It's the weekend so I can't call BUSA. the enclosed pic is of the righ top wing of the 1/3 scale BUSA Sopwith Pup I'm restoring. The rear landing wire on this wing was broken and now that I have it fixed and everything tight I can't seem to get rid of this gap at the trailing edge of the top wing. The gap is normal, having it wider and the wing not pulling tight up against the center section at the rear spacer is not.

I'm trying to decide which of the flying/landing wires probably needs tightening to fix the problem. Can anyone help. Thanks

Splais

One thing to check is whether the faces of the root ribs (both wing and center section) are really flat or whether they have a slight curve that could be creating this problem.

You might also try loosening the forward landing wire, then tightening the rear landing wire before retightening the forward landing wire.

I tried loosening both flying and landing wires on that side but it didn't help. I'm going to demount the wing and check the gap with no tension on the wing.

Steve

As that's the top wing, with a gap at the rear, I'd say you need to slacken the forward flying wire and tighten the rear one.

My experience is that this gap wil be closed during flight, I have the same on my 1/3 scale pup,
the resistance of the wing closes the gap, just try pushing against the outboard leading edge when the plane is fully rigged and see if the gap closes I think it wil

sorry I have to show off and put this picture here, somebody made a great inflight picture last weekend:



Just my two cents as an experienced BUSA pup flyer

Frank

Yes, I can push on the wing and easily close the gap. I'm afraid these 12 year old flying wires need replacing, I just don't look forward to that at all. It does appear the rear flying wire (were gap is) is not tight enough,

I get the same gap on my SE5a. The reason for the gap, in my opinion, has to do with two things.
First the full size plane uses fasteners on the front and rear spars to connect the wings to the center section. Second has to do with the stagger of the two wings. The top wing stagger adds weight to the forward section of the upper wing. Consequently there is a natural seperation from the back part of the wing. You dont see this on the full scale due to the wing attachment method. Just my 2 cents.

Actually I have a minor amount of this on one side of my Snipe's top wing as well. In part this was due to minor curvature which I have fixed. But I also think it's what Bob says. In fact, I've been considering the idea of adding a pair of bracket to the rear to "clamp" the two root ribs together.

I had pretty much decided it was a visual thing more than a flight issue. Now it sounds like it may not be a big deal. The gap also got less after I loosened everything up and and re-thightened. The SE5 I had, had little plates holding things together. After seriously looking at everything though it appears I really do need to change out several of the turnbuckles. Unforutnitely they are a 12-15 year old style Proctor no longer carries. the eye bolts are metric so I'm still back to completely rewiring the whole thing from scratch; but that's the kind of thing I expect from a 12 year old bird anyway.

PS: bob I finally got the Bryant SE5a plans - just incredible.

Steve

Steve super!! I WILL order a set of those plans just because.. Some Day I'll build another!.. I might even order the short kit from Holman along with the fittings.. who knows lol