Certificate of Registration

Yesterday was a good day - received the Certificate of Registration for C-GVSW.

I submitted all the paperwork on Sun, Feb 11, and received the CofR on Tue, Mar 12.  Usual turn around time is ~2 months.  But the real win is they accepted all the paperwork first time!

I had heard horror stories about this, but it all went pretty smooth.

It's now a REAL airplane!  But in pieces... but not for long!

Boost Controller Relocation

The 'only' (current) Sportsman flying with the UL Power 520T had an issue come up approx a year ago where the boost / manifold pressure would fluctuate.  I was fortunate enough to be around and help him troubleshoot this, and more importantly understand how the system works better.

The Turbo is powered by the exhaust (obviously)... But the amount of exhaust gas that hits the turbo is regulated by the waste gate, which is essentially a valve.  There is a spring in the waste gate that 'normally' regulates when the valve opens to start releasing pressure as to not overboost the engine.  The standard spring will fully open the valve at 3" HG above ambient which is about 6 PSI.

Enter the Boost Controller... The Boost Controller 'fools' the spring on the waste gate to allow turbo to spin faster and deliver higher than 3" HG / 6PSI to the intake.  There is a pressure sensor on the ECU in the cockpit, determines what the Boost Controller needs to do.

Below is from the UL manual... and shows the connections.

The boost controller is essentially another valve.  It connects the pressure of the intake manifold and the waste gate.  When the Boost Controller is allowing the turbo to spool up, ONLY those two lines are connected.  The 3rd port on the Boost Controller is a vent.  When an overboost situation is coming (IE Full Throttle) the Boost Controller vents the pressure from the intake manifold to let Waste Gate open up and drop the speed of the turbo.

The target pressure max manifold pressure is 39.5" HG, or roughly 20 lbs of boost.

In the case of the 'other' Sportman...

• The problem just started on day.  Nothing had changed (IE ECU firmware) that would have precipitated the issue.
• At full throttle / boost, the engine would start surging... 1 to 2" HG surge.  Pulling the throttle back would stop the surging.
• Disconnecting the Boost Controller would stop the problem.  However, now you are limited to about 33" HG of manifold pressure.  The turbo is not working to its intended potential, but no surging.
• Many troubleshooting steps were taken.  
• UL sent a new boost controller, as well as a new ECU with special firmware.  They changed to update rate on the boost controller from 30 Hz to 10 Hz.  This did change the problem and make it not as noticable, and the surging delta of inHG was less, but the problem remained.
• The eventual solution... move the boost controller.  In this install, the Boost Controller was installed low on the pilots side of the firewall.  The pressure lines went up to the top of the engine for the intake, and to the waste gate.  The theory is they were too long.  Relocating the boost controller completely corrected the issue.  The original ECU and Boost Controller were reinstalled.

So after all that... I am moving the Boost Controller.  I installed the Boost Controller on the cold side of the firewall, right beside the ECU.  The manual actual says to have it in a vibration free location, and I wanted both the red boxes beside each other.  Oh well...

Not the fanciest bracket, but it should work.  It's now very close to the intake manifold and waste gate.  The problem is I have to extract the harness from the cockpit bundles and fish it through the firewall and dress it in.  There are a lot of cable ties to cut...

Bulkhead A Cover

 Had both the glaresheild and bulkhead A cover upholstered at the same time.

The upholsterer recommended padding it with 1/4" foam, so went with that.

The material was damaged by a previous embroidery attempt where 'EXPERIMENTAL' was not lined up with the Sportsman logo.  Whoever did it just picked out the thread and redid it.  You cant see it unless you get right up beside it.  I emailed Glasair to let them know, and was completely shocked when I did not get a response :-)

Windows - Part II

While the pilots side top deck window is trying (and the cowl), figured I would start on the next window.

