Sikorsky-Boeing helo gets HTS7500 – 42% more powerful engine than T55

WASHINGTON — Defiant X – one of the helicopters involved in the Future Long-Range Assault Aircraft [FLRAA] program and co-developed by Sikorski [Lockheed Martin’s company] and Boeing chose the engine that will power the helicopter – Honeywell’s HTS7500. Honeywell is also producing the current T55 engine for the flagship of the US attack helicopters UH-60 Black Hawks.

See the newest high-speed SB-1 Defiant helicopter developed by Sikorski (video)
Photo credit: Wikipedia

Honeywell says the HTS7500 gives 42% more power than the T55. The HTS7500 is an advanced turbocharged engine and is the latest engine in the company’s product portfolio. The new Defiant X engine will provide much better performance – the helicopter will fly faster over long distances. The HTS7500 delivers a high power-to-weight ratio of any comparable engine, Honeywell said.

HTS7500 will reduce fuel consumption by 18% and increase helicopter efficiency during missions in areas with high concentrations of sand, such as deserts, as it has a very good tolerance of sand absorption. Its maintenance costs during the life cycle of the engine are low compared to the T55. The HTS7500 is 51.2 inches long, 32.2 inches high, and the output shaft speed [RPM] is 15,000 RPM.

Sikorsky-Boeing helo gets HTS7500 - 42% more powerful engine than T55
Photo credit: Honeywell recalls that in mid-January 2022, the Defiant X successfully conducted tests to determine and confirm airworthiness, developing a speed of 236 knots, and then immediately switched to vertical landing in a very limited landing area.

“Defiant X is a transformational aircraft, and Honeywell is giving us a transformational engine to power it,” said Paul Lemmo, president of Sikorsky. “Defiant X is optimized for operational effectiveness, sustainment, and interoperability with the enduring fleet, and will transform the Army.”

Defiant is a joint development between Sikorski [Lockheed Martin’s company] and Boeing under the Future Long-Range Assault Aircraft [FLRAA] program. The FLRAA must offer next-generation US Air Force and US Navy helicopters. According to preliminary plans of the Pentagon under this program, five different aircraft should be developed to be integrated and share the same sensors, avionics, engine, and countermeasures.

Defiant X was officially unveiled to the US Army in 2021 by Sikorski [Lockheed Martin’s company] and Boeing. The new combat helicopter will replace the UH-60 Black Hawks. The other participant in the race is Bell V-280 Valor. Which of the two will be the new combat attack helicopter of the US Army will be known this year.


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