Sunday, May 31, 2020

Wiring Harness part 2 & Panel comes together

The wiring harness is slowly coming together.  All of the wires that will be installed outside of the airplane are in, all connectors that do not have to be run through a bulkhead are installed, and its about ready to be installed.

Some lessons learned for the next time I have to do this.

  • Use 22 awg wire for all shielded applications.  24 awg is a bit small and seems to make fragile connectors and anything larger than 20 awg is just too big for the HD pins.
  • When installing shrink wrap labels make sure they are far enough up the wire that they wont need to be cut to install shield drains.  This is particularly important for wires with the "window" type shield drain like the CAN bus splices.

More wires laid down.  At this point I was thinking I was mostly done....and then the work started.

My flying friend Ben stopped by and took this picture of me working on the connectors.  I started from the bottom of the picture and was working my way up.  The GMA (Audio Panel) connectors were next on the list and by far the most time consuming.  Those connectors had many many wires and almost all of them were shielded wires that had to be grounded to the back-shell of each connector.

Finally all of the avionics connectors are installed and all that is left is the ground wire terminals and the VPX connectors.

I drilled and mounted the center console and that allowed me to finally locate the fuel valve extension handle.

Panel, lower center panel, and the center console installed.  Also in this picture you can see the avionics rack and all but the GNC255 radio tray installed.

Panel inserts are placed in the frame for test fitting.  I think this is going to work well!

Front view of panel with inserts.  Its a little easier to see the engraving in this picture.

Saturday, May 9, 2020

Front windshield install

I ran out of some of the wire I needed and it has been really nice out lately so I moved my work efforts back out into the garage.  I've been busy installing the windshield using the Silpruf method along the top and side edges and then using the traditional fiberglass fairing on the front.  I know I've mentioned it in the past but I really like the Silpruf method.  The install looks so darn professional!

I didn't add a bunch of pictures of the process since I have already documented that pretty completely.  Here is a picture of the windshield after the Silpruf install.

It looks like carbon fiber but its not.  This is several layers of regular fiberglass that has been tinted black.  This allows the inside view to be a consistent black trim all around the windshield.  
Right side with fiberglass layers.

After a little epoxy with micro balloons and some sanding... ok, lots of sanding.

Final sanding complete.  Now all I have to do is remove the orange tape and wait for paint day.

I moved the primary voltage regulator from behind the sub panel in the middle bay to this location.  I was looking in this access hole recently and realized I had the perfect location to install the voltage regulator right here.  Easy access for future maintenance.

Friday, May 8, 2020

CNC Panel work

I mentioned a while ago that I had upgraded my CNC a bit and one of the tasks I have been working on in the past week or so has been the design and cut of my instrument panel inserts.  I used carbon fiber on the 9A but since the frame is all carbon fiber I decided to try something new.  The inserts are .064 aluminum and rather than color them with paint or something I decided to try to go with the brushed aluminum look.  The idea is that I "brush" the aluminum to a consistent smooth sheen and then clear coat it for protection.  So far I like the results.

I also decided to try my hand at engraving with the CNC.  Theoretically it should work great but in practice it didn't start out so good as you will see in the pictures below.  Just for future reference the settings I used for the CNC are 6 IPM at .01 depth for the engraving.  The depth number was a bit arbitrary since its really hard to set it exactly.  What I ended up doing was to run the depth at .01 and then run the job a second time after lowering the Z0 setting by an appropriate amount to get the letter width I wanted.

This was my first real attempt at engraving.  As you can see the letters look horrible!  This was done at a speed of about 22 inches per minute.  Most of the literature I have read talks about engraving at much higher speeds so I thought I was being conservative.  After watching my little home built CNC jump and jiggle during this process I decided to slow it down to about 4 inches per minute.

This is what 4"/ minute looked like.  MUUUUCH better.  But notice that the top engraving is not as deep and in fact the lines disappear on the right side.  Well, my CNC was not perfectly flat nor was the aluminum panel held down consistently.  Next I went through a "leveling" process for my CNC bed, and then I paid a bit more attention to how the aluminum was held down to try to keep it consistent.  The next two pictures are the final result.  

Almost perfect (or at least as perfect as I can get it).  There are a couple of defects in this engraving but they were directly related to me missing a step when I changed out the router bit from an engraving bit to the cutting bit.  The process for cutting this type of panel is to first do the engraving, then change the bit and cut the interior cuts (holes and interior openings).  Finally I cut the exterior as the last step.  In this case I forgot to reset the Z axis depth when I changed out the bit and if you look closely at the Mixture hole you will see the result.  The CNC dutifully plunged into the aluminum and went all the way through.  The system is not rigid enough to take this type of torque and as such the X and Y axis' were skewed slightly.  The hole became slightly elongated and then the remaining cuts were just slightly off center from the engraving.  I ended up redoing this one as you can see in the picture below.

Much better. 

This is the one that I was most happy with.  The engraving looks professional and even the color fill process I went through to fill the engraving went well.  I followed up the color fill with a bit of brushing to see what the final look would be.  I'm pretty happy so far but the final verdict will occur after I do some clear coating of the brushed aluminum.

Just because the engraving was going so well I decided to put the pilot side panel back on the CNC and see if I could get the engraving done on it.  I'm very happy with how this came out!  I did add a little enamel color to the cuts but I will likely add a bit more as it doesn't show up as dark as I wanted it.

Wednesday, May 6, 2020

Wiring harness - Part 1

I finished up the tail feather work (mostly the fairings) and started on a few other tasks.  Mostly my time has been spent working on the wiring harness for the avionics.  This is one task I had done by SteinAir on the 9A and was looking forward to on the 10.  I've got waaaay too many hours in design and now the beginning of fabrication but so far I am enjoying the heck out of the project.

I started out by installing a few of the sub-panel parts as well as the VPX Pro and associated fuse panels.

Then I did a little measuring for lengths of wire runs.

A little more measuring..

A few photo's for connector orientation...

Then I took a piece of 1/4" plywood I had laying around and started laying out some wire runs.  I used Velcro loops and tape to get the basic layout.  Then I started with the power wires.  Here you can see most, but not all, power wires being run.

Here we are with most of the red power wires, most of the black ground wires, and a few of the white data runs.  Still no connectors and not even all of the data runs yet.