Installing Fairings: I have the need, the need for speed!

For a very, very long time, Zenith has been saying they had fairings in the works. Honestly, the lack of factory fairings in Zenith has been a huge gap in their offering. Most aircraft kits have fairings available to hide the ugly bits and make the plane a tad faster. Zenith is a metalworking company, and even the wing tips at one time were aluminum so I understand that this is not their primary expertise, but fairings make a plane look so much cleaner to people and the wind that they are a must-have even for an airplane that is designed to go slow.

Well Zenith partnered with a third party to produce the fairings, they have finally arrived and I have installed them. The kit comes in a box with a bunch of ABS parts with a reasonable finish. Much like the wingtips and other plastic parts Zenith has included in their kits in the past, the parts require some fabrication, prep, and paint, but not anything that can’t be done with readily available tools. The box includes the parts right out of the mold. You need to cut and trim the parts to fit including removing closed ends and cutting slots and adding tabs to close the new slots and connect parts together.

The kit includes some scrap parts for the tabs and finely chopped ABS in a can that you can add MEK to the red line and make a goo that works as plastic glue. Aside from the creation of the goo-glue there are no instructions included in the package. Zenith also does not have a photo-assembly guide yet either, so I wanted to try to document what I had to do to make mine work so others could learn from my mistakes.

Mark Pensenstadler got early access to the kit and made an installation video. He does an excellent job of covering the installation of the prototype set.

There have been some changes since Mark’s video in the kit contents. RivNuts are now included in the kit, and are an easier solution for novice builders since you don’t have to be as careful in drilling, threading, and tightening as you do with sheet metal screws.

Also, the kit now contains some scrap ABS plastic to make tabs to hold the parts together, and some shredded ABS you add MEK to for glue to attach the parts permentently if you don’t intend on removing them and want to fill the seam.

I started by timing the upper strut using the measurements Mark provides in the video. 6.5 inches at the center and it is clear of my bolts, and the 2 1/8 inch slot for the l bracket also worked. I taped and cut the mold cap off the strut profile on the end much like Mark’s video. I also installed and measured the position needed for the slot for the L-Angle. The factory cut on the outside of the upper fairing and then used a long tab to seal it and it may connect better in that location, but does leave visible fasteners. I followed Mark’s inside cut strategy.

I used a heat gun and shop rag to form the tabs to find the curves connecting the parts. Once the tabs had conformed to the shape of the parts. I used blue tape on one side to prevent gluing the parts together and used CA glue and pressure to connect the tab on the other side. I used blue tape to connect parts together while I worked with them so the tabs would form to the shape of the joint between both sides.

Credit: Roger at Zenith

The before and after on the top strut fairings was amazing! They are attached with Rivnuts, described in more detail below.

The bottom strut fairings required some trimming so the bolts and landing gear would clear. I measured the area I needed to cut out and used blue tap to mark it. I used a step drill to round the corners and used a Dremmel cut-off tool to cut along the blue tape then used a sanding block to clean the cut lines up.

Once I had trimmed the parts I fit them on the strut and used blue tape to hold them together and found the position they fit naturally. It took several sets of on and off for me to trip it down. I had to make some notches to accommodate the nut and bolt on the strut. Be careful that you know the natural lie of the whole fairing before you cut the notch, or you might force it to bend and not lie correctly.

Credit: Roger at Zenith

With the fairing halves taped together, I drilled a starter hold with a fine drill thru both the parts and the opposite tabs. I then opened up the hold in the part a bit and used a 6 x 3/8 sheet meta screw to join the parts to the tabs. I used two screws for the slot I cut to fit the fairing over the strut, one screw on the bottom side of the connection

Going nuts over Rivnuts

Once I knew it all fit I taped the fairing into place and drilled three starter holes from the fairing, into the skin of the airplane making sure I did not lie over any structure under the skin. The holes are all located on the top portion of the fairing. The far from and back, and as far from the front to the middle as you can get and clear the strut with drivers and drill and the rivnut tool. Then I used the step drill to open the skin with a hole just big enough to insert the rivnut and then used the tool to pull the rivnut and set it into place. I then drilled the fairing just wider than the bolt shaft and refit the fairing and used the new rivnuts and long bolts provided in the kit to tighten just enough to close the gaps and hold the fairing firm. Don’t over-tighten or the plastic will break.

This is how Rivnuts work. You drill the hole to size, insert Rivnut and pull and it conforms to the hole on both sizes with striations that hold the nut tight so it won’t spin. No access to the back side is required like the pull rivet that made Zenith Famous.

