REWIND: Miller on Dan Gurney’s Indy-winning Eagles

Peter Harholdt

REWIND: Miller on Dan Gurney’s Indy-winning Eagles

IndyCar

REWIND: Miller on Dan Gurney’s Indy-winning Eagles

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If I had to pick my favorite RACER magazine story by Robin Miller, this one could well be it, written in 2015 to commemorate the 40th anniversary of Dan Gurney’s one and only Indianapolis 500 win as an owner in 1975. Gurney’s Eagles had earned two before that with customers, but ’75’s monsoon-curtailed 59th running finally ticked the box for “The Big Eagle” and All American Racers.

When it came to the technical side of racing, Robin was happy to admit it was all pretty much over his head and reveled in telling tales of his mechanical ineptitude. But that didn’t stop him from appreciating the envelope-pushing skill, creativity and ingenuity of the folks building the machines that created Brickyard heroes. For him, the engineers, crew chiefs and midnight oil-burning mechanics were as big a part of the story as the guys behind the wheel.

He had a special respect for Gurney. For his driving exploits alone, Dan was up there on Robin’s Mt. Rushmore, but as an innovator, advocate, and all-’round human being, few came close.

That all comes through in this story. It’s not just about a car, it’s about people doing special things – Gurney, Bobby Unser, Roman Slobodynskyj, John Miller – and it’s told in a way only Robin could.

Laurence Foster, RACER Editor-in-chief

It was the perfect storm: a rulebook ripe for the picking converged on by a wily, free-thinking leader oozing with racing savvy; a top shelf driver who understood chassis and lived for taking it to the edge; a sharp, aggressive engine man who couldn’t get enough RPMs, and a quiet, unknown thinker from the aerospace industry with designs on making a big splash in Indy car racing.

That was the potent lineup at All American Racers in 1972 as Dan Gurney, Bobby Unser, John Miller and Roman Slobodynskyj created an Indy car for the ages that was copied, bought and raced with unparalleled success for five consecutive seasons.

The Eagle 7200 didn’t just break new ground, it sent a tremor through the United States Auto Club, destroyed the record book and shook the status quo to its very foundation.

“Dan built a killer car, Roman did a good job, John gave me great power, and I think we had a better team than we knew,” says Unser, who captured 10 races for AAR from 1972-’76 including the 1975 Indianapolis 500. “And of course, they had the right driver to develop it.”

Gurney’s genius for creativity was never more alive than that period of Indy car history, when aerodynamics ascended and speeds exploded. “We didn’t know what the limits were and we were peering into the unknown,” says The Big Eagle. “It was an exciting time.”

The genesis for the ’72 Eagle was the 1971 McLaren M16, a sleek-looking creation from Formula 1 guru Gordon Coppuck that riled Gasoline Alley because of its engine cover that sported a wing. USAC rules said any aerodynamic device had to be an integral part of the bodywork and Coppuck cleverly created an advantage as Peter Revson blistered the Indianapolis Motor Speedway record by almost 9mph in winning the pole position.

Even though Unser took seven poles and a pair of victories in his ’71 Eagle, Gurney and Co. knew that it was back to the drawing board…

“We were competitive for pole positions and wins because John Miller and Dan were willing to stroke the dickens out of things,” says Unser with a chuckle. “But we knew we needed a new car to try and get ahead of the McLarens.”

During the winter USAC announced that free-standing wings would be allowed for 1972, provided they weren’t attached to the suspension, and Gurney put AAR on the fast track by coming up with a 1/10th scale model for a wind tunnel which produced some beneficial ideas.

Slobodynskyj, who had begun his AAR employment a couple years before as a part-timer doing detail work on gearboxes and cylinder heads, had caught Gurney’s eye in 1971.

“The 1970 Eagle had a lot of problems so I made some suggestions and Dan liked the modifications I made,” recalls Slobodynskyj. “Tony Southgate had left so I was full-time by then and Dan promoted me to head designer.

“McLaren had been a call to arms, and we knew we had to come up with something good if not better. So we pushed the limits where we could and we went for it. Those were the good old days.”

One key to the Eagle’s performance was USAC’s decision to allow rear wings that were non-integral with the bodywork for 1972. Huge leaps in speed caused USAC to reduce boost and wing size in ’74, which cut performance a little, but didn’t alter the status quo – the Eagles still dominated. Image by Peter Harholdt

Indy cars carried 75 gallons of fuel back then and Roman had a couple of major objectives.

“I wanted the polar moment to be as close to CG (center of gravity) as possible, I wanted the fuel low and as close to CG as possible, and I wanted the radiators in front of the fuel,” he explains. “Plus, I wanted to keep the roll center as stable as possible, relative to the CG. And I wanted to feed the wings as much air as possible.”

Adds Gurney: “Roman was very good at packaging things and knew a thing or two about aerodynamics. It was an unknown area, but that’s where Indy car racing was headed. And I also wanted to make sure we provided a friendly spot for the turbocharged Offy.”

Another key component was the infamous Gurney flap, which had come out of its founder’s mind following three days of going nowhere in a test at Phoenix in late 1971. A thin strip of aluminum folded at a 90-degree angle and pop-riveted to the trailing edge of the rear wing was instant magic – and downforce.

Gurney had experimented with wings on his F1 Eagle in 1968 and he struck a friendship with Bob Leibeck of Boeing, who pitched in to help with the ’72 Eagle. “We tried 20 different types of rear wings and Bobby did most of the testing, but we paid attention and found something we liked,” says the AAR founder.

Also collaborating were Champion Spark Plug’s Dick Jones and Art Lamey, along with Fred Carrillo, who built some special rods for the Miller-prepared Offenhauser. Drake Engineering produced lighter pistons for Miller’s short-stroke powerplant, and Leo Goosen developed a pair of oil scavenge pumps that also improved horsepower.

Unser also credits a special turbocharger discovered by Miller as a big boost in the project but, amazingly, the outspoken veteran from Albuquerque had no input in the design of the 7200.

“Dan had forbid me from going into the design room, but that was OK, I shouldn’t have,” he declares. “I didn’t need to because I could pick a hair out of a bowl of soup real quick. I could tell immediately whether things were right or wrong as soon as I got in the car.”

The first test at Ontario Motor Speedway in December of 1971 was either good, disappointing, or somewhere in between – depending on who’s talking.

“I think we realized it was very good before we even hit the track based on what we saw in the wind tunnel,” says Gurney. “And it was good on the track straight away; we just didn’t know how good until we got a little further into it.”

Unser recalls it being “as good a handling car as I ever drove and a keeper, but I couldn’t go quick down the straightaways. So we came back to Ontario and John Miller gave me a real engine with good power. I was hauling that thing so hard into the corners and pushing 200mph. All of the sudden we knew we had a fast racecar.”

Slobodynskyj says: “It was a dog down the straightaway, then we changed engines and the thing woke up. But it was hard to predict it was going to be as fast as it turned out.”

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