By MATTHEW STOSS
GW Magazine / Summer 2018

Murray Snyder remains plainspoken about his research, even in the face of its obvious fun-ness.

A stolid man with a stolid beard and a sense of humor he doesn’t always seem to be aware of, the 58-year-old GW engineering professor studies the air wakes caused by U.S. Navy warships and how those wakes affect aircraft—helicopters, mostly—trying to land on, hover over, or take off from those ships. This involves confirming and/or disconfirming a lot of computer flight simulations but, disappointingly, the use of no actual helicopters and no actual warships.

Instead, Snyder and his coterie of researchers fly sensor-rigged drones off the back of a boat, which is still an admirable level of fun, as is the fact that Snyder, a 30-year Navy vet and a private pilot who flies light-sport planes and autogyros, explored the North Pole while serving on a nuclear submarine. But Snyder, disinclined to hyperbole, keeps, at all times, the fun in appropriate (and necessary) perspective.

“The key things I’ve been able to show, using my research ship and lots of tedious data collection,” Snyder says, “is the computer simulations are reasonably accurate for the area immediately around the ship. What we’re working on now is how accurate they are for regions further away from the ship, which is why we have to fly stuff out there. We’ve validated the computer simulations up close, which no one’s been able to do so far.”

The Office of Naval Research has long considered the work of Snyder and his niche field of peers important because it affects how pilots fly and how ships are designed. Research on the topic, Snyder says, goes back to about the 1960s when helicopters first started landing on ships. The earliest flight simulators came about in the late 1920s.

The ONR has continually funded Snyder for nearly a decade. At the moment, he’s in the home stretch of a three-year, $655,000 grant and trudging through the applications for two others.

Since 2009, Snyder, who started his academic career as a Naval Academy professor in 2006 before coming to GW in 2012, has collected $2.5 million in funding.

“Folks who have been officers, they tend to have a mission-focused approach to how they do things, which is perhaps not found as much in folks who come from just purely the academic side,” says Can Korman, an associate dean for research and graduate studies who’s worked with Snyder since he arrived at GW. “I think that gives him an advantage. … And since he has been in the field and he works with people who had other experiences in the field, he understands the needs of the Navy and can appreciate the needs of the Navy from a technical point of view.”

About once a month, Snyder takes his 108-foot ship, a YP boat in Navy argot, out from an Annapolis harbor and into the Chesapeake Bay. This ship, ordinarily used to teach midshipmen to sail, has been converted to a research vessel and retrofitted with an ersatz flight deck so it mimics the shape and the air wakes of a 500-foot warship.

At sea, a professional drone pilot flies one of a number of anemometer-laden unmanned aerial vehicles off the back of the boat. Airborne, the anemometers record the wind speed, direction and temperature as high as 400 feet—the Federal Aviation Administration’s altitude limit for drone flight—above the deck and as far as 400 feet behind it.

Snyder’s drone fleet started with a $500 remote-control toy helicopter and now is anchored by a 7-foot-wide, 54-pound, $30,000 octocopter that’s festooned with $20,000 of instrumentation and looks like something that’ll end up doing recon for the robots in the forthcoming machine uprising. As far as we know, the octocopter is not yet self-aware.

Snyder also dabbles in fixed-wing aircraft and military drones. It’s the glamorous side of his work, of which Snyder keeps a less-than-glamorous “humble tape.” In it you can see not only what it looks like to crash $50,000 into a large body of water but also Snyder’s scientific mortality.

“But,” Snyder points out, “the flotation system worked. We recovered it and washed it with fresh water.”

And replaced all the electronics. And two of the motors.

It costs just $500 a day for Snyder to boat-and-drone, which perhaps is why the Navy looks so charitably upon his work. To do this research at full scale with a real helicopter and a real warship would cost $200,000 a day, expenses not included. And that’s if Snyder could even find a warship to borrow. Warships, after all, have stuff to do.

Until Snyder, scientists made do with flight simulators, math and, starting in the 21st century, supercomputers. Snyder uses those things, too, but his niche is defined by the drones and the YP boat and the deep résumé—submarine commander, licensed pilot, a mechanical engineering PhD from Johns Hopkins University—that earned him the imprimatur of the U.S. Navy.

Snyder says none of this was his idea.

One day during the Vietnam War, Navy helicopter pilot John Burks had to land a chaplain on a destroyer in the middle of a storm. It wasn’t a typhoon but you could’ve fooled the chaplain. It was 1973 and springtime in the Gulf of Tonkin.

“I was taking a chaplain to a small ship for services,” Burks says. “My job was to go and take the chaplain and drop him down on a hoist. You’ve seen the pictures of the Coast Guard helicopters hoisting people up from the water?”

