The Biggest Bang

Amateur rocketeers from all over North America are converging in Lethbridge, Canada, this weekend for the 24th annual Large Dangerous Rocket Ship convention. Some come to launch small kits, others to fire up giant home-brewed rocket motors, but everyone enjoys the thrill of a good explosion. Check out our preview of this year’s event, from July’s Popular Science.

The visitor who pulls up to this upstate New York hayfield on a sunny July Saturday afternoon might well wonder whether he’s stumbled upon a 4-H Club event or a third-world arms bazaar. There’s a country-fair atmosphere–the fast-talking voice over the PA system, kids eating ice cream and hot dogs–but instead of leading prize heifers to the judges’ table, participants are lugging huge replicas of military missiles (U.S., Russian, Chinese, take your pick) over to the range-safety officer to get final clearance to launch. The owners of the most massive rockets have cleared their projects in advance with the event’s BFR (that would be Big Freakin’ Rocket) committee. “Bring ’em up and we’ll burn ’em up,” the announcer says.

For six days over this extended July 4th weekend, this field on the outskirts of the college town of Geneseo is the setting for the Large Dangerous Rocket Ship launch. The event has been held annually (each year at a different site) since the late 1980s, when significant numbers of amateurs began building projectiles of such size and muscularity that the term “model rocket” no longer applied. This is “high-powered” rocketry. At East Coast launch sites like this one, which tend to be situated close to flight paths and population centers, participants are granted temporary waivers that allow them to fly as high as 12,000 feet. But at desert launch sites in the West, the sky’s the limit. In Black Rock, Nevada, last May, former Hollywood stuntman Ky Michaelson made history, launching a 21-foot, 700-pound rocket called Go Fast that climbed some 70 miles into the outer regions of Earth’s atmosphere–more than 20 miles higher than the previous unofficial amateur record.

At this, the 23rd annual Large Dangerous Rocket Ship event (LDRS 23), Thursday through Sunday will be one big explosive picnic. Kids and families will fly comparatively modest kit-built rockets alongside passionate, not to say obsessive, adult hobbyists who have installed large commercially available motors inside massive balsa-wood or cardboard contraptions that can stand 15 feet tall, weigh a couple hundred pounds, and take months to build. On Monday and Tuesday, the kids and the summer-picnic feel will evaporate, and the field will be turned over to experimental, or “ex,” craft flying on high-powered propellant that the rocketeers have mixed and cured themselves.

To the uninitiated, even the first, relatively mellow days are unsettling, like being dropped into the middle of a mini Cape Canaveral gone haywire, with rockets firing off all around you every minute. The little ones are zippy, energized darts; the big ones, powerful enough to make you jump back if you’re not ready. They take off with throaty roars, leaping from their pads and splitting the sky like arrows shot by a god, leaving trails of smoke and flames.

“We’ve got all sizes of rockets here,” says Lloyd Wood, an investment adviser by trade who, as the president (or “prefect”) of the hosting Buffalo, New York, rocketry club, is the weekend’s launch director. When Wood hasn’t parked his ample frame on a folding chair under the organizers’ tent, he is buzzing around the grounds in a canvas hat astride a four-wheeled ATV, the 21st-century version of a British colonial administrator inspecting the territories. His job is making sure the 1,700 or so launches planned for the weekend don’t backfire, thus intruding on the high spirits and personal safety of the perhaps 500 spectators milling about. As a breed, the ex rockets in play on the last two days are prone to dramatic failure; Lloyd and his team have to be ready to put out fires. Literally. “If you had nothing but successful launches, it wouldn’t be any fun,” he says.

On Saturday afternoon, the buzz is all about an upcoming launch by Florida engineer Rick Boyette. He has assembled an exquisitely detailed 1:17-scale model of the Chinese Long March 2E that shot satellites into space in the early 1990s. Authentic Chinese lettering, lovingly reproduced, runs down the fiberglass body. “It says â€China into Space,'” Boyette explains. “That’s what somebody told me.” The propulsion comes from four strap-on booster motors surrounding a larger central one. Called a cluster configuration, this can be notoriously difficult to pull off. Unless the boosters fire simultaneously and with identical force, the rocket won’t go straight; an unbalanced liftoff can rip an airframe apart. Boyette is known in rocketry circles for beautiful, ambitious projects that sometimes suffer from lack of attention to technical detail.

