This is how I installed the Aithre Turbo Oxygen Maker Portable.  It should be noted this is sold as a "portable" O2 system and it's not terribly "portable".  I also purchased the power connectors (sold separately) so I could hard wire it in.  It's a big unit.  It's too big to sit up front in the SlingTsi, so I had to find a better place to put it.  Because I didn't install the parachute in my plane I had a little extra room in the back.  I installed some rivets in the luggage floor and then match drilled some holes in the base of the O2 Maker so it could easily be installed/removed with just the thumb screws.  The unit is in very securely and is easily removed if I need more room in the back.

For plumbing, I used the same lines that the brake lines were as I had that left over because I have the Beringer wheels/brakes and those come with a stainless steel brake lines.  Oddly enough the nylon break lines are the same size as the adapter to connect the O2 concentrator to the canulas.  So this worked out well.  For the right angle which you see in the pictures below I used an irrigation drip line with the 90 degrees connection so I didn't bend/pinch the hose.  From there I ran it behind the rear bulkhead down through the center console and up into the console where the headsets plug into.  The cool thing is the canulas that come with the Aithre have a rubber end that fits directly over the hose that is being run with a very tight seal.

I've used this config in flight up to 15,500 and it works perfectly with two people.

A few things to be aware of with this particular system.  

The O2 level control is not remote as you can see with the picture, so you need to set the levels high enough for two people and target the altitudes you commonly will fly at.  You also have to be careful when loading the plane not to hit the controller and/or pack too much stuff around it.  At some point in time I'll build a cage around the controller to protect it.

The unit has a manual push button to turn on/off the system.  Given it's installed in the back and you don't want it running every time you turn the plane on, you need a means for turning it on/off even while in flight.  Oddly enough I recalled this really cool Bluetooth remote switch from a while back.  It's very easy to install and works perfectly.  Basically once installed, you pull out your phone, open up the app, which will connect via Bluetooth where you can turn the system on.  Because the Aithre unit does communicate on O2 flow via Bluetooth, once the unit is on, the BT app will report O2 flow to show it's working.

It's also important to note that there is no backup to this system.  If for some reason it doesn't fire up when you go to turn it on, or shuts off while in flight you obviously are going to have an issue.  So I have to fly with awareness that these are the limitations.  I do get audio alerts in my headset from my phone, so I know when the system is on and off.

For the price of this unit it's on par with what two Iogen G5's would run used.  So it's pretty close in price enough that I'm good with just this considering I was just going to get four Iogen's.  Four Iogens would mean two Aithre systems like this for those doing the math.  Then I'd be dealing with all the plugs n' cables and other mess in the cabin.  Given it's usually only going to be and one other person this system suits my needs.  If I go past two I have a spare Iogen available for a third and if I'm going to a fourth person I'll need to get one more, or borrow one.  So it's a good trade off.  Would I have liked to have the fully integrated system?  Sure.  You pay handsomely for it, get a few more features and have a little more control over the air flow.  To me this is a good middle ground as long as I understand and adhere to the limitations.  The other problem with the full system is it consumes pretty much whatever is left over of the luggage area if you have a parachute.  I feel with how I have it configured I've got a lot of flexibility.

I had some time to follow up on the personal website here.  So much of my time spent on documenting the airplane build has been put into making the videos that I've neglected the actual written pages here.

Given it's been 7 months since I updated here I'm going to have to let the videos do the talking.

It's been a while since I updated my blog post.  Most of my documentation efforts have been done through my YouTube channel (which at this writing has 625 subscribers - thank you!).  My intent on the videos isn't so much about subscribers but a video documentation of the phases of the build.  I do have to admit it is fun interacting with the building community through the YT posts and watching the channel grow.  

I do have plans for the channel going into the future.  Hopefully I'll get better at my videography and content development, but that will be when I have time to focus on it more.

In the months since my last post I've put together 8 videos and two more are set to be published shortly after I update this post.  I'm actually at a phase now where I'm almost out of things to rivet!  Yes there are some left to do, but it's probably less than a few hundred.  Considering there are several thousand in the kit I'm definitely on the downside on that part of the build.

Just looking back over the videos I've completed the skins on the inside, got the firewall forward going, engine mounted, canopy on (that was scary), more firewall work, a failed air compressor (my fault), working on getting the fuel fittings together, heater install, uninstall, install, uninstall and so on until I got it just right.  That's been a huge pain.

Anyway - this post serves as a roll up of these events in both pictures and videos.  

I'm writing this to catch up on my blog posting and now about two months removed from when some of the video and pictures were taken.  The videos are setup to roll out once a week in about 10 minute increments as most folks don't watch beyond the 5 minute mark - so I'm working to try to keep them consumable.

