The Sonerai Turns 50

Monnett’s original Sonerai, which debuted at EAA’s Aviation Convention and Fly-in in Oshkosh in 1971, is on display in the homebuilt aircraft display area, flanked by its younger Sonex siblings.

John Monnett, President of Sonex Aircraft LLC, unknowingly launched his homebuilding career fifty years ago at the 1971 EAA Aviation Convention and Fly-in in Oshkosh, WI. The Sonerai, an airplane he designed for himself after seeing Steve Wittman’s V-Witt at the 1970 fly-in, won both the Best Formula Vee and the Outstanding Contribution to Low Cost Flying awards upon its debut. Its reception in the homebuilding community pushed Monnett, then an art teacher, into selling plans and parts. He soon left his teaching career to pursue aviation full time. Variations of the original single-seat, folding mid-wing Sonerai followed and builders embraced them all, though John was less than enthusiastic about the esthetically and aerodynamically disrupting tri-gear configuration. (A sign once hung on John’s door at Sonex Aircraft, inspired by tri-gear Sonerai and the eventual introduction of a tri-gear Sonex, that read, “It will be a cold day in hell I design another tri-gear aircraft. Welcome to hell.”)

The Sonerai, originally sold under the banner Monnett Experimental Aircraft, is the eldest of Monnett’s designs. Its siblings include the Monerai sailplane (as well as the self-launching variant), the Moni motor glider, the record-setting one-off Monex race plane (“It tried to kill me each time I flew it.”) and the AeroVee VW Type I engine conversion. When Monnett Experimental Aircraft closed its doors in 1986, the rights to sell and support the Sonerai were sold to Great Plains Aircraft, and then to Fred Kiep, who sold them as Sonerai Works, LLC. Kiep offered to sell the rights back to Monnett in 2019 and Monnett welcomed his first born into the Sonex Aircraft stable of designs.

Both Monnett and Sonex Aircraft have their sights set firmly on the future, but the Sonerai holds a special place in their hearts as well the hearts of five decades of builders. Sonex Aircraft offers the Sonerai only as a plans-built aircraft and minimal pre-made parts are available, though that may change if demand and rare gaps in new-product development allow. The sale of plans of this 50-year old design continue at a surprising pace, underscoring that scratch-built airplanes and low-cost flying still have a place in this age of quick-build kits.


  1. I know that the names John Monnett gave his aircraft are sort of phonetic versions of more common phrases or names, such as the name “Waiex” being pronounced “Why Ex”.

    So does anyone know for sure how to pronounce “Sonerai”? Is it “Sun Ray” or is it “Sunny Ray”?


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