What I learned from the first window:

1. Put in more silpruf.  I believe there is enough in the first top deck window, but I didnt get the squeeze out I was expecting. But I did get squeeze out around the entire perimeter - just not as much as Zach in the videos.
2. Wet erase pens are truly disposable.  When they get to fat, chuck em (or use the for something other than windows)
3. Review the instructions.  I made some simple mistakes on the first one
4. Take your time with the taping.  When doing a more than 90 degree corner, it really wants to lift.
5. Lock the window in place with wing nut clecos in the corners FIRST - not later.
6. Take your time with the trimming.  I did OK on the first one.  The angle grinder with the disk is so much faster.
7. The double tape line on the bottom of the window is critical for a nice aesthetic appearance.  Make sure it is truly stuck down, and the overlaps are correct.  I had one portion shift, and tried to retape tape #2.  Its not horrible, but not perfect.
8. When you mark the tape line on the joggle, you get wet erase marker on the edge of the window.  DON'T FORGET TO CLEAN IT OFF.
9. When 'smoothing' out the inside of the window, make DOUBLY sure that you cover the gap between tape #1 and #2 with silpruf.  Also, when smoothing out between the window and the window frame make sure it is packed with silpruf.
10. Get more than qty 20 #40 wing nut clecos.  If you are going to do multiple windows at once, you need more.  30 would be good.  The pattern I have fallen into is do a window, and while it is curing move onto the next.  Once I got to window #5 I could have a window trimmed and clecoed in less than and hour.  Sanding and taping is probably a good 2 hours.
11. When removing the tape from the gap between the window and outer window frame, I started running a razor blade along the window edge to make sure that any silpruf that you didnt squeege out is cut away from the window.  THEN, pull the tape from the door / fuselage TOWARDS THE window.  In fact, on # 4 I pulled up all the outer tape around the entire permiter first, and then just did the last 1/4".  There was virtually nothing left in the gap between the window and frame.
12. Take extra time when taping the inside of the fuselage / door, and make sure that the edge is sanded well and there is no paint residue on the edges.  This will help the pen ride better, and gives you a better edge to tape / cut against.

Co-pilot side top deck window trimmed and corner clecos in place.

Working on starboard aft fuselage window.  This one is curved, and much trickier to fit.  I started off leaving the goop on top of the window, thinking it would protect it.  Just makes it harder to see the joggle.

First window (pilot's side top deck) out of clecos and seems to be fine.

2nd top deck window bonded and drying

Finished.

First side window - aft fuselage rear window.

This one was a pain.  I think it took about 8 or 9 passes to get this to fit in the goggle.

As our weather is getting cooler, going to do both of the rear windows in one shot when bonding as I have to keep the shop heated for a couple days.

Starboard aft window fit, taped, sanded, standoffs in and drying.  Once the standoffs are trimmed, ready for the beautification layer.

All bonded in...

And with tape / clecos removed...

Its not bad... There are a couple areas where the silpruf is a bit thin.  I maybe think I can maybe fix it (without making it worse), maybe.  The lesson learned here... when the window goes in and you are 'smoothing' out the silpruf on the inside, pay attention to fill in the ~1/16th gap between where tape #1 was, and where tape #2 is.  That is where I am thin.  I did a much better job on this on the first door, because it was not mounted and I could see the gap (and I knew to look for it).  Hopefully that one turns out much better.

First door window (rear window).  This one fits fairly well out of the box.

The goop on the window would not come off easily this time... so opted to take it all off (which was far easier) and retape the center to keep down on potential scratches.  There is still the goop on the edges of the window which should come off easily with a bit of sand paper or razor blade.

The trimming and drilling went really fast on this one as it fit into the joggle right away.  3 passes, and its good.  Edges sanded, clecoed in.

1.5 windows ago, I switched from a random orbital sander to a angle grinder with a hook/loop pad.  Way, way, way faster... but scarier as the material comes off way faster.  Just need to go slow (but its still 4X faster than an air powered random orbital sander).  Was looking for a hook and loop pad, and most of the ones I found were RPM limited.  This one on Amazon canada is aluminum and is good for 9000 RPM.  Using a Ryobi cordless angle grinder.

All taped and ready.

Same for the door, taped front and back.  Standoffs are next.

Now the 2+ day wait to see how it turns out.  It is very nice to be able to flip the door over to work on both sides with lots of light.

Detaped.  Best one yet!

Onto the front door windows.

So after doing 4 already, the windows certainly go faster.  Trimming to fit to clecoed in probably 30 to 45 min.

And I don't think I did something different, but on the aft fuselage window and aft door window, the drill / cleco punctured the inner skin / paint.  That did not happen on the front door, which I am VERY thankful for.  Less filling / repainting.

#6 ready for tape

I am all geared up to attempt to bond in both front windows one after the other.  Everything is trimmed, fit, sanded, taped, cosmetic layer applied, etc.  Just need to apply the silpruf, cleco it in, and do all the steps required beyond that.  Will see if I am crazy or not.  Its actually not as bad as it sounds as I have 4 or 5 hours between them based on the silpruf cosmetic layer application... but will still be the same day.

