Carlson Skunk Works

October 26th, 2015

AMF 14H MARANDA SN:1026 Making Sawdust October 26, 2015

Posted by Roger in AMF 14H Maranda SN1026, news

Little things are happening, but progress is being made. Having help is a good thing, too. Here is my crew helping with a couple of the little jobs.

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Emmett was tasked with taking out four bolts so that I could remove the control torque tube. Uncle Jeremiah was tasked with helping him. They made a pretty good team.

I needed to have the torque tube removed so that I could take it home and make the aileron cable actuation plate. With the aileron cables close to being attached to the ailerons, I need to design and build something for the other end of the cable that will push and pull on the cables. The last post showed how the cables were threaded through the wing and met the aileron control horns. What I needed to do next was to make some mounting brackets that would allow the cables to be secured to the wing. Here is what I came up with.

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The bracket is mounted to the front of the rear spar. I had to move it forward an inch to get the right length. I went to Menards and got a three foot length of square aluminum tubing. I cut the tubing to length and drilled the holes. The mounting plate was made from the same aluminum plate that was used for the aileron control horns. The cable required a 5/8 inch hole for the threaded mounting area of the cable to go through. Even that hole was a bit snug, but once it is in place it should never need to be moved again.

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Of course I didn’t have the required bolts on hand, so a quick Aircraft Spruce order was required.

Once the brackets were in place and the cables were properly secured I pulled and pushed on the other end of the cable to verify that aileron movement was about equal up and down.

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I thought I might be able to get by without making a notch in the upper trailing edge of the aileron opening, but it looks like the notch will be needed. That is a minor issue.

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The aileron ends of the cables are now secured, so the focus of my effort will now return to the control stick end of things. Here are the pieces that will now be installed.

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On the left is the plate that I made to attach the input end of the cables to. The torque tube has been built according to the plans with a plate where the aileron cables are intended to be attached. However, using the push pull cables requires these cable connection points be moved out horizontally. Therefore the new plate bolts to the torque tube using the cable attach holes. I should be able to provide more pictures and detail in my next post.

All of the steel parts are being painted as I go. Once each part is finished I am using a self etching primer to paint them before I install them for the final time. At least I am hoping that this will be the final time.

October 9th, 2015

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

Posted by Roger in AMF 14H Maranda SN1026, news

Progress has been made! More parts are in place and things are looking good.

The tail is coming together and we should be ready to run control cables before long. The tail needs to be in place before the trim control cable can be run and the trim mechanism tested. The only concern that I have with this is figuring out how to run the Bowden cable through the horizontal stabilizer and elevator, and still be able to remove the stabilizer and elevator and put them back on again. I guess I need to study the plans again.

I decided to use the same approach as Randy Holland for stabilizing the tail surfaces. I am installing jury strut material instead of the cables called for in the plans. This is actually less expensive than using cables. The shackles for connecting the cables to the tail pieces are extremely expensive! Each one is $10.85, so the cost for the 16 that would be needed for the tail comes to $173.60! All the jury strut material for the whole plane came to less than that. Using the jury strut material looks nicer, too.

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The connection points on the fin were changed so that I now have separate connectors for the front and rear jury struts. This was not nearly as difficult as I had envisioned, but I ended up doing it a bit different than the change bulletin that Chris sent out. I made some fir mounting blocks that sit on top of the upper fin rib and cut a couple of pieces of aluminum to go through the fin for the jury struts to fasten to. Then I drilled a hole in the middle of each block and aluminum strip and bolted it all together. I stopped in to see Gary Forbess at Marlatt Machine Shop to see if he had some aluminum that I could use for the jury strut connection points on the bottom of the fuselage. Gary has been a great resource for metals for my project and he is our EAA Chapter Secretary.

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I managed to finish the plates that clamp the internal bracing straps where they cross and they are positioned in the wings. So far I have been able to get two sets of them fully secured in place. It is a bit tricky getting the screws and nuts to tighten fully. It would be a lot easier to use AN3 bolts, but I am not going back to order them at this point.

The aileron cables were ordered and have arrived. These are custom made industrial cables that I got from Baum Hydraulics in Omaha. The cables are 132 inches long and have bulkhead mounts on each end. They come with 1/4 x 28 threaded ends, so I ordered AN665 threaded clevis ends from Aircraft Spruce to go on them.

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The cables go through 5/8″ holes and have a threaded area with two nuts and two 1 1/4″ washers to tighten on each side of the hole that the cable goes through. This mounting area just happens to end up above the front edge of the rear spar. Therefore mounting an aluminum plate on the rear spar is the ideal way to mount these cables.

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Things are moving again!