After everything was fitted I prepped the fairings and painted them with Rustoleum spray paint that is a close match for my airplane paint. Once dry I permanently installed the painted fairings.

The results really clean the look of the airplane up. The rivnuts mean I can remove the parts easily for the annual condition inspection. I don’t know if they will be noticeable in terms of any speed increase, but with my 28″ tires, speed really is not what I am after, but a one to two-knot improvement might help make up for the big tires when I am on a long cross country. The tail fairings were designed for use with the vertical stabilizer skin installed on the inside of the l-brackets. I thought that looked ugly, so I have my skin over the L-brackets and the Zenith-supplied tail fairings just won’t work. I will have to design my own.

Before and After

Tools you might need

Rivnut puller tool from Amazon

#6 x 3/8 Sheet metal Screws

CA Glue and accelerant as an alternative to MEK & ABS used in KIT


The Great Zenith Gravel Gaggle

There are a number of people in the Northwest who have built Zeniths and I have been fortunate to know and meet a number of them. They are a great community up here and many of them enjoy the type of flying that only the Pacific Northwest can deliver. The backcountry grass strips, the island airstrips, and especially our local sand and gravel bars.

Curt was one of those who had built his CH-701 from scratch and has spent countless hours flying it since. His airplane is well known and loved as the “Clownfish plane”. His color scheme looks like Nemo, from that Pixar movie. Scratch building takes a lot of commitment, and since he had added lots of cool gadgets and updated his panel.

Curt had moved away across the mountains for a while and recently at our EAA Chapter 84 meeting he mentioned his airplane was back. He also mentioned that he had never landed on a gravel bar before, but would like to try it. This started a discussion that eventually went online and last week John, Walt and I got Curt on a messenger group thread and decided Saturday looked good and would be the day we would introduce him to the fun of landing gravel bars.

Doing any sort of off-airport activity requires skill and lots of hours to develop. Dealing with managing the wind, rotors, tight corners, and low altitude, all while being under the power curve in slow flight takes time to practice and you have to know your airplane well. Curt definitely knew his airplane and had experience exploring the local rivers at lower altitudes, it was just time to put the wheels down in a safe place.

I have a number of rules when landing off-airport. The location must be legal. The landing zone must be somewhere safe to operate and be legal. You either need permission from the landowner, or it must be public land without rules limiting access. I also must be able to scout the location and ensure there is a suitable area flat enough to land and roll on, and without major obstacles. This means often scouting low. The FAA allows you to overfly people or property below 500′ AGL for takeoff and landing, but not otherwise. If I know I am landing, or have the intent to land then it is legal to fly over a farmhouse or cars on approach to the gravel bar.

An Anonymous Skagit Gravel Bar

For me, it is not just about being legal. I also don’t ever want to be a bother to anyone, scare anyone, or be a nuisance. So I will only land in places where I had a free path in and out of the area without flying close enough to people, buildings or vehicles to be a bother.

There are a few really good gravel bars within a short flight from Anacortes or Arlington that have large, clear spots with clear approaches and departures that would have made a good spot for Curt’s first gravel bar landing.

John’s Seven-oh-fun Max

The four of us met up at Curt’s hangar at KAWO and fired up our cameras and airplanes for what would be an epic adventure. We taxied down to the end of 16 and warmed up the planes and when we were all ready I called “Arlington Traffic, Zenith 19JF, flight of four taking off on runway 6 for a north downwind departure”. The four of us rolled out onto the runway and when we were all pointed straight we powered up and quickly lifted off in formation and climbed to pattern altitude.

Lining up to go

We headed north to the bend in the river with a large gravel bar called “Dog Leg”. While the approach to it is a tight river with tall trees on either side, with several turns, the gravel bar is flat with plenty of space to park all four airplanes off the “runway”.

Flight of four lifting off.

I landed first and got out the drone to capture the rest of the crew landing. Walt, John, and then Curt came in one at a time and we got great video and photos and some great shots of all our planes and the pilots parked on the gravel bar.

Enjoying “Dogleg” on the North Fork Stillaguamish River

After doing a few more videos of planes taking off and landing and doing passes over the river and enjoying some conversation we all took off and headed to the Skagit River to land at an anonymous gravel bar a few miles east on I5. It is a beautiful approach and I was able to get 360 video of the river as well as lots of drone shots of the 701’s having fun.

