Extreme Machine- page 4 | Flight Today | Air & Space Magazine

Extreme Machine

The U.S. Marine Corps' sword gets a brand-new edge.

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(Continued from page 3)

Where Leonard and other pilots may occasionally get outvoted by the three computers is in a region called the "conversion corridor." The corridor is a programmed schedule of airspeed-nacelle angle combinations that prevent the rotors from being overloaded at high speeds. The computer won't allow the pilot to rotate the nacelles back toward upright until the airspeed drops below 220 knots, for example. It will also move the nacelles from five degrees to zero automatically in airplane mode.

In the V-22 simulator at Pax River, Major Kevin Gross, a U.S. Marine with the integrated test team of V-22 pilots, lets me have a go at it. The cyclic control in my right hand feels like any military control stick, with switches and buttons arranged around it and a four-way "coolie hat" switch near the top to trim out imbalance in pitch or roll. But the thrust control lever in my left hand is different, more massive than any throttle or collective I've ever gripped. Instead of moving up and down like a helicopter's traditional collective, the TCL moves fore and aft, like a throttle, yet it feels natural to pick up to a hover by pushing forward to add power.

Normal takeoffs are made not from a hover but with the nacelles at 60 degrees. The airplane rolls for a short distance, and once aloft, I begin pushing forward on the thumb switch to rotate the nacelles forward. The nose dips a bit during the transition, and with Gross coaching me, I add a little bit of back pressure. Within a few seconds we are in a cruise climb at 180 knots. At five degrees nacelle, I can let go of the button and the nacelle will continue automatically to zero. Push the button once more and the rotor slows to 84 percent rpm and we are a pure airplane.

"It doesn't do loops, and it really doesn't do aileron rolls very well. It'll do a wingover," Gross says. Then, with the nacelles set at 95 degrees, Gross flies up the runway's electronic glide path backward, just to show that backing up can be done with an added task like shooting an instrument approach. These are the simple pleasures of the test pilot life, and Gross is quick to add, trying to keep a straight face, "This will not be normal procedure."

Has he ever done an autorotation, the power-off maneuver in a helicopter in which the rotor blades freewheel in a descent to an emergency landing? His cautious answer: "Autorotation has been evaluated. Actually there are three phases to autorotative descent. The entry to the autorotation, the descent itself in a steady-state condition, and then there's the flare at the bottom. We have done the autorotative descent in flight test. The entry and the recovery still have yet to be done, and I don't know if we actually will in EMD or not. That's a pretty big decision above our pay grade." Gross explains that this rotor system is not like a helicopter's in that the system is not free-turning with power off and there is not the same collective power to flare with at the bottom by pulling the blades to abnormally high pitch angles.

On the way home from the simulator flight, it dawned on me that the test pilots are continuing the process of invention: They are inventing how to fly the thing. Someday soon, someone will have to sit down and write a pilot operating handbook. Gross and his colleagues on the test team talk frequently about the coming day when the "lieutenants" get the airplane"When the lieutenants fly it," "We wonder how the lieutenants will handle this."

They freely speculate about some of the things they've done with the V-22, exploiting its talent for hovering in a very stable manner while they use the nacelle switch to alter the deck angle of the fuselage, a condition in which both pilots are looking down at the runway, which fills the windshield at a startling angle. "No other aircraft can do this," they say. But they don't know how many of these capabilities will make it into the syllabus and be taught when they "take it to the schoolhouse"their term for flight training.

They are surely aware that Marines inevitably discover the unusual corners of any aircraft's flight envelope. The British invented the Harrier, but a U.S. Marine invented "viffing," or vectoring in flight. No one had thought to try moving the nozzles of the jets' engines at high speed. It turns out that the use of this peculiar talent can make the Harrier a very difficult target to hit in aerial combat. The service pilots on the V-22 test team tacitly accept that this aircraft will perform feats as extraordinary as its appearance.

Residents of the coastal Carolinas will soon start seeing the V-22 in the skies near Marine Corps Air Station New River near Camp Lejuene in North Carolina. They are likely to stop their cars, jump out, and stare. Switchboards will light up all over Onslow County with reports of alien craft that look like two windmills attached to a big gray schoolbus with a forked tail.

And perhaps someday, a lonely gunman walking guard on American captives in a besieged embassy will hear a soft whirring sound in the night that comes closer and closer until suddenly he is faced with an apparition that stares back as if to say, Hey, buddy, hostage THIS!

About George C. Larson

George C. Larson served as editor of Air & Space from 1985 to 2005. He is currently an inactive pilot, but holds a commercial pilot's license, with instrument and multi-engine ratings. He is between airplanes at this time, but has owned or operated a Grumman American AA-5B Tiger and a Mooney 201. He has been writing about aviation since 1972, when he joined the staff of Flying Magazine.

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