Continued Progress - Started Canopy Fairing

I am starting to plan my move to the hangar now..  It won’t be long, but at the same time I am trying to get every little thing done I can before making the move.  Working from the cold hangar doesn't sound too appealing in December…   So I was able to fit some seals up on the lower inlets of the lower cow.  Using a .040 backing plate and some #6 screws, I cut the baffle material so that it would slide into place and block the air from escaping forward around the lower baffle ramps.   It turned out pretty good on both sides and doesn't make it any more difficult to mount the cowl.

 After that I did some research and decided it was time to start building out the Canopy Fairing.   Here I am venturing again into unknown territory.  So I looked at a few other sites, read the directions that came with the kit and am just jumping in.   The leading edge of my canopy fit across the lower skin very well, so I don’t need to use any rivets or pins to “lock it down”.   Also, some people don’t do this without the canopy on the airplane, I am using a level surface, so am confident I won’t have any warp built into the canopy, but we’ll see.

I started by using some pipe tape (20mls thick) to draw the line where the canopy fairing will come up to..  Then with 40 grit sand paper, I scuffed the plexi and aluminum as much as possible, even under the lip where the fillet will go.  Using standard west system epoxy I mixed in micro balloons to get it super thick and some black pigment since this will be visible from inside the cabin, I got it nice and black.   I used a Popsicle stick and some finesse made the filet to fill the gap under the lip.   This will be sanded down quite a bit before I got to the next steps of applying the fiberglass layups, but it shouldn't be difficult to stand since it has filler in it.

Then I wrapped the thing with peel ply sheets which is supposed to set the epoxy up to be easily sanded, or ready for the next coat of epoxy without sanding.  This was mainly a test, I will be using the peel ply much more when it comes to the actual fiberglass lay ups.

Cowl heat sheild

With the lower cowl now about 90% done I decided it was time to put the heat shield in place.  This is an aluminum heat reflective stick on material that protects where the exhaust runs close to the cowl.  It goes on pretty good, seems to stick really well and hopefully will do the job to protect the cowl.

I might have covered more area than necessary, but this stuff is light and will also work to keep oil off the cowl, which is a good side benefit.

Pin-hole-ing the Cowl

The last couple weeks I have been working on the cowl and the oil door.  Basically the cowl comes Pink and fairly smooth, but very porous as well.    If you just paint it, there are huge pinholes in your paint due to the lay of the fiberglass and honeycomb sections of the cowl.  There is no real easy way to fix this, but I do want to have some primer on the cowl to protect from UV and also want to remove the rough existing surface which can collect oil and dirt really easy between now and when it is painted.   So to avoid this I am working on the surface of the cowl.  Here is my process:

First sand the cowl to smoothen it out and open up any holes that might be covered..  Wash with dawn, then rub down with towel and after its dry use some acetone.   Then take some mixed epoxy and a squeegee, then pour the epoxy on the cowl and squeegee it around.   Getting it as thin as possible, while letting the epoxy fill the divots on the cowl.  In the end, the first time you do this used the most epoxy because it is basically absorbed into the cowl.   Before the epoxy has fully cured, i.e. is still tacky, I put another layer on..  This requires less epoxy, but is a bit harder because it is more difficult to tell where the epoxy is new vs. old.  Anyway, I got another layer on and let it dry.

Then couple days later I sanded it for 2 hours using 80 grit..   Then I used a bit of white rattle can primer to see how it was looking.   Pretty good, only some areas that were major holes still existed.   So I sanded away the primer, cleaned up the cowl like above and did the epoxy treatment again.  This time, it really went on smooth and a glossy finish of epoxy..   Two coats just like above and then sanded again with 80 for a couple hours.  Then went with 150 for an hour or so, then finally with some 220 for another hour.   Looks really smooth now and ready for Primer.  I don’t expect to see any pinholes but just a smooth primed surface.  I am going to use my PPG Two part epoxy white primer which will seal and protect until I get final paint.  Oh, then I need to do the lower cowl, since I have only been working on the upper half.   ;-)

Actually, I wanted to throw a photo in of the now finished upper cowl.  Looks like the additional work seems to have payed off.   No pin holes, and looks very smooth..   I will be happy flying around with this until I can get it professionally painted..

Back to the Cowl.. Time to get rid of the Pink..

