Photos by Teddy Pieper, courtesy Auctions America.

What started out as a way to save lives by studying highway crashes led to a cascade of events that culminated in perhaps AMC's biggest marketing opportunity and one of the more spectacular car stunts put to film, and this fall the car used for that stunt will head to auction, where it's expected to bring at least a quarter-million dollars.

While automotive safety became a topic of national concern in the mid- to late 1960s following Ralph Nader 's "Unsafe at Any Speed" and the passage of legislation that created the U.S. Department of Transportation and the National Highway Traffic Safety Administration, scientists at Cornell University in Ithaca, New York, had studied how to reduce the growing number of highway deaths since more than a decade prior. Their efforts convinced Ford to adopt some safety features such as safety belts and eventually resulted in a pair of safety-minded prototype vehicles in the late 1950s and early 1960s

Raymond McHenry of the Cornell Aeronautical Laboratory and its spinoff, Calspan, thought he could vastly improve on research into automotive safety in the late 1960s by bringing in then-nascent computer technology to model automotive crashes. Working in Fortran IV, he came up with the Highway Vehicle Obstacle Simulation Model (HVOSM) program, which took all the variables that go into a crash -- speed, direction, terrain, obstacles, evasive maneuvers, and vehicle dynamics -- and returned predictions of exactly how a crash would unfold.

However, according to McHenry's SAE paper describing the HVOSM program , he needed to validate the program's results, which meant hiring a bunch of stunt drivers to crash cars under Calspan's direction and observation.

One of the included stunts was a 50-foot jump from a take-off to a receiving ramp. The degree of achieved correlation between analytical predictions and experimental measurements was found to be remarkably good in all of the included maneuvers and stunts. At the time, it was jokingly pointed out that Calspan had unintentionally developed a capability for the design and staging of auto thrill shows. A related, "far out" suggestion was the design of ramps to produce a combination of jump and rollover (i.e., a "spiral" jump), such that the stunt car would land on its wheels after passing over an obstacle in its inverted condition. After McHenry finished his work validating the HVOSM program, he decided to take the joke semi-seriously. Doing so, he figured, would showcase Calspan's capabilities, would provide a good challenge for his team, and would provide a break from the psychological implications of studying the factors that go into fatal crashes. After McHenry finished his work validating the HVOSM program, he decided to take the joke semi-seriously. Doing so, he figured, would showcase Calspan's capabilities, would provide a good challenge for his team, and would provide a break from the psychological implications of studying the factors that go into fatal crashes.

So, in November 1970, he reached out to Walter Jay Milligan of JM Productions in Orchard Park, New York. As a sideline to the demolition derbies he conducted at fairs in Western New York, Milligan ran an automotive thrill show much like Joie Chitwood's or the Hell Drivers. Though newer and smaller than his competitors, Milligan's thrill show was still able to secure a deal with American Motors to provide cars for the show (similar to Chitwood's contract with Chevrolet and the Hell Drivers contract with Chrysler), and he believed that a new stunt like what McHenry described could put him one step ahead of his competition.

After trying out a number of different ramp configurations in the HVOSM program, McHenry and Milligan settled on one that would require a speed of 40 mph -- limited due to the space available for Milligan's thrill shows. McHenry's simulations also required a few modifications to the car, most notably shifting the driver to the center of the car and rearward, shifting the engine rearward (both of the latter to equalize weight distribution), and adding a fifth wheel mounted directly to the rear axle "to achieve the desired combination of linear and angular velocities at the end of the take off ramp."

Milligan prepped an AMC Javelin for the stunt while McHenry prepped a patent for it that would conveniently allow him to claim the rights for any toys that performed the stunt too. Then, in January 1972, at the Houston Astrodome, Milligan's JM Productions took the spiral jump from theoretical computer program to reality with the first Astro-Spiral jump.

Apparently sensing that the jump deserved greater exposure than through fairground thrill shows, Milligan somehow convinced the producers of " The Man With the Golden Gun " to include the Astro-Spiral jump in Roger Moore's second outing as James Bond (and to hire him as stunt driver and stunt coordinator for the film) and to use AMC cars throughout filming in a product placement deal. With the film slated for a December 1974 release and the Javelin no longer in production, Milligan decided to instead use the next sportiest car in the AMC lineup and one that AMC had newly restyled for 1974: the Hornet X.

"Basically he built the car from the bottom up to do the stunt," Milligan's son, Jay Milligan Jr., said.

As with the Javelin, the elder Milligan moved the driver's seat to the center of the car and back to allow for the rearward-shoved engine, in this case a one-barrel six-cylinder. Not much else beyond the sheetmetal and the engine survived Milligan's conversion: He replaced the unibody with a full-frame chassis, swapped out the rear axle with a Ford 9-inch, and added a full roll cage. While the Hornet's dash top remains in place, the only gauge -- a speedometer -- appears to come from an early 1950s Chevrolet.

In fact, Milligan built two such cars and shipped them both to Thailand for filming. According to film set accounts, however, he only needed one: Stunt driver Loren "Bumps" Willard nailed the jump on the first try (cracking the windshield in the process) and netted himself a £30,000 bonus for doing so.

"In fact, they asked him to do it again, but he said no," Jay Milligan, Jr. said.

After filming wrapped, both the stunt car and its backup returned to Orchard Park. Milligan pressed the backup -- later painted red, white, and blue -- into service doing more Astro-Spiral jumps with the thrill show until about 1979 or 1980, but the actual stunt car never jumped again and remained in Milligan's private museum.

Auctions America's Fall Auburn sale will take place August 31 to September 3. For more information, visit AuctionsAmerica.com

UPDATE (6.September 2017): The Astro-Spiral Hornet stunt car sold for a fee-inclusive price of $110,000.