Overcoming Setbacks on the Zenith 750SD Xtreme

It is easy to realize what your true passion is when one thing is continually on your mind. Even with the multiple job duties of farming, agronomy consultation, airplane builder/engineering consulting, (and even some writing every now and then), there is one thing that is always on my mind, and that is building and flying airplanes. 

Some of my friends and pilots in our STOL Bandits group help keep me motivated by sharing pictures, giving flybys and touchdowns while I’m farming, and getting to hear about their flying adventures, as a few of the Bandits are currently flying and exploring out west. I was unable to make this trip with them for a couple of reasons. One is because we have been busy with harvest season on the farm and another is that my current Rotax powered 701 flies a fair amount slower than those Bandit planes are going. Having to fly my plane at redline, while they are having to slow way down, is really not all that fun for anyone. This makes me look even more forward to the expected capabilities of my CH750SDXtreme, which will be able to carry more camping cargo and should easily have the extra speed for much more enjoyable trips with our STOL Bandit flying group.

On the farm, we are currently suffering through a major drought in Southeast Tennessee. It is really a bit scary coming out of what is normally our rainy season being over 20 inches behind our normal rainfall for this year, and now entering what is usually considered our dry summer season. Me, nor my parents, have ever seen it this dry this time of year in our area before. However, being born with farming in my blood, there is inherent programming in my soul to be persistent and push on no matter what. We just finished our wheat silage harvest, and we can’t control the weather, so we continue with planting in hopes that mother nature will be forgiving to the farm’s needs. We now have some corn planted, the forecast is calling for rain over the weekend, and we are constantly moving on to the next big season of farm work. I am also moving on to the next season of after-hours airplane building. I haven’t flown much since our last contact here, but I get some extra exposure to that low-level altitude perspective during my many trips climbing an 80ft tall feed silo during the harvest. It feels like there is a constant reminder that my passion involves flying. The latest example: there are usually some owls hanging around the tops of the silos and it is always a pleasure to see them during these times, especially when they give me a flyby like some of the STOL Bandits!

When things are running smoothly during harvest or while feeding cattle, I am operating machinery for many hours daily and even though I have to give that most of my focus, it still gives me plenty of opportunity to be thinking about engineering and fabricating custom airplane components. Anyway, this farmer mentality and the perseverance to keep on pushing also flows right over into the airplane building. 

Frustrations

Everyone is probably aware by now that my biggest setback with these custom builds has come from the problem related to my determination of designing and utilizing a different nose gear setup, compared to what is offered with the Zenith kits. 

It is now well over 3 years that I have been trying to get this new strut design in my hands. I have a couple of variations of early prototypes that simply will not work and do not match what I have been pushing for all along. 

During all that time of waiting with no results and no recent communication with the first major shock/gear company, I have reached out, and now two more of the biggest companies in the industry have looked at the design and were supposedly going to help get a finished product so I could continue these builds. Unfortunately, after another 6 months of waiting and still getting zero results or even an update on potential progress, I am right back to square one. 

To say that I am very disappointed would be a huge understatement. I am really hoping that by the time you read this article I will have my parts back in the farm shop so I can continue forming a materials list for the pieces and custom machining it will take to personally fabricate this design. It is very unfortunate that there is an overwhelming number of people (and companies) these days that do not have the business ethics or trustworthiness that I was raised on. The whole “handshake” deal may be a thing of the past, but the saying that “a person is only as good as their word” still stands very true today. Stay tuned though, there is good news coming soon!

Comeback

For the “Comeback” part of this episode, I should really brag on the companies that are standing behind these builds and following through with the things they say they will do. One of the more recent companies I am working with is RaceTech Titanium. They have communicated, machined, and delivered beautiful parts flawlessly. It is a pleasure to do business with such a company, and as we keep moving forward, I intend to make them proud of supporting these projects. 

Zenith Aircraft is another trustworthy company that I continually work with. Zenith has been great through the years and still gets things done respectably efficiently and in a timely manner. On their way to Sun n Fun, they dropped some more ordered parts off that will help me continue with a few other components of these airplane builds. One such piece is a new top skin for the rear fuselage of the 750SDXtreme. 