I catch up with Boyette as he and his team scurry around attending to last-minute prelaunch routines. “You guys wouldn’t happen to have some duct tape, would you?” somebody asks. The two onboard parachutes have to be properly folded and stowed inside, and connected to the rocket frame with Kevlar cord. If the Long March launches as planned, two parachutes, set off by a time-delay charge or an altimeter, will deploy when the rocket reaches its apogee. To prevent the heavy nose cone from damaging the rest of the body during landing, a small drogue parachute will inflate to lower it; a larger chute will deliver the rest of the craft gently to the ground. Ideally, the rocket will return undinged, ready to be outfitted with a new motor and launched all over again. Of course, Boyette has already flown, crashed, and rebuilt the Long March three times.

Forty-five minutes pass before Boyette announces, “It’s armed.” We all retreat 1,000 feet, as per regulations, to the vicinity of a few bales of hay. “Five, four, three, two, one . . .”–and nothing. “No smoke, no joy,” as the phrase goes. An inspection reveals that the problem is not Boyette’s: The ignition box provided by the event organizers has malfunctioned. A few quick repairs, and Boyette is ready for a second try.

This time the launch sequence goes without a hitch, and the Long March, all its motors burning brightly and noisily in sync, lifts into the sky–for a few seconds. It rises 1,000 feet or so, then blows apart, a rocket piata, casing, tubing and parachutes raining down like party favors. Boyette looks strangely calm; it’s as if he expected that something would go wrong. “I have no idea what happened,” he says. “I was watching it go up and thinking, â€I’m home free, I’m home free,’ and then . . . Maybe it was just too much force.”

This is what’s known in the trade as a garbage-bag recovery, wherein the rocket returns to Earth in pieces, to be pored over for forensic clues, then deposited in the nearest dumpster. It is but one of the many varieties of failed launch that will take place over the course of the festival.

Sometimes a rocket fails to ignite; it sits on the pad refusing to budge, like a disobedient dog. Or, on successful ignition, hot gases burst through the motor’s combustion chamber, escaping into the relatively delicate airframe, and the rocket blows on the pad, leaving what is sometimes described as “rocket confetti.” (This is a CATO, or “catastrophic at takeoff,” event.) Or the rocket hurtles happily skyward but the forces generated are too much for the frame to withstand and, like Boyette’s Long March, it breaks apart in midair.

But most rockets that come to grief do so on the return trip. You’ll hear the announcer say something like, “It’s coming down hot” when the main chute or, worse, both chutes fail to deploy. Rockets that hit the ground at 100 to 300 miles an hour are known as “lawn darts” or “worm guillotines.” From the human spectator’s point of view, though, the most worrisome kind of rocket is an unstable one–one that’s flying under full power in any direction other than straight up.

If a set of faulty calculations slips by
the launch-safety officer, a homemade rocket may pinwheel out of control after takeoff. As it burns fuel, its center of gravity may shift, causing it to stabilize in a horizontal position and do a fair, if short-lived, approximation of a cruise missile. “People can see it coming,” says Duane Wilkey, a middle-school science teacher who is one of this year’s launch organizers. “So there’s enough time for them to get out of the way.” Many here recall the triangular rocket that flew, briefly, at LDRS 19 and that is affectionately remembered as “the Flaming Pyramid of Death.”

Later that evening at the event’s banquet, held in a Rochester hotel, I describe Boyette’s launch to a bunch of rocketeers who didn’t bother to wait around for it. “It was great,” I say, and then, catching myself, “well, not great for Rick or the rocket . . .” A rocketeer puts me at ease: “You don’t have to explain it to us. That’s why we’re all here. We love to watch rockets blow up–and it’s even better when it’s someone else’s.”

Moments later, the man of the moment, a dazed-looking Boyette, appears. “I had a failure of the tube coupler joint on my number-two booster,” he says. “Either I didn’t put enough glue [on it] when I was rebuilding it or . . . But I will rebuild it again.” I ponder the $2,000 and 100 hours that Boyette has sunk into this 72-pound, 10-foot-long, essentially useless object. Earlier in the day, Stephen Boy, to my knowledge the only rocketeer in attendance who is also a clinical psychologist, had given me his version of Zen and the Art of High-Powered Rocketry: “You’ve got to be able to let go. You build something, you put in the time and money and dedication, but you also have to be willing to have things not work out.”

