hives - Chair}/GWH.{George W. Hancock - Head Chateauroux} c. to By.{R.W. Bailey - Chief Engineer} Hs{Lord Ernest Hives - Chair}/GWH.{George W. Hancock - Head Chateauroux}10/KT.17.10.32. Re. PHANTOM SEMI-EXPANDING CARBURETTER. We have had during our tests with the semi-expanding carburetter a weakness in the metering when accelerating. It chiefly occurs when the engine is hot and whilst driving in traffic. It is not possible to go out and show this feature definitely, as it comes unawares. We have been able to overcome this failure by fitting a light spring under the air valve. The spring is attached to the air valve and is adapted to steady the lift for the initial movement only - i.e., up to speeds of approx. 20 m.p.h. It does not in any way interfere with the general working of the carburetter or consumption. We do not propose to standardise the fitting of this spring, but to hold it in readiness for future use, if and when any customer comes up against the same trouble. It is quite possible that production carburetters will be free from this feature. The spring fitted is as follows - Material, bronze. Diameter .750" Free length 1.400" Compressed to .650" with air piston at rest. The rating is as follows - Compressed to 1.00" 7.250 ozs. " " .900" 9.750 ozs. " " .800" 12.250 ozs. " " .700" 15.000 ozs. " " .650" 16.250 ozs. " " .600" 17.750 ozs. Diameter of wire .044" approx 18.5 gauge. Hs{Lord Ernest Hives - Chair}/GWH.{George W. Hancock - Head Chateauroux} | ||