EAA South Central Ozarks Chapter 1218

Project History

This Sonerai II was built in a two-week period by a group of industrial technical educators. The title of this article is to get your attention to this effort. Actually, many man hours were expended to construct this aircraft during the allotted time frame. As a disclaimer, the average homebuilder would be very successful if he built a Sonerai II in only two years. The Sonerai project was an educational effort. It was not a race to see how quickly a Sonerai or any other aircraft could be built. We would not want the speed of construction to overshadow the educational aspects of the class. This class was to give educators hands-on practical experiences in aircraft construction. The educators could then take these experiences back to their schools, perhaps to start aviation/aircraft-related educational projects.

Workshop Flyer

This exciting class started on the morning of July 15, 1974. There I stood, the instructor, before thirty fellow educators and two Air Force representatives. One of the latter was a Major with Ph.D. credentials who represented the Dayton Air Force Museum. Standing beside me was Dr. Charles Thomas, the official class coordinator for the University. Dr. Thomas deserves much credit. He was the necessary person who did all the paperwork which resulted in the project being accepted by the University. Dr. Thomas advertised the class and did the enrollment of students. He was appointed coordinator and followed the project closely, providing much help with the many minor and major facility and tool problems that arose. The University of Wisconsin-Stout aircraft construction workshop members came from as far east as New York and west from California; and from the northern extreme of British Columbia and south from Alabama. These class members were wishing to gain skills and credits which would allow their own schools to participate in aircraft construction.

The class was designed to provide many hours of hands-on aircraft construction experience. Students were reminded that, over time, work on the project was expected in place of after-class research. The more time the students put into the plane, the greater the development of their aircraft construction skills would be. The class members were encouraged to drift about the project from time to time to observe all the operations. This was a first-of-its-kind class and I explained that building a complete aircraft in two weeks would be difficult—that I was not sure we could complete the plane during the class. Although I had seven aircraft projects completed, most were projects at my schools, my only reference. I knew of the many variables that could develop into serious problems which would delay our progress—problems that could not be overcome in two weeks' time, or less. We were not only depending on ourselves, but also on the FAA and our suppliers of materials. Supplies were the greatest problem because not everything that we needed was on campus at the start of the workshop. They were expected to be delivered during the week by John Monnett. As it turned out, we were not able to fly the plane at Stout, only because of a few missing items which had not arrived on time. Anyway, the class was informed that I was from Missouri, the "Show-Me State," and they would have to show me that they could build the plane in two weeks.

Mr. Rob Hancik, the airport manager at Springfield, Missouri, and Red Monaghan, real estate broker and airport board member, also of Springfield, were the sponsors of the plane kit. The agreement was that they purchased all the supplies and owned the plane. They deserve much credit for gathering almost all the materials in a month's time. We did not want to purchase the parts until we knew the class had adequate enrollment to be held. As there was not time to scrounge for used parts, almost all the parts and materials were new. After purchase, John Monnett supplied the basic airframe kit and engine.

Project Progress

The students were required to pass an open-plans test, on the Sonerai II, the first day. They were given a sample contract of agreement that I use for school aircraft projects. This document states the project is an educational endeavor and is not for profit, outlines the responsibilities of teacher, sponsor and school, and other necessary descriptions.

Color slides and movies of my school flight projects were shown. The students were familiarized with the work assignment sheets that would be used to assign specific jobs to be done in a sequential order. The aircraft project was divided into two sections, which were fuselage and wings. Students were allowed to select the section they wished to work on. Students who had welding experience were identified and encouraged to work on the metal-truss fuselage crew. All this consumed the first morning of class.

The first afternoon was consumed by dividing the materials and moving the appropriate materials to the specific work area. The fuselage jigs and wing jigs were started and, when completed, set up. The fuselage and wings were built in adjoining rooms. The wings were set up in the testing laboratory and the fuselage built in the welding lab. The rooms were connected through large double doors. This made it easy for both crews to check in with each other and see what was going on with each crew.

The Wing Building Crew











The Fuselage Crew

A detailed record of the construction is available but is too large to include in this paper. However, the students did their part in working many hours to complete the plane as parts allowed. The students bonded and worked together cooperatively. The plane was completed through painting. The wing-folding feature was demonstrated. Many photos were taken during construction and the plane assembled outside for a class photo on the last day. The students then departed. Many were going to Oshkosh for the annual EAA convention. A number of the construction class students were to take Dr. Thomas' class at the University of Wisconsin-Oshkosh during the convention. This class pertained to the plans and materials used in construction of an aircraft. The EAA convention grounds were the research source for this class.

The completed plane was not of trophy-class finish. However, it was excellent considering the two-week construction period. The FAA precover inspection was on Monday of the second week. The inspector jokingly asked what took us so long. We wondered what took him so long. The inspection was detailed and consumed three and one-half hours. The inspector met with the class and gave them the good word that the project passed with flying colors.