To a spectator, one successful launch looks much like another, and after a few dozen, enthusiasm can wane. But for the rocketeer, each launch is a thrill that might be likened to sex: The arduousness of the preparation and the predictability and brevity of the climax diminish the intensity of the experience not a bit. The phallic implications of this overwhelmingly male sport don’t escape anyone. “My wife, who is a clinical social worker, says it’s just about a bunch of guys comparing the size of their rockets,” says Boy–who, it must be noted, brought one of the largest, the 16.5-foot, 180-pound O’ Boy.

The banquet is a chance for the rocketeers to let their hair down, have a few drinks, talk shop. Underneath the bonhomie, it’s clear that distinct groups are mingling. There are the guys like Boyette who build meticulous replicas of real-life rockets. Then there are the guys who like to build outlandish, bulky, un-aerodynamic rockets. A few examples this year: a flying-saucer-shaped rocket, a rocketized industrial spool, and a series of rockets meant to launch bowling balls into space. (Admittedly, none of the conceptual rockets is creating the stir that Ky Michaelson, of Go Fast fame, did when he sent up Our Stinkin’ Rocket, an honest-to-god port-a-potty, at LDRS 22.)

This variety of rocketeer is having fun with the relatively low FAA-imposed East Coast altitude ceiling while getting in touch with the machine-shop artist within, an impulse familiar to anyone who watches American Chopper or Monster Garage. At the banquet, I chat with Rich Kroboth, a computer programmer from New Jersey who was in a valedictory mood after his bowling ball, ingeniously perched atop a single fin, turned in a solid, if not quite record-breaking, performance. “It took three months to build,” he says. “I owe my wife a lot.”

The third kind of rocketeer is the sort of person who might be seen around the launch grounds wearing a button that reads “Yes, I am a rocket scientist!” These are the guys, usually drawn from the technical professions, who get off on tinkering with propellant chemistry. Some are bona fide aeronautical engineers on busman’s holiday, others just fanatics drawn to high-wire chemistry projects. Representative of this group are Alan Whitmore, an immunologist, and his co-conspirator Jim Livingston, a retired medical-products manufacturing executive. The two North Carolina rocketeers make an intriguing odd couple, Livingston the avid golfer with a country-club loosey-goosiness about him, Whitmore, techno-nerd author of the self-published paper “Performance Evaluation of Experimental Rocket Propellant.” The two joined forces after discovering that Whitmore was building a breathtakingly large motor and that Livingston had a rocket wide enough for it. This is the biggest motor either of them has ever flown, and they are feeling heady and slightly apprehensive. “I’m not just risking my motor but also wrecking Jim’s rocket,” Whitmore says. “And you don’t like to mess up your friend’s rocket.”

Another pair of experimentalists I run into are Dave Weber and Bob Utley, buddies from the Maryland chapter of Tripoli, the national association of high-powered rocketry. These guys aren’t sweating it. Each is flying a motor of a size they’ve flown scores of times before. Weber, a civil engineer, has been into rockets since he was a kid in the ’60s. “I saw a model-rockets advertisement in Boy’s Life magazine,” he recalls, “and I fell in love.” The rocketry career of Utley, a computer technician, follows a more typical trajectory. He dabbled as a boy, then “got back into it when my kid was 11 and expressed an interest,” he says. “Like with just about every â€born-again’ rocketeer I know, my kid dropped it and I stayed with it.” Both Weber’s and Utley’s rockets will be powered by a batch of propellant that the two whipped up together. The only wild card: Cooking rocket propellant is not unlike baking cookies–no two batches come out exactly the same.

Until the late ’80s, the size of model rockets was limited by the standard propellant–black powder, better known as gunpowder. Brittle and highly flammable, the stuff is cumbersome and dangerous to fabricate into large motors; manufacturers never considered it worth the trouble. That restraint went out the window when a handful of engineer-tinkerers figured out how to fly model rockets with the same solid composite fuel that NASA uses in its boosters. Solid propellant is a two-part proposition: oxidant and fuel. Ammonium perchlorate, the oxidant, releases oxygen when ignited, which feeds the burn of the synthetic rubber, a hydrocarbon fuel that’s enhanced with finely ground, highly combustible aluminum particles. The brew is three times as powerful, gram for gram, as black powder, and far safer.

