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 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 SYSTEMS AND AVIONIC SUBMARINE WARFARE SUBSYSTEMS