You might say that Osprey pilots are neither fish nor fowl.

Air & Space Magazine

(Continued from page 1)

"But I was a Hornet guy," he recalls of the new temptation. "Someone said, ‘Hey, there's an exchange tour going on—you can go fly the V-22 for a couple of years and go back and fly the F-18. If you believe in [the V-22] so much, why don't you go do it?'

"I put in for it, knowing in the back of my mind, back from college, that I thought I might one day be flying it," says Smith. "Sure enough, I got selected."

Back then, the Marines weren't sure how tiltrotor pilots should be trained: Should they train in both helicopters and airplanes? A study to determine the best course of action for training tilters indicated that for Smith and other new recruits already trained as Marine fixed-wing pilots, MV-22 simulator time at VMMT-204 in New River would be adequate.

All Marine Corps pilots start primary flight training in fixed-wing aircraft, then enter the pipeline to jets, props, helicopters, or tiltrotors. Tilters take multi-engine training in the TC-12B, the military version of the twin-turboprop Beechcraft King Air 200, then an abbreviated helicopter course in the TH-57, the single-rotor Bell JetRanger helicopter. About one-third of today's tilters come from medium-lift helicopter squadrons, one-third are from fixed-wing and heavy-lift squadrons, and the rest are newbies.

"Being that the V-22 doesn't have a collective control [a helicopter control for vertical velocity, it governs the pitch of the rotor blades], all I had to do was focus on flying the aircraft," says Smith. "I already knew the gauges, so there was no need to go fly the TH-57." It seemed that tiltrotor controls were similar enough to those of fixed-wing aircraft that fixed-wing pilots could get by without rotary-wing training.

A pilots flies the V-22 from the right or left seat using a thrust control lever in his left hand, a device that takes the place of the throttle in an airplane and the collective in a helicopter. In their right hand is the floor-mounted control stick, which takes the place of the yoke in an aircraft and the cyclic control (which governs movement about the pitch and roll axes by tilting the entire rotor disc) in a helicopter. Flight crews include a commander (a pilot with at least 500 hours of total flight time and 100 hours in the V-22) in the right seat, a copilot in the left seat, and a crew chief in the back.

A typical flight begins with the ritual walkaround inspection and engine start, a highly automated process that takes about 10 minutes for both engines, says Tom Macdonald, senior Boeing test pilot for the V-22. Takeoff can be made vertically by keeping the two wing-mounted nacelles (each of which contains an engine, two gearboxes, and a three-blade, 38-foot-diameter propeller rotor on top) at the 90-degree angle (vertical), or from a rolling start by "beeping" the nacelle angle toward the horizontal using a spring-loaded rate-control thumb switch on the thrust lever. On the ground, nacelles can be pitched backward to 95 degrees for backing up—like a car in reverse—or tilted forward as far as 45 degrees for taxiing. To take off like a helicopter, Macdonald says the pilot pushes the thrust control lever forward "and the aircraft lifts straight up."

The transition between helicopter controls (tilting the rotor disks in various directions to bank, climb, dive, or yaw) and airplane inputs (moving flaperons on the wing and elevators and rudders on the tail) is managed by the triple-redundant flight computers. Macdonald says the process is "effortless" except for the large amount of pitch trim required to maintain level flight during transition from helicopter to airplane mode. The pilot adjusts the trim with a manual control in the cockpit. Once the transition is complete, the Osprey cruises at speeds near 275 mph.

To land, Macdonald explains, the pilot pulls back on the thrust lever within a mile or two of the runway. Once the Osprey slows to below 230 mph, the pilot uses the thumb switch to raise the nacelles, first to 60 degrees for the 125-mph downwind leg of the landing pattern, where the landing gear is lowered. Flaps in all modes are handled automatically by the flight computers.

On the final approach, pilots beep the nacelles toward the vertical position "three or four degrees at a time," says Macdonald, and land either like a helicopter (nacelles at 90 degrees) or like an airplane, with "run on" or "rolling" landings at speeds up to 115 mph and nacelle angles of 75 degrees or more. Macdonald says the same procedures work if one engine is dead, since both 6,150-horsepower engines share a common driveshaft.

Comment on this Story

comments powered by Disqus