Carlson Skunk Works

September 19th, 2016

AMF 14H MARANDA SN:1026 Making Sawdust September 19th, 2016

Posted by Roger in AMF 14H Maranda SN1026

So the wings are done, as you saw in the last post. However, I have been trying to come up with a way to test the wingtip lights and strobes. I have really been scratching my head on this and have come up with several “elegant” ideas, but they were just too complicated. Then my son suggested just using my battery charger. Duhhh! Now why didn’t I think of that?

So here is the result:




And here’s the video:

June 20th, 2016

AMF 14H MARANDA SN:1026 Making Sawdust June 20th, 2016

Posted by Roger in AMF 14H Maranda SN1026, news

Continuing on with covering the left wing, and with significant assistance from my son, Ben, we are now lacing the ribs. After moving the wing to the wing racks I added an “outrigger” to the workbench to provide support for the wings under both spars at the same time. Then I covered the outrigger with some carpet scraps and got a 2’x6′ carpet runner at Menards and put that on the top of the workbench. The carpeting is to help cushion and protect the fabric an wing surface. When that was done we moved the wing back onto the bench and I proceeded to cover the top of the wing.


The top of the wing is quite a bit easier to cover than the bottom because there is only one opening that needs to be made in it. I marked a three inch overlap with the bottom fabric at the leading edge, per Stewart Systems recommendations. Glue was applied to the leading edge overlap and to the trailing edge overlap. When the glue was dry the top fabric was tacked into place along the leading edge, then stretched across the wing and wrapped around the trailing edge and tacked into place there. The interesting point here is that the fabric was EXACTLY the correct width to fit. I did not have to trim any of the fabric along the trailing edge and there was just enough to cover the glue. On the next wing I am going to wrap the bottom fabric around the leading edge to 12″ instead of 11 1/2″ to get just a bit more working room on the trailing edge of the top fabric.

I am using the non-certified 2.7 oz Dacron fabric from Aircraft Spruce. This comes in 62″ wide rolls while certified Ceconite comes in 73″ wide rolls. Be aware of this when planning your covering work. The difference in price is that the uncertified fabric is about 1/3 the cost of the certified fabric.

Stewart Systems and the FAA require a three inch leading edge overlap for certified aircraft. Sawdust is an experimental airplane, so I could claim to be experimenting with a two inch overlap, however, where I can I like to follow established aviation guidelines. The three inch overlap seam will be covered by a four inch wide tape when the finishing tapes are applied.

The other issue was to provide an opening for the push-pull aileron control cable to come through the top fabric. This is a bit different than the opening required for a regular pull-pull cable. The aileron control cable is mounted to a bracket and secured internally to the compression struts. Therefore the opening needs to be cut as the fabric is applied rather than after it is applied and shrunk.




With the opening cut and the fabric secured to the leading and trailing edges of the wing, I took a look at how much of a bump the cable and bracket make in the wing surface.




The bump is not too bad, but I decided that I really should open the fabric enough to allow the majority of the bump to be eliminated. The resulting hole is really fairly small and I cut it close to the cable and bracket.


Now, how to cover the opening and provide some type of fairing? I am mainly concerned with keeping moisture and bugs out of the wing, so I visited the aviation department at my local Menards and had a brain storm. The bracket that secures the cable has a diameter of 1 1/2″. It doesn’t extend above the surface of the wing more than about half way. Therefore I decided to find something that would provide a round cover with a 1 1/2″ diameter inside. Guess what I found:



With that decided I cut a doily for around the cable opening. The main thing that I want to do is keep water and bugs out of the wing, so I thought it would be a good idea to cover the cable opening as tightly as possible.


I then cut the pipe into a wedge sort of shape that would cover the cable mount and extend over the cable to sort of make a fairing. This is not as elegant as what the Stewart brothers show in their videos, but it works. I found that I needed to rough up any area where I wanted glue to adhere to the pipe. I used my little rasp for this and that seemed to work pretty good.




I coated the pipe and area around it with glue and cut some fabric to provide a good fit to the wing fabric.


After ironing the fabric to get it to fit the contours it seems to fit pretty good.


With the cable opening covered we proceeded to do the final two fabric shrinks. Ben helped with turning the wing over a few times. The fabric is now taught and looks pretty good. Ben and I marked the locations for the rib stitches on both the top and bottom of the wing, then moved it to the wing racks for rib stitching.