Jim Livingston happens to have a summer cottage on Lake Conesus, N.Y., a stone’s throw from this year’s launch site, and it is here that he and Whitmore prepare the motor for Livingston’s 14-foot-tall Viper rocket. On this sultry summer afternoon, Whitmore is inspecting his high-test home brew. “When I’m sweating like this,” he tells me, “I don’t know whether it’s because I’m exerting myself so much or I’m just excited being around this much propellant.” Before he slides the sleeve of propellant packets into an aluminum casing that will slip into place inside the rocket body just above the fins, he permits himself a final deep whiff. “Oh, yeah!” he exclaims. “This is one of the most beautiful smells in the world.”

A rocket is basically fuel ignited in a contained space with only one way out. The rapidly expanding gases and flaming particulate matter push against the walls of the combustion chamber and are forced through a narrow nozzle that concentrates their energy as forward thrust. Rocket guru Wernher von Braun once likened the process to continuously firing a machine gun off the stern of a rowboat, pushing the boat forward with the force of the recoil. The simplicity of the mechanism, and the lack of moving parts in the finished product, go a long way toward explaining how it is possible to assemble a sizable rocket motor in a summer cottage.

Whitmore prepares to secure his motor inside the rocket booster stage. He fits a steel compression, or snap, ring into two retention bolts, so that at liftoff the motor won’t push through the forward bulkhead or shoot out the nozzle underneath. “When you see me begin to compress the snap ring,” he says, “step slightly this way or that. If these things slip off the groove, you have a bullet in the house.”

Obeying the first law of high-powered rocketry–“Big is good”–Whitmore has built a motor that, in the nomenclature of the hobby, is N class, meaning that over the course of its burn it will put out between 10,240 and 20,480 Newton-seconds of thrust, the so-called “total impulse.” (A Newton-second is the force applied over one second that would accelerate one kilogram of mass an additional meter per second.) Every time you go up a letter, you double the total impulse, so this N motor has twice the power of Whitmore’s recent M motor projects–M being the standard attention-grabbing muscle motor at an LDRS event–and 8,192 times the power of the A motors that drive the small model kits. “Working with these big motors really gets your heart rate up,” he says.

The other thing that agitates rocketeers: regulations.
To get permission to launch his record-setting Go Fast, Michaelson underwent an epic two-and-a-half-year bureaucratic struggle with an obscure federal entity, the Office of Commercial Space Transportation. The civil servant who held up the launch for a year reportedly told him, “We’re not happy unless you’re unhappy.” To which Michaelson replied (to the enduring satisfaction of high-powered-rocketry enthusiasts the world round), “We’re not happy unless you’re a little bit worried.” And the feds are worried. In the fall of 2001, two agents from the federal Bureau of Alcohol, Tobacco, Firearms and Explosives paid a call to the Whitmore residence to examine his propellant-storage facilities.

Since 9/11, anything that smacks of do-it-yourself pyrotechnics is viewed with suspicion. Officials have suggested that a homemade rocket could be used by terrorists. Rocketeers retort that any terrorist who attempted to deliver a deadly payload with a rocket, which doesn’t have a guidance system, instead of a Stinger shoulder-to-air missile (or a rental truck or suicide vest) would be a terrorist in the wrong line of work.

Still, officials at the Bureau of Alcohol, Tobacco, Firearms and Explosives maintain that they have the authority to regulate rocket motors because the oxidant used in solid propellant, ammonium perchlorate, has been on the official explosives list since the 1970s. The government requires that high-powered rocketeers get burdensome explosives permits. Rocketeers are disgusted. “No one’s ever built a bomb with this stuff,” says attorney Joe Egan, who represents Tripoli and the National Association of Rocketry, “but hundreds of bombs a year are made from gunpowder, which is easy to obtain.” Seconds Doug Pratt, a rocketeer and hobby-industry consultant, “We’re offended by the suggestion that we’re doing something unpatriotic.” At the otherwise jolly LDRS banquet, there are “council of war” moments, with a passing of the hat for the legal defense fund.

The feds’ attack on solid fuel has led some rocketeers to try hybrid motors, which burn rubber or plastic using a liquid oxidizer. Hybrids are nothing new, but until now they were a solution in search of a problem. Post-9/11, they became a way to legally sidestep federal oversight, since nothing in them can be remotely considered an explosive. (Ironically, while one arm of the government harasses rocketeers, another solicits them. NASA has purchased two launch systems–for its educational programs–from Doug Pratt, who makes them in his basement and sells them over the Internet in his spare time.)

