Cowling Log 
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 April 11, 2017

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Cowling
The cowling is made up of two pieces of Epoxy fiberglass. Each half has a honeycomb core that keeps it rigid. The pieces are made oversized and have to be trimmed to fit the plane. It is all held together with piano hinges at the seams.

November 16, 2003 - 1.5 hours
I drilled the hinges that go along the top of the firewall that will eventually hold the top cowling half on.

The cowling is held to the fuselage with hinges. Here is the one that is at the top of the firewall.

November 17, 2003 - 1 hours
Started fitting the front of the two cowling halves together. Looks like there's going to be lots of sanding.

November 28, 2003 - 3.5 hours
I trimmed and sanded the top cowling half trying to get it to fit just right. The front flange seems to have a problem. It is tilted forward at the top and it looks like about a 1/4" is going to have to be removed or added to get it to fit.

It's hard to tell from this picture but the front flange of the top cowling is slanted forward at the top.

November 29, 2003 - 2 hours
I fit the bottom cowling on temporarily just to get a better feel for what it is going to take to get this whole thing to fit right. After much head scratching and sanding I have decided that the top cowling won't fit as is and I am going to have to cut it. Now how am I going to do that?

November 30, 2003 - 4 hours
Okay I think I figured out how to get this thing to fit. I'm going to cut it toward the bottom of the flange and move the bottom forward and then fiberglass it from the back. Today I spent a bunch of time getting it all back together. Then I made the cut and got it all positioned and ready to glass.

I taped a piece of 1/4" hardboard to the back of the rear spinner bulkhead.

After getting the top cowling positioned I marked it so I could get it back in the right place.

I cut the flange of the top cowl half.

Using a couple of popcycle sticks and some Bondo the flange is held in the right position.

The Bondo has cured and now I am ready to glass the inside to hold it all in place.

December 1, 2003 - 0.5 hours
All I did tonight was fiberglass over the cut in the top cowling.

I fiberglassed the inside of the top cowling.

December 2, 2003 - 1 hours
I sanded off the bondo that was holding the top cowling together and then I mixed up a batch of SuperFil and filled the crack.

After removing the popcycle stick and sanding off the Bondo I have a crack to fill.

December 3, 2003 - 4 hours
Sanded the filler that I put in the cut on the top cowling. Drilled the top cowling to the hinge at the firewall and started fitting the bottom cowling.

It's hard to tell from this picuture but there is some Super-fil in the crack that has been sanded nicely. I am really happy with how this turned out.

The top cowling half is clecoed to the hinges at the firewall.

Another shot of the top cowling, also the oil filler door cutout.

December 4, 2003 - 3 hours
Drilled the hinges that attach the bottom half of the cowling to the bottom of the fuselage and started fitting and sanding the bottom cowling half. I put a little bit more filler up front where I had to cut the top cowling.

It took a while but I think I am finally happy with the fit between the two cowling halves.

December 5, 2003 - 3 hours
I trimmed the back of the lower cowling half and drilled the bottom of the cowling to the hinges. I spent a lot of time fitting and sanding.

The bottom of the cowling is held on by hinges as well. Some say these will break easliy and I guess if they do then I'll replace them with screws then.

The fix that I did on the top cowling has caused the cooling air openings to be misaligned. The great thing about fiberglass is things like this can be fixed fairly easily.

December 6, 2003 - 3.5 hours
More sanding on the bottom half of the cowling and I managed to get the hinges on the side drilled.

The bottom half of the cowling is drilled to the side hinges.

December 7, 2003 - 3.2 hours
I think I managed to install and remove the top cowling a hundred times today, but I think they fit pretty well. I drilled one of the hinges along the horizontal seam to the bottom cowling half.

Here you can see the Duck (Yes Duck) tape that I used to hold the two halves together while drilling the hinges.

December 8, 2003 - 1.75 hours
Finished drilling the hinges along the seam between the top and bottom halves.

The last of the hinges on the cowling are drilled.

