NORTH COUNTY - Rep. Duncan Hunter, R-El Cajon, said Wednesday he is determined to continue securing federal funding for a San Diego County company that has been trying for two decades, without success, to design a military jet that can safely take off vertically.

The company developing the jet is one of many defense contractors that have contributed to re-election campaigns for Hunter, who is currently running for president.

Hunter said in a telephone interview, the day after a congressional hearing delved into a string of setbacks that have plagued La Jolla-based duPont Aerospace, that he believes the company's DP-2 plane project is worth supporting even though the Pentagon continues to express serious doubts about it.

"We need to continue to test this thing and improve it until it works," Hunter said.

However, several critics - including a former duPont Aerospace engineer and former experimental aircraft engineer for the Navy, told members of a House panel on Tuesday that the program is poorly designed and managed and has little chance of success. They also cited four accidents that occurred during tests conducted since 2004.

The Science and Technology Committee's subcommittee on investigations and oversight convened the hearing.

Congress has spent more than $63 million on the company's experiment since 1988, much of it the result of Hunter's position on the House Armed Services Committee. He was chairman until Democrats seized control of the House in the November elections and now is the top-ranking Republican.

At the same time, duPont Aerospace has contributed several thousand dollars to Hunter's campaigns.

According to The Center for Responsive Politics, a Washington-based government watchdog group, about $15,000 was contributed by duPont Aerospace President Anthony A. duPont and his wife, Carol, between 1997 and 2006.

Hunter said the duPont contributions have no bearing on his enthusiasm for the experiment.

"After 26 years in Congress, they can point to practically any defense company in America and say that they have contributed to me," he said. "But I do what I think is right for the country."

Hunter pointed to a pair of examples in recent years when he voted to cut funding for projects being pursued by some of his largest defense contributors as evidence he is not influenced by such campaign gifts. One came in 1996, when funding was axed for a third Seawolf submarine, a product of General Dynamics, Hunter's No. 2 contributor going back to 1989, he said.

Still, for some, Hunter's unyielding support for duPont Aerospace's DP-2 plane in the wake of numerous failures raises questions.

"At best, Duncan Hunter has exercised two decades of poor judgment, reflecting his abysmal ignorance of physics, engineering, economics and the needs of the military," said Richard Rider, chairman of the San Diego Tax Fighters, a taxpayer advocacy group.

Rider said it would be a waste to keep pumping dollars into a program that has shown no progress.

"It wasn't like, 'Let's try this for two or three years and see if it pans out,'" he said. "This has been going on for 20 years."

That opinion was shared in large part by Rep. Brad Miller, D-N.C., the subcommittee chairman.

"The U.S. government has very little to show for its investment," Miller said, at the hearing's outset. "Congress appears to have permitted the DP-2 program to become a hobby, not a serious research project, and squandered more than $63 million of taxpayers' money."

Hunter disagreed. He said the DP-2 is a promising project that could pave the way for the military to safely - and quickly - move servicemen and women around in regions where air fields are remote or have been knocked out.

"The DP-2, if it pans out, would go 724 mph," Hunter said. "In other words, more than twice as fast as the V-22 and four times as fast as the CH-46."

The DP-2 also may fly 2,500 nautical miles, several times the range of the CH-46 helicopter, which is being replaced by the V-22 Osprey, he said. The Osprey, a hybrid between a helicopter and a propeller plane, went through a barrage of development failures and deadly training accidents.

As for the concern about wasting money, Hunted said $11.3 billion was invested in the Osprey, and it took 25 years to develop the aircraft. Hunter stressed that just a fraction of that has been invested in the DP-2.

That $63 million was awarded despite opposition from the Pentagon because Hunter exercised his option, as a powerful member of the Armed Services Committee, to use a process called earmarking. Through it, members add funding to the budget for specific projects, usually from their home districts.

Hunter offers no apologies for that, saying it is Congress' constitutional responsibility, not the Pentagon's, to equip the nation's military. And he said that it was through earmarks that he secured funding for the X Craft.

"It's now the fastest ship in the Navy," Hunter said of the X Craft. "That's another experimental craft that nobody said would work. … They may call it an earmark. I call it doing my job."

During his extended job as congressman, Hunter has become one of the nation's largest beneficiaries of defense-contractor campaign contributions.

Massie Ritsch, communications director for the Center for Responsive Politics, said $1.3 million, or 28 percent of Hunter's large contributions - those over $200 - have come from the defense industry going back to 1989.

"Defense companies are very strategic about how they give their campaign contributions," Ritsch said. "They focus almost exclusively on those who control the purse strings of the defense budget and those who set policy."

Contractors tend to consider such contributions as "a tiny cost of doing business compared to the multimillion-dollar and even billion-dollar contracts that they reap. That is not to say that campaign contributions buy defense contracts. But they do give defense contractors the access they need to make the case that their products are worth the government's money."

- Contact staff writer Dave Downey at (760) 740-5442 or ddowney@nctimes.com.