• The Biplane Forum is a large global active community of biplane builders, owners and pilots. From Pitts to Skybolts, to older barnstormers, all types are welcome. In addition to our active community, our content boasts exhaustive technical information which is often sought after for projects and maintenance. This information has accumulated over the 12+ years the forum has been in existence.

    The Biplane Forum is a private community. Subscriptions are only $49.99/year or $6.99/month to gain access to this great community and unmatched source of information not found anywhere else on the web. We are also a great resource for non biplane users, since many GA aircraft are built the same way (fabric and tube construction). Annual membership also comes with two BiplaneForum.com decals.



Upper Wing VIII

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Beej

Creator of this place
Staff member
Administrator
Moderator
Joined
Jan 1, 2006
Messages
6,655
Reaction score
1,887
Location
Austin, TX





<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!)
 

Latest posts

Back
Top