Cowl (2)

I just had a few minutes of plane time today.  I riveted the left lower cowl side hinge to the firewall.  The left side was quick and easy, but as is always the case, the right side had issues, so I didn't get it done.  The hinge has to slide all of the way back against the firewall in order to have okay rivet edge distance.  That was easy on the left side, but on the right side of the firewall, I had butted the fiberfrax insulation and stainless sheet right up against the firewall flange.  That adds an extra 1/8" of material to the firewall and keeps the hinge from sliding back all of the way to the actual firewall. I hadn't given that a second thought when I was laying out the insulation.  I figured making it fit nice and snug where I could was a good thing!  Nope.  I should have left 1/8-1/4" of space around the whole perimeter to leave room for the hinge.  I'm going to have to pull the insulation away near the flange to make room for the hinge.

Cowl (1)

As seems to be the norm lately, my latest shipment is delayed, so I can't finish the canopy yet.  So back to the cowls I guess! In order to fit the cowls, I need them to be accurately located from the back of the prop spinner.  With the Sensenich, the spinner is placed 2 1/4" in front of the starter ring gear.  That means I either need to fabricate a spacer that sets the spinner in the right place, or I have to wait for the actual spacer to arrive with the propeller (probably another month+ out).  If my canopy adhesive stuff gets her soon, I may just keep working on that and wait for the prop to arrive.  If those delays get longer and longer, I'll make a spacer so I can keep working on the cowls.

I put the front top skin back on.  It will need to be in place to fit the top cowl.

I threw the top cowl on to see what it looks like.  It'll have to slide aft a bit and be trimmed - that's the part I can't do without knowing where the front goes relative to the prop spinner.

It looks like I can get the hinges for the bottom cowl sides riveted on, even without the rest of the cowl fit.  I chopped down the left hinge to fit along the flat portion of the firewall.  It can only go up as high as where the horizontal split between the top and bottom cowl will fall.  I got pulled away before I could match drill it all.  That's for tomorrow.

ADAHRS

I have to travel for work this week, but I got a few hours in today before heading to the airport.  I've been putting off climbing into the tailcone again to work on the ADAHRS stuff.  The shelf was installed, but the unit itself wasn't bolted to it.  In hindsight, I would have modified the standard ADAHRS shelf and moved it an inch forward to make it easier to install all of the wiring.  The plans have it butting up against the bulkhead, which means there's about 1/4" of space between the back of the D-sub connector and the bulkhead (after the wiring is cranked to a 90 degree angle).  A little more room to work would have been wonderful.  Oh well.

Climbing back into the tailcone was a job in itself.  Getting under the seat brace is easier said than done!  Of course once I was in, I realized there was more work to do than I thought, so I had to do the contortion a few times.  I gave in and removed the elevator pushrod to give myself more room to lay down.

All I really had to do was put 4 little brass bolts and nuts (non-magnetic) in to hold the ADAHRS unit in place.  With barely any room to get my fingers on top of the shelf to hold the nuts, that took a while though.  I wrapped the 90 degree bend of the wiring with plastic spiral wrap and tape to protect it from the shelf, but I'm still not all that happy with how it's setting.  I think I may need to pull some slack into the wire to allow it to bend away from the shelf a little more.  That sounds simple, but of course I tightened all of my wiring down a while back thinking I was done.  I have a service loop at the instrument panel, but I'll probably have to undo the majority of zip ties to pull some slack all of the way to the back.  I'll mull it over and see.  It might just be easier to put some better protection on the wire at the shelf vs undo everything just for one more inch of slack.

Canopy Prep (2)

More and more canopy prep today!  There's not much to show, but I put the canopy on (again...) to do a few more layout lines for the masking tape.  I also massaged the frame to split the fit difference between the sides.  I'm relatively happy with where I got it.  The reality is it's just never going to be a perfect fit.  I think it's good enough that I can use fiberglass to extend the side skirts over the fuselage side skins and make it look pretty good though.

