With all the airplanes currently flying like this, I'm sure others have found and fixed this problem before. Sorry for the big pics, I wanted to show good detail.
I installed the windshield on my 9A per Vans plans with small aluminum clips riveted to the forward skin, then covered that joint with flox and a couple layers of glass cloth over the top, then skimmed that over with microbeads prior to paint. For 140-ish hours this was fine and showed no problems whatsoever - but now just 28 hours out of paint that area is cracking, showing definite flex outward. I have kept the pictures here full size to show the detail. I'm only showing pics of the right side in this case but the problem is duplicated on the left, both show bowing outboard at the same spot along that joint.
What I'm thinking is that, Vans plans or not, the aft corner is simply not supported adequately and needs to be immobilized with another clip in the area of the triangular steel gusset that is the base of the forward canopy bow. I'm thinking I need to use a grinder to remove the overlaying layers of glass to expose the joint, drill a hole just below the plexi through the aluminum and steel triangle, and install another clip with a screw going inward from the outside. I'll use a nylock on the inside and trim the excess screw length, then re-bury the head and clip with flox and microbeads before repaint.
What sayest the brain trust here?
I installed the windshield on my 9A per Vans plans with small aluminum clips riveted to the forward skin, then covered that joint with flox and a couple layers of glass cloth over the top, then skimmed that over with microbeads prior to paint. For 140-ish hours this was fine and showed no problems whatsoever - but now just 28 hours out of paint that area is cracking, showing definite flex outward. I have kept the pictures here full size to show the detail. I'm only showing pics of the right side in this case but the problem is duplicated on the left, both show bowing outboard at the same spot along that joint.
What I'm thinking is that, Vans plans or not, the aft corner is simply not supported adequately and needs to be immobilized with another clip in the area of the triangular steel gusset that is the base of the forward canopy bow. I'm thinking I need to use a grinder to remove the overlaying layers of glass to expose the joint, drill a hole just below the plexi through the aluminum and steel triangle, and install another clip with a screw going inward from the outside. I'll use a nylock on the inside and trim the excess screw length, then re-bury the head and clip with flox and microbeads before repaint.
What sayest the brain trust here?
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