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).
Test report on carburettor float mechanism, seatings, and needles, including buoyancy and flood tests.
| Identifier | ExFiles\Box 93\2\ scan0233 | |
| Date | 4th April 1938 | |
| -2- Rm{William Robotham - Chief Engineer}/GR.{George Ratcliffe}6/JH.4.4.38. Seatings were also tested with good finished needles and proved to be far more satisfactory than the needles. A buoyancy curve of the float mechanism was taken there being no previous record of this having been checked. Tests were also carried out to ascertain the maximum head required to flood with .140 and .180" seatings; the carburettor being mounted normally and with a forward tilt of 3°. Float set at .650 fuel level. SEATING. AREA NORMAL MOUNTING. 3° FORWARD TILT. Weight at needle. Head. Weight at needle. Head Calculated. calculated. .180 .0255sq.in. 80 grs. 21.4 feet 130 grs. 34.8 feet. .140 .0154 sq.in. 80 grs. 35.4 feet. 130 grs. 57.7 feet. Ethyl fuel used throughout tests with S.P.G. .743. The S.U. high pressure pumps give a maximum head of 9 to 10 feet and in their assembled position give 6 to 7 feet at the carburettor. All test results show that a better finish on the needle is necessary as there is ample loading from the float mechanism. This was taken up with the Zenith Carb. Co. 15th July 1937, and the method of obtaining a good finish passed on to them i.e. using a single point "Lidia" tool on a jewellers lathe. The point was again raised with them in conference last Friday. Rm{William Robotham - Chief Engineer}/GR.{George Ratcliffe} | ||