LH WING AILERON AND CONTROLS
Once the wing structure was essentially complete, I decided to work on the aileron control system in the wing for awhile. As you can see from the dated pictures, I started the aileron control project in the middle of October, 2004. I actually started the right wing first. Some of the photos are from the right wing. You will have to guess which ones.
Fabricating the aileron controls in the wing starts with cutting the AT6-035X1.125 tubing to the length of 65 25/32” per drawing 15A. The best way to cut this tubing is with a tubing cutter. There are some things that you need to be careful of however. First is that the tubing cutter squeezes the ends of the tube so that the VA-111 does not fit very well. I solved this problem by putting a socket that was slightly smaller than the tube inside the tube where the cut was to be made. The next problem was not as serious but I decided to solve it anyway. The cutter can mark the tubing very easily. After I measured the tubing for cutting and marked it, I installed the cutter and went around the tube lightly one time. I removed the cutter and put masking tape on each side of the mark it made on the tube. I then put the socket in place and cut the tube to length. See upper right photo. After the tubing was cut and de-burred I installed a VA-111 rod end retainer in each end.
Next I put a piece of masking tape on the tube and cut it so that its two ends met exactly. See the photo at upper left. Then I removed the tape and put it on the workbench. I drew a line ¼” from one edge of the tape. Next I measured the length of the tape and found out that it was 3.6” long. Since the fitting is attached with six fasteners I put five marks across the line .6” apart. Considering that each and of the tape is actually a mark I now have six equally spaced rivet marks (right photo above).
Next, I put the tape back on the tube (left photo above). Then I drilled the #30 fastener holes on a small drill press.
Next I riveted in each VA-111 retainer to the W-716L using CR 3213-4-3 Cherry Max fasteners (above left). The plans call out MSP-42 blind fasteners but I prefer to use fasteners that were designed for aircraft use. Next I set total length of the W-716L from the center of one rod end of the center of the other rod end at 69 9/32” per drawing 15A. This pushrod is now ready for installation. The photo above right shows the completed pushrod. All of the tools on the bench in the photo were used in constructing this pushrod and the W-818 pushrods. Sheet metal projects get more tools out of the box and scattered around on workbenches than any other type of project that you can name.
I fabricated two W-818 pushrods per drawing 15A (left photo above). I forgot to take pictures during the fabrication process (darn, darn, darn). Next I attached one of the W-818 pushrods to the WD-421L bell crank per drawing 15A (right photo above).
Aileron construction started on January 1, 2005. I moved the ailerons and flaps back to Florida because I was going to be there for most of January and I wanted to complete the wing assembly. The picture above left shows the left aileron on after a brief inventory. The first item on the agenda was to make the stiffeners (above right).
I trimmed the stiffeners on the Harbor freight band saw. I think that I mentioned that this saw is a very good design that is very poorly made. It is a shame that the workmanship is so bad. This is the only small saw that has such a wide throat (12") but the workmanship on its construction is so poor that it is unbelievable. The work platform is not even flat. I have 2 of these, one is in Tennessee. They are dirt cheap at about $120.00 but if quality is a consideration, they are overpriced. Above right, I am sanding stiffeners on my Lowe's sander (Delta). It must have been made in a different part of China because the quality is OK.
In photo above left, I am finishing the edges of the stiffeners with a file. Above right I am in the process of dimpling the stiffeners.
There is a doubler called a "re-enforcement" P/N A-408 that goes on each end of the spar. They come pre-cut. You round the corners and de-burr the edges and drill per drawing 13A (photo, upper left). I cleco'd the spar to the lower wing skin (upper right). I cleco'd the end ribs P/N A-405-L and A-405-R to the spar and drilled the holes from the skin through these ribs. I then removed the spar from the lower skin, cleco'd it to the upper skin, cleco'd the ribs back in place and repeated the process for the upper skin to rib attach holes (no photo). You have to be careful with these ribs. They are not symmetrical. If you mistake the inboard rib for the outboard when you drill them, you will be buying two new ribs.
This is a cute idea. The balance weight is a piece of galvanized pipe. The photo above left shows it clamped to the leading edge of the aileron. At right it is cleco'd to the leading edge. Care had to be taken to keep from twisting the leading edge during the drilling process. There are 2 rivets that get installed from the leading edge to the cast iron pipe....er.... balance weight. Drilling the holes from the rib to the weight was challenging to say the least.
The photo above left was taken when I thought that I was ready to etch, alodine and prime the left aileron parts. I was not quite ready as it turned out. The rivet holes for the skin attachment needed to be countersunk. I thought about dimpling them instead but the material is thick enough for a countersink and this made the chances of twisting the spar more remote.
