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).
On modifications to boost regulators and the development of automatic altitude mixture control units for aircraft engines.
| Identifier | ExFiles\Box 179\2\ img221 | |
| Date | 26th October 1932 | |
| -2- modification required is positive locking of the aneroid in the unit casing, to avoid any possibility of "fidgeting" and forming the metal dust, due to wear in the threads. While still on the subject of Boost Regulator, we must definitely make some provision, to eliminate any possibility of dust entering the relay piston guide, as we are bound to encounter considerable trouble in this respect, when operating on dusty aerodromes in dry weather, and out East. A scheme embodying a dust shield is appended. The Regulator in question was dismantled and new parts substituted where required no modifications were made on this unit as the R.A.E. were anxious to avoid holding the machine up for flying. The unit was returned to Farnborough and refitted and set. We were unable to make a climb owing to fog, but the machine was flown round at low altitudes, with the regulator working, and appears to function correctly. The R.A.E. at present, are very busy developing a form of automatic altitude mixture control, and are concentrating on the unit they have in hand, for fitting to all types of Kestrel engines. The unit consists of a small relay piston, controlled by an aneroid which is subjected to atmospheric pressure. The relay piston working a lever on a floating fulcrum, and can be so adjusted to give any one characteristic. The method of arranging the unit, is to first obtain the carburetter characteristics, of an engine, for all throttle positions at various altitudes. The resultant curves are then plotted, and the mean curve is taken as the compromise of the particular carburetter, the unit is then adjusted by means of the floating fulcrum, to give the requirements of the curve. In construction, the aneroid piston valve ports are cut in a rotating sleeve, so that the relay piston can be "cut out", to obtain full rich mixture, such as for take off, and in case of failure of the system. No provision is made for obtaining ultra weak mixtures for economy. The R.A.E. are very anxious that we should collaborate with them in conjunction with the development of the unit for Kestrel engines, and will probably forward one of the units to us for that purpose. | ||