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Optimal Canopy Frame Skin Gap

T

tx_jayhawk

Well Known Member
I'm about ready to punt this canopy frame skin across the shop...this has been one of the more frustrating parts thus far.

Can anyone advise what the optimal or max gap should be between the front canopy frame skin and the rear of the forward top skin? I can't seem to get it any closer than 1/32", and I'm not seeing where it is interferring. I've already removed material from the spacers, gooseneck, and canopy seal.

Also, any websites or advice on fixing the common bulge near the arc would be appreciated. I've heard people say bend them, but I'm not really tracking how that should be done. It seems you really can't bend it until the splice plate is riveted in. Otherwise, your attempts to bend just moves the two independent fram halves.

Thansk,
Scott
7A Finishing
 
If you're planning on painting it, then you don't want it too close... even 1/32 may be too close when you account for paint.
 
Gap

My gap is about .050 or so and is consistent in width. I have not riveted the skins on yet but this is where it is today.

My bushing holes are almost perfectly centered in the bracket/weldment. If I were to have smaller gap, it would offset the bushing hole location.

I also needed to shim under the forward skin to get a good fit with canopy skin. The tapered shims (.025 max thickness) are at the 10:00 and 2:00 position.

Paul
 
Thanks guys. It sounds like maybe I have it close enough already? Paul, did you have to shim up the front top fuse skin (not canopy frame skin)? Mine looks like I may need to shim up the canopy frame skin in the middle.

Picture of the top and side of the gap as it currently stands:

dsc01058kk0.jpg


dsc01059ps6.jpg


Also, this is a picture of the bulge on the side corners. I'm not seeing real well how this should be bent before riveting (it's pretty floppy without the splice plate).


dsc01060rn1.jpg


Thanks,
Scott
 
Canopy frame

Scott,
I'm right there with you... Anyway I also have the bulges as the curve starts down the sides. A couple of thoughts:

1. I have looked at several planes includeing the factory demo, many have this skin edge rolled/bent to create a better fit. the other approach to consider is filler or spacers for the front skin.

2. Remember that when you finally install the gas struts, they have a tendency to Close the gap. This means we won't know our final fit until later.


Tom T
 
Last edited:
Gap and buldges

Scott,

I had to shim the front top skin to meet the canopy skin exactly where your photos show the bulge. I have it on both sides. My bulge was approximately .030-.040 max height. I used aluminum tape to make a temporary tapered shim then I cut/filed a finished shim. I also had to shim the cent of the canopy frame front bow after riveting the splice plate in as well. About .010". It seems some of these parts do not have the correct profile/curve.

My gap top skin/canopy skin gap appears to be about the same as yours. I used .040 spacer shims between the front and canopy skin while I drilled the hinge holes. When I went to reinstall the frame the gap ranges around .050-.060". I can live with it. I would rather have the hinge hole in the right place.

It appears I am a little ahead of you with the canopy installation. I would suggest the you review some of my recent posting about fitting the glass and side skins. It might save you some time.

Paul
 
THanks Guys.

Vans mentioned the same (shimming the top skin to match the frame skin bulge profile), but I don't see how that can be done. My top skin is *extremely* tight and hard to align with the rib holes as it is. If more material is added under the skin, it seems it would effectively shorten the skin and make it impossible to attach in the side holes.

Paul, did you not encounter the same? You wouldn't have any pics of your "tapered" shims would you?

Thanks,
Scott
 
Tapered shims

Scott,

At first I too thought there might be a issue placing shims under the top skin and getting the holes to align. However it hasn't been. My skin fit tight before the shims and fits just as tight with them. The original hole alignment wasn't very good I might add.

Using the aluminum tape as a temporary shim works well. Lay a long strip of tape on the offending flange. Then lay a slightly shorter piece of tape over the first layer of tape. Continue until you have built up the area to meet the profile you are looking for. Place the top skin back on and pierce the tape with the cleco. Check the fit. If is what you want, remove the tapered tape shim and make a aluminum shim to match. Using the tape is fast and will get you the answers (will the skin fit) before spending a lot of time making tapered shims.

The aluminum tape I used is for sheet metal ducting. You can buy it at Ace Hardware, Home Depot, Lowes etc.

I may have some photos laying around and will post them if I can find them.

Paul
 
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