Van's Air Force
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Cutting the Canopy
- Thread starter n8zg
- Start date
aeromichael
I'm New Here
The tools I used
I started trimming the canopy bubble yesterday evening. For the larger cuts I use my Bosch angle grinder with a cutting disc. For the smaller cuts a Dremel tool works very well.
Make sure that your bubble feels warm and cozy and do not try to rush things. I think this very much the key.
Good luck,
Michael
I started trimming the canopy bubble yesterday evening. For the larger cuts I use my Bosch angle grinder with a cutting disc. For the smaller cuts a Dremel tool works very well.
Make sure that your bubble feels warm and cozy and do not try to rush things. I think this very much the key.
Good luck,
Michael
alpinelakespilot2000
Well Known Member
Just a hint for all of you who are starting to cut your canopies on the side x sides. Don't follow Van's instructions on the order of the cuts. Make the "big cut" BEFORE you trim the sides up to the lower edge of the side canopy rail. If you make the big cut first, you will have a lot more material to work with when fitting the windscreen. If you follow Van's instructions, you essentially be forced into a position where you will not be able to bring the side of the windscreen down over the sides of the forward skin. In some cases, being able to do so will allow for more fitting options and lead to a better fit for the windscreen. Hope this helps.
LettersFromFlyoverCountry
Well Known Member
I kinda followed Van's instructions although I had more help thanks to Dan's site and also Richard Horan's (Dignity) and Walter Tondu's.
That said, I had no problem cutting the side, or the back, or the front, or the big cut.
The reason, I think, is that I didn't go for broke on every cut. You CAN cut the side down a bit. Certainly not all the way to it's final location. In fact, you sort of have to in order to eliminate the corners, which often make the front sit "up" higher than it should.
But, in the end, I probably made 6 separate cuts in the front, maybe another half dozen on the side, and probably 8 or 9 on the back before I got it just right.
I made the big cut on Van's schedule and so far haven't had any problems.
I do need to add my voice to the chorus of those who really don't like Van's design for the canopy frame. Granted, where it doesn't fit quite well is my fault -- in the end I was off just a bit -- maybe 1/16 to 1/8" -- where the hinge "ear" hole was drilled...but enough to make a bit of a gap in the front left frame (the 716).
There's got to be a better way to build the canopy, tho' I'm too stupid to know what that is.
For all the chatter I'd read over the years on what disk to use, I also just went with Van's method. Cutting disk they sent, cheapo die grinder, typical compressor...no problem.
The best advice I got in the whole process came from Darwin Barrie who advised me to "grow a pair."
That said, I had no problem cutting the side, or the back, or the front, or the big cut.
The reason, I think, is that I didn't go for broke on every cut. You CAN cut the side down a bit. Certainly not all the way to it's final location. In fact, you sort of have to in order to eliminate the corners, which often make the front sit "up" higher than it should.
But, in the end, I probably made 6 separate cuts in the front, maybe another half dozen on the side, and probably 8 or 9 on the back before I got it just right.
I made the big cut on Van's schedule and so far haven't had any problems.
I do need to add my voice to the chorus of those who really don't like Van's design for the canopy frame. Granted, where it doesn't fit quite well is my fault -- in the end I was off just a bit -- maybe 1/16 to 1/8" -- where the hinge "ear" hole was drilled...but enough to make a bit of a gap in the front left frame (the 716).
There's got to be a better way to build the canopy, tho' I'm too stupid to know what that is.
For all the chatter I'd read over the years on what disk to use, I also just went with Van's method. Cutting disk they sent, cheapo die grinder, typical compressor...no problem.
The best advice I got in the whole process came from Darwin Barrie who advised me to "grow a pair."
Randy Difani
Member
So when's the first flight, once you get your canopy cut....? 
Rick6a
Well Known Member
Congratulations Bob and welcome to the other side...the side that dismisses all those overblown, overrated horror stories about canopy cutting as so much fear mongering drivel. Now you can file your personal adventures in Plexiglas right alongside its equally overblown shopmate in terror.....dare I say the word?......PROSEAL.Bob Collins said:
LettersFromFlyoverCountry
Well Known Member
You know, of all the parts of the plane I've built so far, I think I enjoyed the fuel tanks the most. Now, I'm not prepared to say my fear of plexi was unfounded. I was very careful because I was ..well.. concerned...and I dressed every edge on every cut because I was ... concerned.
It's possible it came out as well as it did (by my standards, anyway) because of that fear.
But this pair is coming in handy too. (g)
By the way, Randy, by my calculation the first flight is about $30,000 after the canopy is cut.
It's possible it came out as well as it did (by my standards, anyway) because of that fear.
But this pair is coming in handy too. (g)
By the way, Randy, by my calculation the first flight is about $30,000 after the canopy is cut.
Be Careful!!!
I was scared to death when I cut my canopy. Actually, this was one of the first things I did when I bought my project. I finally decided to do my best and if I screwed up it was nothing money couldn't fix. As it turns out, it came out excellent. With mentoring, I layed the canopy up on the frame on the airplane. Found where I thought the "big hole" should be, drilled it, and sit the canopy back on the frame. Marked the "big cut" line, and cut it with a cutting wheel and air tool. I should say that I had already with the front edge of the wind screen prior to the big cut. Don't get in any hurry trimming the bottom skirts. Be sure you bevel all edges with a circular sander.