December 11, 2003 - 0.5 hours
Smeared some Super-fill on the top cowling to help fix the misalignment.

I am building up the gap on top cowling half with Super-Fill. I'll put a little glass cloth over it after I get it shaped to give it some strength.

December 21, 2003 - 0.7 hours
I discovered that I need to have the inlet ducts epoxied to the cowling before I can finish fitting the baffles so I went ahead and did that so they cure overnight.

December 22, 2003 - 2 hours
Trimmed on the inlet ducts of the top cowling to get them to fit the baffles. I couldn't decide whether to trim the cowling or the baffles so I trimmed the cowling to see how that works out. If not it's easier to add fiberglass than to add aluminum. I also did some more work on those areas of the top cowl that have to be enlarged to fit the bottom. I layed a couple of layers of glass cloth over the filler that I had put on previously.

Here is a shot of the inlet duct epoxied to the top cowling.

I sanded the filler down until it was smaller than it needs to be to fit the bottom cowling

This is a really bad picture of two layers of glass BID layed over the filler on the top cowling.

While I was at it I decided that if these things were supposed to smooth the airflow into the cowling the joints may as well be smooth. I like this Super-Fill stuff.

December 29, 2003 - 1.1 hours
I layed up a couple of fiberglass parts for the top cowling. I am closing off the inlet ducts.

December 30, 2003 - 1 hours
I made the other two parts of the inlet ducts tonight. I also realized that I left my digital camera in Littlefield so I am taking pictures the old fashioned way. I really wanted to show how I am closing off these inlet ducts so I will probably scan them when I get the film developed.

January 1, 2004 - 1 hours
Today I trimmed and epoxied the new inlet duct parts that I made to the top cowling. I am going to need to do a lot of filling and sanding to get them perfect but for now at least I have enough of it done so that I can finish the baffles.

February 14, 2004 - 4.5 hours
Started finishing up the cowling work. I countersunk all the rivet holes, deburred all the rivet holes and started riveting the hinges on with some epoxy/microballoons slury to help smooth out the rough spots.

February 15, 2004 - 0.6 hours
I mixed up another batch of microballoons and epoxy and riveted on a couple more hinges to the bottom cowling. One more session and I should have the hinges on the cowling halves.

February 17, 2004 - 1 hours
Finished riveting the hinges to the bottom cowling half and smeared another coat of Superfil on the top cowling half to try and get the front to fit together better.

February 19, 2004 - 1.75 hours
I got a little carried away with the microballoons on some of the hinges and the cowlings didn't want to fit together very well. So I scrapped a little bit between the hinge eyelets to get them to fit better. It is much better but I should not have put so much on. I did a little sanding and mixed up some more Superfil and put it on the inlet ducts to get them nice and smooth.

February 21, 2004 - 1.5 hours
Fiddled with the cowling some more. I really made a mess of those hinges with the micro / epoxy mix.

February 22, 2004 - 2.5 hours
Still messing with the cowling. I managed to get it to the point where it fits together okay. The hinge pins are still a little hard to install but they'll loosen up. Now I am just trying to get the inlets on the front to look just right, and hide all the rivets. So there is some fiberglass and filler in my future.

February 24, 2004 - 1 hours
More sanding and filling on the front of the cowling. It's coming along slowly but it's getting there.

February 26, 2004 - 1.6 hours
More sanding, more filling on the cowling.

February 28, 2004 - 1.8 hours
More sanding / filling on the cowling. I also fiddled around with the baffles a little bit.

March 2, 2004 - 1.4 hours
Prepred the holes where the cowling hinges and firewall attach to the fuselage for riveting.

March 3, 2004 - 1.75 hours
Riveted the cowling attach hinges, forward fuselage and firewall flanges together. Also spent some time sanding on the cowling.

The forward fuselage is riveted to the cowling attach hinges

When I was home for Christmas I got my Dad to help me make this bucking bar. It made getting in that tight area between the hinges and the engine mount real easy. Thanks Pa, it worked GREAT!

