Epic Is Back

I’m not just talking about epic with the 750SDXtreme either. I have definitely been working on the SDX as much as time and custom parts/components availability allow. However, with the unfortunate fact that I am yet still in the holding pattern and waiting on progress to happen with the custom front suspension strut so that I can move forward with getting the SDX permanently on its feet, my focus has at least partially and temporarily shifted to a couple of other big things. First is an epic adventure with ferrying another Zenith 701 from Colorado, across part of the majestic and unforgiving Rocky Mountains, to its new home in Tennessee. I had been watching this Zenith 701 going on adventures in CO through social media for quite some time and it is the only 701 that really made me feel like “this is the one”, to get me back in the air while finishing these other builds, and while my Super701 is grounded for some extensive maintenance. 

The owner of this CO 701 was building another Zenith airplane and once it was completed, his 701 came up for sale. I jumped at the opportunity and ultimately wound up flying commercial to CO to check out, buy, and bring the “new-to-me” 701 all the way back home to East Tennessee.

This is a very busy time on the Humberd Farm with calving season and feeding cattle every day, so in order to make all this happen, I had to do some careful planning and preparations. First, I prepared plenty of extra cattle food for delivery, so it would be reasonably easy for my parents to tend to them while I was gone for a few days. Next, the timing and scheduling with the weather and jet streams that could allow decent tailwinds for the trip home. Then finally, the reality that I’m about to jump into a slow Zenith 701 and travel 1500+ miles to get back home. 

I have racked up plenty of cross-country time in my Super701, so I know what that slow traveling is like, however my ULPowered 701 has an extra 20+ hp available, which is enough to keep it flying at near VNE in smooth/calm winds and easily gaining an extra 20-30mph when desired. Luckily though, I didn’t need that extra power for this trip because I’m already pretty sure I beat some kind of speed record for a 701 with the amazing tailwinds I experienced. Even with fighting some pretty major turbulence over the Rockies and then the “crabbing” flying just after that, I managed to travel the 1500 mile trip in just over 15 hours. That is an average of 100mph in a Zenith 701, and this includes all the engine warmups, running checklists, taxiing, slowly climbing to altitude, etc. There were a few times I looked down and the ground speed was over 180mph!

The best and last leg on the second day was all the way from Oklahoma to East Tennessee in 4 hours nonstop. I felt like a commercial jet going that fast and staying at ~12,500 ft. Even though fast-paced, the trip was still epic, scenic, and even very majestic at times. I already knew that I want to take the 750SDXtreme all the way to the west coast once complete, with this area of Colorado being high on my bucket list. This little bit of newly acquired time actually flying around there in the 701 just cemented those future plans and makes me realize that I need to get back to some serious work on these other builds!

Of course, spending 15 hours in a Zenith 701 in just two days gives you an appreciation for the airplane’s design capabilities, and also time to make a short list of things you intend to change or improve. While I definitely do not intend to spend much time modifying a 701 that I plan to turn around and sell later, there are a couple of easy things that will be changed almost immediately while I am inspecting it with a fine-toothed-comb in my shop. First, it must have my trademark Super701 horn (Beep Beep) installed. I will also be using my Super701 seat cushions in this plane for a while, and of course it will have some cameras fitted to it. Luckily, this 701 already has many of the other modifications that I would consider, such as HT fences and slightly bigger off-airport tires. Once I get the other builds airborne, I might come back around to a few more modifications and upgrades on this 701 before I consider selling it.

The second part of this epic-ness is with my third airplane build that is going somewhat simultaneously with the 750SDXtreme build. We are still discussing how to keep some separation with the two builds, while giving Kitplanes readers some updates for both along the way. So a basic introduction of the project is in order. 

This third very custom build is essentially starting from a Zenith 701 kit, however the fuselage is so different from the standard kit, that I hesitate to even call it a 701. Basically, I am narrowing the fuselage down to a single-seat by removing the right seat entirely and moving the right side of the fuselage inward, which narrows the entire fuselage. It is also shortened a bit (front to back) from the standard kit, which will ultimately make the sporty 701 flying characteristics even more sporty. 

I have already poured a lot of heart, soul, and engineering into this bird, and I also sometimes think about what to call it once complete. With the usual fan-favorite and quickly gained social media following of the “Super701”, I am tossing around the idea of calling this one the Super701/half. Part of the reason I haven’t pursued building this one as much as the 750SDX is because I have spent so much time trying to nail down its actual mission. The mission’s focus has changed a little bit over the last couple of years, but the goal to create an incredibly lightweight single seat airplane based on the Zenith 701 platform remains the same. 

