Astro Spiral: Revisiting the greatest car stunt of all time
Publicity stunts are the unsung heroes of science. Isaac Newton’s falling apple, Benjamin Franklin’s key and kite, and Watson, the IBM computer that creamed the human competition on Jeopardy!—all popularized scientific concepts that shaped the modern world. But as important as gravity, electricity, and artificial intelligence are, those stunts weren’t as spectacularly cool as the Astro Spiral Jump.
Even if you don’t know the name, you do know the stunt. The Astro Spiral is a ramp-to-ramp car jump with a full 360-degree barrel roll in between. It was performed first in the Houston Astrodome, hence the name, and it was prominently featured in the 1974 James Bond film, The Man with the Golden Gun.
It was 1968, 50 years ago. The kernel that would grow into the greatest car stunt of all time was planted inside the Cornell Aeronautical Laboratory (CAL) in Buffalo, New York. Already renowned as the place where the first scientifically useful crash-test dummies were developed and where the efficacy of seatbelts was proved, CAL was pushing forward with a radical idea: Crashes could be simulated inside a computer so accurately as to be predictive of how such events would occur in the real world. The jump was designed to demonstrate the scientific validity of a computer crash-simulation program.
“We were writing in FORTRAN,” recalled project leader Raymond McHenry, in 2011. “We had a roomful of IBM 360 computers with punch cards. We’d submit a stack of punch cards and wait overnight to see what the results were.”
McHenry was a young scientist working under a U.S. government Bureau of Public Roads contract to develop the three-dimensional simulation program. The ultimate goal was to design and build safer roads.
“On our highways we have everything from minicars to tractor-trailers,” McHenry explained. “Slope changes, guardrail designs, and highway obstacles all affect how a vehicle behaves in a crash. But we can’t afford to crash an infinite number of different vehicles into an infinite number of different road obstacles.” A computer simulation, however, makes testing thousands of variables and theoretical scenarios possible in a virtual world.
Proving that what a computer simulation predicts will actually happen in the real world is, however, challenging. “We had impressive correlation,” said McHenry, recalling his testing of the software’s validity around 1970. “At about that time, the Joie Chitwood Thrill Show came through Buffalo. I hired some of Chitwood’s drivers to expand our range of validation. I had them driving on two wheels, spinning, reversing, and jumping, doing more and more violent maneuvers driving our instrumented 1963 Fords. The spiral jump was an extension of that.”
By 1971, McHenry and his team were ready to demonstrate the validity of the CAL simulation software. So McHenry called JM Productions, a company in Hamburg, New York, that was running stunt shows at fairgrounds around the country. McHenry arranged a meeting with owner W. Jay Milligan, and together they came up with the idea that CAL develop a 360-degree jump to perform in Milligan’s thrill show.
Milligan had a promotional agreement with American Motors, and the job of doing the twirl was soon given to AMC’s sportiest and newest car, the Javelin. Milligan also had connections at General Motors, and a Javelin was taken to GM’s laboratories and measured exhaustively. “We measured everything on the spiral car,” said McHenry. “GM had to pull Chevys off their machines so we could measure that AMC.”
With all the parameters of the jump car known, the stunt could now be designed using 18th-century mathematician Leonhard Euler’s equations for the motions of a rigid body in three-dimensional space. This is going to get dense, so hang on.
“You define a reference coordinate system for a vehicle within the sprung mass,” explained McHenry, referring to a computer model of the car and its weight, “and a second coordinate system for space. Then you can measure the two coordinate systems rotating within each other. The differentials can be coordinated into milliseconds.”
So, imagine two boxes—with one box flying through the other—and determining where the edges of each box are relative to the other. The goal is that they never collide.
“We integrate the degrees of freedom—six to define where the body is in space, plus yaw, pitch, roll, and Z, or downward motion,” McHenry continued. “You place the reference point—the center of the sprung mass—and you rotate it to the final yaw, final pitch, and final roll. That’s 10 independent variables. And to solve for those simultaneously we use matrix algebra.”
In layman’s terms, once the edges and substance of the car are known, the computer calculates where it is at any point as it rotates through the air, assuming, of course, no variable has been overlooked or miscalculated and the laws of physics aren’t revoked midflight. All that’s left to do is design a ramp that meets the car’s wheels at the right point in the flight to guide it through the end of its rotation and return to the ground.
Those calculations in hand, CAL concluded that with a 40-mph takeoff speed and a 1.5-second flight between the ramps, the cars would need about 200 degrees of rotation per second. So the CAL team calculated the takeoff ramp shape and ran 32 simulated launches. After that, they designed a landing ramp to catch the car in mid-rotation—about 270 degrees later in the rotation—and gently bring it back down to level ground. They ran another 12 simulations to prove that.
A few tricks were applied to make it all work. The final bit of the left side of the takeoff ramp, for instance, dropped down after the front wheel passed over it since the rear wheel was already rotating down by the time it reached that point. And there was a steel wheel mounted on the Javelin’s rear differential to pitch the tail of the car up enough to complete the jump.
By November 1971, it was time to risk the Javelin in an unmanned test. It was a success. After two more unmanned shots, on December 22, Chick Galiano, a 34-year-old stunt driver, guided the Javelin through a nearly perfect test. In January 1972, after two more manned jumps, the ramps were shipped to Houston, where the first public performance of the stunt would take place in the Astrodome in front of a huge crowd.
