The Marine Corps said it intends to base 24 MV-22 tilt-rotor Osprey aircraft at Kaneohe Bay, along with 18 Viper attack helicopters and nine Huey helicopters as part of a plan that will radically change the aircraft makeup at the air station.

The distinctive Ospreys have 38-foot twin rotors that allow the aircraft to take off like a helicopter, then rotate forward to become giant propellers, making flying much faster than helicopters.

The aircraft stationing is part of a plan by the Marines to restructure and shift their forces in the Pacific. An additional 1,000 personnel and 1,100 dependents would come in starting in 2012, with "full implementation" of the plan by 2018.

On Nov. 19 the Navy announced its decision to base up to 10 MV-22 squadrons, for a total of 120 Ospreys, on the West Coast to replace nine helicopter squadrons.

The bases in Hawaii and on the West Coast are part of a Marine Corps plan to replace its aging fleet of medium-lift helicopters with the more advanced tilt-rotor Osprey.

The Ospreys can fly faster and farther than conventional helicopters.

Military expert John Pike, director of GlobalSecurity.org, said there is one overarching reason for the Osprey buildup in the Pacific: "Communist Red China, what else?" he said.

China’s military buildup is seen as a growing threat to what has been a longtime U.S. dominance in the region.

Defense Department plans call for 458 V-22s — 360 MV-22s for the Marine Corps; 50 CV-22 special operations variants; and 48 HV-22s for the Navy. In late 2009 the Congressional Research Service reported the average cost per Osprey was about $92.1 million.

The MV-22 is designed to transport 24 fully equipped Marines at a cruising speed of about 250 knots (about 288 mph), exceeding the performance of Marine Corps CH-46 medium-lift helicopters.

In Hawaii the Ospreys would replace two squadrons of older CH-53D Sea Stallions, while a third squadron of 10 Sea Stallions would be replaced by newer versions of the CH-53, officials said.

The addition of the 24 Ospreys, 18 AH-1Z Viper Super Cobra attack helicopters and nine UH-1Y transport choppers would nearly double the rotorcraft based at Kaneohe Bay.

Maj. Alan Crouch, a spokesman for Marine Corps Base Hawaii, said the 3rd Marine Regiment at Kaneohe Bay is the only regiment in the Corps that does not have training nearby with Huey transport and attack helicopters.

The choppers provide "very, very important fire support and lift support for troops on the ground," Crouch said. "They need them in theater, and they need to practice with them here in Hawaii."

The Corps revealed the rotorcraft plan details in conjunction with the announcement that it is conducting an environmental impact statement analysis of the Osprey and helicopter stationing in Hawaii.

A "record of decision" on the plan is expected in late 2011.

In addition to using Kaneohe Bay and Bellows, the Marine rotorcraft might train at Wheeler Army Airfield, Dillingham Airfield, at Pohakuloa Training Area on Hawaii island, and on Molokai and Kauai.

A series of public "scoping" meetings will be held Aug. 24-30 to determine what the Marines should examine as potential effects from the plan. About 9,400 Marines and sailors are based at Kaneohe Bay now, officials said. Noise for surrounding residents is sure to be a concern.

"It’s definitely an important topic to be considered as plans progress," Crouch said. The environmental analysis will spell out more of the basing plan.

GlobalSecurity.org said on its website that compared with both helicopters and conventional turboprops, the Osprey has a lower "acoustic signature" due to the tilt-rotor’s reduced rotor rotational speed. It also uses very low thrust for cruise propulsion.

The V-22 flying in aircraft mode produces a distinctive sound, described to be more like a vehicle than a helicopter, the website noted.

Overall, as compared with the CH-46 helicopter, the MV-22 is less noisy while in the aircraft mode and has comparable acoustic levels while operating in the helicopter mode, the organization said.

The controversial Osprey program began in the early 1980s, was threatened with cancellation in the late 1980s and early 1990s, and experienced fatal crashes in 1992 (seven fatalities) and in April (19 fatalities) and December 2000 (four fatalities).

Ospreys have deployed to Iraq several times and have been in Afghanistan for seven months. An April crash in Afghanistan claimed the lives of three U.S. service members and a civilian.

Despite the history, GlobalSecurity.org’s Pike said the aircraft have improved.

"I think the critics have grown silent," he said. "The Osprey that they are flying today is very different from the Osprey that they were flying 10 or 20 years ago. The aircraft they were flying in the ’90s had problems. The aircraft they are flying today does not."

The mix of aircraft at Kaneohe Bay is likely to change in other ways. The Navy finalized a plan in late 2009 to replace all but three of its 27 propeller-driven P-3C Orion surveillance and reconnaissance aircraft with 18 P-8A Poseidon multimission jet aircraft based on the Boeing 737-800, but with strengthened wings, weapons systems and added fuel tanks.

The move to Poseidon surveillance aircraft would result in fewer airplanes and personnel at the Marine Corps base, slightly more noise and an investment of $147.5 million for infrastructure upgrades, the Navy said.

The Navy said at the time that it wanted to begin replacing the Orions in its fleet no later than 2012 and have the process completed by 2019.