The FAA's preflight inspection went equally well, which proved the students' work was up to the safety standards required by the FAA. Remember, this was an educational effort, which demands time from construction for such things as tests, demonstrations, questions, rework, cleanup, critiques, etc. Many important visitors also consumed the instructor's time. However, the class consumed three thousand man-hours, more or less.

Sonerai II at Oshkosh

This was the first plans-built Sonerai II. The yellow airplane was taken to the annual EAA convention on a trailer pulled by my pickup. It was displayed in front of the school-flight tent attended by many of the student builders and their instructors. The plane was looked over by many interested persons, photographed in excess, and the unique wing folding feature demonstrated every morning and evening and at times in between. The plane always had a crowd around it making photography difficult. EAA personnel moved the plane to the flight line, with the wings folded, and photographed it along with Monnett's aircraft and many Sonerai I aircraft. This photo appeared in Sport Aviation.

Sport Aviation Article

A highlight of the Convention was John Monnett giving all the students who worked on the plane a ride in his green Sonerai N22MX. One of the students weighed over 300 pounds. I was given a flight demonstration and allowed to control the plane in slow flight and to stall the plane. It seemed to me to be very forgiving in slow flight and very fast in level flight. John and I got in a race with the Davis V-tailed two-place plane. We passed him doing 165 MPH. Pretty impressive for a VW-powered two-place airplane at near gross weight.

Back at Mansfield

After Oshkosh, I trailered the plane to Mansfield, where completion and test flying was to be done. I found all the necessary parts at Mansfield, when I arrived and we simply installed them where they belonged.

The engine was started and breaking in time run. The Monnett-built 1900 cc. Volkswagen engine would only static at 2200 RPM, which was 800 RPM low. The engine sounded good and we all agreed the problem was a bad and inaccurate tach. We changed the leads to the tach as directed by John Monnett. This did not correct the problem, so we ordered a new electric tach.

We then towed the airplane as designed, on its own wheels with the wings folded, to the airport at Mansfield. There we unfolded the wings and installed them in place on the plane. Our Sonerai used bolts to secure the wings, instead of taper pins as in Monnett's design. We had permission from the designer to do this, of course. All that remained at this time was the test flying.

Test Flight Report

Preflighting the Sonerai II is straightforward. For the engine, drain the fuel strainer, check the oil level and visually check the gas tank level. One should check the airframe by traveling around the plane, checking the prop, spinner and cowling for condition and security. At the wheels, check the tire inflation and wear, brakes, and wheel pants. Observe these things on the wings: that they are bolted in place, aileron hinges and travel OK, At the empennage, check travel, hinges, tail wheel, tail wheel springs and cable ends. Thin reach into the cockpit and check the controls for travel and freedom of movement. Check all the normal inspection points as one would on any airplane.

The Sonerai is soloed from the rear seat. Getting into the rear seat requires a large step over the wing trailing edge and onto the rear seat. For my six-foot-five frame, sitting down required me to remove my shoes. At that, my feet and legs were jammed between the rudder pedals and seat back. This constant pressure was painful. Rudder pedal movement was to relax one foot and push it out of the way by depressing the opposite rudder. Fortunately, very little rudder travel is necessary to control the plane, especially on the ground. Tight taxi turns are the exception. Average-sized persons will have no trouble with the cockpit dimensions. We placed cushions behind the owners so they could reach the rudders. All other cockpit dimensions worked OK for me.

Cockpit familiarization is completed next. Located on the floor to the right of the pilot are the mag switch and tach cutout switch. They operate at right angles to each other, so as not to confuse them. Also, aluminum shields were used on these switches to prevent accidental operation. A red control lever on the cockpit right side is the fuel shutoff lever. It is labeled "FUEL," down "ON," and up "OFF." The throttle and friction lock are on the pilot's left in both front and back. The instruments are basic with the addition of cylinder-head temp and exhaust-temp gauges. An inclinometer or slip indicator is included and is very important to coordinate turns in a Sonerai. However, they seem very forward compared to most airplanes. The tach is electric. The fuel gauge is a transparent plastic tube and of little use. The control stick is located between the pilot's legs and is dual. The front stick is removable. Stick movements are easy and light, stop to stop. The pilot checks that the front seat belt and harness is fastened out the controls' way. The pilot then fastens his seat belt and shoulder harness. The canopy is to be down and locked and checked at all three locking points. Fresh are air vents pointed forward to provide the pilot with cool air needed in August. Distortion through the bubble canopy is very little and visibility is very good, especially so in flight.

