Making a whisper-quiet helicopter is still beyond the means of modern technology, but military defense analysts say the Sikorsky choppers that Navy SEALs used in the raid on Osama bin Laden's compound in Pakistan were clearly an advance toward that long-sought goal.
One of the helicopters was damaged during a hard landing and the commandos destroyed it before leaving with the infamous terrorist's body. Military aviation experts have been poring over photographs of the debris, particularly the tail section.
Precisely how the Black Hawk helicopters were modified is not known, but the photographs of the wreckage, analysts say, offer new clues to the military's cutting-edge methods.
Several analysts agreed the aircraft used technology that appeared to stem from the Comanche, a $39 billion, joint project between Sikorsky and Boeing that employed hundreds of people in Connecticut until it was scrapped in 2004 due to high costs.
"It's clearly something unusual," said Dan Goure, a defense analyst with the Virginia-based Lexington Institute.
But with only the tail boom to look at, picturing the entire machine is a bit like trying to rebuild a dinosaur from one bone, Goure said.
"Nobody could afford to do a purpose-built stealth helicopter," Goure said. "If you're not going to spend $1 billion on a purpose-built helicopter," then a modified aircraft is the next best thing."
Aviation analyst Richard Aboulafia said it's clear to him that Comanche technology was incorporated in the modified Black Hawks.
"I was hoping that something would be salvaged from that thing," Aboulafia said.
The curved, bulbous structure of the chopper is crucial to confounding radar, he said.
"You don't want sharp angles and you don't want gaps to appear in the structure — that's where radar emissions can bounce around," Aboulafia said.
U.S. officials confirmed that the marquee helicopter of Stratford-based Sikorsky Aircraft was the platform for the warbirds that delivered 25 SEALs to the compound. But that's all they would say.
"We have no additional operational details, or comments on operational details, to make at this time," U.S. Army Lt. Col. Elizabeth Robbins, a Department of Defense spokeswoman, wrote in an email Friday.
Sikorsky also declined to comment other than to say the company has not been asked to help investigate why the aircraft sustained a hard landing.