Did Stan Barrett break the sound barrier?

Facts are facts, but the truth can be ambiguous. That’s the paradox underlying Stan Barrett’s quixotic efforts to convince a disbelieving world that he was the first man to break the sound barrier in a wheeled vehicle.

Stan Barrett

Did Stan Barrett really break the sound barrier?

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First, the facts: 40 years ago on 17 December, Barrett – a Hollywood stunt man with no motor sport experience – wriggled into the cramped cockpit of a long, slender rocket with a needle nose, a wicked dorsal fin, a single front wheel and spatted rear wheels mounted like outriggers on a Hawaiian canoe. Known as the Budweiser Rocket, the bright-red projectile was powered by a hydrogen-peroxide motor that produced 24,000 pounds of thrust. Shortly after dawn, at Edwards Air Force Base in Southern California, Barrett lit the fuse and hung onto the dragster-style butterfly steering wheel with his bare hands. Within four seconds, he was doing 250 miles per hour and leaving a huge cloud in his wake. Eight seconds later, he ignited a Sidewinder AIM-9 air-to-air missile – with the warhead removed, naturally – protruding from the tail. The extra 4,000 pounds of instantaneous thrust propelled him past 730 miles per hour and up to the threshold of Mach 1.

Then came the ambiguity.

Some observers said they heard a sonic boom, a sign that the sound barrier had been breached, but others didn’t hear anything. Although Barrett said the ride suddenly smoothed out near the end of the powered run, suggesting that he’d gone supersonic, naysayers claimed that this was merely because his wheels briefly left the ground. The pitot tubes mounted in the nose to measure air speed malfunctioned. Even worse, the crew had miscalculated the rocket’s fuel consumption, so Barrett was slowing rapidly when he blasted through the timing lights at ‘only’ 666.234mph. Fortunately, Air Force technicians had tracked the run with military equipment.

“Here’s what we’ve got so far,” car builder/designer Bill Fredrick shouted as Barrett was levered out of the cockpit. “We ran out of fuel between 200 and 400 feet before the timing lights. But we got 734 on radar and 739 on air speed.” Then, to wild cheering from the crew, he added: “We probably broke the speed of sound!”

‘Probably’ broke the speed of sound?

Breaking the sound barrier is like getting pregnant: either Barrett did or he didn’t. And going supersonic was the whole reason that car owner Hal Needham, the director of movies such as Smokey and the Bandit, had sunk $1 million of his own money into what he dubbed Project SOS, for Sound Of Speed. Needham and Barrett had to endure 11 hours of nail biting while Air Force engineers analysed the data. It wasn’t until after dark that the Project SOS team announced that the Budweiser Rocket had maxed out at 739.666mph, 8mph faster than the speed of sound (which fluctuates according to altitude and temperature).

‘Radar Confirms Supersonic Run’, screamed a banner headline on the front page of the local newspaper. In the story beneath it, Needham declared mission accomplished. “If [Air Force engineers and technicians] are accurate enough to tell the speed of an airplane at 10,000 feet 20 miles away, I’ll take their word on the car’s speed down here,” he crowed. “If they won’t believe the Air Force, who will they believe?”

Sure enough, the Budweiser Rocket graced the cover of the next edition of the Guinness Book of World Records. But the backlash started immediately. Sceptics – which included pretty much everybody in the close-knit land speed record community – pointed out that the Air Force never confirmed Barrett had exceeded the speed of sound. All the military did was provide raw data, which was converted into a top-speed number by the Project SOS team. Initially, at least, the Air Force declined to take a position on the sound of speed controversy. As a spokesman explained: “In our judgment this data would not be certified.”

“It was a tremendous effort, but that car didn’t go supersonic”

The Budweiser Rocket’s most prominent critic was former land speed record holder Craig Breedlove, whose opinion carried extra weight because he was the most famous American in LSR lore. “Frankly, it just didn’t happen,” he said. “It was a marvellous car, and it was a tremendous effort, but it didn’t go supersonic. That claim, in my opinion, was fraudulent.”

Over time, Breedlove’s take hardened into conventional wisdom. The Budweiser Rocket was erased from subsequent editions of the Guinness Book of World Records, and Andy Green is almost universally lauded as the man who broke the sound barrier in ThrustSSC in 1997. The Budweiser Rocket was reduced to the answer of a trivia question, and Needham died in 2013 as a pariah to the LSR community.

From the archive

Barrett is another story. Now 76, he’s still as affable and engaging as ever. A long-time boon companion of the late Paul Newman, Barrett is a devout Christian who’s travelled the world many times over doing good works. Even sceptics who’ve got no time for the Budweiser Rocket stop short of throwing Barrett under the bus. This, after all, is a man who went at least 730mph, which is hauling the mail whether the ground speed translated into Mach 1.01 or Mach 0.99.

Project SOS was often mocked as a stunt – a charge that resonated on several levels. To begin with, Needham had no interest in following the arcane and challenging protocols necessary to set a land speed record. Among other requirements, the rules require two runs in opposite directions within an hour, then averaging the speeds through a measured mile or kilometre. All Needham wanted to do was break the sound barrier and call it a day.

