Carlson Skunk Works

November 16th, 2015

AMF 14H MARANDA SN:1026 Making Sawdust November 16, 2015

Posted by Roger in AMF 14H Maranda SN1026, news

Another week and I am doing another blog post! Well, last week I ended needing to make some new brackets for the cabin end of the aileron control cables. The original brackets looked like this:


They were simply two inch wide pieces of two inch aluminum angle. The new brackets are made from 4130 steel. I marked out the locations of the required holes for mounting the brackets to the fuselage and for the control cables. Then I drilled the holes, cut the steel and bent it to shape. After welding the joint where the top of the bracket meets the side, I painted the brackets with self etching primer. The result looks like this:





When the bolts and cables were properly tightened and the stick was positioned in the neutral position, the ailerons were held in the proper neutral position.


The full deflection of the ailerons appears to be about equal up and down.



The only thing that I am questioning at this point is whether I should modify the brackets slightly so that instead of having holes for the aileron cables to go through, I should cut the area forward of those holes to make slots instead of holes. The advantage of doing this is that removing the wings would be slightly easier. However, I only expect to remove the wings once in the lifetime of the plane. Well, maybe twice if I live long enough to need to recover it.

The DAR that inspected Fred’s plane (Fred used these same type of cables) suggested securing them to the ribs so they do not flop around and cause damage in rough weather. I am planning to use zip ties to secure the cables to the compression ribs. Currently it is fairly easy to move the cables into and out of the wings from the inside of the cabin. Securing them to the compression ribs should eliminate that tendency.

Once the cables are secured I will remove the ailerons and cover them. Then it will be on to finishing the tail surfaces.

November 9th, 2015

AMF 14H MARANDA SN:1026 Making Sawdust November 9, 2015

Posted by Roger in AMF 14H Maranda SN1026, news

Well, it has been a very busy weekend. Actually the whole week was busy, but I did get a bit done on the plane. The quick overview is that I got the aileron control cables connected to the control torque tube. Things are mostly working, but the cable mounting brackets that I made will need to be replaced with new ones. So, on to the full description and pictures.


The first thing to do was to get the proper access to the torque tube control horn and attach the cables. This was all done from inside the cabin. I used a Forstner bit to drill a 1″ hole at each end and then used my little pull saw to connect the new holes to the existing hole. I finished it off using my Dremel tool to smooth the edges.


Just having the ends of the cables attached did not result in the ailerons working correctly. What I needed to do was to make some mounting brackets to secure the outer sheaths of the cables. My first pass at this was to use a couple of pieces of 2″ aluminum angle with appropriate holes drilled in them. I mounted the brackets to the main cabin frame with two AN3 bolts. The hole for the cables is 5/8″.


The cables come from the wing roots behind the seat back and down to the torque tube. Now that the cables are in place, I guess I could have gotten by with cables that are 6″ shorter and saved a couple of dollars. However, what I have should work just fine.


The next step was to put the stick in neutral and see how things look.


The cables are about even and there is plenty of adjustment available.


However, there is a significant amount of “aileron droop” that will need to be eliminated. My understanding is that some aileron droop is a good thing, but I think this is a bit much. So I checked things out and found that the adjustment can be made by moving the mount point for the cables up by about 1/2″. However, what that means is that I will need to make new mounting brackets for the cable ends.

Well, back to the shop to cut, bend and weld some steel.

November 3rd, 2015

AMF 14H MARANDA SN:1026 Making Sawdust November 3, 2015

Posted by Roger in AMF 14H Maranda SN1026, news

How about this? Two posts within a couple of weeks! However, that means that I must be making progress, right?

In my last post I made a comment about probably needing to notch the trailing edge of the wing to accommodate the aileron control horn when the aileron is pulled fully up. Randy emailed me suggesting that I rebuild the control horn to eliminate that requirement. I thought that was a good idea, so here is what I came up with:


As long as I was at it I decided to move the hole where the cable connects to the control horn about 1 1/4″ aft. That would allow me to eliminate the 1″ x 1″ square tube spacer between the rear spar and the cable mounting plate. So what I came up with are the pieces to the right of the two sets. The original control horns are the ones that lean to the right and the new ones sort of look like a hand with the index finger pointing up. I took the new control horns out to the plane and found out that they needed to be thinned a bit. The aft area needed to have a very shallow “V” removed to fit into the aileron.

Once the new control horns were fitted and the spacers were removed, things look pretty good.



Full down is about equal to the full up deflection.



Removing the spacers allows the cable mounting plate to fit flat to the front of the rear spar. I think this gives it a bit more stability than with the spacers. However, even with the spacers it was pretty solid. This should also save a few ounces.


The other thing that I forgot to get some pictures of earlier is the pitot static tube installation.


It is a bit difficult to see because the tubes sort of blend in with the ribs, but it shows where I have located the pitot static tubes. By positioning them between the wing and struts I am hoping to avoid walking into them at some point in the future.


I used plywood to build up a mounting area for the assembly. I drilled three 1/4″ holes and used three AN4 bolts to secure the assembly to the wing.


This is a little more clear, but the internal bracing strap blocks the view of the top mounting bolts.

So one of the issues I will be facing when I cover the wing is how to apply the fabric and allow for the pitot static tubes. But there is plenty of time to figure that out.