What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Tips for fitting the front canopy skin

Draker

Well Known Member
I think I've had this thing off and back on 10 times in the last three days trying to get a better fit and it's not cooperating. Any tips for what to bend, stretch, file or pull to get this thing to line up with the rest of the airplane? There doesn't seem to be much build log wisdom out there on this topic--seems like people get it close and build on.

First up is the fit between the two top skins, shown below clecoed on:



I've got a gap in the center-top between the skins of about 1/16":



The gap gets better as you go outboard, here it's 3/64":



The canopy frame skin also bulges upward on both sides about halfway outboard by about 1/16". No amount of bending and filing of the sub panel flanges seems to correct this. It seems baked into the shape of the welded canopy frame substructure below the canopy skin:



Speaking of which, that flange of that assembly does not even lay flat on the canopy deck. Not sure if it's supposed to or not:



And the skin does not lay flush against the frame itself:



The top skin also bulges outboard on either side by about 1/8" and is not flush against the side skin [looking upward]:



Thankfully I haven't drilled anything yet. Anyone know how to correct any of these problems? I think the outward bulge with respect to the side skins is probably the worst problem and the one that needs the most attention, but no amount of bending of the WD-716 canopy frame assembly seems to help.
 
I'd be careful not to get too small of a gap between the front top skin and the tipup. The two tend to want to butt edges when opened. Plus you need to allow for paint.

Roberta
 
Welcome to the world of the 7 and 9 canopy. The skin fits like **** to the frame. If you look at some build sites you'll see guys have to use spacers between the skin and frame in that gap area. I used washers. I then filled in that gap with epoxy so it looks a little better. I cracked the frame trying to get it to fit to my fuse sides better and had to have it welded. Be careful bending it where the holes are drilled and countersunk. I think I countersunk mine a little too much which probably helped it to crack.
In the spot that you are I had my canopy aligned beautifully to the front skin and was very happy. Then something happened and when the skin and frame were riveted it was way off. Now I am working on the fiberglass fairing and will have to do some fiberglass work to get the skins to match up halfway decent.
The canopy is the worst fitting part of the build and you just have to do the best you can and deal with what you end up with. I gave up trying to make it fit perfectly and hopefully will be happy with the final outcome.
The next thing that happened to me was my canopy cracked. I stop drilled and filled the crack and now hoping it doesn't get worse. Can't fathom starting over building a whole new one. You could say I really hate the canopy portion of the build!!!!
 
it is what it is...

The canopy was the most frustrating part of the build. I played around with the frame, shims, tweaking things endlessly and it never got a whole lot better in the fitment areas you describe. Best advice, build on... and live with it.
 
Thanks everyone. Looks like the magic formula was just patience and elbow grease. Managed to get a fit I'm mostly happy with so drilled the center plate to commit to it. Building on. Too bad it looks like I'm going to be on to the canopy plexiglass around the time it gets the coldest here. Bad timing.

 
Canopy Cutting and Trimming

If you dont have the capability to heat your workspace to 75-80 degrees I would recommend putting the plexiglass work on hold until you can. The pucker factor is really high when cutting, fitting and drilling the canopy and there is a huge amount of other work that needs to be done in firewall forward, wiring, instrument panel and fiberglass for fairings wheel pants etc. putting the canopy work on hold for 6 months will not slow the overall progress - trust me.
KT
 
Thanks for the advice. I am strongly considering "finding other things to do" during the winter. It gets nice and hot here in the summer--I might be able to cut the canopy with a butter knife in July.
 
It can be fitted all the way around.

Ryan, I have a number of posts on my canopy frame and front skin fitting. Looking at your pictures, you have a long way to go, which means lots of opportunities to avoid some common issues.

A post is like instructions of a heart transplant or full IFR training in 50 word or less.

Keeping that in mind, you are having common issues. The good news though, there is a path to make stages adjustments freezing the frame in steps and making it fit nicely. The fit of the front edge to the skin is another matter. I could not live with mine, and fixed the remaining stagger and gaps. Stagger being non planar butting of the canopy and forward skins.

