Hi all, this is Ben, Roger’s son. My son and I just moved to the same town as my parents, and I’ve been able to “help” (i.e. stand around and watch dad work) on the plane a bit!
So, Dad finished the second aileron, with a little help from my son:
Then we started covering the rudder. First we brushed the dust and dirt from the hanger and garage off, then we gently took a file, and a touch of sandpaper to any high-spots from varnishing/sealing them, so they wouldn’t snag the fabric.
Finally we got started covering the rudder with fabric. The first step is putting sufficient glue on the wood, then letting it get tacky. Once it’s tacky enough, we wrapped the fabric on it, dad trimmed it up to fit nicely, then he did an initial low heat (approx. 200-250 degrees if memory serves) pass on just the glued areas with the iron.
He went back and tuned up the fabric, so its a really nice, clean fit, then added a layer of glue, and once dry, ironed it at a higher heat. Once that was cool, then he ironed the whole rudder fabric – not just the glued areas – in a very methodical order so as to not warp or twist it when it started shrinking. Once he was complete, it was very taut, and looks very nice!
Its going to be fun being involved in the build in the coming weeks and months!
At the end of the last post the fabric was on both sides of the aileron and the initial shrink had been completed. What remained to be done was to do the rib stitching, apply the finishing tapes and the perimeter tapes. Now that has all been done. Therefore, here are a few pictures to give an idea of what it all looks like at this time.
Here are a couple of pictures of the hinges. I approached this the same way that Randy did. I removed the hinges, applied the fabric to the bottom of the aileron, then re-installed the hinges.
Tonight I am taking the aileron to our EAA Chapter meeting to show it off a bit. So, what’s next? Well, I plan on moving on to the left aileron, then will paint the two of them together. At least I will apply the primer to provide some extra protection while other things are finished up. I may wait with the finishing coats of paint until everything else is done, so that I have more time to consider the final colors and patterns.
The past several weeks have been quite busy, but I have managed to achieve what I consider a major milestone. The first aileron has fabric on it!!!
Here is a picture of the aileron with its bottom fabric attached.
I am using the Stewart Systems EkoBond glue which is sort of like latex paint. There is no odor and things clean up pretty well with water. It dries fairly quickly and is quite easy to work with. I can do it, after all. There are a bunch of videos on YouTube showing how to use it.
I started by cleaning up the aileron using a fine rasp and then touching up the sealer where I thought I was getting close to the wood. Then I put anti-chafe tape on each of the ribs where I expect to tie down the fabric with a rib stitch. When that was done I “painted” the areas where the fabric needs to be secured with the EkoBond glue. The fabric is pressed into the tacky glue and sticks in place easily without any clamps. The fabric can be pulled off of the glue and repositioned until it is the way one wants it. THEN an iron set at about 250 degrees F is used to heat activate the glue and secure the fabric. When that step is done more glue is applied and worked through the fabric in the glued areas. Finally the fabric is shrunk to 250 degrees for the initial shrink.
The bottom fabric is now nice and tight and looks really good! Here is what it looks like from the top …
and from the bottom.
Notice that the hinges have been removed while I put on the bottom fabric. I reinstalled them before I started on the top fabric.
The top fabric is applied the same way as the bottom fabric was, but it is a little bit more difficult. This is because I needed to make a hole for the control horn to go through and because the front edge of the fabric needs to be secured around the inside of the leading edge plywood. I guess it wasn’t really any more difficult, but it was a bit more messy and took just a bit longer.
The finished product does look good, though.
Around the control horn I added a second layer of fabric. They guys on the Stewart Systems video do this on the wings where the strut brackets need to come through the fabric and I thought it would be a good idea to do the same thing here. I cut a circle of fabric using a quart yogurt container lid as a template. It is about 4″ in diameter. I folded it and marked where I wanted the control horn to come through and cut the opening for the control horn. Then I marked where it would lay on the top fabric and applied glue, positioned the fabric circle and worked more glue through it. I think it came out pretty nice.
Now I need to do the final shrinks on the fabric. The first pass will be to redo the 250 degree pass, then do a 300 degree pass and finish it up with a 350 degree pass. When that is done I will do some rib stitching, but that will be for the next post.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
Has it really been more than a year since I last posted??? Wow! Time does fly!
Things have been busy and life has sort of derailed many attempts at actually doing things to/for Sawdust. Now I think I am back on track and am once again beginning to make some progress. Much thinking and planning have been done and I have a spreadsheet of tasks that need to be done to move construction toward completion. A rough list of items that need to be purchased has been assembled and it should only take me another $10,000 to be flying.
The past weekend was very productive. I started building the trim control. I like the trim wheel type of control and have been puzzling over how to actually build one. Last year at AirVenture I purchased a sheet of plastic that was about a foot long, five and a half inches wide and half an inch thick. I was planning on using it as part of my comm radio antenna. However, there was more than enough material for that purpose, so I used one end of it to make my trim wheel.
