Category Archives: Avionics

Sunday Funday

We got a ton done yesterday. The biggest win was getting all the control surfaces balanced. we did the layup on the new balance weights on the ailerons. So those are locked in place with 2 plies of BID. We checked the balance, and they positively balance now. The balance is past the half way point, so I am pretty convinced that we will even be able to paint them (when that time comes) without throwing off the balance.


About the time we were finishing with the layups, Eric surprised us and stopped by to put in a day on wiring. He got to work populating the instrument panel, transferring everything from the plastic template to the aluminum one. Which involved tapping some holes, drilling a few holes on the back side for anti-rotation features on the dimmers, and cleaning paint out of some holes.


I have to say, I am very very happy with how the panel is turning out. I can’t wait to fly behind this thing.



We also found a location to mount the dimmer circuit board and heat sink. It is in the left nose section. With all the components mounted, Eric took to wiring the dimmers up. The left one controls the “Panel” lights which include the rocker switch back lights, a flood light of the instrument panel, and the led lights in the fuel sight gauges. The EFIS dimmer does exactly what it sounds like and is a dedicated dimmer for the screens.


While Eric was working on that Nate spent some time sanding the elevator that was marginally out of balance. He used the contour checking template as a sanding block and spent quite a bit of time taking off primer and some of the top skin glass (which is allowed) to get it in balance. As you can see here, I think we may even be able to paint and maintain balance. Of course it would have to be light paint.



For those of you keeping track at home, that is all 4 balanced flight controls balanced. Took 3 days to do it, but I’m happy. We will have to be careful and shoot an ever so light coat of primer to maintain balance and make them look decent before first flight, but balanced is good. It was quite frustrating at this stage to be spending 3 days on balancing flight controls. For those of you building, do it after every step. The balance rig doesn’t have to be fancy, and it took me literally 4 minutes to set mine up. It is worth it. It will save you from disappointment when you “think” you are getting close.

I worked on the lathe for a good part of the day. In between my parts of all the above projects, I was working on rudder actuation hardware. I made the adjustable rudder stop. Basically a tapped aluminum slug that gets bonded in to the winglet spar that allows for fine adjustment of the rudder closed stop. The screw is a 6-32 for size reference. On the rudder side there is a block of oak that this screw hits that acts as the stop.


The rudder push tube needed a place to be mounted on the rudder side, so I also turned an aluminum slug that holds the bolt that is the rudder side pivot point for the push tube. This also acts as the washer that prevents the rod end bearing from falling apart if the bearing comes out of its housing. To align this with the rudder, we located the max and min height travel of the bell crank on the winglet and transferred that to the rudder. At half deflection we centered the push tube between these lines. This located the position of the aluminum slug. Five minute epoxy in place to be able to acetate and verify that it works, then it was floxed and BID in place.IMG_3667

Note that we decided to turn things around from this photo. We put the aluminum slug in the position where the bearing could be on top of the slug, and the bolt comes in from the top side. This way if the nut fails and falls off, gravity will keep it in position as much as possible.


It is not very easy to see the assembly here, but I will get a better photo.

Dudley and Kevin were in the workshop today too. Kevin spent a ton of time organizing and cleaning for me. He has no idea how much that helped, it was starting to get hard to work in there.



Where have I been hiding?

Garaggio time has been somewhat limited lately. It is less than one week until the application deadline and just over three weeks until the AirVenture Cup, so distractions abound. And that ugly four letter word… work… keeps getting in the way too. But, today I actually got nearly a full day in the workshop.

Oh and I would be remiss to forget that The Garaggio had a visitor last week. Rick Hall, a Cozy builder from Longmont, CO, was in town and came to take a tour of the workshop. We had a good time meeting and talking canard. I enjoyed his visit and hope to go visit his project sometime soon.


Today Greg was here for the majority of the day. We working on our third attempt at baffles. We first bent the aft baffle piece to add a horizontal flange for the rest of the baffle pieces to mount to. The aft cylinder head baffles have to be redone to accommodate the new aft baffle location, so we used the existing ones as templates and cut new pieces.


