Accession Number : AD0013162


Title :   TEST AND EVALUATION OF ALTIMETER AN/APN-57


Corporate Author : AERONAUTICAL SYSTEMS DIV WRIGHT-PATTERSON AFB OH


Personal Author(s) : GEORGI, J PAUL ; GOLDMAN, ALBERT


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/013162.pdf


Report Date : Apr 1952


Pagination or Media Count : 129


Abstract : The altimeter is designed to indicate the absolute altitude (terrain clearance) between heights of 10,000 and 35,000 ft. A servo-operated 3-pointer dial (calibrated from 0 to 100,000 ft) registers the altitude, and a CRT indicator shows the instantaneous error up to + or - 500 ft. The transmitter- receiver is a modified RT-69/APS-10 with a 0.25-microsec output pulse, 4-kw peak power, and a carrier frequency in the 9345- to 9405-mc range. A 60-in.-diam parabolic antenna reflector provides a beamwidth of 1.6 deg at the half-power points. Flight tests of 16 units showed that the design meets the accuracy requirements, provided that a compensating error of -42 ft is inserted during calibration. An apparent increase is indicated altitude caused by banking the test aircraft as little as 3 deg showed the need for antenna stabilization. The present system of recording altitude indications photographically was considered unsatisfactory.


Descriptors :   *RADIO ALTIMETERS , STABILIZATION , REQUIREMENTS , FLIGHT TESTING , AIRCRAFT , BANKING , ACCURACY , ERRORS , ANTENNAS , RECORDING SYSTEMS , CALIBRATION , COMPENSATION , ALTITUDE , CARRIER FREQUENCIES , CATHODE RAY TUBES


Subject Categories : Flight Control and Instrumentation


Distribution Statement : APPROVED FOR PUBLIC RELEASE