The aircraft-skin-rivet thermocouple is designed for measuring the temperature on the outer surface of an airplane wing under icing conditions. More specifically, its design was motivated by the need to measure the temperature near 32 °F (0 °C) on an aluminum wing skin, with an error of no more than 1 °F (0.6 °C), without disturbing the airflow over the wing.
As its name suggests, the aircraft-skin-rivet thermocouple is a thermocouple embedded in an aircraft-skin rivet, with connections to thermocouple wires routed inside the wing. This design satisfies a requirement for simplicity of installation in the field, without need for access to the interior of the wing (other than for routing and connection of the thermocouple wires). Inasmuch as rivets are used in any event to hold the skin in place, this design satisfies a requirement for compatibility with the skin. Like the other rivets on the wing, the one that holds the thermocouple is made flush with the surface upon installation and therefore does not introduce any surface alteration that would disturb the airflow.
At the time of reporting the information for this article, measurements and calculations to determine the accuracy of the aircraft-skin-rivet thermocouple had not been completed. However, preliminary estimates had been interpreted as signifying that the thermocouple readings would eventually be found to be accurate within less than the design error.
This work was done by David W. Sheldon and Dean R. Miller of Lewis Research Center. For further information, access the Technical Support Package (TSP) free on-line at www.techbriefs.com under the Physical Sciences category, or circle no. 164on the TSP Order Card in this issue to receive a copy by mail ($5 charge).
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Refer to LEW-16397 .