Then it was cut and fit around the exhaust pipes and intersecting baffles to get them to fit nicely together. Luckily, I still had a template from the last round of baffles that isn’t exactly right, but would give us a starting point for the shape of the bottom perimeter of the aft baffle. Since we changed baffle locations, the aft baffle had to be bigger, but it gave us a shape that we could enlarge by 3/4″ to use as a starting point.


From there it was an exercise in cut and fit. We would install the cowl, mark the interference, remove the cowl, trim, repeat. It took a lot of time sneaking up on the shape, but we finally got it to where bot the top and bottom cowl will fit. The gap is still way too small to allow for engine vibration. I don’t want to trim to final gap until everything is secured and we know nothing is going to move opening up gaps to any larger than they have to be.




Next steps on the baffle will be a little more trimming and then working on securing these pieces together. Hopefully I will have time this week yet to do some of that.

Later in the evening, Eric was here. We have been having an issue with our house AC and since Eric is an electrical genius, he looked at the electrical side of it for me. Our troubleshooting was inconclusive. We will have to wait for the technician to look into it deeper.  When we finally got to the workshop, he got some BNC connectors installed on the antenna wires. We were able to hook up Com 2 and receive the AWOS form Flemming. Kinda fun receiving and listening to something on the radio. There is a humming on the intercom coming from something. We didn’t have time to troubleshoot as it was getting late, but I am sure we will figure it out.


EFIS has a new trick

It got to be a little too late last night by the time I could write a blog post that it was bed time. So here is what we did yesterday.


I was able to get the rest of the fuel and oil hoses fire sleeved. Now everything that carries a flammable liquid is protected. Don’t mind the mess, I have to start tidying things up and securing hoses and wires. Murphy’s Law… If I start securing now, I will figure out a reason I have to pull the engine off… May as well be optimistic soon though.



Brown Santa (UPS Guy) came yesterday and delivered more fittings as well. This meant I could finally finish plumbing for the manifold pressure system. This comes from the induction elbow to a 4 way split where it then goes to the gauge transducer and each P-Mag. The silicone hose is a tight fit on the barb fittings off of the 4 way fitting. It certainly won’t pull off, I just hope it isn’t enough stress to crack the hose. It is a non-event if the hose does break. The ignitions then work as traditional mags and the manifold pressure indication is lost. Neither thing being mission critical. For now I am just planning on keeping an eye on it and seeing how it ages.


Lastly, I was able to get the bleed air system plumbed. I know, most people are probably saying what is a bleed air system and why is it necessary. The short answer is it isn’t yet, though doesn’t hurt either. What it does is give an induction air pressure reference to the injectors. Turbocharged airplanes often require this since the induction air pressure is much different than the ambient pressure in the cowl. James Redmon has this system installed in his airplane because he is running cRAM air. I plan on eventually experimenting with different induction setups, so this may become necessary in the future. Airflow performance also recommends it for anyone operating in a dusty/dirty environment as it keeps all air going to the fuel injectors filtered.


As far as I can tell that should complete all of the plumbing in the engine compartment. Onward.

The other task that I did was make up the nut plate washers that get bonded onto the F22 bulkhead for canard attachment. There is no convenient way of getting at the bolt and nut single handedly, so this is what the plans uses so that removing the canard can be a solo activity. I have to bond them in yet, and didn’t yesterday since Eric was here and we were working on wiring.


Eric got the ELT wired up, we can check that one off the list. Boy am I glad that I have an experienced steady hand at soldiering here to help. This DIN connector that the ELT uses is tiny. To land all the wires on it in the proper locations with strong soldier joints is important and actually had to be disassembled and reassembled once to correct a jumper. Can’t thank Eric enough.


Lastly, Eric worked on the discrete inputs to the Garmin G3X. These are a canopy unlatched sensor and a landing gear position sensor. We are still working out the details on the canopy switch installation, but the landing gear comes with a switch already installed, all we had to do was run two wires.

