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).
Alterations and tests on starting carburetters with fixed maximum restriction.
| Identifier | ExFiles\Box 13\3\ 03-page258 | |
| Date | 21th November 1930 | |
| To R.{Sir Henry Royce} From Hs{Lord Ernest Hives - Chair}/AJL. c. to SE. Wor.{Arthur Wormald - General Works Manager} c. to Da.{Bernard Day - Chassis Design} E.{Mr Elliott - Chief Engineer} c. to BY.{R.W. Bailey - Chief Engineer} STARTING CARBURETTERS WITH FIXED MAXIMUM RESTRICTION. In hs{Lord Ernest Hives - Chair}/AJL.1/MJ.14.5.30. we asked for an alteration in design to the fixed maximum restriction starting carburetter so that, whilst retaining the fixed maximum restriction, the needle adjustment would be more practical and useful job. In its original state it was not possible to regulate the petrol flow due to the poor seating obtained by the needle valve in the very small hole necessary for the fixed maximum restriction. We have not so far received any alterations on the lines indicated, but have carried out further tests. It was thought that it might be possible to dispense with the needle valve adjustment altogether, using a fixed jet size for all cars. Tests on numerous cars however have proved that this is not a practical proposition. The size of the jet required varies from car to car, also the jet size which is suitable for summer conditions is not large enough for winter work. We think the inclusion of the filter with its consequent additional complication is unwarranted. If we use the same size needle valve and seating as on the present starting carburetter the annular space between needle and seating will be the same, whilst the area of the maximum restriction jet hole will be slightly larger than this. We have had no experience of the carburetter failing to function due to dirt in the annular space and should not expect the addition of the maximum restriction to make it worse in this respect. We have asked BY.{R.W. Bailey - Chief Engineer} to give us a slight modification to the existing starting carburetter which will give us the fixed maximum restriction effect without the inclusion of a filter. This alteration is so simple and will give the same results that we think it should be tested out thoroughly before going to a completely new design. Hs{Lord Ernest Hives - Chair}/AJL. | ||