Four guys who built their airplanes and love to fly them

This was the same gravel bar I had landed the previous week and when I had the drone up I saw the spot where I rolled about 80′ on takeoff into the wind and two feet shy of a 3-4′ gully my airplane was airborne. Even if I had not been wheels up I would have sailed right over it anyway, but I was bracing for the hop and it never came.

The four friends airplanes and last week’s tracks

When we were all done John and Curt headed back to KAWO and Walk and I headed to Center Island to have a snack and relax on the deck for a while. Walt had never been there and I had never had a fly-in guest before so it was a treat for both of us.

I got some great 360 camera footage from my new rig (covered in a different blog post) and it was spectacular! It worked perfectly thru all stages of flight without any visible artifacts from vibration.

It was a really fun time not only sharing the flight and gravel bars with friends and their Zeniths but also sharing the time we had with all the other Zenith owners online. It is something I will have to do again, maybe we will invite even more pilots next time!

Afterthought: John was joking about who got in the air quicker, so I made a video to see..

Insta 360 Camera mount V2

Three years back I built an expensive, heavy, overly complicated mount for my Insta360 camera and was not too thrilled with the results. The mount was based on a commercial strut mount with Zorbathane and had lots of links, and the post itself was a telescoping monopod and the whole thing vibrated at a frequency that made the video wobble around like crazy. The stills were OK, but the video was worthless at least to the quality I expect.

Here is a link to the V 1.0 version post from 2019.

Now I have the next-gen version of the Insta360 and while having great success using GoPro8 & 9 under the wings, I wanted to be able to frame the airplane “chase plane” style again.

The plan was to get a 6′ carbon fiber tube and replace the telescoping one, but I still did not like the original strut mount either. The thought came to me that if I used GoPro style mounts near the leading edge and spar of the wing, and have two mounting points a few feet wide, I could get the 4+ feet out in front of the wing, and have enough leverage to mount it all with the glue-on go-pro mounts.

This would allow the whole thing to clip in and out in seconds and would provide rigid mounting and a long period oscillation that the in-camera stabilization could easily eliminate. I should get great video quality from such a mount and it would be trivial to install and removed so it would not stay sitting in the toolbox like the old mount that was a pain to install or removed when I used it and ugly as sin.

On Friday I assembled the mount and installed it on the plane for the gravel bar run I was making with friends in the morning. It installed just as I hoped it would, and the results of the videos I got from it were better than I expected.

So this is the parts list I used. This is not complete instructions, there are serious ramifications in adding a camera mount to a certified airplane or any airplane so don’t consider this a “how to”, this is just how I built my setup.

Stuff I used to build this mount

GoPro glue mounts. (2x) (there are flat and curved ones, I used ones that matched the profile where I mounted it)

Go Pro extensions (not flipping) (2x)

GoPro tube mount (2x) modified to remove the nut and the third finger so it can act as camera side instead of mount side.

6′ Carbon fiber tube 5/8 in Inside Dia, 3/4 in Outside Dia from Granger. Specs in the link

Threaded camera mount from Amazon (Metal not plastic)

AN3 bolt about 1cm or so longer than tube diameter to cover two washers and nut.

I drilled a hole in the end of the tube exactly in the middle and just the right height and the thread mount will fit in ALL THE WAY into the tube, with the tension ring at the furthest back. This will trap the round based inside the tube and the AN3 bolt will go thru the holes in the base and trap it on the end of the tube.

I then mounted the carbon fiber rod using the tube mounts on the rod, and the clip in moutns on the adhesive mounts on the airplanes skin. From a forward and mid-mount on the wing skin with GoPro mounts and kept level with the extensions.

I get accused of “black magic” when I show pictures or videos made on this mount, so I am doing this to explain how it works. I built the airplane as well so I know what I am doing and I am fully responsible for my own version of this.

Do your own investigation and make sure what you do is FAA legal and safe. I am not providing a how-to guide, just showing you some of what I did on my EXPERIMENTAL airplane.

Preparing for IFR/IMC

While I had equipped the Cruzer with an IFR capable panel, before I committed to flying in IMC I wanted to have a good history of reliability and make sure that the airplane was ready for reliable flight in the clouds. I committed myself to get at least 200 hours on the airframe before going actual IMC. Now that I am past that milestone I am doing the work to make sure everything is fine-tuned, legal, and documented.

