Boeing is undertaking a “beyond Block II” effort for its CH-47F Chinooks, including a testing program this year of two General Electric 7,500 horsepower T408 engines 2,500 horsepower more than the current Honeywell T55 engines. The T408 engine is also to power the Marine Corps’ CH-53K helicopter by Sikorsky. GE has said that the T408 will allow the CH-53K “to carry a 27,000-pound external load over a mission radius of 110 nautical miles in hot weather conditions, nearly triple the external load carrying capacity of current aircraft.”
The GE-Boeing-Army engine effort is proceeding under a Cooperative Research and Development Agreement (CRADA) that began in 2016. While Boeing has not disclosed any estimates about how much additional lifting capacity or other added performance a CH-47F with two T408s will have compared the existing variant. The GE engines do each produce 7,500 shaft horsepower (SHP), around 2,500 more SHP than the present T55s.
GE also heavily promotes the engines as fuel efficient and easier to maintain than older designs, which might mean a re-engined Chinook might have greater range and be cheaper to operate. The engine maker specifically says that the T408 offers an 18 percent improvement in fuel consumption and features fewer moving parts than its older T64, the latest iterations of which is in a similar SHP class to the T55. It remains to be seen if these benefits over the T64 translate to similar benefits over the T55.