A partner and I Placed the Order for a Kitfox STI last week. (Primary factor in the choice of the kitfox was the ability to fold the wings which allows it to fit in my existing hangar. For those wondering) Due to "Efficiency gains" they'll be able to deliver it this June. Things just got real, fast and you can't imagine how excited we are though feeling a little rushed on the decisions we are facing. We originally were told they were out ~16 months so figured we had tons of time to figure out the small things when ordering the kit right up to engine choices.

Curious if anyone on here has built one? I just started digging in on the kitfox forum and there is a wealth of knowledge but since I'm on here I'd figure I'd ask.

In no order some of the questions we are thinking about.

Engine: Most likely the rotax 915 but the 916 is enticing but is it worth the extra $10k? We live in Colorado so a turbo is happening one way or another. We have looked at the Edge option but not sure I love the idea of boosting up a 912 to the levels they are without the other upgrades a 915 brings.

Covering: Oratex. Damn it's expensive, but not having to paint the plane is appealing. Any experience here.

Struts: Is it really worth over $3k to upgrade to the chromoly streamlined struts. This thing is not built to go fast. I've got the a36 for that.

Autopilot: We are going to put in at least a two axis but the more I read it's probably worth at least paying for the 3rd axis mounting kit. thoughts?

Tires: My biggest concern from what I hear is the big Alaskan bush tires wear a lot on pavement. Both of us are new to a tail wheel and I figure for at least the first year a bunch of our time will be on pavement and the plane will be based at a paved field with no grass options. I'm thinking of starting with a more traditional tire at least as first and making the transition to a bigger alaskan bush tire later.

Interested to hear your opinions.

Tires: Yes, ABWs get chewed up on pavement pretty quickly. People try various kludges, like painting them with truck bed liner, but then they aren't the big pillows you bought. There are other options, like Goodyear blimp tires, but they're heavy.

If you start with something like 8.50's, you'll get a good mix of pavement-friendliness and hayfield floatation. Unless you're landing on sandbars or something -- which is a ways off if you're new to tailwheels -- you might be so happy with the $300 8.50s that you never get the $1500 ABWs.

OTOH, the ABWs definitely look cool (aesthetics are important) and they'll soak up a lot of landing energy, which you'll certainly have too much of when you're getting started. If I were in your place (kind of wish I was), I'd get a set of 8.50s and decide what's next when they wear out.

Thanks Stuart. That's what I was thinking. Sand bars are way off in the future. Though I completely agree on the looks aspect. I think we'll probably start with the 8.5's and go from there. Plus $350 vs $1500 with ever other check we are about to write is pretty damn appealing.

not a Kitfox, but years ago I built an Avid Magnum, which was a competitor and very similar to the Kitfox V (the Avid was slightly larger).

On the covering: don't know anything about Oratex, I used the Polyfiber process. it turned out beautiful, but it was a TON of work. Glue, fabric, iron, iron again, brush, spray, sand, spray, then 2 coats of silver, sand, spray, then paint. and that crap is MEK based, so very very toxic.

I think the covering was 50% of the entire build. If there's a "quickbuild" for covering, I'd 100% spend the money on it.

and for the AP-- If it were me, I'd go simple. 2 axis, if anything. maybe even just altitude hold.

good luck- they are great airplanes. please post pics. consistency is the key to finishing. mine took 10 years (interrupted by medical school, wedding, military service, residency, some kids, etc).

will build another one some day.

not a Kitfox, but years ago I built an Avid Magnum, which was a competitor and very similar to the Kitfox V (the Avid was slightly larger).

On the covering: don't know anything about Oratex, I used the Polyfiber process. it turned out beautiful, but it was a TON of work. Glue, fabric, iron, iron again, brush, spray, sand, spray, then 2 coats of silver, sand, spray, then paint. and that crap is MEK based, so very very toxic.

I think the covering was 50% of the entire build. If there's a "quickbuild" for covering, I'd 100% spend the money on it.

and for the AP-- If it were me, I'd go simple. 2 axis, if anything. maybe even just altitude hold.

good luck- they are great airplanes. please post pics. consistency is the key to finishing. mine took 10 years (interrupted by medical school, wedding, military service, residency, some kids, etc).

will build another one some day.

For the tires, stick with the standard ones. They’re 6.00 x 6, right? That’s plenty good for most grass and gravel, and you won’t wear them out on pavement too quickly.

If you’re looking at soft grass with a little mud, 8.50s work fine.

Most of my tailwheel time is in a 65 hp champ that had 8.5s and it did fine on the grass runway when it was soft after the spring thaw. We mostly didn’t fly because we didn’t want to put ruts in the runway, but the plane would do it.

If an underpowered champ can do it, a Kitfox can too.