Now the EFIS knows if the gear is down or not. The EFIS gives 3 high/low warning tones through the pilot’s headset and also flashes a red “Check Gear” under the altimeter if the landing gear is not down and other conditions are met. Basically those conditions mean that you are in the landing phase of flight. The other conditions can be if the airspeed is below a certain value, altitude below a certain value, etc. I will have to check to see how they are currently set and evaluate if I need any changes. But for right now, it is working, see for yourself.

Update: I forgot, Eric also got the pitch trim position sensor wired up. We need to rig it to the pitch trim yet, but the sensor works.

Home again, Home again, gigity goo!

Made it home from work today, and still managed to get into the Garaggio. My plan was to put micro filler on the cowl repairs. And I did.


But that wasn’t all. While I was at work this week, I started making a list of the things that still need to get done. So I chose a few of those items on the list that were pretty quick to do tonight as well. That included drilling out the static port openings, lower left of photo.


As well as plumbing the pitot and static sources to the Garmin AHRS.


Here is the pitot tube connection.


And the Static port connection.


While I was working in the area, I bolted down the GTN650 antenna as well. Four things to check off the to-do list.  Maybe we can check off a few more tomorrow.

Comb the Desert

It seems as though I am in an every other work day blog post cadence right now. I just didn’t have anything left by the time I got done last night (this morning) to write a blog post, so I will combine yesterday and today.

The major task for the last 2 or 3 work sessions has been tidying up the electrical install and combing wires… which leads me to one of my favorite scenes from Spaceballs… “Comb the desert!”


In seriousness, ‘comb the wires’ is an effort to make things look nicer, free up space, and make them easier to maintain. It has been a lot of work, mostly for Eric. I know he was reticent and not looking forward to cleaning up our installation. However, It is absolutely amazing how much room it seems we have now that the wires are all fastened in specific wire routings and bundles. This helps when needing access to connectors, chasing wiring, installing or removing components. The payoff will be in the years to come. But I could tell Eric was glad he went through the effort and saw the value in doing it. Here are some views of the wire routings and bundles all combed, and fastened. These photos don’t show the cleaned up relay pack wiring, but let me tell you, it looks awesome. (As it should after 3 entire work sessions.)



I should have taken some photos of the rest of the wiring coming off the avionics bay back toward the sticks as they look great too… I will try to do that for tomorrow’s update.

While we were working on tidying up the wires, we disassembled the avionics stack and put the transponder into the tray and wired the antenna. This is an RG400 coaxial cable and we wanted to run the antenna wire because if you accidentally power up the transponder without an antenna, you can do damage to the electronics. So we decided on a location for the antenna, which will be on the sidewall of the rear seat fuselage, low just behind the forward seat back. Another antenna done. Just need to bond it to the airplane.


The location for the throttle friction lock changed after all of the monkeying around with the throttle lever we had to do over the last few weeks. So a change to the pilot left side console was necessary. Plug a hole, add a new one. Love composites when you have to make a fix like that. Glob in some micro, sand smooth, done.


Somewhere along the way yesterday, we realized that we potentially had made some mistakes running wires. Important safety note, if you are wiring an airplane, make sure you are using an up to date wiring diagram when adding wires to harnesses. Weeks ago, we had made some changes to the configuration of the VPX software regarding which circuits were controlling which devices. However, we failed to transfer that new configuration to the Vertical Power online wiring diagram documentation. So when we used the online documentation to add circuits to the airplane a few days ago, we could have made a major mistake. Hooking up the laptop to the VPX gave us the information we needed. Turns out, we only had a few wires going to the wrong pins, but it could have been disastrous. Note to self, keep all documents up to date, or better yet, only use one source as a working document.


With the majority of wire combing behind us, Eric started in on new tasks for the wiring today. The big one was wiring up the rocker switches with permanent wiring. There are two circuits per switch. One is for the LED back lighting, and the second if for the switch function. With the VPX, all the switch does is provide a ground to the VPX to tell the computer to turn on a particular device. As such, the wiring is pretty simple, a daisy chain of grounds to one side of the switch which then goes to an input pin on the VPX. The daisy chain is grounded on both ends of the switch row so that if any one wire connection fails, all switches still work. These switches need to be engraved yet, but for the most part, the panel switch installation is complete.



