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Photo by Laurie
Goossens |
The Air Force has a fast new tool to get
into and out of tight places. It's the CV-22 Osprey, whose twin giant
tilt rotors give it remarkable vertical takeoff and landing capability.
Those same giant rotors, too large to clear the ground when tilted fully
forward, can give the Osprey a maximum sea level cruising speed of 250
knots.
Vertical takeoff weight is limited to
52,600 pounds. Any heavier, and the Osprey must get a running start,
with the giant rotors tilted forward not more than 60 degrees to ensure
ground clearance.
Capt. Buck Kozlowski is a former C-130
transport pilot who is in the midst of his intensive year-long
transition training into the Osprey with the 71st Special Operations
Squadron. He says savvy Osprey instructors fit each pilot to the plane,
which is helpful since he is a fixed-wing pilot while many others coming
into the Osprey world are prior helicopter pilots. In vertical flight
mode, he is out of his previous comfort zone, but Captain Kozlowski says
he comes into his own realm when making steep turns in level flight at
10,000 feet - not typical of helicopter operations.
Are the big rotors loud? What? No, not
really, Captain Kozlowski says, comparing the CV-22 as perhaps quieter
than a C-130. The aircraft is computer-controlled fly-by-wire. Pilot
control inputs are, well, suggestions for the computers to consider when
they mete out a response within the CV-22's performance envelope.
"The computer won't let you over-G (overstress) the aircraft,"
he explains. That includes tilting the rotors. Tilting them forward from
vertical to horizontal flight is called transitioning; tilting back from
horizontal to vertical flight is called conversion in Osprey parlance,
the captain says.
Tilt angle is adjusted for the mode of
flight. "The idea is to keep the fuselage level," Captain
Koslowski says. Sometimes, this calls for a tilt angle different than 90
degrees to counter a headwind, for example. But if the crew wants to get
a better look at the ground in front of them, they can shift the rotors
back beyond vertical to 96 degrees, and produce a nose-down attitude.
Captain Koslowski has participated in
more than one air show display of the Osprey. The Oshkosh crowd, known
for its aviation savvy, asks different questions. "Here we've been
getting a lot of performance-based questions," he says.
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