In the photo above left, I have etched, alodined, and primed all of the left aileron parts. It is time to assemble it. The first thin that I assembled was the A-408 re-enforcements. The picture above right shows the inboard plate. Notice the nutplate. The plans call out an AN365-1032 here but the holes match a K1100-L08 nutplate exactly. I installed a nutplate.
The next thing was to remove the protective coating from the rivet lines (upper left). Then I decided to try something little different. First let me say that this is an experimental airplane. It is being built for recreation and education. The plans tell you to put a dab of silicone across the trailing edge of the skin from each upper stiffener to each lower stiffener to help reduce the possibility of fatigue cracks due to vibration. On all of the other flight controls I did this. On the ailerons, I decided to try something different. I installed each stiffener wet with fuel tank sealer (above right). I just want to see what happens. If I develop skin cracks I will have to buy new aileron kits but I just have to know if the problem is in fact vibration and whether or not this sealer will act as a vibration dampener.
Above left I am back-riveting the stiffeners on to the left aileron skin. At right the stiffeners are all installed. (Note: I have the back-rivet bucking bar installed in the tool I made to back-rivet the aft fuselage skins together with.)
I had some difficulty bending the trailing edges of the other flight controls earlier (elevator and rudder). On the ailerons I decided to use a 2" X 10" like the plans call out. I popped over to Lowe's and purchased a board that was straight. I also purchased 4 hinges. I decided to stay with my idea of using the table as part of the tool (upper left). Bending this trailing edge was a breeze (upper right).
The next item was to assemble the leading edge. First was to countersink the holes in the weight (above left). Next was to put a dab of primer in each countersink (above right).
I then attached the leading edge ribs to the "weight" (above left). Next I mixed some sealer a put it inside leading edge where weight attaches. The sealer is to minimize dissimilar metals corrosion possibilities.
I then riveted the leading edge to the "balance weight" with CR3214-4-3 cherry max rivets. I still can't make myself use hardware store "pop" rivets on this airplane. I was reading the Yahoo groups RV-7 and 7A forums today. They are getting a pretty good squabble started about the design of the RV-7A nose gear. They have already had a long debate that they called the "Primer War." Maybe I could get a "Rivet War" going. I am getting off track here. The upper right photo shows the "balance weight" installed.
The picture above left shows the aileron cleco'd together along the upper surface. This looks like a serene little piece to assemble, doesn't it? The design came right out of the bowels of hell! You have to move the spar off of the table with no clecos in the bottom. You then force your hand through the gap between the leading and trailing edge skins, holding a bucking bar no less! You shoot one rivet and then you go get a band-aid because you have just cut yourself on the first of several thousand (it seams) rivets. I fought every one of those rivets on the upper skin telling myself that there had to be a better way. There was but I didn't figure it out until I needed a blood transfusion. I believe that I have stated my distaste for hardware store rivets in airplane parts a few times. I knew that I was going to try to put solid rivets in the bottom skin to spar attach but I just didn't know how I was going to do it. If you look at the picture above right you see me shooting these solid rivets in the bottom skin.
The photo above left shows the bucking bar that I used. The left half of it is a piece of steel 20" long. I have a piece of wood taped to it with green masking tape about 10" from the end. The total height of the bar plus the wood is the same as the inside height of the spar. The wood is beveled so that the bar is parallel with the inside surface of the spar. The purpose of the wood is to act as a fulcrum so that the end of the bucking bar can be used to buck a rivet. At the other end I have taped a socket extension to the bar. This lets me get the bar all the way to the middle of the aileron from each end. This worked better than I had hoped. I actually looked at each rivet the moment I shot it just to make sure that I was not messing them up. I never screwed up a single rivet. I started at the outboard end and worked toward the middle on each end. If you look at the photo at right above, you can see that the rivets from the left edge of the photo are installed. I have started on the other end and am working my way towards the middle. On the next aileron, I intend to put all the rivets in this way.
Above is a photo of the completed aileron. The fact that all of the skin to spar rivets are solid AN426AD3's makes it look better and gives me a sense of accomplishment.
On February 26, 2005, I installed the left aileron. I went to an all RV fly-in in Richmond, Kentucky to get myself pumped up. This is the second one of these that I have attended this year. Anyway, the photo above left is of the left aileron after I installed it on the wing. The wing is upside down because I can't lay it on its bottom on a table because of the pitot tube. The right photo shows the aileron from the outboard end.