March 13, 2004 - 3.5 hours
Today I put the cowling back on so that I could figure out how much room I had for the EGT probes and wires and I while it was there I decided to install the little brass tubes where the hinge pins are going to run to secure the top and bottom half of the cowling together. Mine is going to run back into the cabin through two small brass tubes (bought at the hobby store) to the forward bulkhead. I managed to get both tubes JB Welded to the fuselage side and it seems to work pretty well. It is tight but I expect that it'll loosen up over time.

Here is the small brass tube that will guide my cowling attach hinge pins through the firewall.

After the initial little spot was cured I marked and drilled the hole.

It's not pretty from the inside but you can't see any evidence of hinge pin anywhere on the outside.

March 27, 2004 - 1 hours
Started working on the little oir filler access door in the cowling.

Once I got the little oil filler access door to fit I duct taped it to the cowling so it wouldn't go anywhere.

March 28, 2004 - 2 hours
Finished working on the oil filler door. I think I will wait to rivet it, at least until I decide how best to paint the thing. After I got that done I went ahead and mixed some thinned microballons / epoxy and smeared it on the top cowling to help fill the pin holes.

I used some hinges from McMaster Carr that will stay hidden and a Hartwell latch for the oil filler door.

This is what the door looks like from the outside.

The thickness of the door is less than the cowling and it was causing the door to bulge a little bit. I needed a little bit more shim between the hinges and the door so I used this piece of angle. It should make the whole thing a little stiffer too.

February 6, 2005 - 4 hours
Shannon started cutting out templates for the firewall insulation. I finished the fuel selector plate. I filled the pin holes in the aft skirt with Super-fil. The micro balloons seem to be causing more problems than they are solving so I went back to the Super-fil. I had fiberglassed some stiffeners into the oil door and didn't quite get them right. The door didn't fit as well after I did that. After staring at it for a while I decided that I could cut some slits into one of the stiffeners and re-glass it. While I was at it I fiberglassed a hinge pin retainer on the top cowling for the hinge pins that hold the top cowling half to the firewall. I started working on how I am going to retain the hinge pins that are inside the cockpit and the two on the bottom of the cowling.

This is how I decided to retain the hinge pins on the top cowling. I didn't want to rivet this piece on since that part of the cowling is the honeycomb stuff and a rivet would probably crush it.

February 22, 2005 - 2.1 hours
I managed to find a way to retain the hinge pins that hold the two cowling halves together. I drilled a hole in the forward bulkhead and put a really convoluted bend in the hinge pin. I spent the rest of the evening tie wrapping wires while they are still easy to get to. It is only a matter of days before the last skin goes on.

February 23, 2005 - 1 hours
Drilled a small hole in the roll bar brace for the compass light wire. Mostly I worked on the retainers for the hinge pins on the bottom of the cowling.

February 26, 2005 - 2 hours
Scuffed, primed and painted the top fuse skin. Riveted the oil door to the hinges on the top cowling. Filled some spots on the cowling with Super-fil. I also removed the roll bar brace in anticipation of putting the top skin on.

March 7, 2005 - 0.75 hours
Installed the foil heat sheild material on the inside of the bottom cowling.

I probably didn't need to put the foil heat sheild over this much of the cowling but I just kept putting it on until I ran out.

May 28, 2005 - 1 hours
Sprayed some surfacing primer on both halves of the cowling.

The bottom cowling with a coat of surfacing primer on it.

May 30, 2005 - 0.75 hours
Sanded on the cowling.


Disclaimer:
This web site and the infomation contained within it are for entertainment purposes only. The opinions expressed on construction techniques are my opinions only and should not be confused with proper construction techniques. There is undoubtedly more than one way to build an airplane and some methods that I use may or may not work in any given circumstance. If there is any question please call the kit manufacturer. I love to help but I am not responsible for the misuse of any information contained on this web site.

 March 3, 2016
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