I have been told several times that I “wear” the 701, and it seems like the late Chris Heintz, the original designer “designed it just for me,” even though Chris engineered it decades before I ever even flew one. I do love the performance, the sporty and light feel of the 701 and it is my goal to keep that exact same feel and ergonomic design with my single seat 701 design.

The ultimate goal is to just make it a lot lighter and with even better performance than my Super701. I have considered many different powerplant options, which even includes looking into some all-electric possibilities for a potential competition-only platform. While that is a very fun thought, I have almost decided to stick with a ULPower engine and build it as another amazing all-around and very capable flyer that would also be even more formidable in STOL competitions. For now, the rear fuselage structure is basically complete and is currently mocked up with the front fuselage that is in-process. Even though there isn’t a huge amount of visual progress lately, rest assured, there is a lot going on behind the scenes.

Become a Sponsor!

One of my latest sponsors for these very custom builds is my titanium supplier, RaceTech Titanium. I was new to working with titanium but have been around Tig welding aluminum for decades and wanted to give it a try. So, after fabricating several titanium control components for the 750SDX, it only makes sense to pursue this even further with the Super701/half, and I am currently looking at attempting to replace all the chromoly pieces in this single-seat build with the strong, yet lightweight titanium. This will require a huge amount of time with one-off fabrication because I am using mostly basic hand tools to do all this unique work. 

There is a lot of tweaking and fine tuning with belt sanders, then jigging up the titanium component pieces in special vises before Tig welding them. I thoroughly enjoy it and would literally be working on these builds 8 hours/day if the time, money, and supplies were available for it, so feel free to reach out it you would like to sponsor a portion of these unique builds. I have tons of ideas that I want to incorporate into this epic build, but I can only do so many things at one time and still be able to keep everything reasonably on-track. While I am very excited about the custom 701/half build, I am definitely pushing the 750SDXtreme toward completion first.

The third epic thing is in continuation from the last 750SDXtreme article. You might remember that there was a heavy chunk of 7075 aluminum sitting at the local machine shop waiting to be turned into a custom billet front fork for the 750SDX. I am pleased to announce that this fork is now complete, and it turned out just as amazing as I had hoped and designed it to be. It took quite a few hours of setup, machining, cutting, and then sanding to get it finished, but I consider it an epic one-off piece that will really compliment the look and mission of this 750SDXtreme! 

To get it started, the machinist took my design file and used a CNC mill to almost completely finish the outside of the fork be removing the excess material. This even included the radius machining on the inside of the fork edges. Once all that was complete, a jig/clamp was made to hold the aluminum block inside a CNC EDM machine. This machine cut out the entire center chunk of aluminum from inside the fork, resulting in an almost completely finished and very custom front fork for the 750SDXtreme. The only thing left to do, is take it home and sand out the subtle machining marks, then put the raw aluminum look uniformly onto the entire fork by hand using standard Scotch Brite pads. This gives the front fork the exact same and “easy to maintain” finish that was used for the aluminum main gear.

For those wondering, on the side of this fork, the HC stands for Humberd Customs, and of course the X is for the “Xtreme” that is being incorporated into the entire build.

Now that I have a front fork that can use the slightly larger AeroClassic tire, mockups and measurements are back in process for the even more custom front suspension strut. The 3-year wait to get a usable strut that is built the way I want has undoubtedly created a bit of a personal mental battle with the motivation of this build. There is plenty of other things that could be done with the rest of the airplane, but that messes with my whole thought process on the order of completion. That extra time waiting is also part of the reason I indulged with learning how to work with titanium, and also why I have taken the idea of lightening the whole airplane to a whole new level. I have come to the conclusion that you can do it fast or you can do it right, but it is difficult and sometimes impossible to do both at the same time. 

Ultimately, I want this 750SDXtreme to be done right. I do plan to build some comfort into the 750SDX (more of which will be talked about later), but in general I am trying to get rid of as much unnecessary weight as possible, while maintaining the robustness that these planes are known for.

So here is my parting thought/quote:

“When you are trying to decide if something is worth adding to your airplane, hold it about waist high and let it go. If it hits the ground, it is too heavy.” I first heard this years ago and paraphrased it from one of the crowd favorites STOL competitor and my friend, Hal Stockman. I have taken this advice to heart and really feel like the value of keeping a small STOL airplane as light as possible is highly underrated. Now it is time to focus sharply on building!