Tipup canopy skin fitting

[Brantel]

I need to continue the quest to get a nice fit on the tipup canopy skin and have a few problem areas and need to know what you guys have done with these areas. Please offer your thoughts on the best way to deal with these spots:



I took seaming pliers to the front lower corners and bent the edge in toward the fuse on the last 1/4" or so at the bottom. You can see that in the pic. Even with this, there is still an gap and you can see right thru there from the inside.

[Greg Arehart]

Brian,

No particular fixes from me - I've been having the catching problem in the center of the TU. I have finally decided that the gap has to be more than one would think - I'm ending up with at least 1/16". Along the sides, I think seeing through that gap is a fact of life until you put some weatherstrip along there - from your photo, the fit looks reasonable to me. I also ended up tweaking the bend just a little by hand to make the canopy fit the fuse. Presuming your plexi is not yet glued in place, this can be done by placing the part upside down on a sandbag and "springing" it a bit. The sandbag keeps it from bending sharply in one place.

cheers,
greg

[Norman CYYJ]

Make sure the gap is wide enough to handle the paint that you apply if not it will chip out and make a horrible mess. About another 10 thou.

[Jim P]

I had to trim the center so it wouldn't catch, and even then once riveted it still caught and dinged the center a little. It still needs a little work prior to final painting. For the outboard leading edges, I ended up shimming the forward skin. Once that was riveted, I found that I could have used a little more shim. You'll probably find that once you think it's fitting great, it's all going to change a little when it gets riveted for the final time.

[Brantel]

Just to clarify... The gap that I concider necessary is the gap between the front skin and the canopy skin in the horizontal but the one I am trying to remove is the air scoop effect of the canopy skin in the corners being higher than the front skin.

That and trying to get the sides to fit the fuse correctly from the front corners (too far outboard) to the splice plate with the side rails (too far inboard).

I will continue to bend the side rail splice plate area out to meet the sides of the fuse and several have told me that the front corners will fit better once the skin is riveted to the frame.

[noelf]

Check out Dan Checkoway's site, in the Nov 30,2003 area. There, he describes the problem he was having and the fix, with pictures even.

Sounds like / looks like what you are describing...

[boom3]

Hey Brian,

It seems there's no way around some of these issues no matter how much reading and forethought you do. I spent a ton of time making sure things were right on the money when I drilled my hinges and the result is pretty much exactly like yours. The hinges turned out perfect but I seem to have some downward pressure in the middle of the tip up skin and the front sides along the subpanels have the slight air scoop you speak of. I have not started on the side and rear portion of the frames but see the same problems coming.

I was nervous about riveting the front canopy frame splice plate so I didn't before drilling the hinges. I noticed that it was down slightly in the middle and have corrected that. Not sure why it ends up low in the middle but it definately shouldn't be in my opinion. I've looked at a lot other peoples pictures and many seem low. I'm sure this causes the center to catch on the front skin. Still nervous, I have the splice plate temporarily riveted with 6 or so AN426-AD3's. I'll commit to the 4's when I see how some of this shakes out.

As for the slight air scoops along the outboard sub panels, that is definately caused by the flanges on the subpanels not following the curve. I really noticed that when I left the canopy frame and skin on, and took the front skin off. Shimming seems to be the answer here since one would be hardpressed to follow that amount of curve with a fluted, more than perpendicular flange. I'm sure many just fill it later when doing body work too.

Not sure what one could do differently at this point in the build. Duct tape, tie down straps, etc get the canopy right where it needs to be when you drill it but when you take all that off....

Here you are! Welcome to the club!

[db1yg]

One other thing to consider as you are fitting the front of the canopy skin to the forward fuse skin is the affect of the hydralic lifts. You can get your canopy opening and closing with just the right amount of clearance w/o the lifts in place, put the lifts in place, and the clearance will disappear or be reduced. The lifts put a forward pressure on the canopy frame as it comes down and changes the fit slightly. It could ruin your whole day. Don't ask me how I know.

Cheers,

db

[Brantel]

I will be installing the jack bolts/brackets like several others to help prevent this problem.

[Pmerems]

Brian,

I too had some issues. Made up some shims and achieved an acceptable fit. Haven't riveted the forward skin on yet but all looks good for now.

I posted my shimming technique some time ago. Search on "shim or shimming" the forward skin and you should find the post.