Can't remember the brands but some brands of 850's are larger than others

I have 8.50's on my Cub, and it will do anything I need to-pavement, grass, off runway without major rocks or holes. They are much cheaper than bushwheels, less drag, and lighter. For extreme stuff, bushwheels are great, but they do wear out on pavement. For most people, bushwheels are a status symbol. Just read the Don Shelton book or any other STOL book written before bushwheels came out. The old pilots did a lot of gnarly stuff on regular tires (L-4 cubs had small tires in WWII and did amazing stuff).

My only comment on Oratex is that you need to look at a couple of airplanes with Oratex in person before you make the decision. It can be a little opaque. It may bother you, it may not. American Legend put white Oratex on one of their cubs and were unhappy with the look. In day light, you could see the tubing underneath the fabric. They ended up recovering it. This not intended to be a knock on the quality or the process-I don't have a valid opinion on either.

That's what I've heard and echo's what the guys at Kitfox mentioned about the oratex. That plus the ~10k (my estimate) price tag makes it hard to swallow. Though the application and no painting is a huge advantage.

Good to hear on the 8.50's and what others have said as well. I'll have to check out Don Shelton's book.

The other big question I'm going to be facing is the affect these Tariff's are going to have on my costs. My kit price is locked in so good there but the big one will be my cost on the rotax, radio's (leaning towards a g3X) are going to add to my estimates. I'd buy the rotax now but by the time I got it hung and running I would probably be out of warranty and not worth the risk.

That's my thought at least out of the gate as I build my tail wheel time. Once I get more confident I'll be over the front range into Moab where the bigger tires might be come a requirement down the road. Time will tell.

I covered an old Tripacer Elevator in Oratex red and hung it outside for a few years in full sun.
No fading so I was impressed by that. You need an iron with enough mass to not lose a lot of temp as you move from open bay to over structure when ironing the finish tapes.

The Oratex is translucent so you can see structure underneath. It can be done well but is a bit different. If your an old Free Flight modeler it's nice look if done well. You can cover with Silver Oratex and paint if needed.

The problem is cost. When you cover an airplane either with an envelope or blanket method there is a lot of cutting and trimming to get the fit nice before shrinking. No problem because the raw fabric is the cheapest part. With Oratex the scraps are all finished product you paid for.

Polyfiber or Randolph is not bad but yes smells and multiple chemicals to deal with. It gives a nice long lasting job even in the simpler cheaper Polytone and you avoid hardener so you can use a respirator with the right filters. I prefer a Breath Buddy brand with full face shield.
For spraying Ranthane or Aerothane with hardener I use a Hobbyair Forced air hood with fabric hood that covers my whole head. And Tyvek Suit.

Polytone finish is a bit cheaper and easier to apply, fix. I have chilled the polytone paint for color coats before spraying cold for better gloss.

For spraying poly spray or dope I use an Apollo HVLP turbine spray setup. Ranthane or Aerothane then a normal gravity feed paint gun.

Stewarts glue is great. It has a shelf life but can be repositioned until happy. The rest of the process is a finicky with humidity and equipment but some nice looking jobs can be done with less toxic chemicals than the other processes. I still have nightmares about the Blue River 7600 process that was similar to Stewarts (waterborne) and cracked/peeled for years on many airplanes. The Stewarts does not seem to have that problem now though.

Airtex seems to work ok. It's a bit different spraying their primer directly on the fabric. The system may be a bit lighter than Randolph or Polyfiber if desiring wet Polyurethane topcoat. Compared to dope or Polytone I think about the same. Airtex you can see light through from the inside but they say the UV protection works instead of Silver like the others.

Funny I have seen a few homebuilt airplanes covered with Ceconite and painted with Latex House paint. And years later it is still looking good. the FlyBaby homepage has some examples.

For Ceconite or Polyfiber be careful with shrinking. The manuals want you to shrink to full tension but the fabric has changed and manuals are not revised. If you go to the full temp with medium or heavy weight fabric it will deform the structure. Fuselage tubes bend, control trailing edges scallop. No way to go back except cut it off. I do like the new Digital irons sold at Aircraft Spruce. They are irons for applying ski wax with much better temp control than household irons. They modify them with a different shoe that works great for covering.

Building the Kitfox is straightforward. The newer airplanes are a lot better than the old Model II through IV I was working with. The main things are no firewall sealed to the boot cowl. That makes maintenance nice but it's different than a certified airplane.

Flying, the horizontal tail is legal highway width. That means the tail can stall before the wing. Later airplanes with an adjustable stabilizer and airfoiled surfaces should be better here. The stick position is a bit forward with your arm more outstretched than a Cub or Champ. Stick travel in pitch seems to require more arm movement though a Cub needs it all the way back in the flare. Nothing that you can't figure out with some instruction.

The early airplanes had no yaw centering. Not yaw unstable they just would not come back if deflected. I have not flown one with the tall tail to know if it's any better.

