The Search For Ultimate Speed

Here’s how one pilot set the world prop/piston speed record and came to dominate unlimited air racing

If you’re determined to make an airplane fly faster, traditional wisdom suggests there are three ways to realize that goal. In ascending order of difficulty, you can increase the power, improve the aerodynamics or reduce the weight. Perhaps no class of airplanes exemplifies the need for speed more than unlimited air racers, and few pilots have pursued the quest for ultimate velocity as tenaciously as ex-Navy aviator Lyle Shelton.

When Shelton opted to build a competitive unlimited air racer in the late 1960s, he attacked all three problems—on a budget. Unfortunately but inevitably, unlimited air racing is a rich man’s sport, and Shelton had no bottomless pit of cash. He became an airline pilot after his military service, but even that salary wasn’t adequate to feed the unlimited race plane’s voracious demand for money. He also hoped to launch an assault on the world 3-kilometer prop/piston speed record, another extremely expensive project. At the time, the record was 469 mph, set by a German Me-209 back in 1939.

Shelton was aware that fellow Reno Unlimited air racer, Darryl Greenamyer, was planning an attack on the record in his modified WWII Bearcat, exactly the type of airplane Lyle hoped he could push past 500 mph. Sure enough, Greenamyer posted four 3-kilometer runs that averaged 483 mph in the late summer of 1969 and brought the world prop/piston speed record to the U.S.

Photo by Bill Larkins - CC BY-SA 2.0/Flickr

Lyle chose tiny Compton Airport in the middle of the LA Basin as home for his race-plane buildup. With only 3,300 feet of runway, uncontrolled Compton might seem an unlikely location for a WWII fighter project, but the rent was cheap and Shelton’s budget was small. In 1968, Shelton moved a truck and trailer full of mangled airplane parts into the hangar next to mine at Compton, including what I guessed to be a Pratt & Whitney R2800 radial engine.

As I helped him unload the pieces of airplane into his hangar, Lyle explained that these were the remains of a Bearcat that had crashed during an airshow several years before in Valparaiso, Indiana. The airplane had been on short final to the airport when a horse ran out in front of it, and the pilot initiated a go-around. Unfortunately, the new owner/pilot had no formal warbird experience other than a cockpit checkout and a few short hops in the single-seat fighter. He firewalled the throttle on the 2,250 hp engine, and the airplane responded with a hard left torque roll and crashed inverted on the edge of the runway. Amazingly, the pilot survived, but the airplane was pretty much totaled. The wreck sat in a heap for several years in the tall brush of the airport, until Shelton heard about it and bought what was left after nearly a decade of weathering and cannibalizing.

Shelton was not without credentials in low-level flying. He was a former West Texas crop-duster and carrier pilot with time in a variety of jet fighters and attack aircraft, the latter including the king of all single-engine, piston-driven ground-pounders, the Douglas A1 Skyraider. Lyle had also flown other pilots’ Mustangs and Hawker Sea Furies at various racing venues but had a dream of someday building the world’s fastest prop-piston airplane, an unlimited racer that could dominate the competition.

Shelton knew the stock Bearcat was already one of the quickest machines flying behind pistons. He reasoned that an engine upgrade from the stock P&W R2800 to the Skyraider’s Wright R3350 powerplant might provide just the power he needed to win the gold at Reno, Miami and the other race locations. With very little money and an all-volunteer crew, he did exactly that. Miraculously, the Bearcat was in semi-flyable condition by September of 1969, and Shelton raced at Reno the same month, finishing a creditable fifth in a field of eight.

Rare Bear in 2004. Photo by Kogo - CC BY 2.5/Wikimedia Commons

Over the next 35 years, I became an unpaid member of Shelton’s crew, providing photographic support, feature stories, press releases and whatever else I could do for Lyle’s shoestring operation. I watched Shelton and his mechanics transform and improve the airplane, eventually named Rare Bear, to a highly tuned, dramatically modified version of the original warbird. The team scavenged parts from everywhere, spares from other F8F owners and wrecked Bearcats, aircraft salvage yards and overseas air forces where the Bearcat was still in military service. Shelton also bought/borrowed a number of junked DC-7 engines in hopes of assembling one that might actually run.

