Accession Number : ADA310374

Title :   Performance of Five Ablation Materials as Coatings for Structures in a Region of Separated Flow.

Descriptive Note : Technical note,

Corporate Author : NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HAMPTON VA LANGLEY RESEARCH CEN TER

Personal Author(s) : Clark, Louis E. ; McLain, Allen G.

PDF Url : ADA310374

Report Date : NOV 1965

Pagination or Media Count : 34

Abstract : An investigation was made of several commercially available ablation materials for use as thermal protection for the sidewalls of advanced air-to-air missiles. Material specimens of different thickness were tested on the cylindrical section of a rounded-ogive-cylinder model. The tests were conducted in the Langley 11-inch ceramic heated tunnel at a heating rate, enthalpy, and free stream Mach number typical of the values of these parameters encountered during a missile trajectory. Oil flow and pressure tests showed that the boundary layer had separated from the cylindrical section of the model and that the entire specimen region was immersed in separated flow. In the separated flow environment, a phenolic cork composition was found to be superior to the other materials studied in limiting the substrate temperature rise. The phenolic cork composition experienced considerably greater erosion than the phenolic nylon, asbestos phenolic, and subliming salt compositions, which ranked second, third, and fourth, respectively, in limiting the substrate temperature rise; however, these materials developed either surface cracks or large fissures in the char layer. Preconditioning of the phenolic cork, asbestos phenolic, and epoxy solid materials by heat cycling to 400 deg F (478 deg K) did not decrease their thermal performance.

Descriptors :   *GUIDED MISSILE COMPONENTS, *ABLATIVE MATERIALS, *CARBON PHENOLIC MATERIALS, THERMAL PROPERTIES, THICKNESS, GUIDED MISSILE TRAJECTORIES, LAYERS, NYLON, BOUNDARY LAYER, EROSION, CYLINDRICAL BODIES, HEATING, PRESSURE, PROTECTIVE COATINGS, MACH NUMBER, EPOXY COMPOUNDS, ASBESTOS, AIR TO AIR MISSILES, FREE STREAM, FLOW SEPARATION, ENTHALPY, CORK, CHARRING.

Subject Categories : Ceramics, Refractories and Glass
      Air- and Space-launched Guided Missiles

Distribution Statement : APPROVED FOR PUBLIC RELEASE