J

jpharrell

Well Known Member
Help! I recently started work on the tip-up canopy on my 7A. Last night I trimmed the excess flange and mold clamping areas off of the edges of the canopy and placed it on the fuselage for the initial fitting. I was not totally happy with what I saw. Along the left side of the plexiglass canopy fits really well. The first photo shows the left side.

canopy1.jpg


The left edge runs generally flush to the skin and side rail with a gap of about 1/2 inch. It takes very little force to press the canopy up against the side rail. You can see the gap in the photo from below looking up.

canopy-2.jpg


However the right side is a different story. If you look at the shadow of the edge in the photo below you can see that the edge flairs or bows out near the black tape.

canopy-3.jpg


The photo from below shows it even better. The gap is 1 inch to 1.5 inch along the right side. My biggest concern is it takes quite a bit of force (~ 5 lbs) to press the canopy edge down flush to the side rail on this side. I don't like putting that kind of stress on the canopy.

canopy-4.jpg


Did I get a bad canopy? It clearly is warped on the right side but is this common? I did a couple of searches on the forums and could not find other reports of something like this. I'm not sure I will be able to make this fit well with the skin with this kind of distortion. There is still a fair amount of trimming before the big cut. Will the canopy somehow fit better in this area as the trimming progresses?

I noticed some distortion on that side when I first unpacked the canopy but I didn't know enough to question it further. Should I build-on or should I be talking to Vans now about the problem?
 
First...you need to tuck the canopy (plexi) under the sheet metal "ears" (where you have the black tape). Try that and see if it fits better. Mine fit really well, I would expect yours should to.
 
It also fits and sits better as you cut away the front portion.

One suggestion for later on that many canopy experts have given me. Don't drill the most forward hole on the side of the canopy on each side.
 
Tucking Under the Ears

Ron,

For this initial fitting the plans say to tape the ears down to avoid scratching the canopy. That said, I can tell that the left side should go easily under the ear, but I'm afraid the right side will be tough because I have to push the plexi in hard in that area to get it down flush to the skin. It is quite stiff in that area. Perhaps when I trim the rest of the front duck bill off it will bend easier, I don't know. But compared to the left side it is night and day different.
 
jpharrell said:
Ron,

For this initial fitting the plans say to tape the ears down to avoid scratching the canopy. That said, I can tell that the left side should go easily under the ear, but I'm afraid the right side will be tough because I have to push the plexi in hard in that area to get it down flush to the skin. It is quite stiff in that area. Perhaps when I trim the rest of the front duck bill off it will bend easier, I don't know. But compared to the left side it is night and day different.
Click to expand...

you're right...good point...like the other posts suggested, trim it a little and then tuck it in when you get it closer. It should slowly work its way into shape. Good luck...I am in the middle of this right now, a little ahead of you...its a pain at times.
 
Also helps to keep the front cuts symmetrical. I found that I got the canopy sitting pretty well, but one side was a slightly different profile (viewed looking straight down on the canopy frame skin). After getting both sides symmetrical it fits perfectly. Mine still bows out a bit on each side, but the force required is minimal to make it sit flush on the sides.
 
keep nibbling. small bites to adjust the fit. Mine fit terrible, but in the end all was well. I bet I trimmed the forward edge 6 times until it fit like it thought it should. I think this is where I learned patience.
 
Also, are you confident that you have the actual center of the canopy centered on the frame? That question caused me a bit of stress while fitting mine.

Charlie
 
jpharrell said:
Ron,

Have you seen similar distortion with your canopy?

John
Click to expand...

Actually it fit pretty darn good once I got it trimmed up. Obviously, sneak up on it...trim a little at a time until you get it just right. Stay symmetric with your trimming and it settles down nicely. Once I got it trimmed and tucked under the ears, it was about 1/2" bowed out on the sides...but it took very little pressure (i.e., little to no stress on the plexi) to push the sides in. I was pleased with how it fit. Now, the tipup frame structure is a different story...that has given me a headache at times :)
 
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