The Sidewinder is a copy of the Phantom X1 that was built by former Phantom Aeronautics employee Fred Bell. It was designed to comply with the US FAR 103 Ultralight Vehicles rules, including the category's maximum empty weight of 2540NaN0. The aircraft has a standard empty weight of 2500NaN0. It features a cable-braced high-wing, a single-seat, open cockpit, tricycle landing gear and a single engine in tractor configuration.
The aircraft is made from bolted-together aluminum tubing, with the flying surfaces covered in Dacron sailcloth. The Sidewinder differs from the X1 in having flaps. Its 301NaN1 span wing is cable-braced from an inverted "V" kingpost mounted on top of the wing. The landing gear has suspension on all wheels and features a steerable nosewheel, plus main wheel brakes. The pilot is accommodated on an open seat, partially enclosed by a fibreglass fairing with a windshield. The standard engine provided was the Kawasaki TA 440A snowmobile powerplant of 370NaN0.