Overview
Sonex Aircraft is an American kit-aircraft manufacturer based in Oshkosh, Wisconsin, known for a family of affordable, all-aluminum experimental amateur-built (E-AB) sport aircraft and for the AeroConversions product line, which includes the Volkswagen-derived AeroVee engine. Its models share a common construction philosophy and the 80 hp AeroVee 2180: the two-seat Sonex, the Y-tail Waiex, the single-seat folding-wing Onex, the Xenos motorglider, and the plans-built Sonerai II.
Heritage
The company grew out of the work of designer John Monnett, whose Formula V-derived Sonerai II first flew in 1971 and established the VW-powered, garage-storable formula the marque still follows. Monnett founded Sonex Aircraft in the late 1990s, and the first Sonex flew in 1998. The AeroConversions division was created to supply the AeroVee engine kit and the AeroInjector carburetor that power the line. The company has continued to develop and support its designs under new leadership in recent years, releasing the updated B-model Sonex, Waiex and Xenos kits.
Design Signature
Every Sonex design shares a riveted aluminum airframe, fixed landing gear and the naturally aspirated AeroVee 2180, giving cruise speeds around 120 to 150 knots on roughly 4 gallons per hour. Wings fold or come off for garage storage and trailering, and clean stall speeds in the low 40-knot range keep the aircraft Sport Pilot eligible. The designs are sold as builder kits, or as plans for the Sonerai, rather than as factory-built certified airplanes.
For Owners
Buying into a Sonex means committing to an amateur-built airframe: build quality and equipment vary with the builder, so a used example rewards a careful pre-buy and a look at the builder’s log. In return the operating economics are among the lowest in general aviation, with VW-conversion fuel burn, owner-performed condition inspections, and the option of home storage. Sonex maintains an active factory, parts supply and owner community, so support for the current kits is strong.