Back-to-School Days
By Peter Garrison
Photographed by Elizabeth Goettee
March 2008
Bill Warlick has had an interesting career. He began flying at 14, graduated from NC State in Aerospace Engineering, joined the Navy, instructed in T-28s, and flew several tours in the P-3 Orion — the Navy's patrol version of the Lockheed Electra — before spending three winters flying ski-equipped C-130s in Antarctica. He did stints in Navy flight test, then four years with Northwest Airlines before being furloughed after 9/11 and going to work for the U.S. Navy Test Pilot School at Patuxent River, Maryland — Pax River, for short. The list of types he's flown reads like the index of an aeronautical history book: F-111, F-18, F-16, B-25, P-51, T-6, B-52, B-727, B-757, MiG-15 and so on, with various helicopters and a few Cessnas, Champs and RVs thrown in for good measure.
This clear fall morning, we're in a De Havilland Beaver on the ramp at Pax River. I've never flown a Beaver before, and so I'm doing my babe-in-the-woods impersonation just in case the airplane turns out to be so tricky to taxi or fly that I would be doubly embarrassed if I had pretended in advance that I knew what I was doing. The Beaver's panel is one of those quaintly cobbled-together things from yesteryear; you all but hear the designers exclaiming, "Eh by gum, we forgot the flap handle!" and a mechanic, his head beneath the panel and his feet on the seat, offering in muffled tones, "We could put it here." Incongruously, a Garmin screen, a visitor from the future, peers out of the middle of it.
The Beaver's 450 hp radial wakes up one cylinder at a time, like a tent-full of kids on a camping trip. I taxi. It's not difficult; the Beaver radiates cooperative good-nature, like a large, amiable dog. Warlick does the takeoff and hands me the controls as we climb through 500 feet, those being the restrictions under which we are operating.
It's quickly apparent that this is what you would call "a rudder airplane." I imagine the jet pilots who come here from Hornets have to learn a whole new meaning of the word "turn," but if you've flown anything built before 1940 you have no trouble leading a bank with rudder and then lightening the pedal pressure as the wing comes down and the nose swings into the turn. "I see you've done this before," Warlick says, and, temporarily setting aside my customary assumption that people don't mean what they say, I elect to take this as an indication that the ball, which is over on his side of the panel, is staying somewhere near the middle.
At altitude, Warlick points out some landmarks on the long crab-cake-filled peninsula that juts out toward Chesapeake Bay, has me do a few turns and stalls, and then demonstrates the kinds of maneuvers that test pilots would use to assess the handling qualities of an airplane. I am interested to see that the maneuvers are mostly small, gentle ones, intended to detect the amount of hysteresis in the controls, the rate of response to a small input, the amount of input needed to bring about a certain response, and so on. Static directional stability — the number and size of tail-wags before the airplane settles down after a rudder pulse — and dihedral effect — the ability to pick up a wing with rudder alone — are tested with gentle, moderate excursions. As Pax River's deceptively youthful Commanding Officer, Captain Tom Huff, told me, "We're not here to go over the edge; we're here to approach the edge cautiously."
Warlick demonstrates the basic parameter of dynamic longitudinal stability, the phugoid oscillation, by pulling up until 20 knots or so bleeds off the airspeed and then just holding the wings level without applying any pitch control as the airplane dives, then climbs, then dives again. The motion dies out after two or three cycles, and the cycles themselves are short. Those of a cleaner, faster airplane would probably be longer and take longer to damp out, or the phugoid might not damp out at all, in which case it would be classed as "undamped" or "divergent." A divergent phugoid is not desirable, but it may still be acceptable because the period of the oscillations is so much longer than the reaction time of the pilot.
Why, you may wonder, is the U.S. Navy Test Pilot School flying big clunking airplanes with radial engines in the 21st century?
The answer is variety. They fly anything they can get their hands on. In fact, they contract with civilian owners for temporary use of unusual airplanes; that's how Warlick happens to have a B-25 and a MiG-15 in his logbook. They also make field trips; recent off-site opportunities have included the F-16, the Grumman Albatross and a Grob sailplane.
Although "touching airplanes" of all sorts plays a very big role and students average 100 hours of flying while at the school, the curriculum isn't all flying — far from it. The 72 students who form two classes a year spend a great deal of time in classrooms, absorbing a demanding syllabus that ranges from basic aerodynamics, with a strong dose of calculus, to practical aeronautical engineering (what is that bump for? why did they put a vortex generator right there?), aircraft systems and flight testing techniques. The school will soon offer its graduates a master's degree in Flight Test Engineering. I sat in on a couple of aero classes, one taught by the hyperkinetic polymath J J McCue, who did all that one can to spin the circulation theory of lift into a standup routine, and the other, on stability and control, taught by Greg Dungan, who judges international aerobatic competitions during lulls in his teaching duties.
The mathematical aspect of much of what was being taught was above my head, but I could see the reason for it. One of the goals of the school is to instill in students an analytical attitude toward airplanes and, in fact, toward every machine and system they encounter. That attitude requires understanding, on the basement level of fundamental physics, every process, every force and moment, and every flying characteristic whose true cause is camouflaged by multiple and intertwined reactions. After attending test pilot school, a pilot won't make toast, get on an elevator or turn a hotel room faucet without thinking about how the thing works and how it might be improved.
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