Spectators went crazy as the AMC bounded onto the stadium’s floor, made its planned roll, landed, and exited the building. It wasn’t a perfect jump—the Javelin was a touch slow due to changes in terrain, according to Milligan. But it was close enough for a crowd looking for death to be defied. Milligan’s crew would perform the stunt around the country about 70 more times through 1975.
At some point, the stunt attracted the interest of Albert “Cubby” Broccoli, who with his partner, Harry Saltzman, owned Eon Productions, which makes the James Bond movies. Always on the lookout for a glamorous stunt, Eon hired Milligan as a stunt coordinator on The Man with the Golden Gun (the second Bond picture to star Roger Moore), and the Astro Spiral Jump became the centerpiece of a chase staged through Bangkok and Thailand’s countryside.
By the time of the 1974 movie, the Javelin was leaving production, so an AMC Hornet was recruited for the job. The stunt went off in one take using ramps disguised as an abandoned bridge. Why there were any AMCs at all in Thailand is unexplained in the movie. And the sound editor, who inserted a slide whistle on the soundtrack during the stunt’s execution, will be doing extra time in purgatory for that sin.
Stunt shows run on a shoestring, and Milligan’s was no exception. The Astro Spiral Jump needed long laces. “It involved 13 people, and it took five trucks to carry it around,” said Milligan. As spectacular as the jump was, it made little economic sense to haul it around the country.
“What are you going to do after you’ve been a stunt director for a James Bond movie?” continued Milligan. “The goals of a lifetime were accomplished in a very short time.” The novelty of the stunt had worn off, the point about the reliability of simulation software had been proved, and there wasn’t much money to be made. Plus, of course, the jump could destroy a lot of AMCs. So the original ramps were stowed next to Milligan’s offices in Hamburg, and there they sat for at least the next 36 years.
“They weren’t in great shape when we went to see them,” recalled Mike Ryan, the Hollywood stuntman and large-truck racer hired to re-create the jump in 2011. “But there they were. And we measured everything.” This time the stunt would be performed in the parking lot of Southern California’s Six Flags Magic Mountain amusement park, with MTV’s Rob Dyrdek driving and a throng of video cameras recording the event to market Chevrolet’s then-new Sonic subcompact to the youth market.
With Chevrolet’s backing, Ryan had two brand-new Sonics on hand at the theme park—one hero car that would be driven by Dyrdek in public and one sacrificial Sonic for testing. Aside from being a car, the Sonic is almost completely unlike the old Javelin. It’s not just that the Sonic is a front-wheel-drive, five-door hatchback with a 99.4-inch wheelbase, whereas the original Javelin was a big rear-drive two-door with a 110-inch wheelbase. “Any little difference has a ripple effect,” explains Ed Fatzinger, an engineer with Momentum Engineering of Torrance, California, the accident reconstruction firm hired by Mike Ryan to help design Dyrdek’s flight. “Anything changes everything.”
But it’s radically easier to change everything today in a simulation than it was in the early 1970s. Using commercially available simulation software, the digital great-grandson of McHenry’s Highway Vehicle Obstacle Simulation Model developed in the early ’70s, Fatzinger could vary everything from ramp twist rate to the Sonic’s spring rates and fine-tune Dyrdek’s jump. It was much easier to collect data from each test jump as well, since the Sonic’s factory-installed airbag module generated and stored much of the data.
In fact, after one test jump at Magic Mountain in the Sonic, GM’s OnStar communications system automatically reported to the California Highway Patrol that the car had rolled.
Ryan’s ramps had clean welds and smooth tire surfaces, professional pieces of show biz equipment. But their basic design was almost identical to that of the original ramps built in the 1970s. On the takeoff ramp, the final bit on the left drops down after the front tire passes over it, and there’s a center portion for the fifth steel wheel mounted on the center line of the Sonic’s torsion-beam rear axle.
Except for safety equipment, the Sonic that Dyrdek used was practically stock. It hit the ramp with an alto-pitched thunk, initiated its counterclockwise twist, and flew into the air. During the flight, there was almost no sound at all, and it was nose high for about 1.5 seconds. Then, with a thick clank, the Sonic’s left rear wheel hit the landing ramp, and the front of the car levered down hard. For the first time in 36 years, the Astro Spiral Jump had been performed again.
Time moves on. Cornell sold its aeronautical lab in 1972, and it has been the privately run Calspan Corporation ever since. Jay Milligan passed away in March 2017 at the age of 85. The World’s Largest Demolition Derby was run in his honor at the Erie County Fair last June. The modified 1974 Hornet used to perform the jump in The Man with the Golden Gun was sold from Milligan’s estate in a September auction for $110,000. Maybe that’s a reasonable price for movie history, but it’s an awful lot for an old AMC.
The hold the Astro Spiral Jump has on the automotive imagination isn’t gone yet. When Jaguar introduced its E-Pace compact SUV last July to the world’s assembled press in London, the new car performed a “barrel roll.”
Whatever they called it, it was the Astro Spiral Jump, down to the ramp design and the fifth kicker wheel welded to the rear axle. Ultimately, the true worth of any publicity stunt isn’t measured by how many people see it performed at a fairground stunt show or on a movie screen. Or by how many Chevy Sonics or Jag E-Paces are sold because of the stunt. What the Astro Spiral Jump did was help prove the value of computer simulation software, and that did, in fact, ultimately lead to better and safer vehicles and better and safer roads.
In 1968, when Raymond McHenry started on his software and the population of the United States topped 200 million people, nearly 53,000 Americans died on the nation’s roads. In 2016, as the population passed 323 million, highway fatalities were down to 37,461.
The Astro Spiral Jump did its part to make that happen.