The elevator trim tab is actuated via a Bowden cable. This cable will run from the elevator, through the fuselage to the trim control mechanism which will be under the seat. I will be using a bench seat arrangement, so the trim wheel will be mounted inside the seat support and will come through a slot at the front. Therefore, accessing the trim wheel will be similar to the way it is done in a Cessna 150. The other thing that I had to figure out was how to move the center wire of the Bowden cable in and out when the wheel turns. What I decided to do was to bend the Bowden cable 90 degrees under the seat so that it ends up running parallel to the wings in that area. Then I purchased a 3/4 inch diameter threaded rod at Menards and a square nut with the same threads as the rod. The rod and nut use coarse #10 threads.
I started by laying out the wheel on a sheet of paper. First, I drew a five inch diameter circle. Next, I divided the circle into twenty degree segments. Where each segment radial crossed the circumference I made a half inch circle. The paper layout was taped to the plastic and I drilled a small hole at the center, then drilled half inch diameter holes at each of the half inch circle locations around the circumference. It ended up looking like this:
Notice that the nut is sitting there as well. I drilled a hole at the center of the wheel that was the same diameter as the nut was wide. Then I used a Dremel tool cutting bit in my drill press to remove the plastic for the corners of the nut. I was careful to ensure that the nut fit quite snugly into the finished hole. Like this:
I drilled two holes through the threaded rod to facilitate a couple of AN3 bolts. These bolts will keep the rod from turning so that turning the trim wheel will move the rod right or left. The bolts will also be used to mount a plate with a clamp for the center wire in the Bowden cable.
In order to hold the threaded rod I cut a couple of mounting blocks from some left over delrin. This is the material that was used for making the elevator and rudder hinges. These blocks have a 3/4 inch hole centered in the block and located 1/2 inch from the front edge. Then two holes are drilled in each of them to allow them to be mounted to the front of the seat base with AN3 bolts.
Well, it is spring and, even though I did install the engine on the fuselage a couple of weeks ago, you are probably wondering what I have been doing all winter. I have been working on the ailerons and elevator. All of them are nearly done, but the ailerons are the farthest along. That is probably because I had some help with them.
A group of young men from church spent a couple of Sunday evenings working on the spars for the ailerons and on the skins for the elevator. Then my son, Nathan, came from California for my birthday and we installed the aileron ribs. The rest of the process I did by myself. Oh, and I did take some pictures.
This shows the aileron spars with the ribs sort of attached. The locations for the nose ribs are being marked.
The trailing edge of the ailerons is being made the same way that I made the trailing edge of the wings and elevator, rather than the way the plans call for. The plans call for the trailing edge to be cut at the appropriate angle with a notch cut lengthwise to accept the gussets. What I have done is to cut a piece of 2mm plywood to run the full length of the aileron, then I marked the desired location of the aileron ribs and glued them in place. Once that much was assembled I cut fir strips to be glued on each side of the plywood. Later I shape the trailing edge with a planer and sander.
All of the aileron nose ribs are identical. I rough cut the ribs, then stacked them together and sanded them to make them identical. I used my little pull saw to cut the notch for the leading edge stringer.
The locations of the nose ribs were marked. These are not all placed directly on the other side of the spar from the rear ribs.
To make gluing the nose ribs into place a bit easier, I clamped a couple of boards across my bench to allow me to hang the ailerons with the front of the spars up. I could mix up some T88 and glue the nose ribs pretty easily. Of course, I stapled the nose ribs as I glued them and pulled the staples once the glue had cured.
Before I glued the trailing edge strips I marked where I wanted to cut out the plywood. This results in some weight savings and makes everything look like the plans. However, I think it makes things a bit more durable and secure.
After the first trailing edge strip is glued to one side of the plywood, I used my pull saw to cut out the area ahead of the trailing edge strip. The areas of the plywood that I left correspond to the gussets that the plans call for. I cut the angles to 45 degrees because it was easier to mark that angle with my combination square, than to mark the 30 degree angle called for in the plans.
The center rib for each aileron was built just a bit differently than the plans as well. The plans call for two ribs to be positioned in the center. These ribs needed to have a gap between them for the aileron horn. Since I plan to use push-pull cable to activate the ailerons, the aileron horns will only protrude above the ailerons. Therefore, the horns can be inserted from one side. Therefore, I used 3/4″ fir in place of the two ribs. Then I cut a notch in the rib to accept the horn.
Partial plywood skins are glued on the top and bottom of the ailerons. Holes needed to be made in the skins to allow the horns to be inserted and bolted into place.
The bottom skin is flat, but the top skin is curved. There is a solid fir strip on the leading edge to hold the top skin while the rest of it is bent to the contour of the aileron top surface.
The way that I did this was to glue the fir strip to the plywood first, then I smeared glue on the top of the ribs and spar. As I positioned the skin assembly in place I glued and stapled the gussets in place to hold things securely. Once all the gussets were in place I could staple the skin to the nose ribs, spar and aileron ribs. I had to carefully work things to fit the required curve. I used enough staples to hold things securely.
When the glue cures things should look nice. Then the trailing edge strips were planed and sanded to the proper shape.
The next step will be to cut the piano hinge to make the hinges for the ailerons.
