The manufacturers of an alternate F-35 Joint Strike Fighter engine this week criticized their opponent’s product in the wake of a showdown between the Defense Department and Capitol Hill on funding for the second engine.

Officials with the General Electric [GE] and Rolls-Royce [RR] F136 engine team said yesterday that Pratt & Whitney‘s [UTX] F135 engine is over budget and will likely incur more cost growth over the course of its development.

David Joyce, GE Aviation’s president and CEO, told reporters that the F135’s cost overruns are in excess of $2 billion. He accused Pratt & Whitney of using "diversionary tactics" to shift attention from their program’s problems.

Joyce said Pratt has spent $7.3 billion to develop its engine, while GE and Rolls have spent only $3 billion. He reiterated the companies’ fixed-price offer to the Pentagon, which he said would save some $20 billion over the life of the F-35 program.

James Guyette, president and CEO of Rolls-Royce North America, said that ending the GE-Rolls development effort would create a "monopoly," which "would not be in the nation’s interest."

"We want an opportunity to compete," said Guyette.

Pratt & Whitney spokeswoman Erin Dick said the cost and technical problems cited by GE and Rolls Royce "simply do not exist."

"The proof that the Pratt & Whitney F135 engine is working very well took place in March when the F-35 performed a flawless first vertical landing," Dick said via e-mail. "The F135 engine is not only performing exceptionally well during flight test, it is also achieving its cost targets, has received government certification, has logged more than 17,500 hours and is in production."

Meanwhile, Navy officials reiterated their opposition to a second engine for the fighter. Rear Adm. Mike Manazir, the service’s director of air warfare, supported the view on operational grounds.

"No matter how many engines are procured for the airplane, the Navy will only deploy one type of engine for the F-35 we take to sea," Manazir told reporters during a briefing at the Pentagon. "We have done that for all of our aircraft, and so whether it is the F135 or the Secretary of Defense decides to buy a second engine, the Navy is only going to deploy with one type. That optimizes our logistics and supply chain."

Manazir added that he is confident that current engine technology does not make reliance on a single engine too risky.

Defense Secretary Robert Gates told Pentagon reporters last week that he would "strongly recommend" that President Obama veto defense legislation if Congress adds unrequested funding for the alternate engine or "directs changes that seriously disrupt the JSF program."

The House is set to take up a Pentagon policy bill this week that defies the White House’s wishes on the F-35 alternate engine after the House Armed Services Committee (HASC) last week approved a $567 billion defense authorization bill that includes funding for it.