Fathers’ Day afternoon provided an opportunity to try out our rib stitching skills. We found that we needed about 21 feet of lacing cord to do each of the long ribs. I estimate that we will be able to get by with about 15 feet for each of the short ribs. Things went pretty well and we were able to complete two ribs in about two hours.


The next effort is to finish the rib stitching, then apply the finishing and perimeter tapes. Then we can move on to the second wing.

June 8th, 2016

AMF 14H MARANDA SN:1026 Making Sawdust June 8th, 2016

Posted by Roger in AMF 14H Maranda SN1026, news

Covering the wings has begun. The bottom of the left wing is covered and now I need to modify my workbench to make it “friendlier” to the fabric as I work on the wings. However, that is what I WILL be working on. What has been accomplished is getting the left wing ready for covering and getting the bottom covered.

The wings have been installed on the plane for a couple of years now. The old hanger was pretty drafty and dusty. Therefore, the top surfaces of the plane were/are really dirty and needed to be cleaned. All surface imperfections and glue joints needed to be fixed and smoothed. This is just like the control surfaces that I covered last winter. I found that a fine rasp worked really well for doing this.


Then I applied anti-chafe tape to the ribs and to the edges of the plywood wherever I thought it might provide an abrasion issue.

Since I have a limited number of extra hands, I decided to cut the fabric at home where I have enough room to roll out the fabric on the basement floor and cut it by myself. I measured the length of the wing and allowed for some excess on each end, then cut a length of fabric 17 feet long. When I was ready to spread the fabric out on the wing there was a pretty stiff wind and I had to close the hanger door.







I forgot to take pictures of the first pieces of fabric that I put on the wing. I started by putting fabric over the ends of the aileron cutout and the wing root. Then I glued the bottom fabric to the wing.


The big decision for me was how to deal with getting the pitot static tubes through the fabric without problems. What I ended up doing was laying the fabric on the wing and tacking the leading edge in place, then I marked where the back side of the pitot static tubes came through and marked a straight line forward as a cutting guide. Then I took the fabric loose and cut a slit in the fabric just long enough to allow the pitot static tube to go through. The cut started at the mark for the back of the tubes and cut forward for about two inches. After the initial shrink of the fabric I made two doilies to reinforce this cut. One doily had a notch cut to fit the back side of the tubes and was installed first. The other doily had a notch cut to fit the front of the tubes and overlapped the first doily. The result seems to be pretty solid.


The lift strut attach fittings needed to come through the fabric as well and I made doilies to fit them, too.


The same went for the jury strut attachment fittings.



Rib stitching will be done where the ribs are open. However, the wing root and the wing tip have plywood covering a rib each. I don’t know how to stitch these, so I decided to glue the fabric to the plywood at those areas. I thought about drilling holes in the plywood to accommodate the lacing needle, but I don’t really like that idea. I will continue to give this some thought.


Figuring out the position of the fabric edge for the leading edge took a bit of thought. I watched the Stewart Systems videos and read their procedure manual several times. What I ended up doing was working backward. The leading edge finishing tape needs to be four inches wide. The top fabric needs to overlap the bottom fabric by three inches. The leading edge tape should cover the fabric joint in such a way that it sort of faces the air as it meets the wing. Anyway … I marked the place where the fabric edge should be glued at 11 1/2 inches forward from the back of the leading edge plywood bottom edge. That works fine for the main length of the wing. I just eyeballed the same type of position toward the wing root on the area where the wing tapers. It seems to have worked out ok.


The bottom fabric was extended to the wing tip. I glued the wing tip fabric on the top of the Hoerner wing tip. I did have to cut out for the wing tip light mount. I am planning to put another doily over this area after the top fabric has been installed.




We moved the wing to the wing racks to allow us to modify the workbench. Once the workbench has been modified I will put the fabric on the top of the wing.

May 31st, 2016

AMF 14H MARANDA SN:1026 Making Sawdust May 31st, 2016

Posted by Roger in AMF 14H Maranda SN1026, news

This weekend was busy, but left some time to work on Sawdust. I started by finishing up the details on the wings, then marked where the jury struts will mount to the struts. Finally, I put together the tool cart that I had purchased at Harbor Freight last December.

My neighbor, Carson, gave me a hand with pulling the wings and organizing the hanger for covering the wings. So at this point I am working on covering the wings.


The wings are off. The right wing is on wing stands at the back of the hanger. The left wing in on the wing stands to the left of fuselage in the picture. The red tool cart is sitting by the fuselage and is loaded with struts, tools and supplies.


