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!
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!)
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!
<Update>
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.
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.
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!
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.
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.
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.
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.
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!
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!
My friend Ajai saw my post last week and wanted to visit Tieton airport. Saturday was the Packwood fly-in. I made a flight plan that would take us to Ranger Creek, Packwood and then Tieton and sent it to him. He was game so we decided we would do a formation flight of two for the trip. Single pilots.
Saturday at 7:00am we met at the airport and there was a dome of fog over the airport. I did some stuff around the hangar and waited for it to burn off. I was game to just go SVFR, but Ajai wanted to wait for more burn off so we did. Made for better video maybe.
We headed out and just overflew Ranger creek because of time and made the ridge crossing to the other valley while in contact with a couple of other flyers crossing the ridge toward us, but one got lost and headed pack. We ended up seeing his buddy on the video still frames, and him at Packwood.
Landing at Packwood we were the 3rd and 4th plane on the field. Not sure if the others flew in or were there already. While we were there another dozen planes flew in including a gaggle of Carbon Cubs.
We got some breakfast sandwiches and drinks and said hi to some new and old fiends. We departed to Tieton and landed over the bay. In the video the battery died, so I had to splice in the approach from last week to make the video make sense.
We checked out the area and then headed out over the lake and flew east thru the valley and then cut over to Easton and home thru the pass. The Hyperlapse came out amazing. I did it in 4k this time!
Mountain flying is challenging. Landing on a short gravel bar near sea level in 75 might be a challenge, but a super long mountain strip with 100 degree + grass runway temps, at 2700′ altitude, but more like 7000+ DA can make for even more challenge.
My friend Diego who helped with the build came out today for a trip into the back country to visit Tieton State Aiport. It was a fun trip and I produced a video out of the Hyperlapse and real-speed takeoff on the trip home.
I had planned to land uphill on the lake side as was recommended but a guy in a T210 was doing landing practices on the curved entry on the mountain side of the airport. The east side of the runway ends in a Mountain and getting in is a challenge with a curved approach then dashing between the trees to catch the end before the ground drops out on you. Go around on that side is not bad because the lake end is clear of trees, but if you don’t make the go-around decision in time, or head too close to the trees or the mountain things might not end well.
The takeoff in the density altitude made what would normally be super short takeoff seem painfully long. It might have been the shortest takeoff ever for a 172, but I knew it was much longer than it should have been. The temperature prediction was 85, but it was showing 100 on my OAT probe and I was parked in the shade.
The trip back was a thermal roller coaster but neither Diego or I got sick. I took the back route out because climbing up to the 9500′ we came in on was not going to happen in that DA!
Every year experimental aircraft need to go thru a “Condition Inspection”. One of the benefits of building on your own is you can sign up for a Repairman’s certificate that lets you sign off on the inspection yourself if you built the plane. I delayed applying for this and then COVID19 hit and the FSDO office that processes the applications was closed to visitors and I could not get it on time. I needed an alternative so I headed up to Arlington (KAWO) where there was a outfit that does manly LSA and EAB inspections ans well as work on them.
They do “owner assisted” where I help them open in all up and it allows me to see everything they are looking at and get an idea of what I should be doing. It is also nice to know another set of eyes is looking at my airplane. I have been the sole builder and mechanic of record so far, so every maintenance item has been done by myself.
The inspection covered all the rigging and mechanical components, checked the ELT, and opened up the engine and took compression and valve clearance measurements. When all was buttoned up again it got a clean bill of health and I flew back good for another year. While I was happy to get my work double checked for condidence, the cost of paying $600 every year means an extra $50/mo in cost. In the future I will make use of a repairman cert most of the time.
Part of the plan of this dual personality Big Tire Cruzer is enhancing the short field and STOL capability of the aircraft. The wheels, tires and brakes help out, and the 80″ prop I am getting setup to install will help it hop off the ground, but for STOL landings and for really steep climbs you need more slow speed capability for the Cruzer.
STOLSpeed has a very nice affordable set of Vortex Generators that when installed properly can nearly the same stall speeds as the STOL and significantly improve handling characteristics in the slow speed regime.
The are installed on the Cruzer at about 4.2 inches back from the wing tip. About midway from the 3rd and 4th rib rivets. The little wings bend the air to cause it to swirl around itself and this vortex it generates (thus the name) helps keep the air from separating when in stall. It will delay stalls significantly vs. a wing without them.
I used the included templates to set 15 VG’s at a 60 mm pitch and then another 30 at a 90 mm pitch. After getting the main wing setup I went for a test flight.
I started with a clean stall at it was clear that the stall speed was lower and the control was much better.
Next was a full flaps stall and that also was much improved. Really there is no stall at all as long as you keep the balls centered. Just some buffet and a 3-500FPM decent, but no break at all.
After that I used some power to get a super high-alpha stall. I saw speeds dip into the 20’s.
Next was the departure stalls.I slowed to rotation speed and then hit the power while pulling the stick back all the way. Surprisingly there was never any stall. I had to increase right rudder until it was on the stop because of the high Alpha p-factor. No matter what I tired it just kept climbing while the power was in and if I kept the ball centered I could do whatever I wanted.
Stalls where easy before, now they were wicket amazing.
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.
Part of the plan of this dual personality Big Tire Cruzer is enhancing the short field and STOL capability of the aircraft. The wheels, tires and brakes help out, and the 80″ prop I am getting setup to install will help it hop off the ground, but for STOL landings and for really steep climbs you need more slow speed capability for the Cruzer.
My 750 Cruzer 