George Stulgatisí Christavia Mk I
By Chad Jensen, EAA Homebuilders Community Manager, EAA 755575
An overall shot of the shop…a very comfortable (and heated!) place to build an airplane.
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A completed Christavia Mk I is a bit of a rare find, but there are thousands of plans out there (now being sold by Aircraft Spruce). The Mk I is the two-place tandem, the Mk II is the two-place side by side, and the Mk IV is the four-place version. The FAA database lists only 55 of all types currently registered, which is the reason I am claiming the Mk I as a rarity.
The airplane was designed by Canadian Ron Mason back in 1982 as a rugged bush-type (mission field as he called it) airplane with a slow stall speed, large cabin, and a high safety factor. It’s roughly the size and shape of an Aeronca Champ and uses similar-sized engines, landing gear, and construction, but is a plans-built only airplane. As an airplane that is inexpensive to build, own, and operate, as well as one that provides its owner with a strong sense of nostalgic flying— the way it used to be—it has a tremendous appeal to me and its many plans holders.
The airframe as a skeleton soon after George brought it home.
Our subject project this month is owned by George Stulgaitis, EAA 845312, of Madison, Wisconsin. I became aware of this particular project from Wisconsin Hall of Famer and longtime EAA member Bill Rewey (EAA Lifetime 42474), who will be the subject of an article in the near future. Bill knows of all the projects in the Madison area, and he is George’s EAA technical counselor.
The story of this particular Christavia goes beyond George. There were two previous owners who, for the most part, built the airframe. George took ownership of the project through an eBay purchase in 2007 which is also when he added his EAA membership card to his wallet. Although he had his first airplane ride in the mid 1960s, George is yet to be a pilot but is taking lessons. He’s built a variety of projects over the years, from a canoe as a kid growing up in Kenosha, to a pontoon boat, sailboats, and now an airplane.
It all started when a friend gave him a VW engine because he had rebuilt a number of them and always was looking for projects. The question always was “What would happen if you…”. The engine prompted an air-powered sled powered by the VW engine to be used on Lake Mendota in Madison. That created the recognition that “if it had wings” he could just lift off and fly. And so a lot of research and education led him into the whole new realm of aviation.
The original plans for this one have a well-weathered look but are
still very readable, and all of the information is clear and legible.
A very nice set of plans from designer Ron Mason.
George always wanted to learn to fly, and his dream started to become a reality when he learned that the VW engine could power an airplane. He was invited to a chapter meeting by Bill in 2006 where he introduced him to a Sonex project nearing completion. One look at that excellent project with the thousands of rivets and George decided that type of construction wasn’t for him; he looked for a different plane among the many he was considering. On eBay, he found the skeleton-framed Christavia being offered from a seller located in central Iowa, bought it, and brought it home to the shop.
George spent weeks trying to understand this new undertaking and where to begin. He bought a gas welding kit and started teaching himself to weld. He also signed up for the Poly-fiber course in Oshkosh given by Jim and Dondee Miller of Aircraft Technical Support (an excellent course).
A welding class was also offered at that same time, so (after a couple of months of practice) he brought samples of his welding efforts to the welding instructor for critique. The instructor examined them and said, “You can fly with these.” Feeling like he was beginning to get a handle on it, he went back to Madison ready to jump in with both feet.
Bill Rewey came over and patiently inspected the plane and plans and reassured George that everything was possible. While the plans were a little faded, they were still readable. They are really well drawn with plenty of detail.
George had a lot of experience with fiberglass boats, so beginning with the complex 19-gallon fuel tank was a good place to start. He has since plumbed the entire fuel system including calibrating the fuel gauge gallon by gallon since the bottom of the tank is much smaller than top. The gallons are marked on a card that will eventually be transferred to a permanent sticker directly on the fuel gauge.
This shot under the panel shows the homemade
fiberglass fuel tank that George formed.
Next, he welded in the pulley brackets onto the fuselage and mounted pulley brackets in the wings, then installed the aluminum leading and trailing edges. The plane is now covered with the Poly-fiber system, and all the fabric is painted with the final base of white, ready for a little artwork.
The boot cowl and engine cowl are done in 2024-T3 aluminum cut, formed, and yes, riveted by George. It was only a few rivets, but he didn’t get out of riveting by building a rag and tube plane as he had hoped. Starting with the help of a friend who had an Aeronca Champ nose bowl to use as a test fit, George eventually bought his own. He fit the nose bowl to the metal cowl and the results are fabulous.