I borrowed the wing stands from my friend, Fred. They have been used to hold the wings from several planes in the past, including the wings for a primary glider that was built by our EAA chapter before I moved to Kearney. They are kind of like the EAA wing rack, but they are designed to hold only one wing per set. This also provides a platform for rib stitching when I get to that point.


We moved the left wing to a workbench that I brought out to the hanger. This will give me a good platform for doing the covering.


The cable for the wing tip strobes is run through the ribs and is secured to each rib with a zip tie. Any place where the internal bracing straps came close to a rib structure I covered the rib structure with plastic tubing. The tubing is intended as a wire organization tool and was purchased in the aircraft materials area of my local Mendards.

The dust and dirt that has accumulated on the wing surface was wiped off. Any sharp edges and uneven areas were smoothed with a fine rasp. Anti chafe tape is being applied at any area where the fabric might wear against an edge.


The plastic tubing from the pitot and static tubes is run along the strobe cable to the wing root. Each tube is secured to the rib structure separately from the other using zip ties. The aileron control cable is secured to each of the compression ribs with zip ties.


The next things to do are to flip the wing over and apply the anti chafe tape to the top of the ribs and install the inter-rib bracing tape. I will also apply more anti chafe tape to any sharp edges. Then covering can begin. My biggest issue now is to figure out how to apply the fabric around the pitot static tubes.

I decided to turn the fuselage around, so it is now facing into the hanger. This gives more room to work on the wings.

May 23rd, 2016

AMF 14H MARANDA SN:1026 Making Sawdust May 23rd, 2016

Posted by Roger in AMF 14H Maranda SN1026, news

Things have been moving along. The ailerons and rudder have been covered and painted. The vertical stabilizer is covered and primed. The plane is moved to the new hanger. The cables to the elevator have been built and installed. Yup, things are moving along.

The last thing that I did was to mount the wing tip lights and run the cables for them.

I started by gluing up a wood block from three layers of basswood that I got from Patrick Schutt. I used this wood for the tips of the horizontal stabilizer and elevator, and had enough left over to make up the wing tip light mounting blocks. Patric provide some really nice wood.


The wing tips are Hoerner tips which really has the ends of the wings cut at a 45 degree angle. The end of the wing is covered with 1.5 mm plywood and the tops and bottom of the wing from the last full rib to the tip are covered with plywood as well.

I purchased the Whelen Microburst II Kit from Aircraft Spruce. These are intended to be installed on the wing ends on a flat vertical surface. Therefore, I needed to build a couple of mounting blocks that would fit securely to the 45 degree wing tip surface and provide vertical surface on which the lights can be mounted.


Once the wood blank has been glued up, I cut it lengthwise at a 45 degree angle.


Then I traced around the lights to see how small I could make the finished mounting block.



Then I cut the block to the final size and rounded the corners with a rasp. Then I marked the wing tips so that I would know where the blocks needed to be mounted. My method of mounting the blocks was to run two pan head screws through the wing tip plywood into each block. I did this by drilling two 1/8 inch holes through the plywood and continued drilling through the plywood on the top of the wing. I then enlarged the holes in the plywood on the top of the wings until they were large enough to allow a screwdriver to access the screws that went into the mounting blocks.


I held the mounting blocks in place and extended a sharpened pencil through the holes that I drilled and marked the locations of the 1/8 inch holes onto the back of the mounting blocks. I drilled pilot holes into the wood blocks, then mounted them using the screws.





The wires for the lights come out of the back of the light approximately in the center of things. The cable kit comes with a cable that has a plug connected on one end and a mating plug and pins that need to be crimped onto the wires protruding from the light. The plugs are nearly an inch wide by almost 3/8 inch wide. So I needed to drill holes in the mounting block and wing tip to allow the plugs to reach into the wing for proper connection.


The lights can now be (temporarily) mounted to the wing tips.




The cables were run through the wings and secured in place by zip ties. At this point the wings are ready to be removed from the plane for covering. The mounting blocks will be left in place and the fabric will go over them.

April 1st, 2016

Moving to a New Hanger

On the 1st of March (yep, It’s been a month already!) dad got a new hanger at the airport, and so Emmett (my son), dad and I went out and moved Sawdust to it’s new abode. Dad moved the airplane, Emmett pushed the engine stand, and I… ummm… well, I took some photos and provided moral support.




This hanger seems quite a bit cleaner, brighter, and maybe a touch bigger than the old one. It should also keep the wind, rain, dust and snow out better.