The “Legacy Free” IFR panel. Dynon HDX1100 Primary, Garmin G5 backup, Garmin GNS-625, iPAD MDF

One particularity of my airplane is that is is “Legacy free” IFR. There are no nav radios at all. No VOR. No ILS. No NDB. Just WAAS GPS and normal GPS. The FAA says it is legal to fly IFR this way, but because of misinterpretation of rules regarding testing it has been impossible to use such an airplane for the IFR long cross country, or a check ride. Thanks to the FAA recently rescinding this legal opinion it looks like I can finally get my green light for my IFR check ride in my own airplane! The notice can be found here.

Last summer I suspended my IFR training when I could not find a DPE who would do my check ride in my own airplane because of the issue, so I excitedly restarted my training when I heard the news and was able to go out and do a 3 hour IFR flight and shoot some LPV approaches to 200′ minimums with my instructor. All the approaches would have been perfectly landable on center with the runway, but practiced the missed procedures anyway.

CFII Dick Oman and I on a 200 Mile IFR training. The glasses are “Foggles” that only let me see the panel.

IFR flight has to have exceptionally good navigation, communication and safety system. This means reliable radio, accurate instrument readings and a good transponder. The last item has haunted me since moving to Anacortes. Virtually every time I leave Anacortes to the south I have to contact Whidbey Approach and ask for a transition thru their airspace. The problem is that climbing out of Anacortes they could never see my transponder replies and would often deny me entry into the “Charlie” airspace until I was high enough to get the ping. This would often leave me circling or skirting the airspace to get around the issue.

I honestly never had any transponder issues with any other ATC facilities, and never a complaint other than Whidbey Approach. I thought the unique geography might be the issue. I finally concluded I needed to change something on the airplane to fix the issue. The antenna for the transponder and ADSB IN was under the tail behind the landing gear to be out of the way, but because of the way the tail slopes up I wondered if the ground plane tilt was causing the beamforming on the transponder to point into the ground and backward in the air, rather than forward. If this was the case it could explain why they could not see me at lower altitude while I was heading toward them, but once up high or flying away, they always pinged me.

I decided to move the antenna to the far right under the flat section of the cockpit right under the passenger. I got a second antenna from Dynon and a 6′ cable and rigged it up. A quick test flight later and they pinged me right away just out of the pattern at Anacortes. Problem solved!

The next issue I need to deal with is my static port. I have been getting higher than expected airspeeds and this needs to be fixed to get the most accurate data for IFR flying, as well as just good data for flying. The issue is that there is a low-pressure area on the sides of the panel after the bend in the fuselage where the static ports are mounted. Between the bubble doors and big tires, a vacuum is created behind that point, and thus the faster we go, the more pressure difference and the less accurate the static port becomes. This will impact both airspeed and altitude.

I will need to either move the static ports or provide a device to compensate for the suction location to cause pooling of air around the static port to counter the vacuum effect. This might be a difficult job to do right so I am going to experiment with different static port options till I can get one that will give me correct airspeed when doing a box pattern, and correct altitude vs GPS altitude flying a low pass over the runway.

Additionally, I have ordered a second Sky Cowboy helmet with Bose A10 adapter to wear for long IFR flights. I will still use my Dave Clarks for the superior engine and airframe noise pass-thru for landing backcountry strips, but the A10 will make for nice cross country and IFR comfort.

An airplane is a time machine

Saturday April 16 I headed out to Anacortes Airport early and dropped 12 gallons in the wing tanks. I fired up the Viking 130 ad taxied out to the run up area. Less than 1.5 hours later I was on the ground just before 9:00 am in Cle-Elum. It would have been a 2:45 minute drive.

My old friend Rob picked me up at the airport and we went back to his place for breakfast. While breakfast was being prepared he showed me his huge VRBO he was working on. Amazing place with 4 huge suites, a rec room that is more of a family arcade from a mall and an indoor swimming pool. Meant for rentals for family reunions, corporate retreats, etc.

After eating and a long talk we headed back to the airport and I flew towards home. The conditions thru the pass were incredible in both directions. The clouds were following the air currents over and around the peaks and ridges. It was stunning.

As I was overflying Arlington airport I knew I had a few minutes to burn. I flew over a gravel bar a friend of mine had posted about on Facebook so I decided to check it out and land it if it looked good.

I took a pass over it and it looked good so I descended and dropped into the river under the tree tops and followed the river slowing until I stalled as I touched the gravel. I rolled to a stop and positioned the plane for a few quick photos.

