Abstract: A serpentine etched foil heater has a segmented serpentine conductor group made up of a plurality of spaced-apart elongated serpentine conductive strips that are connected in parallel and are everywhere aligned with each other. Advantageously, central conductive strips are wider than are conductive strips along the edges. Further advantageously, the conductive strips are bridged by conductive regions that extend along lines of constant voltage. This makes it possible to handle the heater element without causing it to become tangled. The heater is especially suitable for low voltage applications.

Abstract: Unconditioned, sub-freezing turbine exhaust air is employed to cool liquid coolant from radar electronics in an aircraft. This is accomplished by utilizing a liquid/air exchanger. However, in order to ensure that the air-cooled heat exchangers do not experience freezing of moisture droplets, sufficient heat is supplied to a liquid/air heat exchanger, located at the turbine exhaust, to maintain all surfaces (fins) above freezing, and also to heat the entire turbine exhaust air stream to a temperature above freezing as it exits that heat exchanger. Use of this anti-icing liquid/air heat exchanger, in conjunction with the proper air and liquid flow controls, will permit savings of total cooling air (i.e., engine bleed air) flow by negating the need for a hot air bypass to reheat turbine exhaust air.