Speaking of stunts, Needham himself had come to fame as a stuntman, while Fredrick designed equipment for movie stunts. But Fredrick moonlighted as the builder of ingenious LSR and drag racing machinery. In 1962, he created one of the first jet-powered cars, the Valkyrie I, and he soon progressed to rocket motors. In 1977, stunt woman Kitty O’Neil drove his SMI Motivator to a woman’s speed record of 512.710mph. Needham later achieved 620mph in the same car before his parachutes failed and he embarked on history’s fastest off-road excursion. Although he wasn’t hurt, the mishap inspired Needham to retire from driving. But he was still committed to breaking the sound barrier. So he hired his protégé, Stan Barrett, to drive a new car he had commissioned from Fredrick.

A former Gold Gloves boxing champion and black belt in two forms of karate, Barrett was fearless by definition and as precise as a high-wire trapeze artist. But he’d never driven faster than 150mph before, and he was shaken by the molar-rattling violence of the ride during his first run in the Budweiser Rocket at the Bonneville Salt Flats.

“Everybody was so excited when I got out the car,” Barrett recalls. “They asked me, ‘Do you have any idea how fast you went?’ I almost said, ‘Did I just break the land speed record?’” Actually, he’d gone only 350mph, and the speed of sound seemed light years away. “Ain’t no way!” he thought. “I may have written a cheque that I can’t cash!”

It didn’t take long for Barrett to find his groove. On his ninth run at Bonneville, he hit 638.637mph. But the forged-aluminium wheels of the rocket car dug deeply into the salt, nearly causing him to wreck. Needham realised he needed a stouter surface to go supersonic. So he leaned on his friend Chuck Yeager – yes, that Chuck Yeager – to get the team access to Edwards Air Force Base, the hallowed home of the Right Stuff, where Yeager had broken the sound barrier in ’47.

The hard-packed surface of Rogers Dry Lake was perfect, but the hydrogen-peroxide motor ran out of oomph at 677mph. Needham bought six Sidewinder missiles, and Fredrick jury-rigged a mount for one of them in the tail of the Budweiser Rocket. During the first twin-rocket pass, Barrett reached 714mph. And on his 18th and final run, he exceeded the sound barrier.

Or did he?

“The data looked like what you’d expect – ugly and primitive”

Dick Keller is the most persistent and persuasive non-believer. An engineer by training, Keller was one of the creators of the Blue Flame, which Gary Gabelich had driven to the land speed record of 622.407mph in 1970 (and which was the template for the Budweiser Rocket). After enlisting the aid of a US senator, Keller was able to get his hands on the raw data the Air Force had provided to the Project SOS team.

Keller discovered that the range data provided by the radar tracking the Budweiser Rocket had been compromised by all the other activity at the base. (It was later reconstructed by driving a heavily instrumented truck along the path followed by Barrett.) Also, since the radar had been operated manually, the azimuth – or angle to the object being tracked – wasn’t perfectly consistent. “[The data] looked like what you’d expect – ugly and kind of primitive,” says David Audley, who was then a captain at Edwards.

After laborious calculations and mathematical gymnastics, Audley and his cohorts came up with three data points where the car appeared to have exceeded the speed of sound. The Project SOS team then averaged these three data points, which yielded a speed of 739.666mph, or Mach 1.0106.

Keller dismisses the numbers as fantasies. “Typical calculated speeds alternately increased and decreased continuously by as much as 100mph 20 times per second during the 1.4 seconds of released data!” he wrote in a detailed analysis. “The obvious lack of precision suggests that the calculated speed cannot be known at the one per cent level. Not even close! So a claim of Mach 1.01 is even more ridiculous than the claim the car was ‘timed’ by radar.”

The Air Force also had doubts of its own. But it also had access to additional resources. An accelerometer was removed from the car and sent to the instrument calibration laboratory of Northrop Corp. By comparing acceleration with two known speeds and distance points – 0 at the start and 666.234mph at the timing lights – the device was accurately calibrated. After that, it was a straightforward matter of using calculus to translate acceleration into velocity. This prompted the Air Force to officially adjust the speed to 736.4mph, or Mach 1.006.

Even so, Audley wasn’t absolutely convinced. A few years later, while teaching at the Air Force Institute of Technology, he was the advisor to a student – Captain David Reinholz – who was looking for a subject for his master’s thesis. At Audley’s suggestion, Reinholz wrote a 183-page paper memorably titled ‘Stochastic Estimation Applied to the Land Speed of Sound Record Attempt by a Rocket Car’. According to two alternate but equally valid forms of analysis, he concluded that Barrett had gone either 740.94mph, or Mach 1.0123, or 737.75mph, Mach 1.008.

“I’ve got a very high level of confidence that the car was barely – barely – over the speed of sound,” Reinholz says. “We had really good accelerometer data. Without that, the USAF never would have claimed anything.” Audley, who is now a professor of applied mathematics and statistics at Johns Hopkins University, stands by his one-time student’s findings. “I don’t have any skin in the game,” he says, “and I’m convinced that they did it.”

But there’s one final wrinkle. The speed of sound fluctuates according to air density, and density is affected by temperature and altitude. The calculations for the Budweiser Rocket were based on an ambient temperature of 20 degrees. But what if it had been a few degrees warmer? “Nobody knows how fast the Budweiser Rocket went, nor what the target ground speed was for Mach 1.0,” Keller says. “I would suggest a hung jury at best regarding the sound barrier.”

Your mileage may vary, of course. Still, Barrett is entitled to the last word. “I know what I did, and the prayer I prayed was that God would get the glory, not me,” he says. Then his blue eyes twinkle, and he adds, “I welcomed Mr Green to the club. But he was not the first member.”