ADAHRS Platform and Misc Plumbing

Now is the point in the build where you really go off script in the build which is imtimidating because until now I have been following fairly detailed directions.  There will be times when I come back to the directions, like when I attach the wings and do some final assembly, but for the most part, Electrical, Avionics, and Firewall Forward have no details.  This is because the installations vary so much between builders.  There is tons of information available for this part of the project, but it takes along time mainly because you want to be sure of everything before you go.

Today I focused on the platform for the ADAHRS, which is really the brains behind the glass cockpit..  This device will tell me tons of flight information including "Bekah's Attitude" so it needs to be installed on a level platform away from any magnetic materials.  Many builders choose to install it in a similar location as I did.  Here I will have enough room for two ADAHRS if I choose to down the road.

You can also see how I chose to route the Static line..  Eventually both the Pitot and AOA (angle of attack) lines will be routed to this location as well.  I had to split the static line so that I could route it to the ADAHRS as well as forward to the Panel..  I will have a Trutrak Gemini as back up in the panel, which is why I may only go with one ADAHRS.

After working on the static line I went ahead and installed the vents and Scat tube forward of the panel.  This may be temporary as I will probably upgrade to aviation grade tubing down the road, but these came with the kit and are good to have in place for now so I have an idea where they stand so I can run wiring effectively..

Finally, I made some "drift" pins for when it comes time to temporarily mount the wings.  That will happen after thanksgiving, but these guys are ready..  They look a bit rough, so maybe some more buffing before I use them finnaly.  These guys took way longer than I thought to make..  I will have to "sell" them if I ever give them away to another builder..   Just jokes..



Rear Top Skin

The last couple days, Bekah and I took to riveting the rear top skin.  It went well for the most part but did take a couple sessions.   We were able to do it without climing in the tailcone.  I also attached the seatbelt anchors.

Tail Cone Odds and Ends

Bekah and I are about ready to rivet on the rear top skin so am taking care of everything I can in the tail cone to minimize the amount of times I have to crawl around in there.  You'll see, I actually will have to crawl in several times in the future.  This past weekend I was able to run the wire for the tail position and strobe lights.   I am planning on LED lights, so am using a shielded 18 gauge wire with 2 conductors (one for the position and one for the strobe).  The ground is in the shield which works out well and I also ground it to the airframe per the wiring diagram on Aero LEDs.   (My tail strobe will not flash in sync with the wing strobes).  After running the wire I took a crack at lacing the wires together.  This keeps them tight and looks good to boot..  It was my first attempt, but I think I did pretty well.  Also, to keep the CG forward, I am minimizing what goes out to the back of the plane.  The only items I will have out back are the trim servo, lights, and potentially the ELT antenna.  I am going to wait on the ELT though because it will get a separate run which I already have planned out.

I also added some nutplates to the rear bulkhead which will be the attach point for the empennage fairing.  Looking forward, I went ahead and installed these now, lets hope I got them in the most appropriate spot.  I also installed the mounts for the seat belt anchors..  These aren’t torqued because they will need to be adjusted as I rivet the skin, but at least they are in place and I will be able to rivet and torque them all at once when I am laying in the tailcone.   I also drilled out and tapped all the holes for the lower emp fairing..  I was planning on prosealing this one, but I figure might as well follow the plans since it was an easy step to drill out those rivets and tap the holes..

 

Finally, I installed the rudder cable exit Fairings.  These guys look good and since I riveted and prosealed them, they are on for good.   I had wanted to just proseal them, but adding the rivets helped ensure they were compressed tight to the skin.

Basically other than mounting the ELT antenna to the aft deck, working the emp fairing, and rigging everything up, I am complete with the back of the plane..  At least I think so..