For Burks, retrieving and depositing via winch and cable a serviceman, supplies or mail on the deck of a warship was an everyday operation. Burks would hover his SH-3 Sea King—a 73-foot, 6-ton helicopter the Navy used until the mid-2000s for search and rescue missions and logistics (like the transporting of hapless chaplains)—above a ship too small to accommodate a landing helicopter. Then a crewman would hoist or lower the passenger/victim who was affixed by padded strap, or “horse collar,” to the end of a steel cable. Strong winds and angry seas imperiled the proceeding.

“We typically hovered 15 or 20 feet above the deck,” Burks says. “However, with higher winds and rougher seas, we often had to hover higher. Envision the aft end of this 300-foot-long ship heaving up and down as it plows through high waves—which it must do to maintain control—swaying left and right, and the sides rising and falling as the ship rolls to port and starboard.”

Which means...

“Your landing area is moving back and forth and up and down. At the same time, the wind coming around that superstructure is creating all kinds of turbulence and vortices, and it’s making the helicopter rock back and forth in a lot of directions in close proximity [to the ship]. You have to try to pilot it in such a way that you touch down softly and you don’t break things.”

Like a chaplain dangling in a sling at the end of a rope—a God-fearing pendulum swinging in a 25-foot radius across the deck of a several-thousand-ton destroyer that’s moving up, down and side to side, cutting forward at an angle through 12-foot waves. There are also 30 mph winds, 50 to 60 mph’s worth of helicopter rotor downwash and the ship’s ever-swirling air wake.

“When I next saw the chaplain,” Burks says, “he said he was praying all the way down. There was so much movement that the chaplain was swaying from side to side; the ship was swaying from side to side, heaving up towards him, and it took a tremendous amount of skill to hold the helicopter in place and try to get the chaplain on the deck without getting smacked by either side of the ship.”

The chaplain, whom in a likely understatement Burks called a “good sport,” made it down intact and alive, his faith perhaps reinforced in perpetuity.

Burks went on to become a test pilot before retiring as a Navy lieutenant commander in 1978 and joining the Air Force Reserve. He also spent 20 years as an aeronautical engineer at NASA and had two stints teaching at the Naval Academy, where he met Capt. Murray Snyder.

Snyder recently had become a researcher and professor after a family illness prematurely ended his tenure as a submarine commander in 2001. Academia offered Snyder, always scholastically inclined, a chance to stay involved with, and useful to, the Navy. So he went back to school.

The Navy bankrolled his doctorate in exchange for his teaching at the Naval Academy when he finished it. Snyder became a professor at Annapolis in 2006 and he got his PhD in 2007. He was 47.

“This was an opportunity to stay in the Navy and do something I thought was of value and productive,” Snyder says.

At the time he met Burks, Snyder, still on active duty, was teaching fluid mechanics and thermodynamics to midshipmen, researching bubbles and droplets in isotropic turbulence—the same topic as his PhD thesis—and running computer simulations on reactive metals. He describes these things as “equally unexciting.”

Burks and Snyder were in different departments but occupied nearby offices. Proximity brokered their relationship, and Burks learned about Snyder’s unique résumé. This, plus his test-pilot past life, sparked an idea that fermented in Burks’s brain for six months before coalescing into cogency: Snyder could use his rare combination of maritime, engineering and aviation expertise to study ship air wakes, both theoretically and practically, and in the process maybe make life safer for military pilots.

“What really made him suited to do this was his having commanded ships,” says the 71-year-old Burks, who now lives in Annapolis. “He’s a sailor. He knows about ships and so he could request from the Naval Academy that he get one of these ships and really be in charge of a program. They had complete confidence in him doing that. And he was a researcher doing the computational fluid dynamics”—that means simulating in a computer the interaction between air and an object—“which is the basis of what the research is, so you don’t always have to go out and do the testing on a ship. You can actually do it in simulation. He was uniquely qualified to do both.”

Burks made his pitch. It was 2009.

“I’ll be honest,” Snyder says. “When this helicopter pilot came in with this idea, I was like, ‘Hey, that’s a lot more interesting than what I’m doing right now.’”

Murray Snyder’s office on the second floor, or “deck” if you used to work on submarines, of Science and Engineering Hall looks like… an office. It’s a standard-issue fluorescent square off a standard-issue fluorescent hallway. The most interesting things about it are, in ascending order, the bookshelf serving as tabernacle for Snyder’s regally bound PhD thesis, the window overlooking a reasonably grassy courtyard, Snyder’s stacked boxes of research Legos and Snyder himself.

He spent 27 months as commander of the USS Nevada, one of the 14 ballistic missile, or “Trident,” submarines that compose the sea prong of the United States’ nuclear triad.

Snyder spent 11 of his 30 Navy years on submarines, serving as a propulsion assistant, weapons officer, engineer, and executive officer, one of only two posts that come without a roommate. He still had to share a bathroom with the captain, though—and his spare bunk, if the sub had a visitor, like an admiral.