Even thought I was at 15PSI (for paved airport use) the landing was only a bit bumpy. I got my shots and fired up the engine. With RPM set for best trust I firewalled the engine and got up in under 100′. I headed back to the airport and tucked the plane away for the day. 15 minutes later I was at home and my brother had show up to work on building our art studio / game room in the back yard… at about noon.

I had already had an adventure that would have taken all day until late in a car and my day was just getting started!

Re-powering the Big Tire CruZer (April 1st Edition)

An airplane is never done. After a while even the amazing power of the Variable pitch prop on the Viking 130 was starting to feel normal again, dare I say I was getting board with 1000+FPM at full gross. I was also tired of the paltry 104KTAS cruise speed at 11,500 feet. It was time for a change!

The inspiration came to me when I came on some mid-time Rolls Royce Turbo Fan engines on e-bay that were ending soon with no bids. They were taken off a Gulfstream jet and in good shape, and included the ECU’s for both engines and the fuel pumps! The buyer had put to high of an initial opening bid on the pair and had gotten no bidders, and only a few watchers. Clearly he priced them too high and no one was thinking he would drop the reserve price and minimum bid with 15 minutes till the auction ended!

After having picked these two thrusters for a song, I did not know what to do with them at first so I put them in my workshops and they sat until I opened the crate and my wife said “The paint on the cowlings matches your CruZer”. That set the gears in my mind spinning so off to Solid Works I went.

First I had to design the reinforcement for the main wing Spars. I was able to hire a local shop to take my CNC plans and create a spar “Doubler” that was much more that double the strength. It extended just past the strut and spanned the space between the main and rear spar and added cross bracing and a directly milled strut brace mount point, as well as mounting points for the new engine.

I replaced the main strut with a solid milled aluminum member to handle the enhanced load.
Since I had already installed a oversized main gear legs and updated the tires and wheels to a load rating that was meant for DC3 retrofits I did not need to either change the brakes or wheels. I had to now run the tires at 25PSI instead of the 8PSI I normally use to handle the same load.

Rigging the ECU was fairly straight forward. I purchased a Raspberry PI4 and a CAN bus SPI adapter and wrote the software to connect all the control and sensor signals between the RR ECU and the Dynon EFIS and EMS setup. I put the code up on GITHUB if anyone else wants to try it.

Now with the mounting points and control in order I using a motorcycle lift to raise the engines up onto each wing. I had to install both engines at once because of the moment on the wing, the plane would tip over if I tried to install one at a time.

Once the rigging was done I called the FAA Flight Standards District Office (FSDO) and told them about the “major change” as required by my special airworthiness certificate and went back to phase 1 testing.

The initial taxi tests were ok, but I realized I was using all my usable fuel to taxi from my hangar to the end of the runway, make a pass and taxi back. I realized that might have been an issue so I kept the Viking 130 and VIP on so I can taxi, takeoff and climb to the flight levels and then turn on the Jet engines for cruise.

Since Jet engines are far more efficient at that altitude this hybrid approach gives me the best of both worlds.

Update: As it turns out some of the *real* things I do are so outlandish and unbelievable sometimes that the level of ridiculousness I have to go to in order to make it clear that I am doing a April fools jokes really gets out there. Sorry for those who I let down when it all turned out to be me having way to much fun in Image Composer (The image editing app I worked on in the 1990’s and still use today!)

Do I finally have the Big Tire Cruzer of my Dreams? Installation of Viking Inflight Prop (VIP)

When I set out to build a plane that could fill the roll of both a great back country bush plane and a cross country cruiser there was always the “reality” that I had to compromise on both roles in order to do it. Or did I? When I realized at altitude I was getting factory cruise numbers even with the big tires mounted, I knew that the Cruiser part was really not compromised much. Because doubling the speed means quadrupling the drag, when you get to altitude your True airspeed determines how fast you get there, but your indicated airspeed determines the drag. The slower you go the penalty for the big tires is reduced. So at 8500-11,500′ the Big Tire Cruzer was able to slide along at between 100 to 104 KTAS depending on temperature and density altitude.

The challenge was that when I would set the prop angle to maximize the cruise speed at altitude the takeoff roll and ground performance would not be ideal for STOL. It was certainly more than enough to operate out of any of that back country strips in the northwest, even at density altitude all loaded up I still used a fraction of the runway of the certified planes that I shared the fields with.

With the complete set of vortex generators and practice with managing energy I had gotten my landings down to be extremely short. So short that I might be able to land on sandbars where I could not take off from later! Additionally I fly a lot with my friend Ajai who got a constant speed prop for his Kitfox and it has transformed his performance. Since the first time I flew with him and his new prop I knew that eventually I would have to get one.

