The Smyth Model S Sidewinder is an all-metal, two-seat side-by-side, low-wing homebuilt aircraft, designed and developed in the United States.

[2][3] In 1958 Jerry Smyth began the design of a monoplane sport aircraft, intended to be easy to build and fly as well as stressed to +9g for aerobatics.

[1] Constructed of welded steel tubing with aluminum skinning, the Sidewinder has all-aluminum wings and is stressed to ±9g ultimate loading to allow aerobatics.

An unusual under-fuselage spoiler is used for approach control.,[5] The original design shared the same windscreen as a Thorp T-18.

[6] The prototype attended the 1969 Experimental Aircraft Association convention at Rockford, Illinois, winning the Outstanding Design Award.