Articles with tag: "flight test"

(Note: figures do not appear in the summaries below)

  1. Tools

    Published: Mon 12 February 2024
    Updated: Sat 18 May 2024

    Aircraft designs for flight in icing are improved and proven effective by several tools, including analysis, icing wind tunnel test, and flight test in icing conditions.

    Design handbooks

    Design handbooks have charts and tables that can be used to perform analyses for aircraft icing and ice protection.

    Figure 2-47. Airfoil profiles for impingement parameter plots in Figures 2-48 through 2-59.
    from "Aircraft Icing Handbook", DOT/FAA/CT-88/8 apps.dtic.mil

    Analysis

    There are computerized icing analysis tools available from NASA, and from commercial vendors. There is also "bespoke" software created for special purposes.

    LEWICE3D. LEWICE3D prediction of collection efficiency (color contours) and the resulting ice shape (at discrete cuts) along a wing.
    from "Glenn Research Center Software" www1.grc.nasa.gov

    Laboratory tests

    A wind tunnel is a large tube with a fan to produce air flow at a calibrated airspeed. Wind tunnels are used to study many effects on aircraft, including icing. Artificially produced ice shapes (often 3D printed) may be adhered to airplane models, and the effects studied.

    To simulate in-flight icing conditions, "Icing Wind Tunnels" often use refrigeration …

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  2. Notes on Flight Testing

    "Tests to determine the performance of an icing protection system ... are of little value ... unless they can be subjected to an analytical treatment, and reduced to a generalised form which is applicable to conditions other than those under which the tests were actually made."

    Lecture No. 12b, "NOTE ON THE FLIGHT TESTING AND ASSESSMENT OF ICING PROTECTION SYSTEMS" 1

    Summary

    An alternative view of how to correlate icing conditions to ice protection performance.

    Key Points

    1. The concepts of protection system "failure" vs. "deficiency" are discussed.
    2. Test conditions specifically planned to find the point of failure or deficiency are recommended.

    Abstract

    Flight tests of an icing protection system consist of functioning tests, tests to determine the internal efficiencies, and tests of the performance in icing. The performance in icing can be determined only if the appropriate measurements are made, and if the flow of protection or the icing severity can be …

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  3. NACA-TN-1598

    "It is significant that the control response of the airplane approached the point of being marginal when all of the airplane except the propeller had accreted ice"

    Figure 13. Formation of ice on horizontal stabilizer. Average icing rate, 4 inches per hour; liquid-water content, 0.4 grams per cubic meter; drop size, 17 microns. (Painted stripes are 1 in. wide)

    NACA-TN-1598, "Effects of Ice Formations on Airplane Performance in Level Cruising Flight" 1

    Summary

    Airplane levels effects of icing are measured, and broken into major components.

    Key Points

    1. Numerous, excellent quality photos show how icing flight test "should be done".
    2. Airplane levels effects of icing are measured, and broken into major components.
    3. "It is significant that the control response of the airplane approached the point of being marginal when all of the airplane except the propeller had accreted ice."

    Abstract

    A flight investigation in natural icing conditions was conducted by the NACA to determine the effect of ice accretion on airplane performance.

    The maximum loss in propeller efficiency encountered due to ice formation on the propeller blades was 19 percent. During 87 percent …

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