Oh, and one benefit of accidentally breaking the plastic instrument panel proof, is that it makes a good wiring jig so that the switch wiring could all be done at the relative comfort of a workbench. That is until you forget to land a wire in the switch grouping and have to work on your head…


Greg was also here today, and he and I worked mostly on baffle and cowl fitting type stuff. We trimmed many baffle parts including the exhaust brackets.



As part of this, we put on the cowl a few times, and determined that we needed to shave down our throttle and mixture cable mount bracket. You can just barely see the hole where the lower cable used to pass through the bracket. We will have to add a new hole to retain the cable. But now the cowl will fit with ample clearance on the bracket.


In the process of installing the cowl a few times, we also located some interference on the exhaust system. We need more clearance on 3 of the 4 pipes. It will require modifying the cowl again. We have extra thickness there, but probably not enough, so we will have to change the exterior contour. But we have a plan, and it should all work out just fine.


Another thing we did was start to fasten the fiberglass pieces to the aluminum baffles. Here you can see the cylinder fin baffles cleco-ed to the aft baffle. All I need to do is drill to final size and add some nut plates. Have I said how much I hate baffles and how happy I will be when they are done? Once they are done, I can start going through and securing hoses and wires, working towards engine start.

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I saved the best two photos in the last 2 days for last. We had company over today, So we had to get everything looking presentable for our after dinner show and tell. It is always nice to see things cleaned up and operational. I can’t wait until the interior is painted. I think it will look great!

3 more days off, so hopefully we make a bit more progress… lots of little details to sort out.

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Lets Catch Up

The last two work sessions I didn’t get to writing a blog about, so lets catch up on what was done since the last post. Most of the work was electrical and Eric was here both days. Lets start with this past Sunday.

First thing was making a heat sink for the dimmers for the interior lighting and EFIS. Eric had some sitting around the house, so we made an assembly with the dimmer circuit and the heat sinks. We will wire it and see how hot it gets, but there should be enough mass here to keep it reasonable temperatures. Then it will be bonded to the top of the NB, where the nose tire retracts between my legs.



Next, we were working on the avionics on the forward shelf and decided we needed to clean up some of the wiring. One step toward that was shortening the antenna leads for the G3X GPS antennas. So Eric clipped the wires and put new ends on. This sounds pretty simple, but working with these shields and conductors that are this tiny is certainly a challenge.



Additionally we spent some time working on verifying the wiring diagram for the ignition and I disassembled part of the instrument panel to send some parts off to John of Laser Logic so that he can make the final aluminum instrument panel.

I think that mostly brings us to yesterday. Before Eric got here, I was able to get the last and final fuel line bent and installed. This for the most part completes the fuel distribution system with the exception of torquing everything down, fire sleeve, and securing hoses and standoffs. Feels good to say that. Additionally, note the bleed air rails are installed to the injectors.


When Eric got here, he got all the remaining connections done on the ignition connector. Then worked his way forward to the switches.


There are a few more connections to make on the switches, but all the wires are routed.


While we were doing that, we got sidetracked into cleaning up more of the wire routings and bundles. This included having to install a larger forest of tabs for the ground block. Luckily we had planned ahead and had plenty of room for it. It is amazing how many grounds there are. Everything is getting labeled so that we can tell what it is.


While we had connectors unplugged and were routing wires, we also installed any remaining pins into the VPX connectors. This allowed us to neatly route the wires into their bundles and then run the wires off in the direction they would eventually need to be. These circuits we added were for things like the strobe lights, nav lights, landing lights, fuel pump, etc. Until we figure out what we are forgetting, all the required power distribution wires are added into the VPX harnesses. We still need to wire the switches to the VPX.


In between helping Eric with wiring tasks, I also added some phenolic plates with nut plates on them. These will be the mounts for the seat heater relay and the electronics module for the fuel pump.


Devil is in the details so they say… and there are lots of them. Check back later for checking off more details.

