All versions of the Pitts S1 series offered by Steen use the stretched fuselage design (identical to the certified S1-S) which features bungee landing gear and power options from 85 to 200 hp. The typical engine choice is a 180hp Lycoming O-360. The S1-C plans are used as the basis for both versions, with supplemental wing plans offered for the S1-SS.

The S1-C is the "Flatwing" Pitts Special, which was the first model for which plans were offered back in 1962. The S1-C uses the M-6 airfoil on both wings, and has ailerons on the lower wings only (a four-aileron model is available, please ask for details.)

The S1-SS is similar to the certified S1-S "Roundwing" Pitts Special, but it uses the "Super Stinker" aileron technology developed by Curtis for championship-level aerobatic competition. This aileron technology allows for very light stick forces, very high roll rates, and good centering while eliminating the need for aileron spades. The S1-SS has four ailerons, and the wings have symmetrical airfoils. The upper (and furthest forward) wing uses an airfoil that stalls first, whether the plane is upright or inverted. Supplemental wing plans for the S1-SS are available from Steen Aero Lab.

Website: Steenaero.com