In 1998, Snyder became captain of his own ship. Snyder says he did a lot of “fun” and “interesting” things while serving on submarines, many of which he demurs about because those things are classified.

Life on a sub, he says, is cramped, even for someone who’s a svelte 5-foot-9. The beds are 6 ½ feet long and could function admirably as coffins. Even a captain’s stateroom is no larger than an office cubicle.

Claustrophobia and the pall of waterborne catastrophe, Snyder says, are mitigated by exhaustion which, conveniently, also makes it easier to fall asleep. Two decades of submarine conditioning have left Snyder incapable of enjoying any more than an edge-ward sliver of his king-size bed.

Snyder grew up in a military family. His father was a West Pointer and paratrooper but discouraged his son, who was nourishing a lifelong interest in a military career, from attending an academy. The elder Snyder told his son that he’d have more fun at a regular college. Murray Snyder ended up at Duke University, where, he confirms, that he did have fun, before graduating in 1982 with a mechanical engineering degree. Then the Navy commissioned him an ensign, and he volunteered for the submarine service, eventually sating a National Geographic-inspired childhood fantasy of exploring the icy Arctic in a submarine.

“It is pretty scary up there,” says Snyder, sitting behind his standard-issue office desk and speaking in the tone you and I might use to describe how we boil water. “There are times when you realize you’re really on your own. We were up during the late summer, early fall, when the ice is broken up in places and you have these things called polynyas, which is just a lake in the ice.

“You keep track of where you can surface, so if you have a casualty, like a fire or something, and you need to come to the surface to ventilate, you know where you are and where you can do this. … One of the things you would do on a watch-turnover is, ‘OK, where was the last surfaceable feature?’ And I remember one day, ‘Oh, it’s 250,000 yards behind us,’ which means there’s no way you’re going to get there. It’s just too far away. That’s 125 miles.”

Snyder says that on one submarine (he served on four), he spent eight weeks straight submerged in the Arctic, traversing cold, unknown waters and immured in ice channels.

“The ice gets broken up and it moves around and it has a tendency, if you’re close to land, to build up and get jammed in there—and it gets really deep,” Snyder says. “You can get ice down to 300 or 400 feet under the surface of the ocean. I can remember one night where we’re in a place where the ice was deep and the water was relatively shallow, and we came all-stop and the ship was about 400 feet down. I had about 5-foot clearance above the top of the sail and about 2-foot clearance under the keel.”

Going to sea, Snyder says at various, almost regular intervals during more than two hours of in-his-office chats, is dangerous. He stresses, albeit in less alarmist language, that the ocean is an easy place to die.

“On my first submarine,” Snyder says, “I can remember being 400 feet beneath the surface, rolling 10 to 15 degrees, when a typhoon went over us. Normally when you’re in a submarine, you don’t feel any wave effects below 150 feet but this was like 30-foot waves up there, and I can remember just the whole ship rolling because you have a typhoon above you. But going to sea, it’s a dangerous environment, and it’s nice to see how things work to keep it safe.”

One of Snyder’s more difficult moments as captain came when a petty officer second class suffered a pulmonary embolism. At the time, the Nevada was about 250 miles away from its homeport near Seattle and returning from a patrol in the pelagic waters of the Pacific Ocean.

Submarines aren’t staffed with regular doctors because the Navy long ago determined the military equivalent of a physician’s assistant, a corpsman, sufficed for the medical needs of the average submariner. A PA, though, isn’t qualified to handle a pulmonary embolism, and further miring the situation were the Navy’s rules of water-space management.

“It’s like air-traffic control,” Snyder says. “Submarines are really quiet, so typically, two submarines, if you put them in the same water, they could hit each other. The bottom line was we didn’t own the water from where we were at to get back to the place where we could put the person in for medical care.”

Snyder had a decision to make: Violate the “rules of the road,” surface and break the 7-knot speed limit or follow those rules and risk a sailor’s life.

“I went 15 knots,” Snyder says. “I made the conscious decision to not follow the rules of the road because I had this guy who was near death. … I made the conscious decision to drive well above the speed limit for 12 hours or something like that to get the guy off the ship, and we got him off and he lived and we didn’t hit anything—and we weren’t stupid about it. We had extra personnel on watch, extra radar.”

Snyder also informed the Navy of his decision, communicating with doctors on shore, and he made gratuitous use of the Nevada’s foghorn. Had he hit something, like another submarine or a merchant ship, he would have been “relieved for cause.” That’s official Navy for “fired.”

“I’ve done a lot of interesting stuff in the Navy,” Snyder says. “A lot of it was fun. A lot of it was scary. But in the end, the people you work with in the military and in the Navy, as a group, are pretty good people.”

