How Reno Racers Keep Their Cool

At the Reno air races, pilots know that to go fast, you have to stay cool. That’s where Pete Law comes in.

Since 1966, thermodynamics engineer Pete Law has been showing up at the National Championship Air Races in Reno, Nevada, with his toolbox and a career’s worth of knowledge about cooling systems. (Dan Whitney)
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Greenamyer’s Bearcat was later enshrined in the National Air and Space Museum. Law and Boland became the Lennon and McCartney of the Unlimited air racing community. “Systems by Pete Law, Aerodynamics by Bruce Boland” was the legend painted on the fuselage of Strega, the nine-time Gold winning P-51 Mustang, but it could have been affixed to virtually every competitive entry at Reno. Red Baron, Dago Red, Dreadnought, Stiletto, Tsunami, Miss America, Rare Bear, Jeannie, Furias, Super Corsair, Mr. Awesome, Critical Mass—their fingerprints were on each of them. Boland died in 1995. “There isn’t a day that goes by that I don’t think of him,” Law says.

Wednesday, Day Three
Heat is the enemy of engines. The problem is especially acute at Reno because more power generates more heat. Back in the 1930s, aircraft engineers began cooling engines by injecting a mixture of water and methanol through a water regulator into the combustion chamber. This prevented a potentially catastrophic event—the detonation of the fuel-air mixture in each cylinder ahead of spark-plug ignition. Early, unwanted detonation, often accompanied by a death rattle known as engine knock, produces a spike in heat so extreme it can melt the aluminum on a piston. The cooling system enabled pilots to use more manifold pressure and more fuel in the air-fuel mixture that runs an engine; both translated into extra power. By the end of World War II, ADI systems were fitted to most high-performance fighters and bombers. These days, at Reno, all of the fast guys “go wet,” or run ADI.

Shortly after Law got involved in air racing, Greenamyer introduced him to Al DiMauro, the owner of Aircraft Carburetor in Burbank, California. “Al taught me everything there was to know about carburetors and water regulators,” Law says. He learned his lessons so well he began refurbishing and modifying units for DiMauro. And when DiMauro retired in 1978, Law essentially took over the part of the business that supplied the units for airplane and hydroplane racing. For an overhauled carburetor or water regulator, Law charges around $200. Law doesn’t do much hands-on carburetor work himself these days, but he remains a major supplier of ADI systems, based on water regulators that are nearly as old as he is. An ADI regulator can run as much as a grand, but, as Law told Sport Aviation editor Jack Cox in 1986, “When I sell a water-injection system, it’s warranted for life, effectively, and I come with the warranty.” At the races, his charges depend on the time he spends with a team to test and tune the cooling systems: anywhere from $50 to a couple hundred—enough, he says, to pay for his motel and meals while he’s there.

One of Law’s first customers was storied P-51 builder Dave Zeuschel, who sought his expertise in 1971. Unlike the air-cooled radial engine that Law had been working with in Greenamyer’s Bearcat, the Mustang was powered by a water-cooled V-12, so it needed an air inlet to cool the radiator. Law theorized that he could reduce the size of the scoop—and the consequent cooling drag—by spraying water into the face of the radiator. So he laboriously drilled dozens of tiny holes into quarter-inch stainless steel tubing and mounted this so-called spray bar in front of the radiator. Working with Zeuschel, he added deflector tabs and, later, injector nozzles to better atomize the water droplets. The spray bars were so effective that pretty much everybody copied them.

This year, Law has at least one of his cooling systems on 10 of the 11 fastest airplanes at Reno. And even if he hasn’t worked on a racer, he’s a resource. “If Pete’s got the time, he’ll answer any question,” says Mike Nixon, who built the Merlin engine powering Strega, which is the only top Unlimited that Law isn’t officially following. “He’s committed to the whole group, and everybody knows he won’t share your discovery without your permission.” Hence Law’s nickname in Unlimited circles: Secret Pete.

But despite all of Law’s efforts, at Reno, where engines are routinely run at twice the power anticipated by the original designers, things can still go wrong. Wednesday morning, when Law checks in with the 232 crew, Dale shows him a damaged piston that had been removed from the engine after Gibson’s 467.054 mph qualifying run.

“We’re officially out,” Dale says.

“Did he [engine builder Ray Anderson] have any comment about the little spot on the piston?” Law asks.

“He said, ‘Let’s have a biopsy, not an autopsy.’ ”

After Dale walks off, Gibson sidles up to Law. “I told them they were acting like a bunch of girls,” he confides. “We’re here to race, aren’t we?”

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