Honeywell's auxiliary power units selected for Sikorsky-Boeing's Defiant X as testing ramps up

A Sikorsky-Boeing team selected a modified version of Honeywell's GTCP 36-150 APU, main engine generator, and APU generator for its Defiant X helicopter. (Sikorsky-Boeing)

A Lockheed Martin Sikorsky-Boeing team announced on 25 April that it had selected Honeywell's GTCP 36-150 auxiliary power unit (APU), main engine generator, and APU generator for its Defiant X helicopter.

The awards come after Honeywell was selected on 10 February to supply the HTS7500 turboshaft engine for the Defiant X platform.

The APU for the Defiant X is a modified derivative of Honeywell's GTCP 36-150 APU series in use with the Boeing AH-64 Apache and CH-47 Chinook helicopters and in several Gulfstream jets, but customised to meet US Army specifications. The new APU is “equipped with the latest compressor technology originally developed for the commercial aircraft sector”, according to Honeywell.

The 36-150 APU “delivers compressed air for main engine starting, air conditioning, anti-ice, and heating systems. They are capable of delivering air and shaft power simultaneously or individually”, the company said.

In addition, Honeywell's main engine generator will provide electricity to the aircraft while in flight, and the APU generator will provide electricity to the aircraft on ground, according to the company.

Honeywell has completed several tests on the front end of the engine and its compression system.

A second developmental test engine is being built and will be used to test “the performance of the compressor and how that operates” next quarter, John Russo, Honeywell's vice-president of turboshaft engines, told reporters on 25 April.