You might wonder why I need a new skin since you have already seen this plane’s fuselage mostly assembled for quite some time. This all pivots around my indecisiveness and ongoing debate of whether I actually want to incorporate the bubble top window into the rear fuselage. I have gone back and forth with this decision many times since I started the CH750SDXtreme build. 

My most current train of thought is telling me to get rid of the top window completely and replace the rear top skin with a new skin that does not even have a cutout for the window. Simpler, lighter, and less plastics that would ultimately need to be replaced at some point down the road. I would have to give up a little headroom in the rear jump seat area, but to be honest, the actual need and desire to carry a 3rd person will likely be very rare. Also, the short engine mount along with the goal of trying to shift the center-of-gravity rearward for better STOL flying, might limit the jump seat area’s weight capacity to a smaller sized person anyway, so the lack of the bubble top window could be a non-issue for headroom as well. 

The rear fuselage is currently clecoed together, so changing the top skin will not be too difficult of a task. The only disadvantage for now is that I will have to clean, prep, and paint the ceiling area of the new skin like I already did with the current top skin. Most of the CH750SDXtreme interior will have a foam rubber insulation or a vinyl covering, for both sound dampening and aesthetics, but I do not intend to adhere any plastics overhead because of all the experience with farm equipment over the years. I just do not trust the films and insulation materials to stay stuck to the overhead surfaces for the lifetime of this airplane.

Zenith also dropped off a set of 27.5” Super Duty tundra tires that I was considering for use on the single-seater Super701/half. There is no doubt these beefier tires would look amazing on the 701 build, but they are substantially heavier, which goes completely against my super light weight theories and goals for the plane. I am still undecided on this one, but as of now, I am leaning toward sticking to 22” smooth tundra tires like I use on the original Super701 because they are much lighter and have always been plenty of tire for the various abuses I put the plane through. I believe the nose gear and tire is the limiting factor for extreme off-airport abuse anyway, which is why I have been pushing so hard to include a better shock/damping system for the front of these two builds.

Along with several other smaller parts, and some more progress with the Super701/half’s titanium cabin frame, I also received the top window for a standard 701 which will be trimmed down significantly for the very narrow single seater, as well as an extra set of 750SD top window ribs. I don’t need the extra headroom, but I still plan to use these extra top window ribs on the Super701/half to create a bit of a smooth curve in the top window which allows it to more closely follow the profile of the top of the wings, creating a little extra lift, and even possibly giving a slight improvement with drag along the cabin area of the fuselage. This added curvature is a popular modification with the older 701 kits, and the Zenith community calls it a “beanie mod”. 

Since our last visit, I have worked on getting the first pieces of the titanium cabin frame cut, coped, mocked up, and Tig welded into place. These first titanium tubes were all meticulously fitted by hand to match the mocked-up fuselage. This is a process that needs to be done with precision and extreme attention to detail. 

The first piece of this puzzle is the upper tube of the cabin frame, which also serves as the attachment points for the front spar of the wings. I went with a slightly thicker material for these pieces, which also had to be compensated for on the wing pickup templates’ dimensions. With a fair amount of time involved, these first five cabin frame tubes are now Tig welded together, clecoed to the fuselage, and are ready for the next pieces. Now comes a lot more planning, figuring, and mocking up ideas for a very custom engine mount, which will ultimately need to tie nicely into the firewall, front strut structure, and the cabin frame. In the meantime, you might catch me working on the custom front side skins for the fuselage.

As for current flying, I have been too busy to log as many hours as I wanted to. However, along with a little farm flying, I did manage to pick up my daughter from school on one of her last days as a graduating elementary school kid, with the airplane! It involved a bit of planning and permissions, but this was a very fun experience for both of us, as well as the school. I believe it is the first time a parent has picked up a kid with an airplane at school in our county, and with all the current growth and development, it may be the only time this will ever be done here locally. Of course, on our way flying home, we made our rounds to check on all the crops and cattle at Humberd Farm.

With everything that is going on recently, the physical aspects and progress of building these two custom planes may seem slow, but I assure you the planning and engineering haven’t slowed down a bit. So, I want to thank all the people and companies who stand behind this farmer’s crazy projects and I assure you, “the Comeback will be bigger than the Setbacks!”