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Aviation History
1960
1960 - 1980.PDF
Newmark Mk J9 ASW he/icopter autopilot with, I to r, attitude indicator, vertical gyro, prfof's controller, caMes, unit, compass controller and unit and main computers Round the Stands . . . using instiuments to direct him on one axis and the direct visual contactfor other axes. Perhaps the major factor which Smiths have proved is that the triplex system is a successful way of producing an autopilotwhich has greater control authority than it could safely misuse. Sperry are associated with Smiths in the development of certain por-tions of the Trident flight control system, and particularly provide three VGL.2 vertical gyros and two C.ll Rotorace compasses. The VGL.2is a gyro of nonnal perfonnance but 31b lighter than the previous Sperry unit or others of its kind. A weight saving of 91b is thereby achievedin the three gyros employed. One feature is a steel gimbal ring which provides good temperature compensation. The azimuth gyro has beenduplicated mainly to ensure stand-by service for the drift kick-off phase of automatic landing; and azimuth reference is raised to "2i channel"level by the presence of the normal magnetic stand-by compass as an additional monitor. So far Sperry have produced about 40 Rotorace systems, most ofthem CL.llFs intended for the Fiat G.91. Rotorace provides a near- inertial quality azimuth reference suitable for combination with theBendix Doppler in the G.91; and azimuth indication in the cockpit will be on the indicator of the PHI navigation computer. The VGL.2vertical gyro has been chosen as a standy-by gyro reference for the Litton inertial platform in the German F-104G. Stand-by azimuthindication will be by modified CL.2. Sperry are also producing the twin Rotorace master reference gyro which stands fair to become a replace-ment for the RAF MRG.l and has also been designated as the short- term inertial element of the Doppler-inertial system for the FrenchMirage IV. The Doppler element in this aircraft is the Marconi AD.23OO —an important British contribution to this French supersonic bomber.Sperry in America produced the inertial platform providing Sight refer- ence for the X-1S. At first, this employed Minneapolis-Honeywell MIGgyros but these are now to be replaced by Sperry's own SIG.1000 minia- ture gyros. Sperry are now offering a modified version of the X-15platform with SIG.1000 gyros in an inertial system whose performance is claimed to be better than that of the remarkable Litton system for theF-104G. New portions of the Trident system shown for the first time on theSmiths stand included the combined control panel for the autopilot and its various height, speed, coupling and automatic landing phases.Airspeed or height may be selected on veeder indicators, selected heights captured from climb or descent, and i.a.s. altered by progressive selectorlike the conventional pitch-knob. A changeover switch allows either flight system to control the autopilot, so that one may be in use whilethe other is being set up for the next operation. Doppler track coupling is also included. A further panel allows verification of individual portionsof the overall system. Trident instrumentation evidently includes an almost completely newset of flight instruments centred on roller-blind attitude and navigation displays. The technique is broadly similar to that of the traditional Pilot's controller of the Elliott autopilot tor a supersonic tighter SFS in that the attitude display is the main flight director with thenavigation unit as a situation display and mode selecter rather thana "live" director. A roller blind here presents VOR position, course line orblue and yellow ILS display with a glidepath cross-pointer. The auto- matic landing monitor instrument is basically the radio altimeterindicator with marker lines at 150ft and 30ft to show beginning of attitude hold and flare-out phases. Warning flags show engagementof the phases. A new concept in instrumentation is the servo-operated a.s.i. in whichthe needle revolves through two turns. The dial face is spiralled so that at low speeds the full length of the needle points at the outer scale'At 2S0kt the second turn starts and the end of the needle disappears behind the outer scale and points directly and only at the inner scale.Ambiguous speed readings are thus avoided. The v.sx, also being servo-operated from an air data computer, reads up to ±7,000ft/minThe altimeter is a version of the servo-operated counter /pointer type with veeder indication down to the nearest 50ft and a single needlereading from O-l,OOOft intervals. Thousands of feet are shown only by direct counter numbers, eliminating traditional 0 or 10,000ft confusion.It is reported that BEA are considering fitting all their aircraft with such servo-operated altimeters on the first pilot's panel. A developed version of the SCI autostabilizer and control system,whereby pilot demands are superimposed on autostabilizing signals, was shown on the Short stand, together with a location drawing of thecomponents in the PD.49 VTO fighter. Attitude references are six Smiths miniature gyros, three for pitch and three for roll. Hydraulicservo movements are sensed by AC pick-offs and fed to the fault- detection unit where they are compared with each other and with gyrosignals in a sequence by which one or two faulty channels may be identified. Separate switches on the pilot's control panel allow indi-vidual elimination of any pitch or roll channel when a red light shows a failure. Printed circuitry and potting is extensively employed. Develop-ment of an effective fault-detection system was one of the main tasks for the SC.l autopilot and this has now been done. The developedsystem exhibited is soon to be installed in the second SCI. Newmark Technamation Division have evidently been working forsome time to »ngliri«» a Lear automatic anti-submarine control system for helicopters called the Mk 19 autopilot. It probably applies to theWessex and incorporates very comprehensive facilities for automatic hovering, (a) stationary with reference to a ground or water surfacewith the aid of Doppler, (b) stationary in space by short-term inertial reference, (c) vertically over a suspended buoy which may be drifting ina tidal current. The Doppler resembles the Ryan APN-97 ordered by the Navy for the Wessex. Barometric height lock is provided fornormal conditions, but radio altimeter or a pendant cable may be used for precise height control. Standby remote-gyro attitude indication isprovided and any of the four control axes may be individually switched off. Newmark also showed portions of the light helicopter autopilotfor stabilization alone as well as manoeuvre, heading and height holding using flight instruments for reference. It weighs 501b. Newmaif holdthe licence for the Lear MARS, two-gyro remote attitude system already ordered for the American F-105, F-106, F4H and A4D-2. A newcomer to the English scene is the Minneapolis Honeywelluniversal adaptive autopilot which, it is claimed, adapts itself in night to any conditions of turbulence, speed or height. It was designed inAmerica and is being offered for sale or manufacture by Honeywell Controls Ltd in Britain. Considerable Continental interest already exists,the same autopilot unit being suitable for any type from fighter to VIV aircraft. . Little was to be seen this year of the Elliott autopilot equipmentfor the VC10, the other automatic flare-out airliner now in preparation. A computer based on that of the Bendix PB-20 showed the moduleswhich are being incorporated in the Elliott system and an automatic throttle control unit was shown. This last facility is apparently Bein,introduced in Fleet Air Arm aircraft. ., More significant were certain components of two military autopilotsbeing developed by Elliott for a supersonic fighter aircraft now entering service. A feature of the control panel of one of them was the use ™mechanical interlocks between mode selecters to save panel space, A climb setting covers optimum climb perfonnance under autopilot con™and the inclusion of "track" and "glide" switches indicates autonwuc or near-automatic landing. Automatic throttle control is mcludea. ij>main hand control is designed for use with the right hand a"1*"* j"5 field of vision. Airpass has a controller for the left hand. It wasisiaicuthat the autopilot hand controller could govern either extent or of turn, according to the mode in use. The barometric heigm '«*
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