Hybrids have a crucial safety edge, which derives from their combustion of two components–an oxidizer, usually nitrous oxide, and a fuel source, usually a machined chunk of PVC plastic (although most anything, including a hard salami, has been used)–both of which are chemically inert at less than superhigh temperatures. Within the high-powered-rocketry community, a zealous minority sees hybrids as the wave of the future, while an as-yet-unpersuaded majority is unconvinced because of the hybrids’ finicky resistance to ignition and their hollow, flatulent sound (it’s hard to let go of the solids’ manly roar).

The experimental days begin with a whimper. Both the Whitmore-Livingston and Weber-Utley teams have expected to launch Monday, but the wind whips up, and the rest of the day is scrapped. Tuesday dawns cloudy, but as the morning progresses, a blue hole opens that you could shoot a fleet of rockets through. “Morning, LDRS 23, this is Dave Weber,” comes the impromptu announcer’s voice over the PA. “This will be the eighth flight of a rocket called Super Tuber. Motor manufactured by Bozo Motorworks out of the Maryland-Delaware Rocketry Association. We expect 3,600 feet. The range is clear, the sky is clear, and launching in five, four, three, two, one . . .”

The rocket gods are not happy. Super Tuber lifts about a foot off the pad and pauses. “As soon as you see that hesitation,” Weber says, “you know something bad is going to happen.” It’s a CATO, all right. The motor’s combustion chamber can’t contain the pressure, and Roman-candle flames pour from the bulkhead and the nozzle, sending Weber and launch organizers sprinting to the scene with buckets of water to douse the charred remains.

Weber’s pal Utley now finds himself between a rocket and a hard place. He’s got a slim new craft on the pad, modeled from a news photograph of a Russian SAM missile captured in the Iraq war. Utley’s rocket is packed with propellant from the same batch that went into the ill-fated Super Tuber. If Super Tuber’s problem was mechanical, something to do with improperly fastened snap rings, say, then Utley’s craft should soar. But if the propellant was at fault–if, for instance, bubbles formed in the curing process, a common misstep that increases surface area and speeds up the burn–then for Utley, launching is tantamount to rocket suicide.

“I could have taken the motor and [test]-fired it,” he tells me. “But I can’t do that to my buddy. He lost his rocket, so I had to push the button on mine.” The explosion–“deflagration” is the preferred term of art–when it comes, is fabulous. Utley, big, relaxed guy that he is, merely says, “I pretty much knew what was going to happen.” It turns out that the top half of his rocket is salvageable, so he’ll rebuild it with the burn marks intact, a badge of honor.

Whitmore and Livingston’s launch has a bittersweet tinge, for a fundamental reason: Whitmore isn’t here. Two days earlier, his wife, Sallie, was taken to the hospital for emergency abdominal surgery, and he has rushed back to Chapel Hill to be with her. The N motor is mothballed, and Livingston installs his own M motor, held in reserve, in the Viper. With the drama uncomfortably prolonged, he’s feeling antsy. One way or another, let it be done. The countdown goes without a hitch, and the liftoff is textbook–the motor roar, the piercing straight shot. There’s a moment of suspense when a slightly malfunctioning parachute threatens to land the Viper in the middle of a nearby field of classic WWII planes, but through sheer luck, disaster is averted.

LDRS 23 concludes soon afterward, and for most rocketeers it’s time to start plotting next year’s event. But for Livingston and Whitmore, there’s one more chapter. Once Sallie Whitmore has recovered and the Viper has been touched up, the two decide to send their mighty N motor up once and for all. Rockets, Whitmore tells me over the phone, were the last thing on his mind during his wife’s illness. “But by August, I started to get my head around my hobby,” he says. The Whitmore intensity was returning. I remember something he told me when we first met: “Rocketry contains four essential elements of little-boy fun: smoke and fire, loud noise, speed and flight. You wish you could go along every time the rocket goes up.”

And so on a mild, sunny afternoon last October, he and Livingston launched their rocket from their home field off the North Carolina coast. “It was special to put it up together,” Livingston says. “An altitude of 5,825 feet, 478 miles per hour.” The moment, Whitmore says, “was everything we wanted. A terrific noise.”

Pumped-up Model

High-Drag Whimsy

Homemade Motor #1

The Faithful Reproduction

Homemade Motor #2

The Faithful Reproduction

Bowling-ball Launch

OH NO, IT´S A CATO!

Hybrid Hotshot