SYNCHROPHASERS FOR AIRCRAFT PROPELLERS; ENGINE PRESSURE RATIO TRANSMITTERS; ELECTROCHEMICAL CELLS, NAMELY, GAS GENERATORS, FUEL CELLS, COMPRESSORS AND SENSORS; ELECTRONIC FLIGHT CONTROLS FOR AIRCRAFT; ACCELEROMETERS; ELECTRONIC GROUND SUPPORT APPARATUS FOR USE WITH AIRCRAFT; HELMET-MOUNTED ELECTRONIC GENERATED DISPLAYS; SHIPBOARD ELECTRONIC APPARATUS FOR CONNECTING SHIPBOARD SENSORS, SUCH AS SONAR OR RADAR, TO THE SHIP'S WEAPONS SO AS TO PROVIDE DATA OR A CONTROL THERETO; AIRCRAFT-MOUNTED ELECTRONIC APPARATUS OPERABLE TO COLLECT SIGNALS ON THE CHARACTERISTICS OF A SUBMARINE UNDER SURVEILLANCE AND TRANSMIT THOSE SIGNALS BACK TO A MOTHER SHIP FOR ANALYSIS AND FIRE CONTROL PURPOSES; COMPUTER AIRBORNE FLIGHT PERFORMANCE MONITOR APPARATUS; AIRCRAFT-MOUNTED ELECTRONIC APPARATUS, NAMELY, A COMBAT COMPUTER INTERFACE TO ENABLE COMPUTERS AND CREW TO MONITOR ORDINANCE ACTIVITIES, OPERATION AND CONDITION THROUGHOUT THE AIRCRAFT; MICROCOMPUTER CONTROL OPERABLE TO TUNE THE RADIO FREQUENCY ANTENNA COUPLERS WHICH COUPLE MULTIPLE SHIP RADIOS TO ONE OR MORE ANTENNAE; RADIO TELEMETRY APPARATUS OPERABLE TO COLLECT INFORMATION ON MISSILE FLIGHT AND PERFORMANCE FOR TRANSMISSION TO GROUND AUTHORITY; ELECTRONIC APPARATUS FOR ADOPTING AIRCRAFT RADIOS FOR USE ABOARD SHIP WHICH FROM AN ELECTRONIC PROTECTIVE COCOON AROUND THE AIRCRAFT RADIO AND INTERCONNECTS AIRCRAFT RADIOS TO SHIPBOARD PARAMETERS SUCH AS, SHIPBOARD POWER, COOLING SYSTEMS AND ENVIRONMENTAL CONTROLS; PORTABLE ELECTRONIC TESTERS OPERABLE TO GROUND TEST THE VARIOUS AIRCRAFT FLIGHT SYSTEMS SUCH AS, AIRCRAFT AVIONIC SYSTMES AND AVIONIC SUBMARINE WARFARE SUBSYSTEMS