The one he got was expensive and heavy, while I wanted the performance I did not want something that heavy on the nose. With all the optional gear and IFR avionics, auto pilot, etc. I am already heavier than a lot of 750 builds.

About a year ago I asked Jan at Viking about putting a constant speed prop on my plane, and told him what I was planning on ordering. He hinted that he had something in the works and eventually told me to hold on and wait for his project to develop. I waited and spent that time developing the slow flight and controllability on the Big Tire Cruzer.

A couple of weeks before the Zenith Homecoming Jan send the first part of the setup. It was a new gearbox with some special modifications. A hole thru the middle of the final drive assembly that allows a mechanism connected behind the gearbox to move a shaft that goes thru that hole into the prop hub to control the pitch. A linear actuator on the side of the engine extends and pushes a lever arm that in turn amplifies the force pushing the prop from fine to coarse. This very simple system means that the carbon fiber hub has about the same rotating mass as a conventional prop with metal hub.

While I was taking thinks apart I realized to make the actuator fit I would have to re-route the cooling system. I had the original smaller radiator and under extreme ambient heat I would push into the yellow doing touch-and-gos. I don’t like flying in 105+ temps anyway, but Jan had send over a new cooling system with 30% more cooling and the new mounting system because he knew that when the constant speed prop made full takeoff power available, there would be a lot more heat generated with the extra takeoff HP and the marginal cooling in high temps would mean inadequate cooling with the extra 25 Takeoff HP I would be tapping into.

This particular radiator had been shipped with all the Viking 130’s for the last few years. Since my engine was an earlier 130, I still had the original radiator so the update was in order. Most Viking users already have the radiator update.

Most of the work updating the radiator was just removing all the old radiator and ducting. This new design is so much cleaner than the old one. It goes on with 6 screws and nuts. Aside from the drilling the holes and popping a few rivets to assemble the air box there is no fabrication required. The old system required a couple of days for me to install. The new radiator was cakewalk.

One I got the radiator installed I setup the new path for the coolant that would leave room for the prop actuator on the side. I also had to relocate my AMP shunt and 100AMP fuse. that were near where the actuator was going.

Installing the new gearbox was straight forward. After removing the prop I emptied the gearbox oil, removed the temperature sensor and replaced it with a plug and finally removed the oil overflow box. I removed the four main bolts that connected the gearbox to the engine and slid out the existing gearbox.

Installing the gearbox was the reverse. The two important items is to always use a new centering spacer, and to make sure you get the dampening connectors so they always pull and don’t push. They work under tension, not compression. The drive pins were aligned and the gearbox was mounted and torqued up.

The new gearbox required a mount for the other end of the actuator. This shared bolt locations with the alternator. I had to remove two of the alternator bolts and replace them with longer bolts that would connect the actuator and give it something to push against. Before installing the mount I rounded off the inside corners so the actuator would clear when rotating the tiny bit it does.

I then installed the actuator and connected it to the leaver arm and set the cotter pin. I wired the control wires thru the wiring harness and installed a 1AMP fuse from the engine power positive to the switch, wired the center center pin to ground and the two outer pins connected via a cross over to the actuator. I tested to make sure up on the switch pushed the shaft forward. I did not have a prop to install yet so I tested this with just the actuator.

I used the existing double throw, double pole momentary contact switch I was using for the flaps, that was immediately above the throttle as the prop control switch. I purchased a new switch with a Cessna Flap Style paddle handle for the flaps and relocated the wiring for those. It takes a bit to adapt to not changing the prop pitch when I want flaps, but the flap style handle helps remind me.

Early the week of the homecoming the prop showed up on Monday. The prop is a three blade DUC propeller with a super-light carbon fiber hub. It is absolutely gorgeous in design. It is unique in that the mechanism in the head is super light and most of the “work” happens behind the gearbox.

Monday night after work I headed to the hangar and got as much done as I could on it. I had to trim the bolts for the spacer and calculate the length of the push shaft. Each cut mean sharpening the end to mate with the lever arm. After a number of tires I got it set perfectly. I was able to have the fine setting be set for Max Static RPM for STOL takeoff.

Once the prop was installed I had to trim the existing cowl for the new radiator size. The actual work of the prop upgrade was trivial compared to the radiator update.

I had everything back together and was able to get the radiator filled and purged and started doing run-up tests with the new prop. It was cool to be able to add exercise prop in my run-up checklist! I did a couple of rounds of adjustment to get the RPM’s just right and I was ready to go… almost.