With the frame on, I finished taping around the entire perimeter.  I also finished up the last of the taping on the canopy itself.  The last thing to do was to scuff off the primer and paint anywhere the Sika primer will go.  I put popsicle sticks on the roll bar so that the canopy will set about 1/16" above the frame.  This will allow the Sika to form a bead and fill any uneven areas vs just having the canopy set flat against the frame and potentially have areas where there isn't great contact.  With that, I THINK I'm ready to glue the canopy down, as nerve wracking as that is.  It'll be a multi-day process.

Canopy Prep & Engine Control Cable Brackets

Van's throttle and mixture cable brackets won't work with the Airflow Performance throttle body on my engine.  I found out that as of 6 months ago, Van's is actually now selling all engines with this same throttle body, so I emailed them to ask if they have a new bracket available now.  Unfortunately, they said their engineers haven't had a chance to design a new bracket yet.  I was hoping to get away with a cheaper solution, but in the end had to go to Airflow Performance and buy their brackets.  They are not just gold anodized, but must actually be made of solid gold given the price!  The kit comes with a new plate that sets on top of the throttle body, then two brackets that bolt on the aft sides.  The cable brackets themselves will be drilled to the large aluminum sides.  I put the whole setup onto the engine to see where things fit - it's going to be really tight with the new elastomer landing gear.  That takes up a lot of room that I don't think this bracket was originally designed for.  I'll be able to make it work, but it's going to take some thinking.  I don't have the cables in-hand yet, because I was waiting to order them until I knew what the routing through the firewall will be.  It's a chicken or the egg problem.  Like most things these days, I set it aside and moved on to something else so I could mull over it for a bit.

Back to the canopy - I used the plexi edge scraper to smooth out the edges that I cut the other day then put the canopy on for the 300th time to check the fit.  I think it's where it needs to be in terms of shape.  The next step is to try to mark out where the Sika primer needs to be laid down on the canopy.  It's easier said than done to get inside to mark where the sides meet the frame (so I know where to tape off a line for the primer).  Instead I drew a line on the outside of the canopy at the level of the side skin.  For the aft edge, I went with a measurement taken off the roll bar.  For the front, I'm going to put about an inch high strip of the primer.  The adhesive itself will probably only go up 1/4" or so, but the primer is black and by extending it up an inch it'll help hide the fiberglass fairing that will be on the outside.

Once I had the lines laid out, I pulled the canopy back off and used electrical tape to mask off the areas.  When I'm ready to actually use the adhesive, I'll scuff and prep the edges with the Sika activator, put the primer on and cross my fingers I got it all laid out correctly.

When the canopy was on, I had drawn a line indicating where the front edge was on the glare shield.  I taped off an area about 5/8" wide and sanded off the primer and paint to get down to bare aluminum.  I'll cheat the bead of Sika towards the rear line.  Once the canopy is in place I will put additional adhesive down on the front side to fill in the gap created by where the 90 degree edge of the plexi sets on the skin.  That front area doesn't have to be exact.  It'll all ultimately be covered with fiberglass.

Canopy Fitting

More canopy fitting.  I think I had it off and on at least a dozen times today.  The transition point from the front to the sides was hitting the frame skin and causing the sides to spread out, so I took another 1/4" off of the canopy right where the ear of the skin is.  I also notched the skin out more so the canopy could set down in the notch without binding up (this area will be covered with fiberglass eventually, so there's no need for an exact fit).  I also used a round dowel and hammered in a little divot into the forward edge of the notched skin.  This allowed the canopy to nest down into the area better.

After I had the front as good as I think it can get, I clecoed the side skirt on to see what it did to the shape of the canopy.  I wouldn't say it's a perfect fit, but pretty good overall.

I took the canopy off a "final" time and trimmed the glare shield paper to match the curve of the canopy.  I'll use this as my template for scuffing the glare shield for the Sika.