Keeping two bidders in competition for a major US Army engine contract is being strained by the government's budget pressures, industry officials say.
And, in a twist from the F-35 alternate engine competition, a joint venture including Pratt & Whitney is lobbying to keep both bidders in the running for the army's advanced affordable turbine engine (AATE) contract.
Meanwhile, General Electric, which is fighting to remain in the F-35 engine race, appears more ambivalent about competition for the 3,000shp (2,235kW)-class army engine.
The AATE is envisaged to replace the GE T700 engine on all Boeing AH-64 Apaches and Sikorsky UH-60 Black Hawks, as well as serve as the basis for the propulsion that will power a next-generation family of helicopters under the Joint Multi-Role (JMR) programme.
"The way it looks right now, [the army] has funding for one," says Michael Sousa, product development manager for new and derivative products at GE, which is proposing the GE3000 for the AATE contract.
But the P&W/Honeywell joint venture building the rival HPW3000 believes there is a way for the army to fund both. "There's strong army support for the [competition]," says Craig Madden, president of Advanced Turbine Engine (ATEC).
In December, the army issued a notice to both bidding teams asking for ways to save money. The army's baseline plans calls for funding two bidders through most of a six-year development phase, downselecting to one just before the first test engine is ready for installation in a helicopter.
ATEC officials proposed a plan that could accomplish the army's goals with two bidders in a shorter period of time, Madden says.
The army is still developing requirements for the ATEC engine even as the aviation branch starts working on concepts for the JMR fleet that is expected to enter service in 2030.
The JMR is supposed to travel at speeds above 200kt (370km/h). If this requirement is retained, the army will need an engine very different from a conventional helicopter, which is limited by the retreating blade stall of the rotor to 170kt. But it is not clear if the AATE engine will need special characteristics, such as the ability to articulate upward or downward such as in a tiltrotor configuration.
Sousa says the technology exists to enable such a capability even after the AATE engine is designed, but ATEC officials are not so certain.
"It would be difficult to build [articulation] back in," says Jerry Wheeler, ATEC vice-president. "That's why [AATE] could be a basis for JMR rather than the actual engine for JMR."