In August 1948, a 22-year-old air show pilot named Betty Skelton paid $3,000 for an aircraft she had never flown. It was a tiny single-seat biplane, at the time the smallest aerobatic aircraft in existence, built two years earlier by a designer named Curtis Pitts. She painted it red and white, put a skunk on it and called it Little Stinker.

The next year she won the International Feminine Aerobatic Championship in it. The year after that she won it again. A design dynasty had begun. For the next three decades the Pitts Special would be the aircraft every serious aerobatic pilot either flew or had to beat.

Here is how one man’s backyard biplane came to rule competition aerobatics, and why, eighty years later, it is still the aircraft many pilots learn to fly upside down in.

Small, light and twitchy on purpose

Curtis Pitts began designing his single-seat aerobatic biplane during the Second World War, and the prototype flew in the mid-1940s; Wikipedia gives September 1944, the Smithsonian dates the S-1 to 1945. His idea, as the National Air and Space Museum describes it, was an aerobatic aircraft that would defy gravity and be crisp on the controls.

The big pre-war aerobatic biplanes were heavy machines with large radial engines. Pitts went the other way. He built around the new, smaller and lighter horizontally opposed engines, kept the wingspan short, and swept the upper wing slightly, which helped with access and balance and, the Smithsonian notes, made snap rolls snap more sharply.

The result was revolutionary for exactly the reasons the museum lists: small size, light weight, short wingspan and extreme agility. The prototype was wrecked a few years after its first flight, but the second aircraft, the S-1C of 1946, survives. It is Little Stinker.

Betty Skelton and the Stinker

Skelton made the Pitts famous. She flew it at the Cleveland Air Races and across the American air show circuit, took it to displays in London and Belfast, and mounted a second ball-bank indicator upside down on the panel so she could keep her flying coordinated while inverted.

She had a sense of humour about it, too. According to the Smithsonian, she fitted a bright red, non-functioning button to the instrument panel labelled “Spin, crash and burn”. Because the registration NX86401 was so long and the Pitts so small, she asked the authorities for a shorter one and got N22E, which the aircraft still wears. In Little Stinker she also became the first woman to perform an inverted ribbon cut, flying inverted close enough to the ground to cut a ribbon stretched out by her friends Steve Wittman and Bill Brennan. Few aircraft of the day could have done it so precisely.

She and fellow performer Caro Bayley both won women’s championship titles in Pitts Specials in the late 1940s and early 1950s. Skelton sold Little Stinker in 1951, later bought it back with her husband and donated it to the Smithsonian. Restored by volunteers between 1996 and 2001, it now hangs in the Udvar-Hazy Center in Virginia.

The National Aviation Hall of Fame’s biography of Betty Skelton, the champion who made the Pitts Special famous.

The S-1S: built to win

In 1960, Pitts realised the S-1C needed more to compete internationally. The answer was the S-1S, which the Smithsonian credits with three key changes: four ailerons instead of two to boost the roll rate, symmetrical aerofoils so the aircraft flies the same way upright or inverted, and generally a 180 hp Lycoming engine.

Pitts also opened the design to homebuilders. More professional plans went on sale in 1962, and hundreds of Pitts Specials were built in garages and hangars around the world. Pitts built the first S-1S examples for a who’s who of American aerobatics, including Bob Herendeen, Mary Gaffaney, Gene Soucy and Tom Poberezny.

World champions, 1972

Then came the results. The US Aerobatic Teams of 1970 and 1972 won the world team championships flying the S-1S almost exclusively. At the 1972 World Championships, five members of the winning American team flew the S-1S and two flew the new two-seat S-2A, and both individual world champions, Charlie Hillard and Mary Gaffaney, flew S-1S Pitts Specials.

According to the Smithsonian, between the late 1960s and 1974 almost all US national men’s or women’s champions flew an S-1S or S-1C. British pilots flew it at the 1972 Worlds, and Canada’s team arrived for its first world championship in 1974 equipped with Pitts S-1S and S-2A aircraft.

Two seats, and a factory

The two-seat S-2 first flew in 1967 and received its type certificate in 1971. It turned the Pitts into a trainer: an instructor could now sit in the same aircraft as the student. Factory production was set up at Afton, Wyoming, and the certified S-1S followed in the early 1970s. The 260 hp S-2B followed, and the current S-2C is certified for +6 and −5 g.

The Pitts also went into uniform. Wikipedia lists Chile and Venezuela as military operators, and the Royal Jordanian Falcons once flew four Pitts S-2As. Civilian teams such as the Goodyear Eagles flew S-2Bs.

The International Council of Air Shows inducts Curtis Pitts into its Hall of Fame in 2002.

Dethroned, not retired

Over time, newer and more powerful designs took over the top Unlimited category, which the Smithsonian notes is the one level where the Pitts is no longer competitive. Everywhere else, from basic to advanced categories, it still wins, and it remains the classic aircraft for advanced aerobatic training.

Curtis Pitts died in 2005 at the age of 89, still working on a new two-seat Unlimited biplane. The rights to the Pitts name now sit with Aviat Aircraft in Afton. And according to Wikipedia, in 2016 air show pilot Spencer Suderman used a modified single-seat Pitts to set a world record of 98 consecutive inverted flat-spin turns.

Curtis Pitts visits Kermit Weeks at Fantasy of Flight, a rare chance to see the designer himself.

Not bad for a little biplane that Curtis Pitts began sketching in the middle of a world war. Betty Skelton said she wore it rather than sat in it. Eighty years on, pilots around the world are still putting it on.

Sources: National Air and Space Museum (Pitts S-1C Special; Pitts S-1S Special; Meet Betty Skelton), Wikipedia (Pitts Special)