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School Days

August 15, 2016

 

 

Bill Warlick had an interesting career. He began flying at 14, graduated from university in Aerospace Engineering, joined the US Navy, instructed in T-28s, and flew several tours in the P-3 – the Navy’s patrol version of the Lockheed Electra – before spending three winters flying ski-equipped C-130s in Antarctica.

 

He did flight test stints in the Navy, then four years with Northwest Airlines before being furloughed after the 9/11 attacks and going to work for the Navy Test Pilot School at Patuxent River, Maryland – Pax River, for short. The list of aeroplanes 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 autumn morning, we’re in a de Havilland Canada Beaver on the ramp at Pax River. I’ve never flown a Beaver, and I’m doing my babe-in-the-woods impersonation just in case the aeroplane 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, “Damn, we forgot the flap handle!” and a mechanic, his head deep beneath the panel and his feet on the seat, offering in muffled tones, “We could put it here.” Incongruously, a Garmin screen, like 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 exudes the cooperative good-nature of 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 call ‘a rudder aeroplane’. 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 if people say something nice they probably don’t mean it,  I elect to take this as an indication that the turn-and-slip ball, which is over on his side of the panel, is staying somewhere near the middle.

At altitude, Warlick points out a few landmarks on the long crab-cake-filled peninsula that juts out toward Chesapeake Bay. He has me do a few turns and stalls, and then demonstrates the kinds of manoeuvres that test pilots would use to assess the handling qualities of an aeroplane. I’m interested to see that they 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. He tests static directional stability – the number and size of tail-wags before the aeroplane settles down after a rudder pulse – and dihedral effect – the ability to bank the aeroplane with rudder alone – with gentle, moderate excursions. As Pax River’s youthful-looking 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 the airspeed bleeds down to 20 knots or so, and then just holding the wings level without applying any pitch control as the aeroplane first 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 aeroplane 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 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 US Navy Test Pilot School flying big clunking aeroplanes 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 aeroplanes; 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, a Grumman Albatross, and a Grob sailplane.

Although ‘touching aeroplanes’ 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 indoors, 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 a master’s degree in Flight Test Engineering to its graduates. I sat in on a couple of aero classes, one taught by a hyperkinetic helicopter guru, JJ McQue, who did all that one can to spin the circulation theory of lift into a stand-up comedy routine, and the other, on stability and control, taught by Greg Dungan, who judges international aerobatic competitions during gaps in his teaching schedule.

 

 

 

ABOVE - Phugoid oscillation tested by
pulling up until the airspeed bleeds down
to 20 kt or so, and then holding the wings
level without applying any pitch control.

 

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 instil in students an analytical attitude toward aeroplanes and, in fact, toward every machine and system they encounter. That attitude requires understanding, on the level of fundamental physics, every process, every force and moment, and every flying characteristic whose true nature may be camouflaged by multiple and intertwined causes. 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.

The school, which was founded after World War Two, draws students and staff from all military services, notably the Army, and serves a host of international customers as well as its natural Navy constituency. Some students and instructors are also exchanged with test pilot schools in England and France. Despite the opportunities to fly a lot of exotic hardware, “it’s getting increasingly difficult to recruit guys into test,” says Tom Huff. Test pilot training, it seems, doesn’t fit neatly into the Navy’s preferred career path.

The course is a demanding one. “We joke with them,” Huff says. “We tell them, you’ve got half a day of flying, half a day of classes and half a day of report writing. Good luck getting that all in!” The course culminates in a long report – some run upward of 100 pages – on an unfamiliar aircraft that they may travel halfway around the world to fly.

Although finding ways to lose control of an F-18 or blasting things away with underwing munitions at China Lake sounds like a lot of fun, much of a test pilot’s life actually consists of trying to hold 400 knots, 5 Gs, and 5 degrees of yaw accurately enough, and long enough, for the guys on the ground to grab a data point. It’s work tailor-made for people who live and breathe aeroplanes. Surprisingly, Greg Dungan said, you also run into test pilots who aren’t aeroplane fans from birth. “I had one guy,” Dungan laughed, “who, when he was at the Academy, they asked him, ‘Do you want submarines or surface or aviation?’ and he said, ‘Aviation sounds like fun.’ That was the first he had ever thought about it.”

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