Well, got them done.  Now to wait 2 or 3 days to see how good / bad they are.

They are in the house so I dont have to heat the shop.  Shhh.... dont tell my wife.  But in reality they do not smell at all.

All done.  On to the front window.

Glareshield Part II

 The cowling is in full swing, and working on FWF stuff.  I did the glareshield in Nov 2022, but there were a couple things that needed work.

1. It is really tight to get in and out.  I have a feeling this is a COVID glareshield, that is not up to Glasair's regular spec
2. I was not happy with the corners around the cage.  Needed more clearance.
3. Need to mount the compass.  I mounted it in the middle of the main section of the panel, which is not the center of the airplane - and have to fill a couple holes.
4. I did not open up the holes for the fans enough.
5. I screwed up on the rounded edge on the pilot side, and tried to bond back in the piece I cut out.  Well, that did not go well so time to do it right.
6. The finish on the glareshield is spotty.  The whole thing needs sanding, maybe some filling and a fresh coat of primer - or not.  Not sure what contact cement will stick best to.

So on a Sunday afternoon it is time to right these wrongs.  I have the material (leather) to finish it, and want to do so soon.

The glareshield has been trimmed, and the fiberglass deficiencies have been fixed.

I put the seat in so I could satisfy myself that I could see the indicators at the top of the panel with the glareshield in, sitting in the seat.  And yes I can.

This picture is taken from eye level.

Time for upholstery.

Glareshield and Bulkhead A cover going to the local upholstery guy tomorrow, and need to do a bit of hasty sanding and filling on the glareshield.  I really hope this works out...

Bulkhead A.  I painted it with JetFlex 'slate grey'... this was actually the first piece I painted (with a roller).  It looks lopsided, but it has been installed (which doesnt mean its not lopsided...)

This was originally 'zolatone' grey, but i sanded it and painted.  You can see a lot of defects in the fiberglass.

Dropped both pieces of with an upholsterer.  He is going to add a 1/4" foam pad to the bulkhead cover.  When he was starting to prep everything, he sent me the following picture.

There are a number of needle marks from some kind of previous embroidery attempt.  He asked me if I wanted to get a new one before he starts - but with Glasair moving to China, I think the chance of getting anything from them is less than zero.  Not very happy about this, as the kit was NOT CHEAP.  But guessing this was done by whomever they purchase it from.

Got everything back last night.  Looks really good.

All assembled, fit and working!

Need to get some brass screws for the compass, but other than that it is complete.

Wrap vs Paint - Wrap Test

I love wrap, and would like to use it to finish my Sportsman.  However, there are a few challenges that I want to experiment with to see if wrap is viable - specifically control surfaces (ailerons, flaps, elevator, trim tabs).  The challenge is the rivets along the trailing edge:  The shop heads are square, and how will the wrap cling to them.  I have asked multiple people that have wrapped their airplanes about this, and have never received a response.  I think most people do not wrap the wings and control surfaces...

Paint is expensive.  Lead times at shops are long.  I am an average painter at best.  Plus, best case is multiple months to get an aircraft painted.

I had some silver (White Aluminum) 3M 1080 wrap, and used that on my elevator trim tab as a test.  The trim tab has been completed for years.  All components were alodyned, and primed with zinc chromate.  My plan is to wrap right on top of the primer.

The elevator trim tab is big enough to get an idea of how this will work, but small enough I can work on it solo.

Based on my wrap experience to date, I had the following expectations:

• Material would lay down easily.
• Dome head rivets should be minimal effort to get the wrap to conform
• Rivet tails will be the challenge on the trailing edges
• Protruding arms / tabs will be a challenge and require a separate operation, or paint.
• Corners / edges should be very doable

My first attempt was aborted as I messed up on the placement, and the wrap folded on top of itself - plus some stray fiberglass was on the table and got stuck to the wrap.  The wrap came off no issues, and did not visibly disturb the primer.  4 hands is better than 2 during initial placement of the wrap.

The seam is on the forward side of the tab, top and bottom of the hinge.  I layed the trailed edge down directly on the wrap and slowly worked forward on the top.  Same process for the bottom, but I needed to slit the wrap around the arm.

As stated above, my expectation was the wrap would conform to the 3/32nd rivets no problem.  That was NOT the case.