Anyways, that’s today’s update – he’s also been busy priming and painting the various empennage pieces, but I’ve been pretty focused on work, and buying a house to get too involved. Hopefully I’ll have more time to help this summer!


February 28th, 2016

Horizontal Stabilizer Bracket Welding

Dad spent some time today welding on the horizontal stabilizer bracket, which will allow adjustment of it. It’s hard to describe, but essentially, once he flies the plane, he can use this bracket to fine-tune the horizontal stabilizer angle, sort of like a coarse adjust trim.


February 9th, 2016

AMF 14H MARANDA SN:1026 Making Sawdust February 9th, 2016

Posted by Roger in AMF 14H Maranda SN1026, news

So I went to the airport at lunchtime today and checked out a different hanger. I should be moving the plane into the new hanger about March 1st. The new hanger is larger, has a power bi-fold door and a level floor. I think it will be a good move.

So, remember that the rudder had the primer applied? Well, now it has two coats of the finish paint.
Here it is with the primer …


… and here it is with the finishing color.


I had originally intended to go with Cub yellow (or brighter), but the gal at the Sherwin Williams store said that the yellow would fade really badly and quickly as an exterior paint. My second choice was the blue and I really like it.

Currently I have completed two coats of the blue. The next thing is to sand it to eliminate a few small imperfections, almost like dust particles. Then I need to add four or five more coats of blue before the final buffing and polishing.



I am using a small (4″) fine foam roller to apply the paint for parts that I can bring into the house. Ben & Emmett gave me an HVLP spray gun for Christmas and I am planning to use that on the wings and fuselage. I don’t think I can talk my wife into allowing a paint booth in the basement.

February 8th, 2016

AMF 14H MARANDA SN:1026 Making Sawdust February 8th, 2016

Posted by Roger in AMF 14H Maranda SN1026, news

Thanks to Ben for adding the last couple of posts. That gives a slightly different viewpoint than my “standard” approach to the progress being made.

So the ailerons and rudder have been covered and I have applied five coats of latex primer.



I am following the technique used by Malcolm Morison on his site I attended Malcolm’s presentation at the last two AirVentures and decided that this was the way that I wanted to go. The advantages to using latex paint are several. First, it is readily available. Second, it is easy to apply. Third, latex does not give off noxious fumes, so special breathing equipment is not required. Fourth, the cost is much less than traditional aircraft paint. Check Malcolm’s site for the details of the process and listen to the webinar that he did for EAA which is available on the EAA site.

The primer went on pretty quickly due to the blizzard that whipped through here last week. We were stuck in the house and needed to find things to keep busy with, so I chose to apply the primer to the ailerons and rudder. Just think what applying traditional aircraft paint would be like in the basement of a house closed up tight due to cold weather and occupied by five people. I was able to apply the primer and nobody complained about the odor.

After spending a week moving snow and getting things to the point that we could wiggle, Ben and I decided that we would go to the airport and do a bit of work on the plane. We stopped off at the aviation supply area of our local Menard’s, then went to the airport. The gate would not open which was a bit unusual, so I went to the FBO, checked with them and went through their gate. Things had been cleared so that access to the hangers was easy. However, when I opened the hanger door here is what I saw:


We didn’t expect this and did not have any snow shovels with us, so we closed it up and went back home to get some shovels. We spent some time digging and clearing the snow off of the plane. Then we moved it back a couple of feet. Hopefully the warm weather predicted for the next couple of weeks will melt all the snow. Maybe we will get enough time to shovel more of the snow to the outside.












Even Fred’s engine hoist which was in the corner of the hanger got covered.


Well that was quite an unpleasant surprise!

I did order the control cable and supplies which should be here sometime this week. Hopefully the snow will be melted enough to allow us to run the cables and finish getting the tail rigged. Then I can bring home the rest of those parts and cover them and paint them.

January 13th, 2016

amf 14h maranda sn:1026 making sawdust january 13th, 2016

Posted by ben in AMF 14H Maranda SN1026, news

Dad and I spent some time in the past few days working on the rudder. He showed me how he does his rib stitching, and made a couple of different needles for it using welding rod. He smushed one end with a hammer, then drilled a hole, and smoothed things out. He has a longer one (shown below) and a shorter one he just made which he said worked better.

Rib Stitching

He finished the rib stitching on the rudder while I was out and about, and I helped him get the reinforcing tape cut and in place. He also put some of the access hole reinforcing “things” (for lack of a better term) in place, and I cut out some cloth to cover them. I’ll try to post photos of that process in the next few days.


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