By Garth Calitz

Originally designed and built by Curtis Pitts in 1944, the Pitts biplanes were the leading aircraft in world aerobatic competitions during the 1960s and 1970s. They continue to be a strong contender in lower-category competitions today.

Curtis Pitts started designing a single-seat aerobatic biplane in 1943. Although the design has been continuously refined since the prototype's first flight in September 1944, the current Pitts S-2 remains very similar to the original in both concept and design.

Many of the aircraft constructed by Curtis Pitts featured a skunk illustration and were named "Stinkers." Aerobatic performer Betty Skelton named the second aircraft built by Curtis "Lil' Stinker" after purchasing it. The prototype S-2, the first two-seat Pitts, was dubbed "Big Stinker." The prototype Model 11, later known as S1-11B, was called "Super Stinker," and the prototype Model 12 was named "Macho Stinker."

Aviat Aircraft in Afton, Wyoming, currently manufactures certified versions of the Pitts. The S1 model is a single-seater equipped with a flat-4 Lycoming engine that can reach up to 200 hp and has a wingspan of 5.28 meters. The S2 is a two-seater variant with a flat-6 Lycoming engine producing 260 hp and a wingspan of 6.1 meters. Pitts Specials have been fitted with engines capable of delivering up to 450 hp.

Aviat Aircraft offers plans for the single-seat Pitts S1-S. Steen Aero Lab, located in Palm Bay, Florida, provides plans and kits for the S1-C and its derivative, the S1-SS. Since the plans became available in 1960, many hundreds of homebuilders have successfully completed and flown the Pitts.

During the 1940s and 1950s, Pitts manufactured a small number of aircraft. The Pitts Special set the benchmark for evaluating all other aerobatic planes. Initially, several homebuilt aircraft were created using rough, hand-drawn plans by Pitts. In 1962, more professionally drafted plans became available for purchase.

During the 1960s, numerous homebuilt aircraft were constructed, establishing the S-1 as a renowned aerobatic aircraft. Concurrently, Pitts developed a two-seat aerobatic trainer variant, the S-2, which took its maiden flight in 1967 and received its type certificate in 1971. In 1973, production of factory-built aircraft was expanded to include the single-seat S-1S.

In 1972, the U.S. Aerobatic Team secured victory at the World Championships using exclusively Pitts biplanes.

In 1977, Curtis Pitts sold his stakes in the Pitts S1 & S2 to Doyle Child. Child subsequently sold the rights in 1981 to Frank Christensen, who maintained production at the Afton facility under the name Christen Industries. In 1994, the rights for homebuilt versions of the Pitts were sold to Steen Aero Lab, while the Afton factory and production rights were transferred to Aviat.

Curtis Pitts passed away in 2005 at the age of 89. When he died, he was collaborating with Steen on the prototype of the new Pitts Model 14, a completely new two-seat biplane designed for unlimited aerobatics and equipped with the 400 hp Vedeneyev M14P radial engine.

Pitts Model 14

The world record for an inverted flat spin stands at 98 rotations, accomplished by air show performer Spencer Suderman on March 20, 2016, over Yuma, Arizona. Suderman flew the Sunbird S-1x, an experimental variant of the Pitts S1 equipped with a Lycoming IO-540 engine. The maneuver commenced at an altitude of 24,500 feet above the Yuma Proving Grounds and ended at 2,000 feet AGL. The previous record for consecutive turns in a flat spin was 81, also achieved by Spencer Suderman on March 13, 2014, in a Pitts S2-B from an altitude of 23,000 feet over the Naval Air Facility El Centro.

In South Africa, alongside numerous privately owned Pitts S-1 and S-2 aircraft, there are two renowned Pitts aerobatic teams: the Goodyear Eagles and Team Torre. Many of the nation's leading aerobatic pilots have honed their skills on these aircraft and continue to fly them occasionally at airshows throughout Southern Africa.

Over the past 73 years, numerous versions of these Magnificent Machines have been constructed.