Next, we will consider startup procedure. Fuel is turned on until the engine man notices the first few drips from the Posa carburetor overflow tube. Then the gas is turned off. The engine man gives the prop a few turns clockwise to prime the engine. Then, when called for, apply contact and brakes. This is tricky for the pilot as the throttle must be cracked a little and locked in place with the friction lock. The brake handle is pulled up with the left hand. The right hand turns on the mag switch, returns to the stick and moves it aft. Then the pilot calls out, "Contact," and brakes. When the engine catches, the pilot checks the throttle setting, checks that the prop man is out of the way ("Front clear"), moves the right hand over to the fuel lever and turns it on, and returns the right hand to the stick. All of this must be done before the engine starves for fuel. There must be a better way! And doing all this by oneself is a whole different thing involving tying the tail wheel and performing all the above from outside the cockpit.

The engine runup is not necessary as there is only one mag and no carb heat. One can check the mag switch by cycling it rapidly and noticing if there is an RPM drop. When the oil pressure and temperature are normal, it is a "go." Check the tach for full power on takeoff roll. One could hold the stick back, the brake on, and apply full power to check the tach, but it requires three hands to do so. That is why I check power on takeoff roll.

After checking for traffic, my first fast taxi down the runway was exciting and full of surprises. I opened the power full and maintained a three-point position with aft stick. The left wing came up unexpectedly and aileron was applied to force it down. This resulted in the front wheels coming off the runway and we were flying, rolling the tail wheel behind us at 30 MPH indicated. I chopped the power, the plane dropped and the rudder became very active. The engine hung on 1000 RPM. The new tach had not arrived and, you will remember, the old one read several hundred RPM low. Speed did not decrease rapidly and I was running out of runway fast. I managed to keep the plane confined to the runway's width, change hands from the throttle to stick and the other to the mag switch, killing the engine. I reversed hands and reached for the brake lever that was farther forward than I remembered. The plane stopped in plenty of time. This taught me to raise the tail as soon as possible as the plane flies off at a low airspeed in the three-point position with full power. This characteristic also causes the plane to be three-pointed in landings. I never wheel-landed the Sonerai even though I tried. I found the rudder pedals only need small but immediate correct inputs to tame the plane on the ground.

The FAA certified the airplane on August 26. No major problems were found and they signed off the plane for flight testing. A waiver was provided to fly to Springfield after the initial test flights. We could not fly on that date because of IFR weather. On Sunday, September 1, the weather was nice. The owners arrived in the afternoon after church. The wind remained calm and I was selected to fly the plane.

The plane came off well and climbed rapidly at 90 MPH indicated. This gave a good over-the-nose view for the pilot. Slower speeds climb at greater FPM but give little forward visibility with so much plane up front. After a few low passes for movies and photos, I decided to land. I was anxious about the landing. I flew downwind at 110, base at 100, and final at 90 MPH. I used almost all the 3000 feet of runway to float, flare, land and turn around. The airspeeds I used were too high. I couldn't let the landing go at that. I took off circled my home in Mansfield and returned to land. I flew everything 10 MPH slower, coming over the fence at 75 using a slight forward slip down final. The landing was smooth and on the first part of the runway. All following landings were three-point. The plane settles on nicely.

Critique of the Airplane

In the air, the plane is responsive. Wind and engine noise are very evident. Stability is excellent and the plane does what it is asked. Rudder is very necessary to keep the ball centered in turns. It will not turn on aileron alone like we are used to in most factory planes. The Sonerai II is indeed fast, and 145 indicated in level flight was no problem. The plane picks up speed rapidly when the nose is lowered. We found our airspeed to be 10 MPH slow when flying beside a new Cessna. (The above-listed speeds are all slow by 10 MPH.) The Sonerai II is a semi-racer type and not a trainer like a Cessna 150. A careful pilot with a lot of tail-wheel time should have no trouble with the plane if he follows a step-by-step self-training program. The plane will teach the pilot about its own tricks in a manner one can control. Stalls were beautiful with plenty of buffet and straight-ahead falloff.

We did have an engine cooling problem, as our engine is the 1900 cc. VW. This was the largest engine put in a Sonerai II at that time. A tighter engine baffling corrected the problem. This was after adding extra oil capacity, an oil cooler, enlarging the air dump and increasing the fuel mixture.

The Sonerai II is a good little plane and a joy to fly. It is constructed from aircraft-quality materials and is strong. This should give the pilot much comfort. However, it has a non-certified engine. This lowers initial cost, gives fuel economy and is low cost when repaired.

The construction of a Sonerai I or II is not difficult and is comparable to other designs. But do not expect to do it in two weeks. Two years would be fast. An experienced builder might do it in a year. John Monnett is very helpful to Sonerai builders. So, if you are building a Sonerai, or are planning to build one, get at it! You will have a great fun flying machine when you are done.