As for the build series here.  I put in the heater and took it out a number of times.  Each time I took it out because I needed better access to the firewall.  After about three times I decided to just leave it out until there wasn't anything else left to do.  It was quite fun to have it in there though because it makes the front of the plane to really start taking shape.  

Speaking of taking shape - the canopy was the major change over the month of building here.  It was a bit stressful to do because you have to match drill each of the holes but you have to also have it lined up first.  So lots of fiddling to try to make it look just right.  The plans are kinda useless here because the amount to "put it in, make it look pretty", but I think I got it to where it needs to be.

The next phase also was working on the fuel system on the firewall.  I'm following the plans done by a gentleman out of Germany who has done a very nice job documenting the process of the fuel system.  It's clean, it removes a lot of the extra tubes as well.  Parts were getting hard to come by with some deliveries taking up to 3 weeks to ship.  But slowly they started arriving.

I also had to rework the braking system to take into account the Beringer braking system.  It's just easier to use this brake to keep the lines all with the stainless steel system.  There's more to come on all the steps I needed to do to get it to work and I have yet to resolve some of the other problems it introduced.  In the end I think it'll work well - as I only have a few challenges left to resolve with that part.  The pictures below document the work I did to widen the mount for the Beringer brake valve.

So that's all for now - I'll work on getting the next update out here as soon as possible.

It's been about a month or so since my last update.  The main reasons was due to "life" getting in the way.  The week before going to Hawaii I needed to focus on getting all the dive gear and other necessary items for the trip together.  A little over a week in Hawaii and then when I got back I promptly got a cold.  The cold has lingered on for a little while so working in the cold garage hasn't been super high on my list.  

Now that I'm starting to feel better I am getting back at it.  I did get the canopy over to a local hot rod paint shop who did an excellent job in finishing the canopy and getting it painted.  I needed to have that done before I could attach the canopy to the fuselage.  With that out of the way I'm progressing there.

The series of videos below are my getting the fuel tanks sealed up and attached to the leading edge of the wing.  This part ended to get done so I could get the wings tucked away and move the bench against the wall to open the space up for more work.  Thankfully once I got the rear part of the tank on, they sealed up nicely and went onto the wings super smooth.  

I also spent some more time running some wires in the rear fuselage potion of the plane.  As of this posting I really feel like I've gotten this taken care of - unless of course I find something else to change my mind on... 

Another thing I addressed was how the rear seat bench stopper was configured.  In the videos I talk about this a bit.  The "C"-channel for the lower portion of the forward most rib can only go in one direction - and I'm certain I have it in correctly.  The problem is the way the stop mounts there are a minimal number of rivet holes for it to connect.  So I fashioned a bracket to go in-between the open space and create a more rigid mounting point.  

Items coming up in the next few weeks will be getting the firewall forward on, engine mounted and avionics installed.  

I'm catching up again on the previous months activities here.  I don't think I'll get over how much work gets done in retrospect vs. what is standing right in front of me.  I often feel like I'm making no progress whatsoever and then to have to journal about the progress - it's a good reminder to keep pressing forward.

The biggest highlight is obviously getting the fuselage on the wheels for the first time.  I still need to torque out the bolts on the wheels themselves so they hold air.  There's a gentle leak in the two mains but it's not enough to worry about at the moment.

I've had some challenges in retrofitting the Beringer wheels onto the Sling provided parts but those were overcome with consulting a few local folks with expertise in their respective areas.  The nose wheel was one of the more interesting ones in that the axel for the wheel wasn't going to work with the Sling supplied bolt.  This necessitated boring out the Beringer axel to allow for the mounting bolt to be inserted to actually mount the wheel.  The machine shop I tool the problem to was able to bore out the axel to within 1/1,000th of an inch and has a nice smooth insertion of the bolt with no wiggle whatsoever.  The bore removed a small amount of material and I believe it won't be a problem - ah the joys of an experimental airplane eh?  Let's hope I'm not wrong on this one.  

The wheels overall presented the bigger challenge, but through conversations with other folks who have crossed this challenge before I did I believe I have arrived in a good spot.

I also used my time this month to replace the incorrect wing hinge which was installed way back last fall.  It only took a few days to correct this problem and I can now safely say the wing is done with the aileron and flap for the right wing is complete.

The fuel tanks presented a whole new challenge.  The biggest hurdle was that I missed steps 5.- Cleco the back channel, and 6. - Remove the fuel tank assembly from the wing and complete assembly.  Had I understood the weight of what I was doing a bit better I would have realized that when I assembled the rear portion of the fuel tank in the fuel tank jig I would have realized I wasn't aligning to the wing but to the jig - which wasn't square for the wing.  Because of this I introduced a twist to the fuel tank resulting in it completely not fitting.

