Review of remote indicating systems for aircraft instruments

Abstract

As aircraft have increased in size it has become necessary to use remote indicating systems to transmit many readings to the pilot's or/and flight engineer's instrument panels. Such systems will be essential for future large civil and transport aircraft, and a number already exist operating on different principles and power supplies. Many operate from a low voltage d.c. electric supply, but it seems certain that a higher voltage a.c. supply will be used in the type of aircraft under consideration. A review was therefore required of all known and possible remote indicating systems, whether operated by a.c., d.c., or by any other source of power, in order to indicate how activities could be directed into the most promising channels, and to see if an ideal system for all remote indications is possible or known. Information about remote indicating systems already in use in aircraft has been collected from systems still being developed, from applications in other fields of engineering, and from published information concerning devices which might be applied to the problem of remote indication. Some original contributions are also included. The main conclusion arising from the review is that it is considered that electrically operated systems are more promising than anv of the other systems, and that, apart from coping with the transmission of unrestricted rotation, much can be done in devising an ideal system for dealing with all other remote indications.