Alan Mertens on creating the Indy-winning Galmer G92

Image by Dan R. Boyd

Alan Mertens on creating the Indy-winning Galmer G92

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Alan Mertens on creating the Indy-winning Galmer G92


Thirty years ago at the Indianapolis 500, a most unexpected victory was earned. Al Unser Jr. and Galles-Kraco Racing teammate Danny Sullivan were more than capable of winning the race on talent alone, but with the custom Galmer G92-Chevy commissioned by team owner Rick Galles as their only chassis option, the Indianapolis Motor Speedway should have been the car’s Achilles heel.

On road and street courses, where maximum downforce and even aerodynamic drag can be an asset, the G92 was a fearsome tool for its drivers to wield. But at the big Speedway, where slippery aerodynamics and an extreme lack of drag are critical components of success, the boutique Galmer chassis was an undeniable liability.

Lola’s new T92/00 looked like a needle and had the likes of Michael and Mario Andretti, plus powerful new Ford/Cosworth XB engines, to set the performance standard at Indy in 1992. On a normal warm day in late May, carrying all that extra drag that couldn’t be shed, the Galmer G92 would have been a giant headache for Unser Jr. and Sullivan.

But the race was anything but normal as the coldest Indy 500 in modern history was run, and by chance, as the rest of the field piled on all the downforce they had to give their icy tires a chance to work on the frigid track surface, the Galmer’s Achilles was transformed into its greatest asset.

Carrying more downforce and drag than any other car was a perfect fit for this most specific weather where an absence of grip caused driver after driver to spin and crash while grappling with cars that struggled while the G92s thrived.

Looking back on the achievement where Galles and Unser Jr won their first Indy 500, the car’s designer, England’s Allan Mertens, gave RACER the G92’s origin story to help celebrate the 30th anniversary of the amazing victory for all involved.

Marshall Pruett

The author and Al Unser Jr. Dan R. Boyd photo

It starts with a brief history going back to my days working for March. After March’s first Indy car, the 1980 Orbiter, failed to hit the mark, then-chief designer Ian Reed left for unrelated reasons to move to America with his American wife. I had co-designed the March 801 F1 car for Robin Herd and John McDonald, but Robin asked me to go back to March on the IndyCar side to fill in for Ian.

As a joint effort with Gordon Coppuck, we modified the 801 to IndyCar spec and the 81C was born. I was given the role of heading up the IndyCar program leading a small team while the rest of the drawing office focused on IMSA GTP, Formula 3000, Formula Atlantic and F3.

Although we were credited with five Indy 500 wins, after a couple of years, things started to become difficult. Clearly, my weakness was a lack of aerodynamic talents, and luckily, we had Adrian Newey cutting his teeth on the GTP cars — he was an obvious talent — and in the background Andy Brown was working on the F3000 cars. His name would crop up again later.

Adrian was the aero mastermind on the March 85C and 86C, without question our two best Indy cars, and Adrian would say, “This is the shape, now fit an Indy car inside of that shape.” Then Adrian left at the end of ’86 and the March progressively struggled again in ’87 and ’88.

At the beginning of ’88, after I had finished the 88C, March had gone public, lost its focus, and I was lured away by Galles Racing to work with Al Unser Jr. running the 88C. Within six months, with Al’s support and Rick’s enthusiasm, Galmer (Galles+Mertens, shortened to Galmer) was born. We won four races and finished second in the championship.

In 1991, Galles, now merged with the Maury Kraines’ Kraco Racing team, gave the go ahead for the Galmer G92 chassis. CART was going to introduce new regulations to be implemented in ’93 for minimum specifications for the thickness of honeycomb and the thickness of carbon skins in the chassis. When we got to production we decided to adopt these rules for ’92. That was our first problem.

Not until we had finished the car and torsion tested it — there were no computer simulations at the time — did we find the chassis to be massively stiff. In one respect this was fantastic, but in the interface between the engine and gearbox, our bellhousing was too soft, made worse by our approach to housing the turbocharger. Now we had lost our linearity of the fifth spring from front to rear axle; the bellhousing allowed the car to twist in the corners, which was not favorable.

The turbocharger arrangement, a fundamental part of our design, was turned 90 degrees so the inlet pointed forward and the exhaust pointed to the rear. Now we were able to have twin inlets, each side of the engine cover, and that gave us twin exhausts with twin wastegates that would blow the diffuser at the back. The tail of the gearbox, which was exposed to the air, had the casting done with the stiffening ribs on the inside of the casing so the smooth exterior was an extension of the center part of the tunnel.

Moving the gearboxes’ strengthening ribs from the outside to the inside gave the G92 an aerodynamic advantage thanks to the smooth profile for air to pass over on its way out the back. Dan R. Boyd photo

Ironically, although this was to prove troublesome, it was this innovation that won Galmer the Louis Schwitzer Award at Indy that year.

The complex inlets and outlets from the turbo took up a lot of space and further compromised the bellhousing size and shape. We tested the configuration in the wind tunnel and although we saw huge gains, the results were inconsistent as the air lines into the model kept freezing. We decided early on to commit to it anyway.