Sonerai Factoid 3 --The Fiberglass Sonerai
Jim Cunningham
Author: John Monnett: from Sonerai to Sonex
July 22, 2008


There have been a number of Sonerai II variants since its inception—the midwing, trigear, and stretch models, but there were also a few that never survived the prototype or testing stages at the factory. One of the first—and the most radical—logged little flight time. Long before production aircraft made use of composites in their construction, Dick Rutan revolutionized the experimental aircraft market with the EZ design made of such materials, and the design was an instant hit in the 1970s. For Monnett and the Sonerai, the success of the EZ meant finding a way to incorporate composites in some way in order to keep up with popular developments. Reviewing the Sonerai’s design, John concluded that the best course of action would be to replace the fabric on the fuselage with fiberglass. The factory airplane modified, N12MX, utilized square tubing longerons for a simplified truss as well as a metal tail. Unfortunately this variant was simply too heavy and impractical. In spite of its being displayed at the EAA Convention in 1976, the airplane was put in mothballs and all but forgotten. N12MX was later pulled out and became the factory prototype for the much more popular low wing Sonerai II variant.

Ed's Essays - Covering Your Aircraft Part 3
Ed Fisher
July 14, 2008

Some suppliers sell an un-certified dacron in the lighter weaves, such as 2.7 oz. and 1.8 oz ultralight style. Since our Sonerais are not certificated factory builts, these fabrics can be used and will save you a couple dollars per yard over the FAA-PMA approved fabrics. I have used certified coatings over un-certified fabrics, and have noticed no ill-effects.

'Several' years ago, (1988), I experimented with Latex coatings on 1.7 oz. ultralight dacron on our 'Skylite' ultralight. Sherwin-Williams flat black Latex house paint was purchased, and to it I added 1 qt. per gallon of 'flowtrol' latex additive, to keep the paint flowing while it was being applied with a foam brush. Two coats were applied, then the fabric was lightly sanded with Scotch-Brite. Painting was then done with an inexpensive synthetic tractor and implement enamel. The results were initially acceptable, but over 2 or 3 years the Enamel became brittle and started to crack. I then found that if I painted the airplane with Latex color topcoats, by taking 1 gallon of paint, adding 1 qt. of flowtrol, and 1 pint of distilled water, I could spray the mix on the fabric with my Binks #7 siphon gun, at 25 psi. I did later jobs with DuPont Centari over latex, and used the DuPont flex additives, and got fairly good results, enough to win an Oshkosh grand champion award...

Sonerai Factoid 2
Jim Cunningham
Author: John Monnett: from Sonerai to Sonex
June 24th, 2008

Most plans for homebuilt airplanes are fairly large in size to allow intricate details to be shown for builders. The Sonerai is different—ever since the plans appeared in 1971 they have been printed on 8 ½ x 14 inch paper in a ring binder. Why aren’t the plans larger in size? The answer to that question lies in the origin of the airplane and the occupation of its designer, John Monnett.

The first Sonerai I—actually two were built virtually simultaneously but one was rushed to completion for the Oshkosh Convention in 1971—was built from sketches and wire models, not plans. Plans were not drawn up until late that year, and were reverse-engineered from the airplane itself and some data from the sketches. The world was a different place in 1971… there were no copy shops standing by to run off plans for a dime a page, and running larger sheets as traditional blueprints was expensive. John and Betty were newly-minted teachers with only modest salaries. So John did what he always does best—he came up with a creative solution based on available resources.