Single Seat Variants

S-1

This basic single-seat Pitts aerobatic biplane features a flat M6 aerofoil section and has ailerons only on the lower wing. It was equipped with various engines. Two units were constructed: the first was named Special, and the second was called Li'l Stinker.

S-1C

The S-1 single-seat aircraft, constructed by amateurs, features a flat-bottom wing with ailerons solely on the lower wing. It is intended for engines ranging from 100 to 180 hp. Initially flown in 1960, the S-1C can now be built from plans provided by Steen Aero Lab.

S-1D

The amateur-built S-1C features ailerons on all four wings and is generally similar to the S-1S.

S-1E

The S-1C, constructed by amateurs using kits from the factory, features a symmetrical airfoil.

S-1S

The Aerotek-built certified S-1C is designed for competition aerobatics, featuring a round airfoil section and four ailerons, powered by a 180 hp Lycoming AEIO-360-B4A engine; 61 units were produced. This model is also offered by Aviat Aircraft as a plans-built aircraft.

S1-SS

Comparable to the certified S1-S "Roundwing," this model features 180–200+ hp, is a single-seat, homebuilt aircraft with a symmetrical wing design and four symmetrical "Super-Stinker" style ailerons, offering a roll rate of 300 degrees per second and equipped with a fixed-pitch propeller. Plans and components for this model can be obtained from Steen Aero Lab.

S-1T

The Aerotek-constructed S-1C features a 200 hp Lycoming AEIO-360-A1E engine and includes minor modifications; 64 units were produced. It is a single-seat aircraft with four ailerons, factory-built, equipped with symmetrical wings and ailerons, and a constant-speed Hartzell propeller with either two or three blades. The top wing was repositioned forward compared to the S-1S to optimize weight and balance. As of 2008, Aviat Aircraft offered this model as a made-to-order product.

S1-11B

Referred to as the Model 11 "Super Stinker," this aircraft features a Lycoming engine with over 300 horsepower, a four-aileron design, and a single-seat configuration. It can be built from experimental plans or factory-assembled with factory components. It has a symmetrical airfoil and a three-blade constant-speed propeller. The aircraft boasts a roll rate exceeding 300 degrees per second and a climb rate of over 3,000 feet per minute.

Dual Seat Variants

S-2

Enlarged S-1 featuring a tandem two-seat fuselage and equipped with a 200 hp Lycoming AEIO-360-B4A piston engine.

S-2A

The Aerotek-built S-2A features a 200 hp Lycoming AEIO-360-A1A or -A1E piston engine and a constant-speed propeller. Later models include a longer landing gear and a 51 mm front cockpit. A total of 259 units were produced.

S-2B

The Aerotek-manufactured S-2A features a 260 hp Lycoming AEIO-540-D4A5 engine and an auxiliary fuel tank on the upper wing. The landing gear and upper wings were repositioned six inches forward. A total of 196 units were produced. Although the aircraft is no longer in production, it continues to receive support from Aviat Aircraft.

S-2C

This current production model features four ailerons, two seats, a factory-built symmetric airfoil, and a 260 hp Lycoming engine that powers a constant-speed three-blade propeller. It evolved from the S-2B model, boasting enhanced ailerons and rudder, a flat-bottom fuselage, a lower-profile bungee gear, improved inverted handling, and is certified for +6/-5g. As of 2008, it is produced by Aviat Aircraft.

S-2E

S-2A assembled by amateurs using factory-produced kits.

S-2S

The Aerotek-built S-2B features a single cockpit and a dual-tank fuel system. The fuselage is shortened by 14 inches (35 cm) in front of the cockpit to accommodate the heavier 260 hp (194 kW) Lycoming AEIO-540-D4A5 engine. It has a wingspan of 6.10 m, with 17 units produced. Although this model is no longer in production, Aviat Aircraft provides support for it.

S-2SE

Amateur-built S-2S from factory-produced kits.

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