Good brakes and good tailwheel makes all the difference. Also getting the adjustment of the toe brakes correct. Many homebuilts I get in have the toe brake pedals setup with the brake pedal tipped aft of the top of the main pedal so your foot needs to be rocked back to a negative angle. (toe towards your knee) This is very uncomfortable and it's easy to get too much brake accidentally. Tipped forward too much is also bad because with full pedal deflection your toes hit the firewall or slip off. The original Kitfox ATV wheels and hubs worked not too bad. Original MATCO brakes were terrible but I see they use better systems now. Seated your legs are also very straight extended which is a bit different than an average Cub. Again newer seating may be better.

Tailwheels there are some options. Full swivel is actually not too bad and keeps the tailwheel friction disks from making the rudder drag and have trouble returning to center in flight. I think this is how Trent Palmer has his setup. But shimmy might be an issue with the normal leaf spring angles so a steerable locking is best.
Some of the cheap tailwheels on Aircraft Spruce are just that. cheap and wear out fast. I wore one out in a single trip from PA to Oshkosh.

ABI, Scotts are good. A rebuilt Scott 2000 is very small tire but works ok. The Lang tailwheels have worked well also for us. Maules not so much. Scott 3200 is a bit heavy and has friction drag when setup not to shimmy but it's a good tailwheel. I think a good Scott is a bit better than a new ABI. AC Spruce has all the parts to rebuild but pay attention to the proper spring, chain and link setup.

For the Maules it is how they unlock at full rudder deflection that can be an issue. Depending on width of rudder horn it can move the tailwheel too much with full deflection and it will unlock right when you need it most. This has wrecked a lot of Aeroncas over the years.
A little research and testing helps prevent this.

I have not found any issues with the wood ribs bonded to aluminum spars on a Kitfox , Even with some fuel leaks from early fiberglass tanks and ethanol fuel.

I always worried about the myself and passenger weight hanging in the fiberglass seat pan over top of the elevator and aileron pushrods. The only thing holding the weight was zip ties around the tubes at front and back of the seat pans. If they popped all controls would be jammed with no way to lift yourself off and possibly not at neutral either. Hopefully the later airplanes changed this setup.

Don't walk into the aileron counterweights. That hurts.
Full flap is full down trim. Flaperons were the pitch trim in cruise between a bit of reflex for nose up or extension for nose down. The early airplanes had no pitch trim. You just held the stick pressure if flaps were used on landing. Like landing with full down trim.

Charlie, thank you for all of the great information. The painting process seems overwhelming at this point but I think it's the path we are going to take on this project.

When building an airplane everything seems overwhelming and then one day you are sitting there looking at your latest accomplishment. Good luck and enjoy the journey.

I'm a fan of the stewart system.

The glue has already been mentioned. It is easy to work with and re-positionable for awhile with heat. It doesn't smell, and doesn't make ridges that have to be ironed out.

When you get to the coatings they are all water-based. The UV block is charcoal-based. You can brush it on and then lightly sand. Stewart topcoats are also water based. Or, in an experimental you can paint with pretty much anything else you want after the charcoal.

All the components are non-metallic and you can bury com/nav/gps antennae inside the structure with no reception issues.

I have covered ailerons and flaps in my basement with my wife and kids in the house and there was no smell, no complaints. Try that with any of the other (non-oratex) systems.

One thing to consider. The earlier Kitfoxes all had no wing rib stitching. I don't know about the newest ones. The wood ribs have a wide cap strip top and bottom. The kit finishing system was Polyfiber. You precoated the rib capstrips with Poly Tac and after covering brushed more thinned Poly-tac through the fabric onto the ribs. This was to bond the fabric to the ribs and replace rib stitching.

Having the fabric glued with a peeling tension load is exactly against the STC instructions but on a homebuilt that's what they did. The glue joints should be in shear only.

But it worked. I have not heard of one coming unbonded.

Replacing with a different system this method may be an issue. But to rib stitch with the wide capstrips and supported edges may allow the stitching to saw into the capstrips?

For painting it's just a step by step. Once you get through the initial coats you find out what to do and it goes well. If you do use Polyfiber for a first time I'd stay with Polytone for an easy finish. It does seem to work ok over the fiberglass gelocated parts. But over metal maybe match with a bit of enamel with hardener or Ranthane. Matching with local automotive paint is also ok on the aluminum parts. I have not tried Polytone directly over the EP420 Epoxy primer that Polyfiber sells. It may bond just fine but some testing is needed.
Amazon and other places have the inflatable paint booths but a garage with box fan works fine.

Just do all work from initial gluing on up as it's going to be visible in the end. Good Friskars Scissors are a must and turn spring clothes pins around so the handles are the grip areas. The wood clothes pins won't have paint to dissolve in the MEK like Harbor Freight clamps.

MEK is the biggest drawback to the Polyfiber and Randolph glues. Mask and gloves needed.
But that stage goes pretty fast.

I have not covered a whole airplane with Stewarts but we have two Stinson 108 projects here and I think we are going to give it a try.

Any of the systems work fine. Just follow along with the build manuals and there is school of YouTube. The Oshkosh and Sun Fun build tents are a good place to visit and get a little hands on.