Susan Polsky has been researching the air wakes of Navy ships since 1999 when she decamped from NASA’s Ames Research Center in California, where she studied hypersonic aerodynamics, to Naval Air Systems Command in Patuxent River, Md., so she could be closer to her hometown of Rockville.

Ship air wake research had been going on for decades but it never rated enough to be anyone’s concentration, always fizzling before the research went anywhere sexy. The technology didn’t exist to model ship air wakes, and inevitably, the Navy fell back on the subjective experience of test pilots to develop the parameters (flight envelopes) for the average pilot to safely take off from, and land on, sea ships. The advent of supercomputers in the early 2000s and their comparably super processors changed that.

“Until that time,” says Polsky, now a senior computational fluid dynamicist at NAVAIR where she specializes in ship air wake research,” there just simply wasn’t enough computational power to do what needed to be done.”

The typical personal computer has a single processor. The computers Polsky uses today for flight simulations and the various sophisticated feats of algorithmic legerdemain have hundreds of thousands of processors. A supercomputer in the early 2000s ran on 200 or so processors. These supercomputers didn’t come about because of the air wake work of military engineers. Rather, those engineers—a small band that at the time consisted largely of Polsky and an infant’s handful of her associates—saw its application and co-opted the technology.

Polsky, who started by developing flight simulations for Army helicopters landing on Navy ships, emerged as a pioneer in an invigorated field, publishing her first paper on ship air wakes in 2000. Later, she fit 20-foot poles with ultrasonic sensors and placed them around Navy warships to take air-speed measurements while the ship moved through the water. She ended up with just 20 to 50 data points because of her limited access to Navy vessels, and none of those points were behind the ship or higher than 20 feet. She also missed out on recording aircraft turbulence, another factor considered when developing flight envelopes.

In almost 20 years of ship air wake research, Polsky says that she’s been out on a Navy boat with her sensor poles no more than four or five times.

“We’re too small potatoes to do something specifically for us,” Polsky says. “The way it’s always occurred is there’s a flight test going on … and they don’t have anything else going on at the time other than the flight test, so they say, ‘OK, we’re not doing anything else. We’re already stuck because we have to accommodate this aircraft testing, and as long as you don’t interfere with this aircraft testing, you can bring your anemometers aboard and collect data.’”

It took someone flying a sensor-loaded drone off the back of a ship to fill in Polsky’s research blanks. That’s where Murray Snyder and Polsky intersect.

“Murray has added a piece of the puzzle that allows us to have confidence in our simulations,” Polsky says. “... We can go in a wind tunnel, but one of the aerodynamic gotchas is that air flow doesn’t necessarily behave the same on something you have to shrink down to fit in a wind tunnel versus what the full scale is. This is true for airplanes and it’s also true for ships.

“Murray has been able to give us that access where we can go back and collect more data as we need it. So if we hit some point where we’re thinking, Hmm, the simulation doesn’t really compare very well here; we’re not really sure why, we can ask Murray, ‘What if you go out and test in such and such conditions?’”

The practical applications of ship air wake research are less than grandiose. Suggesting to Polsky or Snyder that their work prevented an aircraft-to-ship crash—crash statistics are classified by the Navy—provokes a contravening response that is as immediate as it is impassioned.

“I have incrementally helped them quite a bit,” Snyder says. “But please, do not say that I’ve saved a helicopter—or saved anyone. There’s no way of knowing that. Science these days is incremental improvement, and I’ve helped make a whole bunch of incremental improvements.”

Snyder has established more than 190 data points around a warship using his UAV-borne anemometers that measure the space within a roughly 16-centimeter cube of air. He’s made flight simulations more reliable by virtue of testing them in praxis and has broadened the qualitative scope of Polsky’s supercomputer models.

For example, they now have simulations for aircraft as large as the 64-foot, 7-ton H-60 Seahawk helicopter, the SH-3 Sea King’s successor. (It’s harder to model larger aircraft because they’re physically more complex—more bumps, protrusions—and they create their own big air wakes.)

According to Polsky, Snyder’s also determined, despite being designed from the same plans, each ship has individual imperfections that create ship-specific air wakes. Thus far, no boat has been so air-wake terrible as to merit a from-scratch redesign, and no one would design a warship solely with its air wake in mind, either. A ship has too many other superseding duties and functions, especially stealth, which necessitates streamlining and smooth surfaces, both things that exacerbate air wakes. But Snyder’s research, concomitant with Polsky’s, has led to occasional tweakings, like moving a gun turret to act as a windbreak. It’s all stuff no one would know if not for the drones and little boat of Murray Snyder the Reluctant Academic.

“The issue is of interest to me because it’s something that impacts sailors and ships,” Snyder says. “It allows me to go to sea on a ship, and I like going to sea on ships. … It’s a fleet-relevant issue, and in the end, I’m a Navy officer more than I’m an academic.”

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