At first I tried the fingernail trick to get the wrap to sit down on the rivet.  That kinda worked, but did not look great.  I then bought this tool for getting fine detail to lay down.  The air bubbles remained.  Some times I could push them out, but most of the time no.  Heat seemed to make it worse.... the heat would expand the air pocket and make the wrap very pliable, which made it prone to wrinkling.

At this point, the experiment is pretty much dead.  Just for shits and giggles I tried a rivet tail, and as you would expect - no go.

Honestly, I have never had so many issues getting wrap to lay down.  BUT - this is 1080 wrap, and usually we use 2080.  So I have ordered some 2080 in the white aluminum colour - and will try again.  The 1080 is definitely a no go, plus if I had to do each rivet individually I would go insane.

Pulled the wrap off in a couple minutes.  No primer removal at all.

The new white aluminum wrap that showed up was 1080 again... I tried again, and no joy.  Same result.  I ordered a similar colour in 2080 but it is backordered.

So I tried with some yellow 2080.  Rather than trying to wrap the whole thing I am just going to do some test pieces and see how this is going to work.

First 2080 test.  Bottom.

Top

Marginally better.

I think my problem is technique.  I was starting at the trailing edge and pulling the wrap forward and then working the rivet flange.  I think I just had to much tension on the vinyl and it wasnt sucking down.  So I tried another smaller piece, but worked the flange and rivets first, and then started moving forward.

Bottom

Top

I think this is approaching acceptable.

I have been searching for tools and/or techniques for wrapping rivets.  Yesterday I came across this YouTube video that talked about this product.

Essentially you place the vinyl down and squeege everything but the line of rivets... leaving a channel for the air to escape.  Heat up the line of rivets, and run over it with the RollePro and done.  But, how well will it work on rivet tails?  

Ordered.  Will see how it works.

Received a did a quick test.

The rivet heads are really good using the RolleePro.  The tails are better, but not great.  

I saw on a YouTube video someone that put a straw at the end of the air channel to stop the vinyl from collapsing (as it tends to do when heated).  That will be the next test.

Putting this exercise on hold... when I get closer will go to a pro wrap shop and get their opinion, but at this point unless they have a super awesome solution, the aircraft will be painted.

Prop / Spinner / Hub and Cowling

Lots of fun ahead.

I have been putting this off, because I know it will be a lot of work.  But the cowl, baffles/plenum, prop/spinner all have to work together and fit correctly.

First step is to put the brush mount on for the slipring.  This is easy :-)

The cowl has to be notched for the slip ring mount, as does my cowl alignment fixture.

Next I put on the hub, blades and spinner (temporarily).

I could not resist connecting the hub to the controller.  IT WORKS!

Under no load, the prop draws about 1 amp when moving. Full feather is pretty darn cool.

Installing the prop was simple.

1. Add slip pickup mount bracket and pickup to engine.
2. Put the bushings in the hub
3. Mount the hub
4. Put in the hub bolts (through the back)
5. Attach the blades.  Blades are marked both on the hub and each blade.  Align the cam, and wind in the threaded hub
6. Done...

Because the shop needed to be cleaned, I pushed the plane outside yesterday.  Gives you a very different view of it not in a confined space.

Next is the start cutting up the front of the cowl.  Opening up the inlets.

The goal is to open them up so the inboard side of the inlet meets up with the spinner.  I roughly got there yesterday.

Back on the plane, plus cut the opening for the oil cooler.  It needs to be a touch larger still.

I want to get the hub and spinner put away, and also have a working surface that I can sand against.  Made a ring out of 1/8" plywood, split it horizontally, hot glued it and slid between the backplate the cowl.  The backplate has holes in it, and I drilled through the ply and cowl for clecos.

Next... need to sand the cowl and get it ready for bonding foam, filler, etc.

After some emails and a call with Zach, not going to go the foam route - but epoxy and micro balloons.  Only slightly heavier, but much easier.  New plan :-)

After HOURS of sanding... yes, hours... everything is prepped and ready for the filler.  The gel coat was really thick around the prop flange.  Used 80 grit paper and an air powered orbital sander - but it still took hours.  I went to far as well, but thats fine as I saved the weight of the gel coat (at least that is what I tell myself).

The plywood templates have been wrapped in packing tape, and the clecos waxed just in case it runs down.  Plus the crank has been bagged.  Last thing is to cover the oil cooler just in case.

Used a mixture of West Epoxy, microballons, and a touch cabo.  It is no where near perfect, and going to need sanding and another coat.

