ANDERSEN AIR FORCE BASE, Guam - Critics claim the Osprey is unsafe. Backers praise its flexibility and cite its track record in Iraq, Afghanistan and Libya. Queasy fliers have lost their lunches as it makes the mid-air switch from helicopter to airplane.

No matter what you think of this hybrid aircraft, one word fits best: unique.

When the MV-22 takes off in helicopter mode, it doesn't hover when separating from the ground like a conventional chopper does.

Instead the Osprey, its tilt rotors at a 60-degree angle, accelerates and lifts off the runway while moving forward. Fast.

Then comes the moment of truth, when the pilot swiftly switches to "airplane mode" and the rotors tilt forward to look like airplane propellers - a conversion most of its 24 passengers can't see but sure can feel. The Osprey zooms upward with a jolt, as if booster rockets have kicked in.

The sensation is fleeting. The 10-minute ride allows photographers near the back to shoot out the open cargo door while the Osprey cuts through the windy skies above Andersen, banking left over the rocky, ocean-sprayed cliffs near Ritidian Point into the Philippine Sea.

Once in airplane mode, the ride gets quieter, slightly smoother. The initial force of the switch would have sucked out anything not strapped down from the back of the Osprey at take-off but evens out mid-flight. Upon descent, the switch back to helicopter mode sends the force up toward the cockpit.

The Osprey pressurizes only above 10,000 feet. The cockpit is air-conditioned to help preserve the avionics, aircrew members said, a plus for pilots when flying in the desert or the tropics.

Ospreys typically are accompanied by fighter jets - usually one of the Marines' F-18s or an Air Force A-10 - but are also equipped to hold a machine gun from the open cargo door when needed.

With the flight nearing completion, the MV-22 hovers like a helicopter and slowly drifts down till wheels kiss the ground.

The experience was enough to impress a group of dignitaries, politicians and reporters who got a ride last week when three Ospreys from the 1st Marine Aircraft Wing based in Okinawa, Japan, arrived to participate in exercise Forager Fury, making time for two "familiarization flights" in between missions.

One Marine said his measure of the Osprey's risks is his mother's peace of mind.

"I know it's safe. My mom would kill me if I wasn't flying something safe," crew chief Sgt. Jeff Schneider told Stars and Stripes.

While deployed in Afghanistan, an Osprey he was flying in absorbed rounds from an AK-47 through protective gel on the hull's interior, he said.

It's proven in combat.

"I've seen this machine do some amazing things," Schneider said.

Most of the VIPs on the short flight seemed amazed.

They asked questions of Schneider and other aircrew members, as well as the general in charge of them, before and after the flight.

"It's so much smoother than a regular helicopter," said Mark G. Calvo, a retired Army lieutenant colonel and Guam native.

"It felt like you were in a plane the whole time," said Calvo, special assistant to the governor of Guam and director of the state's military buildup program. The U.S. territory is preparing for the arrival of 5,000 Marines from Japan - but not their Ospreys.

Among the other VIPs was Toshio Matsumura, Japan's deputy consul general, who said his worries about the Osprey dissipated after he got the chance to fly in it and talk to aircrews.

"Originally I was very scared," said a windblown but smiling Matsumura. "I didn't think it was that stable."

Forager Fury is the first exercise the Japan-based MV-22s are participating in since they began replacing the Marines' aging CH-46 helicopter fleet on Okinawa this fall.

The 1,500-nautical-mile trip from Japan to Guam alone was a "huge success," a trek beyond the capabilities of the CH-46, Maj. Gen. Christopher S. Owens, commander of the 1st Marine Aircraft Wing, told the civilian group.

Owens explained how the Osprey works: It can land and take off only in helicopter mode, when the rotors are oriented vertically and provide the lift. As the aircraft transitions to airplane mode - ideally about a 10-second process - the rotors move to a forward position and the wings take over the lift. In full airplane mode, the wings provide all the lift and the rotors provide thrust.

"I hate to use the word revolutionary because it sound cliché," Owens said. "But that's what this aircraft really is."

The Ospreys can fly further and faster and carry more than helicopters. Unlike cargo planes, they do not require runways - a boon both for combat and humanitarian missions.

"We can get supplies in where otherwise we couldn't reach…and can get in and get out a lot quick than we could with helicopters," Owens said.

What's more, the Osprey's "low signature" characteristics mean the enemy "won't hear us coming, they won't see us coming," he said.

The U.S. already has deployed the Ospreys to Iraq, Afghanistan, Haiti and Libya, where two MV-22s helped rescue a downed F-15 pilot last year.

However, their arrival on Okinawa in October ignited a backlash on the island, where critics are leery of the aircraft's safety record after crashes in Florida and Morocco this year.

"I disagree with the criticism being leveled at the aircraft but I understand the concerns. We're doing our best to operate the aircraft as safely as we possibly can and to be as friendly [a] neighbor as we possibly can," Owens said.

Opponents on Okinawa say they will never be satisfied as along as Ospreys are there.

"If they can conduct exercises and operations (on Guam) what makes it necessary to base them on Okinawa?" said Yasuhiro Miyagi, who leads one of many groups staging rallies and protests around the gates at Marine Corps Air Station Futenma on Okinawa where the Ospreys are based.

Calvo said Guam would be open to hosting the Ospreys because of the benefit more military operations would bring the local economy.

Still, the staunchest advocates of the Osprey were the Marines who fly them daily.

The Osprey can practically land anywhere, pilot Capt. Brian Psolka said, from parking lots and roads to cliffs and ships., and it's strong enough to transport a Humvee.

"The capabilities this aircraft brings are phenomenal."

Reporter Chiyomi Sumida contributed to this report.

reedc@pstripes.osd.mil