SwiftFox - S7 Super Sport Build (Vancouver, Canada)

[nathan_s]

It’s been over two months since I posted an update. Apologies, between being back home for a friend’s wedding, then having some family visiting me there has been a lot going on. But there’s been a lot of progress on the Kitfox in between, so let me catch you up on that.

Flight controls are in! This was a bit of a slog, and while rewarding to finally be done, it wasn’t without frustration. The difficulty was mostly centred around mounting the Control Column into the fuselage.

I messed up the control column mounting bracket and column bearing block and had to order some replacement parts to make them again.

On the control column bracket, I made two mistakes. The first was that I pressed in the bushing into the bearing, where the bushing would not spin/turn like it should. I immediately realized my mistake, and it would have been recoverable except for my second mistake which was botching the mounting holes in the bracket.

The first hole I drilled was right up against the inside wall of the bracket so you wouldn’t have been able to get a tool on the head of the bolt. I tried drilling a new hole, but because I had to have it off the centre line of the internal box part of the bracket to give it clearance from the errant hole, it meant that the two mounting holes on the outer side of the bracket were now too close to the outside wall of the bracket.

For the bearing block, I ended up drilling the second mounting hole crooked, which meant the whole block was kinked, and I’d have to remove a lot of material to get the control column to move smoothly.

Basically, my problem was back drilling from the underside of the fuselage. I wasn’t able to get enough force behind me to keep things straight and I think the bracket shifted as I started drilling as I hadn’t gotten it clamped as well as I’d have liked. That’s probably the big downside of having the fuselage mounted in the stand I made; I couldn’t just tip it over on its side to drill.

I ended up ordering new parts from Kitfox to redo it all, and learn from my mistakes. Instead of back drilling into the bracket itself, I back drilled into a piece of scrap plywood and used that as a drill template when drilling into the bracket proper. I found where I wanted the bracket positioned in the fuselage, used a sharpie to mark it, then lined up the plywood template over the markings and drilled. It worked really well.

The second bearing block deformed while drilling the second mounting hole (has it not deformed for anyone?), but the hole was straight through the block this time. I used a drum sander bit in my drill press to remove a lot of material to get the hole in the block back to a circular shape and a clearance fit for the control column.

I had seen a thread on here about someone suggesting using sleeves around the bolts to stop the block from deforming, and I was hoping to go that method, but the tube I received had not been made with tight tolerances and I didn’t have the tooling to correct it so I had to go with the manual’s way in an effort to keep the project moving. It would be nice if this area was improved in the design and fabrication. It probably many days to get everything moving smoothly.

Control Column Mounting Bracket.jpg Control Column Bearing Block.jpg

The centre console is in now too, and I’ve got the detent brackets placed and drilled for riveting. I was a little confused here with regards the instructions for the pre-fab kit parts when it comes to the rivets to use. I had consulted with Brandon on a different part of the instructions earlier and he said they’re a bit out of date so I suspect its the same story with the rivets. Basically the rivets that are specified in the pre-fab instructions didn’t come in the kit (not listed in inventory) and the rivets that are in the manual are too short. I’ve ended up measuring the length of rivets needed and have ordered solid flush head rivets in place of the pop rivets. I’m probably going to paint my centre console the same colour as my panel, and I’d like it to be as smooth as possible, hence the solid flush rivets.

Next I moved onto the door frames and window frames and have just finished bonding and riveting them in. This process was easy enough after watching Aaron Butte’s video where he discusses with Brandon how Kitfox does their doors and windows and what tips they have for builders. I’d highly recommend giving this a watch if you’re about to start your doors and window frames, it really helped me understand what to do.

I'm going to start working on the body work for the window and door frames next.

Window and Door Frame.jpg

I’ve been documenting my build on YouTube, mostly for my folks, family, and friends back home, but figure I should post a link here too. It’s not much more info than I’ve already written. Here’s the latest video...



Lastly, I want to give a shout out to Martin. I don’t know if he’s on the forum here, but he flies a Kitfox Model 4 in Clifden in the West of Ireland, and while I was home I had the chance to go out and visit him and see his Kitfox and chat all things flying for a couple of hours. It was great meeting another Kitfox owner and pilot, especially someone from my home county in Ireland. He's got a video on YouTube with him flying around some parts of Ireland and it is stunning https://www.youtube.com/watch?v=aT4CUU0ehXU

Martin.jpg

[Kitfox Pilot]

Looks like you got it done right and that's the main thing. Everybody has some redos for sure. Keep posting we enjoys watching people build! Harlan

[nathan_s]

Thanks Harlan!


Sent from my iPhone using Tapatalk

[olsonCCR]

Nathan,
Nice work on your build. I'm building an S7 as well. (Working on my window and door frames now, and am almost ready to start work on my wings). I just watched your video and had the same idea as you, and used flush rivets for the center console in place of the pop rivets in the kit. I really enjoyed the experience having not worked with flush rivets before but keeping the bucking bar in place when using the rivet gun was way more difficult than I thought working in such a tight space. Every time the bucking bar came off I dented the underside of the console which is visible from the top.