To correct this it required removing all the rivets holding the back portion of the fuel tank, gently prying off the rear portion of the fuel tank, cleaning all of that up and then reassembling it correctly.  As of right now I have one of the two fuel tanks completely done, tested and mounted to the wing with rivets.  I gotta say - following the instructions would have been a HUGE game changer because the whole thing went together easy-peasy the second time.  In speaking with Evan about this he said by about the second set of wings you get good at them.  I just didn't realize I was going to get to do that on my first plane.  Lessons learned - let's try to stay away from doing that again now shall we?

Another fun challenge to overcome was to have the brake selector mount re-engineered to have a better mount than the two mounts provided from Sling.  Someone someday is going to have to explain to me how Sling ships a brake valve they know doesn't fit to the right angle adapter.  The options to resolve this is to re-thread the valve (not my first choice) or buy a new valve that does fit.  So I opted for the new valve - but it didn't fit well with the mount Sling provided.  A buddy at work is really into 3D printing, so I took the problem to him and he spent a day modeling up and printing a mount that fit perfectly.  I am really happy with that arrangement and I really doubt it'll be a problem - ever.

Mounting the engine mount to the front of the plane involved getting the nose wheel yoke working smoothly.  This was a task in and of itself because the only way to really test it was to assemble the entire setup, test and then back it out if it didn't fit well. It's hard to do this because I want to use bigger more powerful tools to move faster.  The problem with that route is if you take too much material off then you're in a worse spot than if you don't take enough off.  But I do think I struck the right balance in this case.

The next few weeks I have a couple of vacations coming up which will impede my progress for the rest of the month of October - but I think the avionics will be the next thing to go in after the heater.  We'll see.  I do spend a fair amount of time testing fitting stuff and then seeing what goes in next before I make something permanent.  

Ever since Oshkosh I've been keeping super busy working on the plane and less work on the actual documentation work.  This has created a bit of a backlog of work to get caught up on - and these next few videos go back into early July.

As you can see from the first video here I'm still working on finalizing as much of the interior of the fuselage that I can so I can get the side skins on.  The idea was to get all of this done so I could reach in from the side of the airplane than down into the fuselage to do the work.  As you can see from the video I got the side skins on and the firewall attached.  Once those were attached it was on to working on the landing gear.

I did an independent video based on the Beringer wheels and the differences between them and the Matco wheels.  Now it's time to work on getting them together.  Wandering off the beaten path presents it's own unique challenges for building.  Some of them are easy, some of them are hard.  I would chalk the different landing gear being up there on the harder of the items.  To do this I needed to first have a new shim made to match the square one, but this time in rectangle to match the axle for the wheels.  It wouldn't be a big deal except for the fact that shim also had a bevel to it - which I didn't have the tools to make.  So I found a local machinist who has spent his career doing machine work.  He made quick work of these bevels - and they matched perfect.

I had to backfill the open holes for the 1/4" bolts used for the Matco mount with a fiberglass epoxy resin.  This resin is amazingly hard but also easy to work with.  I patched up the open holes to refortify the landing gear structure.  After that I created new holes for the 3/8" bolts for the Beringer wheels.  I also backfilled an open cutout no longer necessary because of how the Beringer wheels attach to the landing gear.

To make matters even a bit more interesting - as you'll see in the pictures and I believe the video the front nose wheel yoke is built for the Matco wheels.  The bolt to hold the Matco wheels on is obviously designed for that wheel - but the Beringer has an axel made for it's wheel - and the Sling supplied bolt is slightly bigger than the opening for the Beringer axel.  This presents a new issue on how to match the two up.  Again - back to the machinist to discuss.  Showing him what I was trying to accomplish with the Beringer Axel, Matco bolt and yoke he understood the engineering problem.  He was able to bore out the Beringer Axel to within 1:1,000th of an inch tolerance to allow for the Matco bolt to pass through the Axel.  There is still a fair amount of material on the Beringer Axel and zero play between the bolt and axel.  So the axel won't spin on the bolt thus causing wear.  

While waiting on the parts and gear to finish up I wrapped up the throttle quadrant.  The problem I ran into was with the mount for the valve I purchased for the breaks.  The factory supplied mount wouldn't fit snugly, so I called up a friend from work who dabbles in 3D printing.  He gladly took it on and created a mount for the brake line which if you ask me is actually more secure than the factory one.  If you're at all interested in going this route, he has the file online at ​https://cults3d.com/en/3d-model/tool/sling-tsi-parking-brake-panel-mount.  