Every time I tried to touch something up, something else got worse - so i just left it.  Once it is all dry (which will be quick with our temperatures) I will take it apart, sand it all flat, and do another coat.  No big deal, just more time.

It turned out pretty good.

Already have given it a light sand to knock off all the high points.  The face of the flange has some gaps, so the plan is to fill those, then put the plywood back on and fill again.

I thought the 2nd coat would be easier than the first, and it was not - due to some crappy prep.

On my plywood ring (that is covered in packing tape) I picked off the bits of resin that where on it.  Well, I didnt get them all and its not perfectly smooth and was grabbing on the large 12" putty knife.  Lesson learned - put on new tape on subsequent coats.  Also, the mixture was slightly runnier than before (not enough micro).  So more sanding is in my future.  Not happy.

Also... The face of the prop flange needed some cleanup as well (gaps between OLD edge of the cowl and the filler), so i touched them up and then put on the plywood ring.  There were a couple problems with this approach.

1. When i put the packing tape on the plywood, there were some wrinkles.  
2. I didnt put packing tape all around.  The inside edge was bare wood in some places

I realized this after I did it, so I took it off before it was dry, which made a mess.  After dry, I sanded it down and used a touch of body filler where needed.

All sanded now after the 2nd coat.

The top and bottom came out very nice.  The sides are going to need work.  I could be chasing this for days, so I am going to get it as good as I can, take it apart, and cleanup more.  Once it is 95%, going to glass it (the two halves separately) and see what happens.  Still need to radius the edge to somewhere between 1/8" and 1/4".

Test fit before moving onto the next step.

Looks pretty good.  Need to sand down the sides by the inlets, but the top and bottom line up just as they should.  The two halves are not attached at the flange, which is why its a hair off.  I have a cleco that holds them in place, but cant have it installed with the hub and spinner on.

Now that the spinner ring is pretty much ready for glassing, I started to rebuilt the inlets are more importantly the inboard side of the inlets where it is going to feed the plenum.  Trying to get smooth airflow past the spinner inbound.

I foamed everything up with hot glue to hold it in place temporarily, then put down 2 layers of glass with peel ply on top.

The whole purpose of this step is to start the rebuild.  I am going to split the center along the cowling split line when dry, and then I can start finessing it to make it look right.  Just trying to get some structure I can work off.  The challenge is going to be cutting the slit.  I have an oscilating tool that might work, and a air saw.  Hopefully one of those 2 do the trick.  The issue will be access.  Normally I would use a dremel with a cutoff wheel, but can't get in there to make the cut.

With the peel ply removed

This should do exactly what i want / need.  The big gaps are closed up and I should have a good surface to start the next step on.

Next is glassing back up the expanded spinner ring.

I figured I would take a small step.  In consulting with Zach, he recommended a layer of glass of the curve, and then another on the whole thing.  So I started with the smallest part first.

Its amazing how the right weave on the right bias will form itself to the correct curve.

Everything not resined up is going to be cut away or sanded away.

2nd layer applied after sanding.

This time I peel ply'ed everything.  After the first layer, you could really see the weave.  Hopefully the peel ply works.  I had to put it on it small strips because of the compound curves.

After removing the peel ply and cleaning up the edges, figured I would test fit everything again to make sure I am going in the right direction.

It all lines up pretty nicely.  Needs some finessing around the cowl split behind the spinner, but everything is lining up as intended.  That is a huge relief as I dont want to do this again

Just finished trimming the upper inlets after extending and re-profiling them.  Started by bonding in foam and glassing against it.  Sand the foam away, fill for profile (mixture of cabo and micro), sand, then 2 layers of glass on both the top and bottom, then sand again.

Now I have to do the bottoms.

The exit air ramp at the bottom rear of the cowl needs to be extended.  I've been thinking about how to do this for over 9 months.  The plan is to use aluminum to conform to the existing partial ramp, and just extend it in height and width.  With the extra large oil cooler and intercooler I need more exit area.

I've had the aluminum for weeks and have been staring at it.... well finally said just do it.

I started out by working one side... getting the curve right, and drilling / clecoing as I went.  I think it took all of 15 min tops.

Next was trimming back and sanding the cowl.  Debur a few holes, clean the mold/aluminum, mold release, re-cleco, and start mixing resin.

