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DOX8

Member
I did the bend on the rudder skin and thought it came out really nice. Then clecoed it to the spar and ribs and it developed a noticeable bow along the trailing edge.:mad: Some how, I did not get the bend exactly in the middle. Looking through the forum, it seems there can be .100 inch variation. I haven't measured, but I estimate it's off more than that. Not sure how to fix.
 
Not happy with my attempts to fix the bow problem. New skin and stiffeners are on their way. :eek:
 
bowed rudder

Hi, did you use the 2x8 with hinges to close the bend the whole length at one time? That is the best way to get a straight fold on it. Refer to figure 5-5 on page 5-10 in section 5, construction materials and processes of your manual. Try to do this well because you will need to do this on many other parts as well.:)

bird
 
I used a 2x10 hinged to the edge of my table. It looked great until I clecoed the skin to the spar and ribs. Thats when the bow showed up.
 
flat table

If you clecoed and assembled on a fairly flat table, it should come out great after all the riveting is done. Only thing I can imagine is that it somehow must have gotten twisted while riveting or something like that.
 
It appears the bend did not form in the exact middle of the skin. I made the bend a little at a time but I did all the bend with the same side up. I SHOULD have made gradual bends on both sides to make sure the bend was even. When the skin is clecoed to the ribs and spar, one side has more tension than the other. It pulls the trailing edge to one side and cause the entire trailing edge to bow.
 
It may come out

The bow probably has more to do with drilling the skins to the spar than bending the trailing edge. A very slight amount of movement can make bad things happen when you rivet.
I'm guessing that if you drilled out the rivets along the spar, clamp everything down so it is straight, run a drill through all the holes and rerivet, while it is still clamped down, the bow would disappear. You would have to drill out both sides first, then reclamp each side and rivet.
If you take the entire skin section off and look at the trailing edge, and there is a slight bow, you could attempt to straighten it by rebending in the wooden brake, but make sure that is straight, too. The brake should be able to capture the entire length of the trailing edge at one time.
 
I actually never riveted the skin in place. Just by using the ole eyball, I estimate the skin to be off by a little less than half a rivet hole from one side to the other. I'm sure the holes would be too sloppy if I drilled it to fit. I'm throwing in the towel on this skin. The new one should be here on Thursday.
 
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