Accession Number : ADA298803

Title :   Ice Prevention on Aircraft by Means of Engine Exhaust Heat and a Technical Study of Heat Transmission from A Clark Y Airfoil,

Corporate Author : NATIONAL AERONAUTICS AND SPACE ADMINISTRATION WASHINGTON DC

Personal Author(s) : Theodorsen, Theodore ; Clay, William C.

PDF Url : ADA298803

Report Date : 1931

Pagination or Media Count : 27

Abstract : This investigation was conducted to study the practicability of employing heat as a means of preventing the formation of ice on airplane wings. The report relates technical problems regarding the extraction of heat from the exhaust gases and its distribution over the exposed surfaces. A separate study has been made to determine the variation of the coefficient of heat transmission along the chord of a Clark Y airfoil. It reveals that the local transmission is very high at the leading edge and that it decreases rapidly to a minimum value at a point located about 30 per cent back along the chord. Experiments on ice prevention both in the laboratory and in flight show conclusively that it is necessary to heat only the front portion of the wing surface to effect complete prevention. The marked variation n the heat transmission over the front portion of the wing makes the problem of an efficient heat distributing system a matter of some technical difficulty. The quantity of heat needed for ice prevention is surprisingly small, being in the order of one-tenth of that available in the engine exhaust gases. The relative merits of various methods of ice prevention by means of heat are analyzed with the result that a vapor system is found to offer the most satisfactory solution, especially for airplanes which are not constructed entirely of metal. In "all-metal" designs it may be entirely practicable to employ a direct exhaust heating system. Experiments in flight show that a vapor heating system which extracts heat from the exhaust and distributes it to the wings is an entirely practical and efficient method for preventing ice formation.

Descriptors :   *HEAT TRANSFER, *AIRFOILS, *AIRCRAFT EXHAUST, *ICE PREVENTION, EXPOSURE(GENERAL), WATER, EFFICIENCY, SURFACE PROPERTIES, INFLIGHT, LEADING EDGES, HEAT TRANSFER COEFFICIENTS, EXHAUST GASES, HEAT TRANSMISSION, WING SLOTS.

Subject Categories : Military Aircraft Operations
      Air Condition, Heating, Lighting & Ventilating

Distribution Statement : APPROVED FOR PUBLIC RELEASE