By this time I realized that we had been IFR for two weeks from the smoke and I would never be able to make the Zenith Homecoming with the Big Tire Cruzer. I booked a last minute flight on Alaska and headed off to a fun weekend. When I returned rain had finally come and cleared out the smoke.

I then had to modify the cowl for the new wider radiator and then modify the inlet baffles to direct air into the radiator. The first test flight caused the cowl to suck in so I knew the baffles were needed. I re-installed modified versions of the baffles I was using that that helped ensure that the negative pressure behind the cowl extracted air thru the radiator, and not thru the exit in the cowl.

Another test flight showed this was mostly fixed. I still need to modify and balance a spinner for the new prop shanks. The old snipper has too small of openings for the new blades. The new DUC blades are thin, but the shanks are huge in order to rotate to adjust the pitch.

As I got more confident I was able to so full STOL on takeoff and the plane just rockets into the sky. The ground roll has been cut down so much and now I can rotate confidently at a much lower speed and pop off the ground and it keeps accelerating to a high angle of attach and goes up like an elevator. I took a trip up to see my new hangar in Anacortes Thursday night and the plane was already in the air very quickly and we climbed over the water to 3500 feet in just under 4 minutes. I set the prop for cruise and made good time at a lower than usual GPH setting. So far I am really liking this setup!

The biggest shock is that now when I setup for a cruise at 4.5- 5.0GPH it is soo much quieter than it used to be! The Viking 130 an the Whirlwind were a great setup, but this setup is absolutely no-compromise in any way. It gets me outstanding STOL performance and optimizes my Cruise performance for whatever the altitude and temperature is. The shocking part is that buying this setup is still cheaper that getting a 130hp engine with fixed pitch from any other turn key Zenith power provider.

I still need to finish the nose cone, open up the air inlet around the spinner and do some more testing. I want to finish the break in on the gearbox and then take it out so some sandbars and see what it can do!


My airplane is solidly a E/AB and not an LSA. Things to consider if you have an LSA, if you want similar capability and keep it LSA legal, then mount the control switch on the front of the fire wall and set the static RPM on the ground. Set to cruise, fly to your location and drop your baggage, etc. and then set the static RPM to STOL.

Now fly around and hit your sand bars, etc. with the STOL, and then set static back to cruise for the flight home. This would be a bit expensive compared to a couple of tools and a angle gauge, and not give you the in-flight adjustable feature, but would give you the convenience of setting the pitch for each flight. A couple of minutes to set the static could give you the best settings for your particular mission at hand.

Thanks to Roger for pointing this loophole out. He is not sure who mentioned it to him at the Homecoming, but thanks to them as well.

Hitting the bars during COVID19

There is not social distancing like Extreme social distancing in an airplane. The last few weeks I was taking advantage of the end of summer low water flows in the local Pacific Northwest Rivers to chart out some sand/gravel bars and land them. This is the type of thing I build the Big Tire Cruzer to do. While I am still waiting for the Variable Pitch Prop, I still have to compromise between the speed I get there and the ground roll and climb performance getting out of tight places. I am very dialed to Cruise in my current setup because none of the back country strips I have been to so far are even remotely a challenge for either takeoff or landing. Most of these strips might be tight for some bigger/faster planes but have 4-10 times more length than necessary for a takeoff or landing.

Sandbars are more of a challenge. They are constantly changing and are neither groomed or maintained for purposes of landing. They also have challenging approaches and departures. Some you can go-around, but you really want to reverse direction for taking off. And scout as you may, its hard to judge exactly how much useful roll distance you have. Additionally winds thru river valleys can either help or hurt the situation. A particular gravel bar I was aiming for my first landing in the Cruzer was perfectly crosswind to the prevailing winds, and had tall trees just upwind of final that would kick up rollers surprising you at the last minute.

I flew several low passes and got a good feel for this target on Ross Island. The next Sunday morning the winds were calm and I got up early and flew up to the Skagit River and did a low pass over the site and came back around and executed the approach. I had so much room it was overkill! Even with the Cruise pitch I was in ground effects fairly quickly and had the speed and altitude I needed by the river. I really should have taxied down to use all the “runway” but I was exploring the limits to it was a good exercise of progressively getting comfort in both the airplane and my skills.

I took the “Dirty Birdy” back to the wash rack and gave her a well needed bath.