The bottom of the cowl, all hand formed out of 2024-T3.
Underneath that cowl resides a zero-time overhauled Continental O-200 that has ties back to Oshkosh and to the late Al Ziebell. His daughter Mary Bowman knows Joe Norris and Bill Brennand, and they helped her list her father’s assets for sale. George contacted Mary and ended up with the engine. The engine mount wasn’t yet built when he bought the project so he fired up the welding torch and got to work. He really has done a nice job on the parts he fabricated.
Modifications on this Christavia are few, but they are good ones. The entry door is one that certainly doesn’t appear to be modified, but as soon as George opened it, I knew something was different. Most Christavias have their door on the right side of the airframe, and they typically either swing open and downward or have the two-piece clamshell style of a Cub. George’s door is on the left side. That’s not significant in any way, but what is significant is how he hinged it.
The leading edge of the entry door swings into the cabin.
The two angles of the leading edges usually mean that the door has to swing out and down into the wing strut. The door can’t open all the way. George didn’t care for that, so he made the hinge line vertical using a pin sliding up into the upper frame with a hinge halfway up the lower door angle. That means the door actually swings its leading edge into the cabin (just a bit) but doesn’t seem to encumber entering to the pilot’s seat. The latching mechanism is simple using old storm door guts to produce a lightweight, aerodynamic mechanism with vertical latching pins that slide into the upper and lower frame. This gives four secure points between the hinge and latch.
The landing gear options for this airplane range from the typical bungee system to the flat spring steel (Soneri type) to cross-braced springs. With Bill Rewey’s suggestion and drawings, George chose the latter and built it himself. It’s modeled after the common types seen on production planes of this era.
George built the landing gear from scratch.
Another mod that I really liked is the entry step. Where we usually see a step jutting down and then out from the lower longeron, George chose an alternative because he felt the original was not aerodynamic enough and it also created a stress point on the longeron. Instead he welded a tube inside a tube to the landing gear front strut and over a reinforced rear landing gear strut. The tube has a large washer on the end to serve as a step. I thought this was a very nice touch that gives it a “faster” look in my opinion.
The plans version of the seat had no adjustment, which made entering difficult. So George decided to use some polycarbonate machined to slide inside a “C” channel as a track. The poly was machined to fit the tubing of the bottom of the seat frame and was glued and bolted in place. Polycarbonate has many good uses, it’s easy to work with and is very strong, and it pretty much lasts forever.
The “faster” looking, and very well built, step to enter the cabin.
George also used polycarbonate for sliding window tracks, and he offered me a bit of a tip that I haven’t come across yet—mixing graphite with epoxy to provide a long-lasting smooth bearing surface for the control torque tube. He mixed a spreadable batch and applied it to both surfaces and then pressed them lightly together with wax paper between as a parting agent. This is something I haven’t had a need for at this point in my building career, but be sure it’s a tip I’ll put in my memory bank for future use.
Like the first two airplane projects I’ve written about, the Christavia has a stone-simple, no gyro instrument panel. Front and center is the airspeed indicator with the fuel gauge below it. Off to the left he has placed a vertical air-speed indicator (VSI), an altimeter, an amperes meter, a digital tachometer with an hour meter built in, a key switch, fuses, and the primer. Over to the right side of the panel are just a few engine instruments with the throttle and mixture controls. Simple VFR flying is the goal here, and George is hitting his mark.
The polycarbonate plastic used in the seat tracks.
George is hoping to base the airplane on a grass strip in the Madison area, and he’s getting close to being ready to move the project to an airport somewhere. The items left on his to-do list are fairly short, but they include the windscreen and side windows, finishing the interior, and of course mounting the wings and control surfaces. But that will happen at the airport.
He has done all of this work in a car-and-a-half garage that has no sign of a car ever being in there. His shop has a great “shop” feel to it, including a huge rack of a variety of woods, various bins spread across the walls, an oversized worktable, and most any tool needed for a project of this magnitude. It’s a fantastic place to build an airplane, and it’s heated to allow year-round building even during the Wisconsin winters.
Owner and builder George Stulgaitis.
George is on that “slippery slope to completion,” so when he gets to the point of having a flying airplane, I fully intend to get a full report from him on how his flying is progressing and how the flight testing is being handled. With the resources available to him in the Madison area and with many EAA members ready and willing to help along the way, he will have a great time finishing up the airplane and getting it flying soon.