Idle – WOT – ICO – Rich

Today I started where I left off yesterday, on the throttle issue. I started by verifying our trig from yesterday for the slave tube between the front and rear throttles. While I was doing that, I realized that I have two problems I am working and I had better work them in the right order.

The fact that I couldn’t get the front throttle to rig exactly how I wanted it was most important. The problem there was that I could get the throttle to positively make contact on the idle stop, or the wide open throttle (WOT) stop. But not both. If I pushed on the FI servo arms, it made contact, but the lash in the cable was enough to allow it to back off. There was about a .050″ gap on either end depending on rigging. While it is acceptable to positively hit idle, and have a small gap at WOT, I wanted positive contact on both stops.

The only way for me to correct this was to increase the lever arm from the pivot to the attach point for the cable. With all of these things in play, I ended up making a new throttle lever. The plan was to make a new throttle lever blank much longer than it needed to be (Thanks James) and start by drilling holes. The longer lever would give me multiple shots to get it right without having to start from scratch. To start with, I moved the pivot hole up the lever about 1/2 diameter or ..625 inches. I reinstalled and tested. It wasn’t enough.

So I tried a little bit further. It was too much. Turns out that right in the middle of attempt 1 and attempt 2 was the sweet spot. Positive contact on both idle and WOT. It still had about 1/16″+ of over travel on both ends of the lever. Perfect. But, there wasn’t enough edge distance anymore to make it an airworthy part. But it was a good template. So I continued.

Next I drilled a series of holes in the front throttle to test for the slave tube between the front and rear throttles. When I reassembled, I was able to determine which one worked. Armed with a “swiss cheese” template. I now could make yet another throttle arm. It is kind of a shotgun method… just need to keep track of which holes worked.


After transferring this to a new piece of metal, I checked again. Everything still worked, So I went ahead and attached my handles and the saga of the throttle lever is conquered. Incidentally, the mixture has been flawless all along. ICO and Rich stops are positively contacted without need for further adjustment. I didn’t get a photo of it fully assembled, but here it is before I added the handle.


By this time, Eric had come by to do some work on wiring. We were going to work on the dimmers for the interior LED lighting, but true to form, my organization (lack there of) reared its ugly head. We couldn’t find the connectors we needed. So we switched gears to engine sensors. Eric was a machine. He was able to get ALL of the engine sensors wired. That is all of the EGT, all of the CHT, the fuel flow, and oil temperature transducers wired. In addition he has gotten a start on the Tachometer pickup from the P-Mag. The routings have been set, but in these photos we have not secured the bundles. I am anticipating one more time of removing the engine from the airplane, and we will more than likely end up having to disconnect the connectors. So no need to secure them right now. The bundles look nice when they are secured, but you will have to wait to see the beauty of this until a bit later.




While he was working on that, I was able to do some wiring too. Or at least wire routing. I started on the alternator wiring. The alternator comes with a pre-wired connector for the field wire. So I routed that up to the VPX. The wire was a bit short of what it needed to be, but we needed to transition to the VPX style connector anyway. So Eric got the soldiering iron out and spliced the wires. Field wire is installed. I also planned on running the big wire to carry the alternator output, but I need to order the right size ring terminals.

By this time it was the end of the night so we had to do one more thing. Turn the EFIS on and see the indications. All of the temperature probes were showing indications. The EGT and CHTs were between 60 and 63. The oil temperature probe was showing 70, which was very close to ambient temperature. I would guess the variance is due to the sensing ranges of the probes. The EGT and CHTs operate in the 1100-1400 and 330-450 range respectively. They may not be accurate at such low temperatures.


Throughout the day, I was thinking about tasks remaining before engine start. Specifically some of the wiring tasks, so I made a list. I am hoping this will help me get some organization in finding parts I have and ordering things I need. Today we got to cross three of them off and get started on a few more. Plenty more to do, but the lists are shrinking to a more manageable size.


There are plenty of engine tasks remaining, I just didn’t start writing the down yet. Hopefully scheduling leaves me alone tomorrow and we can knock off a few more things.