I still need to work on landing with absolute minimum energy and getting super short roll outs. I also pitched up my prop to get shorter liftoffs but my flight with Ajai was scrubbed when his plane would not start. Problems with his ignition on his Rotax have grounded him for a while.

Meanwhile I have taken my airplane apart to swap to a new larger radiator, the new gearbox with Viking VIP variable pitch control and a new flight adjustable prop is on its way. I will have more on that in the next post. In the meanwhile it was fun to finally have use the plane for off-airport fun.

Here is the videos of the scouting…

… and the landing.

Halden passed his check-ride!

20200824_221550132_iOS (2)The last two and a half years have been a roller coaster. While the building of the airplane went smoothly, Hal’s road to his pilot license not so much. First his solo was long delayed because a incompitence by an AME (FAA authorized Doctor) who incorrectly deferred him and included test results from another random person who was not my son as the basis for it. Then “recommended” a sleep apnea study with no symptoms or call for it for a healthy 16 year old boy. It was a long road making up for a few minutes of incompetence. Make sure you get an AME who is well recommended.

Finally Hal got is Solo in Dec 2018 and worked his way thru until he was almost ready for his checkride, then school and weather intervened and it got to fly maybe 3-4 times over the winter. When spring finally came back he blew of the rust and was ready again… then covid hit and he could not fly for 3 months.


Finally the flight schools opened again and he worked his way back to proficiency and today on August 24th he did his check ride and passed!

This was his checkride path.

hals checkride


Vortex Generators for the Empennage

I have been flying for a while with the VG’s installed on the wing. During the test flight I found significantly lower stall speeds and better control, but still the elevator and rudder still get washed out at low speed and I wanted to get better crispness and more positive control authority out of them. Before I start trying to get absolute crazy short Takeoff and landing distances out of the bird I want to make sure I have good control ability of it and have confidence in the planes handling.

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The Horizontal Stabilizer VG setup is quite well understood and even the 650 project I have has VG’s on the elevator, its not just a STOL thing. It helps with control authority. Installing them was setting up a reference line 100 mm ahead the hinge line and setting the VG’s at a 30MM pitch across the bottom side of the Horizontal Stabilizer. I used the clear STOLSpeed VG’s sanded flat. The standard VG’s they ship have a curve for the profile of the wing, not the flat profile of the stabilizers.

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The Vertical Stabilizer presented more of a challenge. The instructions were very unclear on how to set them up and I could find no pictures of any installed on Zenith Cruzers. It was late Sunday so I called STOLSpeed in Australia where it was Monday morning and I was able to get the owner on the phone. We discussed the options with him and he had some suggestions. Looking at the rudder, there was a rake back on the hinge line and I decided to have all the VG’s follow 100mm in front of that parallel to each other and orthogonal to the hinge line. After sketching out the design I headed over to pick Halden up from his end-of-course exam at the FBO and checked out the STOL kit on the Cessna 172 I fly. I looked at the Vertical stabilizer and surprise! It was almost exactly what we had decided on for our setup.

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This setup would give them a good angle to create the vortexes when the plane was at a high angle of attach when they were needed most. I was hoping this would give me more control authority at low speeds with the rudder.

After getting them all installed I decided to take them for a test flight. I left KPAE and headed out over Lake Stevens. After gaining sufficient safe altitude I started first a steep climb with full power and full elevator back pressure. The rudder had plenty of control and I was getting over 600FPM climb with full back elevator and under 40kts speed. I then went back to 75KTS and 800+FPM climb.

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At 4000 feet over the lake I slowed to 40kts and went full power and full back pressure. Again total control and crips rudder control without having to go to lock like before. I recovered and setup for flaps up stall with no power. Very crisp control with some shuttering on the roof window and 500FPM decent with no break. Very controllable.

I then setup for a high-alpha slow-flight with power and flaps and got down to 30 KTS before any sign of shudder. I set at 33/34 kts and did 360 turns in both directions. They were very clean. No loss of control or loss of altitude and super tight!

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I then tried some aggressive slips and it felt way better than it used to with all the VG’s working for me. I headed back into KPAE and alone in the pattern I setup for a STOL approach and came in a tight pattern. Slipped very low approaching the threshold and went high alpha with power. I hit a few feet onto the pavement with a solid plant and threshold braking to slow roll. I could have exited off the end intersection! I did put some power and it took for ever to taxi to the intersection where the touchdown target normally is.

This is roughly the landing spot and brake run. I think it is time to put the 80″ prop on the Viking 130 and see what we can do with it!