3 layers of cloth, 1 layer of peel ply.  Once this is cured, take the peel ply and mold off... then will grove/dish the seam on the outside and put 2 layers of glass on the outside seam, then fill to flush.  I will probably put a 4th layer on the entire outside.  That should be plenty strong.

I want to put a lip on the aft edge of the ramp... apparently this helps draw out air.  But I have not figured out how I am going to do that yet.

Took the mold of yesterday.  It definitely worked... however it is very big.  It is currently too long as well, which makes it look even bigger.  The good news there is plenty of room for the exhaust.

Got a lot done on the cowl in general.  Sanded the outside down in preparation for the 2 layers of glass to tie the outside of the exit air ramp extension - glass applied.  Started filling the slot for the nose gear.  Bonded in foam to fill the taxi light depressions, plus a layer of micro where the foam did not fill completely.  2 layers of glass on the outside of the oil cooler inlet.

Plus, I layed up 2 strips 44" long 4" wide of glass for my new cowl joggles.  When I finally cut the cowl sides down the size, most of the joggles will be gone and will need to be rebuilt.

Now it all just needs to dry, and then more sanding - YAY!

If the cowl wasnt ugly enough.... after lots of sanding, working on filling the gaps from the last layers of glass.

The light depressions have a layer of glass on them.  The oil cooler inlet has been faired.  The outlet ramp has been faired, and I started on the last of the 'oopses' from the lower cowl extension.  Tomorrow will be lots of sanding (again).

The top cowl needs some love.  For some reason (either erosion, or something moved or both) the top cowl does not line up with the fuselage goggle.  In some places its right on, and it one spot is almost 1/8th out (erosion), and it a few places its just a hair off.  

After consulting with Zach, I am going to extend the hole top edge of the cowl about 1/4", refit it, and them trim.

The mold is aluminum.  For the most part, I used the holes already in the cowl to temp mount it - but added a few more where the aluminum was not laying correctly.

I taped the the top (bottom in the pic) with packing tape to try and minimize the amount of resin that bleeds through.  Mold release on the aluminum, and cleaned everything.  One 5/8" layer of glass with peel ply on top.  Once this is cured with flip it over, give it a light sand and then another layer on top.

All gooped up.

Looks like it turned out OK.  I extended the edge for more than I needed.  Also started filling holes...

It sure looks ugly...

Test fitting after all that work... and marking the cut line

Came out not too bad...  Way better than it was

So ran into a problem.  When I cleco the cowl in place, it shifts slightly to port and its hitting something hard.  Finally realized its the slip ring hitting the inner ring of the cowl.

The opening in the cowl is 8" wide on the aft side (it tapers slightly with the curve of the flange).  The slip ring assembly is 8 3/8".  I am going to shoot for a 1/2" gap (I think that is safe), so the new inner flange will be 9 3/8".

The plan:

• Make an MDF ring the fits into the space on the inside of the cowl with room to fit the slip ring with no interference plus 1/2" or so on each side.
• Route the inside of the ring to ~1/4" radius.  Sand and finish the ring, wet sand to a nice finish
• Cut out the existing flange, sand the freshly cut edge to a taper
• Attach the cowl halves
• Drill and cleco the ring in place
• 1 or 2 layers of glass on the outside.  Probably 2, so I can sand one partially away
• Remove ring.  2 layers of glass on the inside
• Trim edges, cut slot between rings
• Pray it worked.

The big benefit to this change is the brush bar for the prop / slipring no longer needs a notch in the cowl.  OK, minor benefit LOL.

Everything fits much better now.

Finally got up the nerve to do the big cut on the lower cowl to remove the excess material (due to the stretch and reprofiling).  

Now the joggle rebuilt begins...

New joggle strip cut and fit.  It's 3 layer of glass that was bonded up separately

Bonded in place using a mixture of resin, milled fibers, and a dash of cabosil.  Clecos were spaced every 1.5".  I put 2 additional layers of glass between the cowl and joggle in the extension, as it was noticeably thinner than the rest of the cowl.  All the squeeze out was cleaned up after everything was in place.  There was a lot of material to remove... I probably over did it a bit.  I put a lot of tape on the inside to catch the squeeze out, and then cleaned it up with a bit of acetone.  Once this is dry, going to add 2 more layers of glass on the inside to strengthen it up, overlapping the joggle onto the cowl.

Other side done.  Time to add more glass to the flange and create an overlap.

2 more layers of glass on the inside to bond the joggle flange in.