I decided it was time to do something with that crazy pink cowl shipped from Vans.  It will take a while, but I am finally getting rid of the pink.  First step was on the inside of the upper cowl.  I started by sanding for an hour or so to make sure the surface was clean and smooth.  Then sprayed with hose and washed with soap to clean it up, then to seal the surface I used a thin coat of standard west systems epoxy.  Started with a brush and realized it was going on way too think, so a hard plastic squeegee did the trick and made the epoxy go really far.   I covered the entire inside with a small cup of the stuff.   Let it dry overnight in the cool garage so this morning it was dry to touch, but not fully cured..  Perfect time to hit it with some heat resistant white paint..  Since the interior of the cowl isn't critical I originally used Rustoleum heat resistant paint, but the surface came out chalky and I figured it wouldn't hold up to oil, so I got a heat resistant engine enamel from the auto-parts store and it worked great.  The surface is White so that I will be able to  see any grease/oil problems and it is now sealed so that nothing soaks into the cowl.    After this, I will probably do the lower interior before attempting anything on the exterior of the cowl.  Might as well get through the learning curve on the less visible inside.

No More Clecos on the Cowl !

I have been pretty busy epoxying and riveting the cowl over the last couple days and today before running into work it had cured enough to set it on the plane.   Looks really good and I am excited about it for sure, but I did learn one important point.    Don’t let epoxy ooze out between the hinge eyelets.   I thought it wouldn’t be a problem, but the other hinge join interferes just enough to make it very difficult to slide the connecting rod in place.   I have a small dremel bit that I will use to clear out the excess, so I will be fine, but would have rather avoided the extra work.

I also was able to install the nutplates on the center cowl join.  I used two for now on each side and may add 3 later, but there is a conflict with the flywheel that I want to avoid.  Others have stuck with two and have had no issues.  I didn't use epoxy here in case they needed to be replaced in the future.  

Continued with Cowling and started Oil Door

Some ups and downs in my recent work on the airplane.   I am excited about how the oil door has come together, but also made a mistake (recoverable) on the cowling..  So we’ll talk about the oil door first.  I got a “hidden” hinge on a previous order and was excited to finally be able to use it.   First I gut the square hole in the cowling just over ½ inch inside the edges of the indent for the oil door.  I rounded the edges and it looks pretty good.  Then I started drilling the two pieces of the hidden hinge.  I put a piece of .040 under the piece of hinge that attaches to the cowling to help offset the door so that it was flush when closed.  Also, the way I placed the hinge, it heat the upper section of my cowl cut out when I first functioned it.  Took off about 1/16 inch additional and am really happy how it finally turned out.   I have some “Hartwell” trigger lock flush latches on order that will be installed this week, to finish the door, apart from the riveting.   Also, I would not be nervous about making the door smaller than the “frame” on the cowling.  I have a good 1/8 inch outside of the door to the frame, which is good as it ensures a flush fit.  The additional space will be filled in later as I finish the cowling, to frame the door in nice and tight.

Onto the cowling.   I am happy the way it turned out, but after the fact realized I used the wrong hinges to secure the upper and lower cowl.   I used the hinge that was intended for the gear leg fairings.  It’s a very slightly smaller hinge and I assumed it looked good for the job.  Also, the hinge I was supposed to use I had previously used somewhere along the line,  probably for the seat backs, so I will need to order more.   The fix will be easy, just bummed due to the time involved.   But that said, the cowling now completely supports itself and I am really happy with the tightness and flush-ness of the install.   Hopefully when I replace the forward hinges I will be able to keep it the same.

Also, this weekend we had good weather for the first time since I could remember, so I pulled the plane out and let her see the sun for a while..

The Pepto Pink Cowl !

This weekend I started in earnest on the pink cowl.  First on the list is to start drilling the hinges to the forward top skin.  I used cleco clamps here and was able to get them drilled with the appropriate shims in place.  Then I added the other hinge (cowl side) using the full size aluminum hinge pin just to make sure I could get the pin through the hinge.  This will help make sure the hinges are inline, then when the plane is in finished I will replace this aluminum pin with a smaller (stronger) stainless steel pin.


After drilling the hinges, I pulled them off to start initial fitting of the pink cowl.   My initial take is that the cowl is going to be quite a challenge.  Lots of fitting and removing, and sanding, fitting removing and standing etc..   I trimmed the forward center flanges so that the spinner circle on the cowl was flush and as circular as possible.

Then before drilling anything the top half of the cowl, I test fit the bottom.  I trimmed the landing gear egress through the cowl, which took many more iterations that I had hoped.   I taped up the landing gear pretty good to protect from the abrasive cowl.  Getting it all together and roughly fit I am able to start seeing how this will go together.   The edges didn't overlap much if any at all.  I was worried a bit because some builders have had trouble with the cowl edges not being long enough.   By letting the cowl fall where it wanted and using some duck tape to pull up the edges, they eventually fit quite well.

After Fitting and sanding and fitting and sanding, I drew up the rivet lines on the top cowl at 1 inch apart and drilled the cowl to the hinge.  The cowl kind of has a mind of its own and wants to lie where it lies.   I had the bottom cowl taped up when I drilled the holes so that hopefully it was as square as possible. Seems to have turned out well so far.  The prop spinner is about exactly 1/4 from the cowl as indicated in the plans.