I may be missing a few things in this post, but the videos are most current.  I'm trying to catch up on my documentation to be more current with the end of September (as I'm posting this) - stay tuned for more fun!

This is the progress pics for the Beringer wheels installation.

I generally do my write-up on each months post after I've got the videos done so I have to go back through and review them from time to time.  The distance between when the initial recording started (mid-June) and now is quite a bit to recall.  

The work has continued on the wiring and at this time it's reasonably close to being run and near completion.  I'm not tightening anything down at the moment because I'm sure there will need to be some additional adjustments as I move through the cabin.

I've got the rear fuselage skin cleco'ed into place at this time.  I am going to need to make one more run on the left hand side of the skin to adjust a few more things with the wiring.  I also think I have the ELT antenna sorted out.  I think if there is anything that bugs me a bit is the instructions up to this point are great, but when it gets to wiring, Sling is pretty hands off and expects Midwest to pick up the slack.  They do a great job and everything, but even the plans on that are bit of a "well, however you want to do it"...   At Oshkosh I looked at 3 different low wing TSI's and there were three different ways to do the ELT... anyway - I think I have it sorted out.

Other than the writing - it was back to (wait for it...) you guessed it control tube work.  It still needed a bit of TLC, so I was back at it again.  I think I've got it there now and things move along a lot better.  Of course now I found a few I've probably shaved off a bit much so I'll have to replace those going forward.  That part shouldn't be too hard to resolve as they are the controls on the outside of the control rods.

With the control rods seemingly in good shape I moved onto closing in the sides and getting the firewall installed.  One thing for sure is putting the actual physical structure of the airplane, ribs, skins, etc. is super satisfying.  It feels like you're getting something done.  It's the small stuff that feels like you're not making much progress.  The sad part is I'm pretty close to being done with the big stuff and going to be spending far more time on the minutia.  

I got the main landing gear installed for the most part.  I have to remove one side so I can get the final rivets done which I missed thinking I could sneak them in after the gear was in place.  Oh well, it's an easy fix with the bolts quick to remove and put back in.

​Next up on the schedule is to get the wheels on the airplane and then I can move stuff around a bit easier.  I'm looking for getting the wings tidied up.

I'm finally getting around to doing the written portion of the documentation on the build videos.  Over the course of the  previous month we got the seats built/assembled with only some minor issues needing additional work.  I also spent a big chunk of my time working on the fuel lines and getting them set so they would work with the other finishing pieces.  I had originally intended on having a single line run from the side firewall to the fuel selector position.  That process was proving to be very difficult with the needed bends in the line.  So I switched up things a bit and changed the fuel lines into segments.  This obviously introduces some potential issues where leaks could occur, so I will have to make some conscious effort to test and ensure these joints are sealed.

I received all the avionics this month as well.  The wiring harness, panel, avionics, etc, so it was time to start getting the wiring installed.  Yeah more things to learn how to install!  There are no real solid instructions on how to do these steps, so I hopefully won't wear out my welcome with questions with Midwest.

I had the EAA Chapter 43 Technical Counselor Jim Sutton over again to review my work.  Overall he's been very helpful in making sure my work is on par with where it needs to be.  There's some subjective areas since this is only the second SlingTsi being built here in Colorado and Jim hasn't seen one of these before.  The control rods are especially tricky to get right because you have to remove/install everything to test it, and if it isn't done well enough (ie: not sticky) then you get to do it all over again.

My father-in-law Harold and I got the front and rear seats put together over the past month.  They aren't terribly difficult other than getting the rivnuts lined up correctly so they receive the screws just right.  I'll have some cleanup work to do on those when I get closer to installing them.

I also had to fix/repair a wrinkle in the right rear fuselage skin.  Until starting this project I didn't know you could manage minor wrinkles in metal by "rubbing them out"... I basically found a dent repair kit at a local auto shop which contains some steel "plates", I put down some tape to protect the skin from any sort of deep scratches and then rub out the wrinkle.  If I do it right you can't find/see the wrinkles after that.  It saves some time/expense in getting a new piece of skin in.

Beyond that, all of my focus has been to get as much in the center fuselage of the plane done before putting the side skins on because once those go in I will be working from the top-down vs. the side-in.  The side-in is obviously an easier process.

Next steps as of right now are to finish up the wiring issues, finish securing anything else inside the front fuselage, get the side skins on, the main landing gear on, wheels on the landing gear, firewall so I can get the main nose wheel on and then the wings finished up.  Still lots to do.  With Oshkosh coming up at the end of July I'll lose a few weeks there but hopefully have things moving along quickly here come August.