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Here is a view of the rear ribs all lined up. 6/17/99 |
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Here are the front ribs all lined up. 6/17/99 |
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Here is a view of the reinforcements that go behind the aileron belcrank pivot point on rib # 9. You can see that I attached the flanges at the top and bottom of the reinforcements. I should have waited (as Tony Spicer suggested) to attach these flanges until the ribs were in place on the spars so that they would sit flush with the skins. 6/17/99 |
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Here is a close-up of the aileron belcrank pivot point. To make the belcrank itself I used double-sided tape to stick the two plates together. That way when I cut and drilled the belcranks they were a perfect match. 6/17/99 |
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Here is another view of the aileron belcrank pivot points. 6/17/99 |
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Here is the aileron belcrank pivot point with the rib attached to the spar. 6/17/99 |
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Here are the steel bushings that ride inside the bronze bushings. I first cut them to length and then chucked them into my drill press. I then turned the drill press on and used a file to smooth down and square off the ends. After the file I did as Tony Spicer suggested and ran the end of the bushing down onto emery cloth to ensure that the ends were perfectly square. 6/17/99 |
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Here is the mandrel I used to chuck the bushing into my drill press so I could smooth down the sides and reduce the size so it would fit inside the bronze bushings. It is important that the pivot point moved freely but without any play. 6/17/99 |
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Here is a push rod's view of the belcrank. 6/17/99 |
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Here is the view through the read spar. 6/17/99 |
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I tried a new technique to form the leading edges. I learned it from a Sonex builder that had used it successfully. I, however, was not having the same success. The technique is to tape the trailing edges together and then tape plastic over the holes at each end. 6/23/99 |
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You then cut a small hole in the plastic, insert the hose of your shop vac and turn it on. On my first attempt I let the vacuum run to long and sucked the sheet flat. I was amazed at how fast it happened. I bent down to turn on the vacuum and by the time I had stood up to check the progress it was already to late. 6/23/99 |
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On my second attempt I was more careful with the switch. However, I was not getting the proper radius on the leading edge. I keep checking the radius with the template from the plans and it looked as though if I went any farther the leading edge would be to pointed 6/23/99 |
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When I untaped everything, the angle formed was about 120º rather than the 85º called for in the plans. I have decided to give up on this method and build one of Tony's presses. Press Brake Plans I bought the materials for less than $40. I think I can still salvage one of the sheets. The other one is a complete loss. BTW be careful handling the leading edges after you have formed them. It is easy for the large sheet of AL to flop around and put a nasty kink into your nice smooth leading edge. 6/23/99 |
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Here is my press. I made two changes from Tony's plans. Instead of screwing conduit onto the 2X10, I used my router and a 3/4" radius round over bit to put a bull nose onto the 2X10. I also already had a 12" 3/8" drill bit so I was able to drill all the way through the 2X10 without cutting a slot. I also had to use shims to straighten out the female part of the press because my garage floor was not perfectly flat. 7/13/99 |
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Here is a close-up of the press in action. It worked perfectly. I laid out all the edges and pilot hole locations before I bent the skin. I waited until after the bend to drill the pilot holes, just in case some thing moved during the bend but nothing did. 7/13/99 |
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Here is the bent leading edge skin being test fit to the ribs. I rough cut the skin to size but waited to do the final cut until after I had test fit the skin to the ribs. As it turned out I had miss-measured slightly and I was able to make a correction without trashing the whole sheet. 7/13/99 |
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Here is the aft upper skin being drill and clecoed to the ribs. I first laid out the edges and pilot hole locations and test fit the skin before I cut and drilled the skin. I was having difficulty getting every thing to line up until I realized that I forgot to level the spars. So I blocked up the rear spar and checked that every thing was level and the wing had no twist in it. 7/13/99 |
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I started at the trailing edge and worked forward. You will find that the spars have a slight fore to aft bow in them. The bow is corrected once you get the skin attached to the trailing edge. I drew a centerline down the rib flanges so I could be sure the holes were drilled in the center of the ribs. I used the scratch awl from my combination square as a pick to jog the rib left or right so I could drill dead center. 7/13/99 |
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After the top skin was drilled and clecoed I flipped the wing over. I had to block up the rear and forward spars to clear the clecos. It is important to level the wing again because any twist will be locked into the wing once you get both skins attached. 7/13/99 |
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I again worked from the trailing edge forward. When I laid out the skins I used the factory edge of the sheet as the trailing edge. This way I was assured a straight lay out. I had to drill the aft skins up to #30 and install 1/8" clecos so I would have enough 3/32 clecos to do the leading edge. Even then, I bought 150 more 1/8 and 3/32 clecos. However I did NOT drill up to #30 the trailing edge or the main spar. I will drill them up later 7/13/99 |
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With the aft skins installed I started on the forward skins. I worked from the trailing edge of the sheet forward. I measured 3/8" from the trailing edge and drew a line across. This would be the location of the matching holes from the rear skins. I then tucked the trailing edge under the aft skin and lined up the mark with the pilot holes in the aft skin. Once lined up, I drilled and clecoed. 7/13/99 |
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Once the trailing edge was secured I moved forward one row at a time being sure that the holes lined up with the center line on the rib flange. 7/13/99 |
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Now comes the tricky part. I used some straps to gently pull the skin around so I could tuck the trailing edge under the aft skin. A board will help keep the skin down on the ribs. Don't tighten the straps to hard or you will bend the flanges of the rear spar. 7/13/99 |
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Once I got the skin tucked in, I lined up the mark with the pilot holes in the aft skin, drilled and clecoed. 7/13/99 |
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Once the trailing edge was secured I moved forward one row at a time being sure that the holes lined up with the centerline on the rib flange. At this point it was getting harder to hold the skin flat against the ribs. 7/13/99 |
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At this point, every thing is laying flat but there is a lot of tension on the last cleco, the one closest to the leading edge. I am tempted to rebend the leading edge to be more like 70º rather than the 85º called for in the plans. 7/13/99 |
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It is important to remember that when the wing is finished the leading edge skin will overlap on top of the aft skins. Right now the leading edge skin is tucked under the aft skins only to hold it in place and so that you can transfer the pilot holes in the aft skins to the fore skin. (What, why are you laughing? What is so funny???) 7/13/99 |
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