Couple sad days for us and work on the Overhead Console

Things have been rocky for the last few days.  First off, Bekah and I have lost our little dog Levi earlier this week.  He was a Cocker Spaniel who was 14.5 years old and outlived all his litter.  We loved him tons, were so sad to lose him, and will remember him always.  He had an awesome life though for a little dog, Bekah took amazing care of him and he saw many sites, traveled near and far, snuck many snacks and chased tons of cats…  So when he got to the age where he couldn't manage anymore, it was difficult for all.   For now we have Libby (Wiener Dog) and Swoop (Mangy Cat) who will still keep us busy into the future.  (note: the cat in photo below is Lucky my sisters old cat)

So understandably things on the plane have been a bit slow, but I have played around with the overhead console and think I have something that we will like.   I used some LEDs and a switch/dimmer in a location where it can be reached from the ground or while in the plane.  This will be wired fused direct to the battery bus and will act like a dome light in any vehicle.  The forward facing lights shine on the pilot and passengers lap, and since dim-able will work as a map light in flight.  The Dimmer is too deep for the roll bar channel as it stands, so I fabbed up some balsa spacers coated with epoxy, painted yellow..  Adds a cool flash of color to the assembly..   Looks great and tested out works great too.

Running the Trim Wire

Now I know how long wiring is going to take..  The last couple nights I have been contemplating and running the trim wire which is really a 5 wire bundle in a single sheath.  Per the pics you can see I haven't terminated it because just running it has been a bit of a challenge.  Many builders make this run in different ways, but I think I have found a reasonable path that will accommodate the tail strobe and position light as well.  I still need to do some tidying up along the route, but in general I think I am going to like this path.  Next I need to determine if I am going to put the ELT antenna run and the Outside Air Temp (OAT) out to the back deck as well.  For now I am leaning towards keeping those runs in the fuse or wings to keep center of gravity as far forward as possible.  Don't mind the string in the photo coming from the conduit under the seats.  That will always be there as I need it for future wire runs.

Rudder Stops

I finally got the pesky rudder stops done..  Second time is a charm I guess in this case.  The first ones I drilled ended up allowing too much swing of the rudder.   Correctly built, the stops should stop the rudder when it is 1 and 1/8th inch from the elevator.   You have to get this pretty darn accurate or else the crimped end of the cable up by the peddle will start hitting the first bulkhead.  I am pretty sure it isn't a good idea to allow that first bulkhead to stop the rudder by hitting the crimp on the cable.

In a recent order from Vans I got the Passenger warning placard..  Check this out, pretty cool hey?  Do you think this will scare anyone off ?

Elevator Trim Tab Wiring

I approached my first bit of wiring on the elevator trim servo.  Most cases in aviation you don’t solder terminals or wire joints..  Where possible you try to use crimp fittings because they handle vibration better.  On the trim servo though it is difficult to work with crimp fittings since it fits into such a small interior space.  Also the wires are really small (#26)  so many people solder them.  I used multiple layers of heat Shrink to dampen the vibration.   I also chose to run the wire through the existing manual trim cable hole on the horizontal stab since I am not going to be using manual trim.  I did however drill an additional hole in the elevator as you can see because the servo actuator moves in and out of the existing hole.   Basically I think I got a pretty elegant solution here and of course it will last 20 years..  ;-)   I will be using a D-Sub connector on the top of the aft deck to connect this to the line that I have yet to run through the fuse.

Continued EMP, Vertical Stab and Rudder Bottom Fairing

This weekend I made tons of progress..  I was able to fully mount the vertical stabilizer as well as the rudder along with running control cables running all the way up to the pedals..   The only part that didn't so so well is  the elevator stops, they will have to be re-worked.  The stops are fairly critical to set up the amount of swing that the rudder can travel so it doesn't hit the elevator, but also almost as importantly so that the cables don't ground out on the forward bulkhead that they go through just before the pedals up in the front.  Anyway, I will need to rework them to make sure the rudder stops 1 and 1/8th inch from the elevators..

Below are some pics of the mounting of the vertical stab.  Note that it is Offset at the tip 1/4 inch from center line, to account for torque and p-factor etc from the prop.  This is intended to allow straight flight with no control inputs during cruise..  Also, you can see that I drilled the 3 main holes that go through the stab and the tails spring holder.  These were critical holes drilled blindly, but I was able to get good edge distance on all of them.

I also went on to working the rudder bottom fairing..  This was a bit tricky because you need to remove some of the top forward part of it to ensure the bottom is high enough to clear the tail spring..  I leveraged some other sites (Mike's RV-7 rudder fairing) for information on this, but think I got it fairly well nailed.  It looks good too.. In my case I wanted it removable so I could maintain the light that will be on the very aft point.   I just need to drill a couple additional holes for wiring and I will be good to go.