Just sharing my experience in case you haven't started with your flush rivets. I should have protected the top surface better and practiced using the rivet gun with the bucking bar more before starting.

I used both a manual squeezer with a 3" yoke, and a rivet gun. The squeezer wouldn't fit in between the bracket and the side of the console as it tapers, which required the rivet gun resulting in the surface denting. Great learning experience but I will definitely need to use some super fill to clean up the surface to prep it for covering. Originally, I thought it would look cool to have the console top and rivets exposed.

In the sun, my finished console looks pretty rough! Inside the plane, not very noticeable but I do still plan to cover it. All in all, I'm pretty happy with the final result.

One other unexpected challenge I had (which I still need to address) was after finishing riveting, the console surface bent ever so slightly near the adjustable rudder handles from the use of the rivet gun, resulting in the handle notch tolerances being slightly too tight when moved from each ratchet position, making the handles difficult to lock. Once I remove the console again, I need to "press up" the console top from the underside a bit, which should solve this issue. Everything works fine and locks in place but it's not perfect.

Anyways, look forward to watching your progress!
Good luck with your build.

Kevin Olson
Building an S7 STi

[nathan_s]

Thanks for that info, Kevin. I'll definitely be keeping it in mind.

My only previous experience with a rivet gun was at AirVenture in 2019 when I attended a Sheet Metal workshop where we riveted a small piece of aluminum sheet to a couple of angle brackets. I might try and find some way to do some more practice before doing it for real on the centre console.

Also I've been following along with your update videos on YouTube. Looks like you're making great progress with your build!

[olsonCCR]

Thanks for that info, Kevin. I'll definitely be keeping it in mind.

My only previous experience with a rivet gun was at AirVenture in 2019 when I attended a Sheet Metal workshop where we riveted a small piece of aluminum sheet to a couple of angle brackets. I might try and find some way to do some more practice before doing it for real on the centre console.

Also I've been following along with your update videos on YouTube. Looks like you're making great progress with your build!

Thanks Nathan. I really enjoy using the rivet gun but am still figuring things out. I'm following your build as well. Look forward to seeing the progress! I'm trying to get more involved on the forum and share my progress but it's been a challenge finding time. Working on my door frames and windows still. I kept putting them off and can't wait to get them finished now!

Keep posting!

Kevin

[nathan_s]

Door and window frames are done! It took a bit longer than expected (isn't everything?), primarily due to a mistake I made which I'll speak to in a moment, and some more family I had visiting, but I'm really happy with where it is at now, and I don't think I can improve it much more with my current Superfil-skill level.

Left Side.jpegRight Side.jpeg

The mistake I made was a really dumb one, but I've been reassured by a mate a couple of hangars down it is one that everyone makes from time to time. I mixed the SuperFil incorrectly, 1:1, instead of 2:1. This was after I had correctly put a little on some in a couple of places as a test and sanded back to get a feel for how it works. When I was satisfied with that little test I put SuperFil on all the remaining joints, but in the wrong ratio so it never hardened. It ended up being this mess that I had to spend a couple of days scraping off. I've since written "1" and "2" on the tops of the SuperFil containers to remind me in future.

berryP also called out to the hangar one afternoon to see the build, and even applied some Hysol onto the window frame for me. Thanks for the help, berryP!

I've also finished riveting the detent brackets into the center console. Fortunately, I didn't have the same problem as yourself, Kevin. I was a bit worried about it, so I riveted the adjustable rudder pedal brackets first, going from aft to fore. Followed by the flap detent bracket going fore to aft. I thought that way it would be stretching the console if any, instead of bowing it. Not sure if that is a reality, but figured it was a good way to go about it anyway.

Center Console.jpeg

I just published the latest build update video, covering the door and window frames.

[nathan_s]

Does this look wrong?

Header Tank Fittings.png

I'm working on the header tank, and inserting the fittings. I can only twist the fittings in three, maybe four threads before they're getting too tight to go any further. I would expect I need to have these fittings fully in with maybe only a single thread out? Should I pull these out, clean them up and tap the holes again so they go in further?

[jiott]

I would re-tap and then thoroughly deburr and flush the tank. I wouldn't worry about a couple threads showing, but 4 is too much in my opinion. Better yet, the engineering specs on an NPT thread are as follows:

Hand tight thread engagement = 0.1615" for 1/8 npt and 0.2278" for 1/4 npt
Maximum thread engagement = 0.2639" and 0.4018"

Thread engagement is measured from the bottom of the fitting to the top of the female thread on the boss, when wrenched in to proper torque.

[Kitfox Pilot]

[QUOTE=nathan_s;105846]Does this look wrong?

Header Tank Fittings.png


I had to re tap my header tank and the main fuel tanks to get the right amount of threads in. More threads in= much less chance of a leak.