The Wright R3350 engine was famous for its power but had thousands of moving parts and suffered from poor reliability in military service. TBO on the early models was about 100 hours, and even the later, improved versions only managed a 400-hour interval between overhauls. The powerful Wright engine fitted to Boeing B-29s in WWII was prone to overheating and had a nasty habit of catching fire during long Pacific bombing missions to Japan. Still, it was perfection from hell for those seeking high power at any cost.

Adapting the double row, 18-cylinder Wright radial to fit the Bearcat was a demanding task, and fitting the airplane with a giant, four-blade DC-7 propeller made Lyle’s F8F a permanent tailwheel machine. The blades were so large that Shelton’s modified fighter had to be flown off and back onto the ground in a three-point attitude to avoid a prop strike.

Given enough power, you could probably blast the Queen Mary into orbit, but Shelton was willing to settle for double the P&W’s motive force. More accurately, the stock Pratt put out 2,250 hp, and the big Wright super-nova-on-a-leash employed 550 additional cubic inches to generate nearly 4,000 hp. Add water injection and nitrous oxide, and you might see as much as 4,500 hp…for a very short time. The problem was/is that drag increases as the square of speed and power required increases disproportionately. Shelton knew power alone wouldn’t get him to his goal of 500 mph.

Rare Bear in 2007

As a result, Lyle’s crew incorporated a long list of aerodynamic improvements, most notably clipping a whopping 4 feet from each wingtip, replacing the large stock, wraparound canopy with a smaller, more aerodynamic shape, and reducing intersection drag at the critical wing root leading edge dramatically. There were myriad other minor changes to Rare Bear, all intended to improve the drag signature.

Lyle was always amazed at what his crew could accomplish on very little budget and short notice. He used to tell anyone who’d listen, “The pilot is the least-valuable member of the ground crew.” In fact, Lyle was actually fairly proficient at turning wrenches.

Reducing any airplane’s weight is a trick even David Copperfield on his best day would be challenged to duplicate. Some of the aerodynamic improvements helped lower Rare Bear’s empty weight, but the major contributors to speed were unquestionably the massive introduction of power and the major drag reduction. The Bear was a work in progress for the next half century, but when the initial iteration was completed in 1969, the airplane weighed in at 8,700 pounds in race trim, and it flew with 4,500 hp. That’s less than 2 pounds/hp, the lowest power loading I’ve heard of among unlimited race planes.

The result of Shelton’s modifications and improvements was indeed a record-setting machine. In 1972, Lyle took his F8F to Thermal, California, and established a new world time-to-climb record for prop/piston aircraft, high jumping from brake release to 3,000 meters (9,843 feet) in 91.9 seconds. That’s a climb rate of 6,475 fpm, nearly the same as a Lear 23.

Rare Bear in 2014. Photo by Don Ramey Logan - CC BY-SA 4.0/Wikimedia Commons

Rare Bear’s power and speed made it a frequent winner on the air racing circuit as well. Between 1972 and 1988, Shelton scored eight first-place Gold victories and four second-place Silver finishes. In 1989, Shelton flew an NAA-approved 3-kilometer course in Las Vegas, New Mexico, in hopes of capturing the world prop/piston speed record, then held by Steve Hinton in a P-51 Mustang at 499 mph. The crew had the Bear running perfectly, and Lyle made two low-level, two-way runs at an average speed of 528.33 mph, confirming Rare Bear, officially, as the fastest piston-powered airplane above the planet.

Shelton’s record stood for 28 years, but in September 2017, Steve Hinton Jr. edged past Rare Bear’s record. Hinton flew a P-51 named Voodoo and posted a speed of 531 mph. Rare Bear went on to win six more Reno Gold races and finish second four times, making it the most successful unlimited racer in the history of unlimited air racing.

In 2006, oilman Rod Lewis of San Antonio, Texas, purchased Rare Bear from Shelton for $2 million, and pilot John Penney has campaigned the airplane at Reno since then.

Lyle Shelton died in 2010 at age 72, but it’s unlikely his racing record will ever be surpassed. In a life dedicated almost exclusively to the pursuit of speed, Lyle could never afford to do everything he wanted with his Bearcat, yet he still somehow managed to win more races and set more records than anyone else in the world’s fastest motor sport.

As of January 1, 2016, Senior Editor Bill Cox has logged 15,100 flight hours in 321 types of aircraft. He also holds 28 world city-to-city speed records, has made 211 international delivery flights, and owns and flies a LoPresti Mooney. You can email Bill at

Check out more Cross-Country Log flying stories from ferry pilot and Senior Editor Bill Cox.