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Upper Wing VIII

Beej

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<TD vAlign=top>Getting prepared for the big clamp-up...


Joining the two uppers was always going to be a time of stress. If something was out of line, out of level, oreven dirt under one of the spar jigs, the error would be cast in stone once the splice/doubler join was made. So without further a do, the wings were taken off the bench, and the bench was re-checked for flatness and twist.


I had fabricated the shallow anglesplice blocks months earlier, so they were all ready to go. I made a boo bootho... - I have an existing salvage fuselage that has been mothballed for 18 months, and it has cabanes fitted. Therefore I should have checked the centres between the bracket points on the cabanes before making the upper wing. It turns out that the centres were 1/4 inch off. So I had to fudge a little with the 1/8 ply doubler thickness fore and aft to get an exact fit.


The glue-up turned out to be a pretty smooth event. The splice blocks/doublers would potentially slide all over the place during glue-up, so to remove the vertical slippage factor, I screwed some resting blocks to the bench, the splice blocks then rested on these, so I could focus upon lateral alignment while clamping.The1/8 ply doublers werefitted later.The destruct test alsowent well.


Thedoublers I had made with surplus height, so I could plane down to a flat level because the join in the spars is infact a shallowcompound miter. I wanted the spar joinflat so as to laminate the spar filler in one piece. I have decided to omitt the lower center section ply [that the gas tank sits on]until the cabane brackets have been fitted later.


Clearcoating was the final task. Seeing as I was at a very monumental moment in the build,I invited the wife to help me brush on the last coat in the center section:)


The only thing not done is the ply leading edges. I have some ply from a previous failed bend idea/attempt 2 years back,whichI was going to play with, but I have decided to buy the vacuum moulded LE's from Steen. These LE's I used on the lowers last year and fitted like a glove. More importantly, because they were a good fit, there is no post stress in the ply or the wing, which I am sure was the cause of a slight twist inmy ailerons a while back. As soon as I add the LE ply, I can take the monolithicbench apart, and make room for finally focusing on the fuselage.





Beveling the splice block...

All clamped up... (lightly!)
 

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