Accession Number : ADA298732

Title :   Accuracy of Airspeed Measurements and Flight Calibration Procedures,

Corporate Author : NATIONAL AERONAUTICS AND SPACE ADMINISTRATION WASHINGTON DC

Personal Author(s) : Huston, Wilber B.

PDF Url : ADA298732

Report Date : 1948

Pagination or Media Count : 42

Abstract : The sources of error that may enter into the measurement of airspeed by pitot-static methods are reviewed in detail together with methods of flight calibration of airspeed installations. Special attention is given to the problem of accurate measurements of airspeed under conditions of high speed and maneuverability required of military airplanes. The accuracy of airspeed measurement is discussed as limited by errors in each of the quantities that is directly measured in flight. Existing data on the errors at the total- and static-pressure openings associated with the geometry of pitot-static tubes are summarized, followed by charts and a qualitative description of the errors caused by operation within the pressure field of the airfoil. The errors introduced at the measuring end of the system due to lag in pressure transmission are reviewed and some new material on this subject is included along with methods and charts for making appropriate lag corrections to airspeed measurements. A brief discussion is given of the magnitude and type of errors introduced by the mechanical and elastic of the conventional airspeed indicator and altimeter. Similar material is given for typical NACA pressure-recording instruments. Since knowledge of true airspeed is dependent upon a temperature measurement, existing material on the accuracy with which temperature can be measured with various types of probes is summarized and discussed. Methods used by the National Advisory Committee for Aeronautics in flight calibrations of airspeed and temperature installations are outlined.

Descriptors :   *ACCURACY, *AIRSPEED, *CALIBRATION, *AIRSPEED INDICATORS, MEASUREMENT, MECHANICAL PROPERTIES, MILITARY AIRCRAFT, DATA MANAGEMENT, ELASTIC PROPERTIES, TRANSMITTANCE, AERONAUTICS, FLIGHT, ERRORS, PRESSURE, INFLIGHT, DELAY, CORRECTIONS.

Subject Categories : Flight Control and Instrumentation

Distribution Statement : APPROVED FOR PUBLIC RELEASE