Articles with tag: "natural icing"

(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. NACA-TN-1904

    "... the rotating-cylinder indications of drop-size distribution are so unreliable that they are of little or no value"

    NACA-TN-1904, "Observations of Icing Conditions Encountered in Flight During 1948" 1

    Summary

    Meteorological data from flight observations in icing conditions during the first 5 months of 1948 are presented.

    Key points

    1. The average liquid water content varies over distance traveled in icing.
    2. The value of the multicylinder method for determining drop size distributions is questioned.
    3. Other flight test instruments are described.

    Abstract

    Meteorological data from flight observations in icing conditions during the first 5 months of 1948 are presented. A total of 335 measurements of liquid-water content and mean-effective drop diameter were obtained by the multicylinder method in the course of 40 flights in icing conditions covering most of northern United States. Cumulus clouds were predominant during approximately two-thirds of the flights. A continuous record of liquid-water content covering a major portion of …

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  3. NACA-TN-1393

    "The rotating-cylinder method of measuring liquid water content is generally regarded as being the most accurate and dependable procedure thus far developed"

    Figure 5: Liquid water content and drop size by rotating cylinder measurement as compared with Weather Bureau scale of icing intensity. This is a graph of Mean effective drop diameter in microns vs. Liquid water content in g/m^3. Lines for the intensity values 1, 6, and 12 g/cm^2-h are shown, as well as several flight measurement values

    “A Flight Investigation of the Meteorological Conditions Conducive to the Formation of Ice on Airplanes"

    1

    Summary

    A multicylinder and other instruments measure natural icing conditions in flight.

    Key points

    1. The accuracy of multicylinder instruments used to determine liquid water content and median water drop size is assessed.
    2. An icing intensity index as related to the ice growth rate on a 3-inch diameter cylinder is detailed.
    3. Results from agree well with the Python implementation of the cylinder analysis.
    4. "Tentative" values for icing design conditions were determined.
    5. An effect of distance on icing conditions is noted.

    Abstract

    Data from flight measurements of the meteorological factors related to the intensity of icing conditions are presented. The physical factors that establish the distribution of liquid water in clouds of various types …

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