Abstract: An aircraft supplemental air heater including a coiled composite having a series of passes defining a spiral shaped airflow passage therebetween. The composite includes a heating element that provides a controlled heat output when a voltage potential is applied across it. The composite also includes a convective heat transfer surface to which the heat output is transferred whereby as air flows through the heater's spiral shaped airflow passage, it passes over the convective heat transfer surface and heat is thereby transferred to the air through convection. The aircraft supplemental air heater maybe installed in-line with an air supply duct leading to the cabin of the aircraft and/or may be installed downstream of a fan. The heater may be made by assembling a composite panel and then forming this panel into the desired coiled shape.

Abstract: An aircraft supplemental air heater including a coiled composite having a series of passes defining a spiral shaped airflow passage therebetween. The composite includes a heating element that provides a controlled heat output when a voltage potential is applied across it. The composite also includes a convective heat transfer surface to which the heat output is transferred whereby as air flows through the heater's spiral shaped airflow passage, it passes over the convective heat transfer surface and heat is thereby transferred to the air through convection. The aircraft supplemental air heater maybe installed in-line with an air supply duct leading to the cabin of the aircraft and/or may be installed downstream of a fan. The heater may be made by assembling a composite panel and then forming this panel into the desired coiled shape.

Abstract: The invention is in the field of electrical resistance heaters, especially heaters for tubes, pipes, or flexible hose. More particularly, the invention is directed to an electrical heater formed as a strip that is permanently set in the shape of a helix. According to an aspect of the invention, an electrical heater is provided comprising a flexible electrical insulation strip bounded by a first longitudinal edge and a second longitudinal edge, wherein the flexible electrical insulation strip is permanently set as a helix such that the first longitudinal edge is adjacent to the second longitudinal edge; and, a flexible electrical heating element encapsulated within the electrical insulation strip.