I shimmed the front skin as the final adjustment to those two structures. That necessitated replacement of the front skin with a custom drilled piece. So - I have an extra factory skin left over if you need one. Shipping is more than the skin -ugh.

When you are ready and have studied the situation, give me a call and we can discuss the picture, large and small. Check all my canopy posts and they begin to give a picture.
 
My canopy fitting took months, since each little change induces an
effect somewhere else (usually in an unexpected place). Just keep at it.
I too ended up with a custom made front skin which helped a lot.


Gary Kohler
RV-7A flying
 
1/4? gap

I think I had almost a 1/4? gap between the forward skin and the glare shield skin
On the pilot side. You have to shim up the rib or cut off the flanges and make new ones. I matched the curve with a custom front skin and used flox and epoxy to shim the rib. The rib is not the right size and should be dealt with at Vans with a new rib form block but has never happened. I had Van?s send me a custom cut skin. I matched the holes with the old skin and left the sides long so the radius can be bigger on the custom forward skin. The end result is they mesh up with an equal radius and came out well. I personally saw no other way than to have a new skin made.
 


To those who have added shims between the skin and tube here: How did you get a CS4-4 to grip all the way through the shims to the tube? It's looking like about a 3/8" deep shim will be needed here. Substitute with a longer pull rivet?
 
my process was to scuff and clean the tube really well, put packing tape on the bottom of the skin. Tape from the skin pulled tight down the back side of the tube frame. Then fill the void between the skin and tube with epoxy and flox about the same thickness as the tube 1/2" ish.

Once it cured drill the holes in the epoxy and the CS rivets will hold in that.
 
I took a slightly different approach and filled the void with flox (the coloring it's just me testing and not needed).
IMG_1087_heic-X2.jpg


That will give it structural support as well.

Smoothed it out with balloons:

IMG_1091_heic-X2.jpg


Finished:

IMG_1108_heic-X2.jpg


I did use spacers on the voids on the sides, glued small spacers of aluminum:

IMG_0835-XL.jpg
 
Last edited:
Yes, it seems to have worked just fine and is still in place after 750 hours of flying. One of them came loose at one point, but I just used some more epoxy and glued it back in place.

How did you figure out the right final shape for the skin without the plexiglass fit yet?
 
The Crack

i share your pain on the crack. I was doing my screws on the canopy, everything went well until awkwardly using a electric screwdriver the screw homed in a little too hard and CRACK! The sound is with me today, but i stop drilled and it isnt all that bad.

Welcome to the world of the 7 and 9 canopy. The skin fits like **** to the frame. If you look at some build sites you'll see guys have to use spacers between the skin and frame in that gap area. I used washers. I then filled in that gap with epoxy so it looks a little better. I cracked the frame trying to get it to fit to my fuse sides better and had to have it welded. Be careful bending it where the holes are drilled and countersunk. I think I countersunk mine a little too much which probably helped it to crack.
In the spot that you are I had my canopy aligned beautifully to the front skin and was very happy. Then something happened and when the skin and frame were riveted it was way off. Now I am working on the fiberglass fairing and will have to do some fiberglass work to get the skins to match up halfway decent.
The canopy is the worst fitting part of the build and you just have to do the best you can and deal with what you end up with. I gave up trying to make it fit perfectly and hopefully will be happy with the final outcome.
The next thing that happened to me was my canopy cracked. I stop drilled and filled the crack and now hoping it doesn't get worse. Can't fathom starting over building a whole new one. You could say I really hate the canopy portion of the build!!!!
 
To those who have added shims between the skin and tube here: How did you get a CS4-4 to grip all the way through the shims to the tube? It's looking like about a 3/8" deep shim will be needed here. Substitute with a longer pull rivet?

My spacers look like Bruces, but are solid aluminum. I epoxied them to the tube, match drilled and then measured the depth. I used various lengths of pull rivets matched to engage the tube where possible. I made a dimple tool for the few rivets where the skin is in contact with the tube, otherwise there are issues with the thin wall.
 
Last edited:
Back
Top