Somehow the cowl has shifted slighly.  I have pulled out my hold alignment jig that attaches to the crank.  Originally it fit inside the inner ring on the cowl, which is no longer there.  I aligned it by hand and drilled new holes for the aluminum.  I have successfully got it back into alignment with the spinner.

Going to work from the front to the back and align the cowl and drill the holes for fasteners.

Going with 6.4" spacing across the 39" from the aft of the cowl up to the last 5" where it curves to much for skybolt fasteners.

Also, before doing this I sealed up all the holes in the aft of the top cowl.  1 layer of glass on the bottom, filler on top.

Once everything is aligned, I put 2 new holes in the top cowl, straight through the goggle and firewall stainless.  Then I used a ratchet strap to pull everything relatively tight.

Fastener pilot holes drilled on the cowl sides and top.

Test fit of the hub and spinner.  It all lines up like it should.

Now I have to deal with the bottom, including cleaning up the exit air ramp.

Small problem encountered with the top of the cowl at the seams for the extension.  As the cowl is thicker at that location, it wants to bend less - so is not sitting nicely in the joggle.  You can push it in with your finger.  The plan will be to relocate the fasters to these 2 areas on each side to get it to suck in.  That will mean respacing all the fasteners - but its worth it if it works.

Working on the top/bottom cowling seem at the front.

Same picture as above, but after lots of sanding and filling.  All of the 'real' faster locations have been drilled and the cowl is now rock solid.  Because the cowl has been on and off so many times many of the holes had started to oblong and the fit was getting sloppy.  Its all good now.

So it's time to prime.  I could keep chasing defects, but my current theory is a high build primer will eliminate the small stuff, and then I can focus on the big stuff.

Initial impressions are really good.  I am using a SEM rapid primer / filler procured from the local auto supply shop (Lordco).

Most of the minor imperfections are gone - which is great news.

Before sanding

There is a fair bit of stuff that needs addressing, mainly around the ends (cowl trailing edge, and the inlets where they have been enlarged).

After initial sanding.

I did the cowls in separate stages.  Started with the top because it was 'better' (less defects), and I had not final sanded the bottom cowl yet.  After sanding, I went after all the little issues.

As for filling... up until the primer stage I used West Systems Epoxy with their 410 Microlite Fairing Filler.  I can mix this up in larger quantities, and depending on where I am filling I can add Cabosil, Milled Fiber and/or Filler and I can adjust the quantities to get the necessary consistency / strength.  Now that I am at the priming stage and going after the little stuff, I am switching to Total Boat / Total Fair fairing compound.  Total Boat works really well for the fine details.

The upper cowl has been primed, sanded and filled and is drying - so onto the lower cowl.  Unfortunately the lower cowl has been butchered, extended, reworked, stuff added etc.  It needs some love.  I am very confident in its strength... now I have to make it look beautiful.

Prior to priming...

I am using my 'shed' for the RV.  Its covered and somewhat sheltered from the wind.  Prior to doing anything, I water down the area where I will be working with water to keep the dust down.  I usually start on the top surfaces, and then flip it over and work on the bottom.

Doesn't look to bad in the picture, but in reality it looks like an obese person wearing yoga pants (that shouldn't).  Lots of defects.  But man, it sure is nice to see everything one consistent colour and not a hodge-podge of crap.  Plus, the SEM Rapid Primer Filler dries really fast, which is awesome.

Test fit after 2nd run of primer / filler.

It actually looks not too bad.  There are a lot of little things to chase.  The seams between the bottom and top halves need work, and there are some little pinholes.  But, basically its together.  Everything lines up.

Here is the progression over a year....

I stopped working on the cowl in approximately October 2022 when the weather cooled, and started up again in June 2023.

So today has been all about chasing gaps between the upper and lower cowl.  They were not consistent.  When I marked the cut line, I used a long straight edge and clamped it to the cowl.  However, the cowl curves, so the cut line had a curve on the forward end.  Its not huge, but you have to follow it.  I made the decision to do small portions of the gap individually... which means lots of top cowl on and off.  More work and longer, but it seems to be paying off.  Working to get to a consistent ~1/16th gap from the back to the front.  Sure would have been easier to just hold my nose and buy a Lycoming... especially with all of the UL issues of late.

Started installing fasteners along the upper cowl aft edge.  Its coming along...

Going to leave the rest of the cowl for now and focus on windows, oil cooler, intercooler, etc.  The cowl is 90%+ complete thankfully.