Advanced Turbine Engine Company, a joint venture of Honeywell and Pratt & Whitney, submitted Phase II of its proposal for the engineering and manufacturing development phase of the US Army’s Improved Turbine Engine Program (ITEP).

ITEP is the US Army’s engine replacement program for the Sikorsky UH-60 Black Hawk and Boeing AH-64 Apache helicopters. The Army plans to drop the turboshaft into 1,300 UH-60s and more than 600 AH-64s after 2025.

The ITEP engine is also to power the US Army’s forthcoming Future Vertical Lift Capability Set One aircraft: a scout and light attack helicopter.

The joint venture is competing against GE Aviation, which submitted its Phase II proposal on 17 July and is the manufacturer of the T700 turboshaft, the current power source for the UH-60 and UH-64 helicopters.

The US Army wants its new ITEP engine to be 50% more powerful – 3,000shp (2,240kW) – 25% more fuel efficient, and provide a 20% longer design life over the current engine. It will also have to maintain high levels of performance at 6,000ft and 35°C (95°F); conditions common in Afghanistan where the UH-60 and UH-64 have struggled to fly.

To achieve those requirements GE Aviation and the Advance Turbine Engine (ATEC) joint venture are taking different approaches to engine design.

GE Aviation is sticking with what it sees as a simpler and more maintenance-friendly design, a single-spool turboshaft engine, which places rotating components on one shaft, spinning at the same speed. The company calls the engine the T901, and claims its single-spool design will be less complex, less expensive, and lighter weight compared to a similar dual-spool.

In contrast, ATEC is pitching a dual-spool engine, which allows certain turbine blades to spin independently, at faster or slower speeds, in order to more efficiently generate power. The joint venture calls its engine the T900, and claims its dual-spool design will allow it to operate at cooler temperatures and save an additional 3% to 4% in mission fuel burn compared to a similar single-spool engine.

The US Army Contracting Command in Redstone Arsenal, Alabama plans to award a single contract for engineering and manufacturing development of the ITEP in the first quarter of 2019, with low-rate production beginning in 2024.