I found the sucess of your canopy project is more determined by fitting the frame carefully than the actual glass cuts. You need to tweak that frame where it will slide back under its own weight and have the frame just where it runs inside on the tracks, the glass when you add it will pull it out just a little.
Final mating is done with a sanding block or fine file, ultimately just using a doubled over piece of sandpaper being pulled where the glass mates, with the canopy closed.
I finished mine off with a metal band going across the windscreen and around the front of the windscreen. Lots of shrinking and stretching and english wheel.
When I was fitting must have had that thing on and off 100 times.
There's a reason those back skirts are numbered "666"
Don't get in a hurry. It does no good.
I was scared to death when I cut my canopy. Actually, this was one of the first things I did when I bought my project. I finally decided to do my best and if I screwed up it was nothing money couldn't fix. As it turns out, it came out excellent. With mentoring, I layed the canopy up on the frame on the airplane. Found where I thought the "big hole" should be, drilled it, and sit the canopy back on the frame. Marked the "big cut" line, and cut it with a cutting wheel and air tool. I should say that I had already with the front edge of the wind screen prior to the big cut. Don't get in any hurry trimming the bottom skirts. Be sure you bevel all edges with a circular sander.
I found the sucess of your canopy project is more determined by fitting the frame carefully than the actual glass cuts. You need to tweak that frame where it will slide back under its own weight and have the frame just where it runs inside on the tracks, the glass when you add it will pull it out just a little.
Final mating is done with a sanding block or fine file, ultimately just using a doubled over piece of sandpaper being pulled where the glass mates, with the canopy closed.
I finished mine off with a metal band going across the windscreen and around the front of the windscreen. Lots of shrinking and stretching and english wheel.
When I was fitting must have had that thing on and off 100 times.
There's a reason those back skirts are numbered "666"
Don't get in a hurry. It does no good.
alpinelakespilot2000
Well Known Member
Bob-Bob Collins said:
I can't speak to the proper order for the tip-up canopy, but Neal is building a slider canopy where order does significantly limit your options when you get to the windscreen.
LettersFromFlyoverCountry
Well Known Member
D'oh. You're right. I forgot.alpinelakespilot2000 said:
n8zg
Well Known Member
Order?
There's an order to this stuff? I look at the manual and just shake my head - a hand-full of words and precious few photos.
In all honesty, the manual is open on the bench, but it has been NO help at all for months. It does a much better job of cluttering up the workspace than actually lighting the path.
Thank Heaven for friends who have walked before us and continue to share their experience.
There's an order to this stuff? I look at the manual and just shake my head - a hand-full of words and precious few photos.
In all honesty, the manual is open on the bench, but it has been NO help at all for months. It does a much better job of cluttering up the workspace than actually lighting the path.
Thank Heaven for friends who have walked before us and continue to share their experience.
Stephen Lindberg
Well Known Member
Slider vs. Tip Up
Bob, you are building a tip-up, right? I think Steve is building a slider, as am I. I concur with Steve, don't trim the sides of the canopy before the big cut. I didn't make the final trim cuts until after I had clecoed the canopy to the frame. Then, I took off the final 1/2 inch or so. I have largely abandoned Van's instructions and have just done what it takes to make it work. The plexi really does bend the frame about 1/2 inch outward when clecoed on. Right now I am trying to bend the frame inward just the right amount to counteract the plexi. Just about have it. So far, this canopy job hasn't been all that difficult (knock on wood). However, I have the side and rear skirts to go. Any advice from those that have done it? I would like to use the alumimun rear skirts and not resort to fiberglass. BTW, I cut the canopy with a 90 die grinder and Van's cut off wheel. Worked well. Sanded with a vibrating electric sander with 120, 220, and 400 grit paper. Smooth as glass, and goes fast. Took less than a week after work to get to this point. An easy mistake to make with the slider would be to postion the frame too far forward in the uncut plexi, thereby stealing from the windshield. The aft end of the canopy will get floppy and come down onto the rear frame bows just fine after the excess is cut off the rear of the canopy. Like most things Van, there is enough material but not a lot extra.
Bob, you are building a tip-up, right? I think Steve is building a slider, as am I. I concur with Steve, don't trim the sides of the canopy before the big cut. I didn't make the final trim cuts until after I had clecoed the canopy to the frame. Then, I took off the final 1/2 inch or so. I have largely abandoned Van's instructions and have just done what it takes to make it work. The plexi really does bend the frame about 1/2 inch outward when clecoed on. Right now I am trying to bend the frame inward just the right amount to counteract the plexi. Just about have it. So far, this canopy job hasn't been all that difficult (knock on wood). However, I have the side and rear skirts to go. Any advice from those that have done it? I would like to use the alumimun rear skirts and not resort to fiberglass. BTW, I cut the canopy with a 90 die grinder and Van's cut off wheel. Worked well. Sanded with a vibrating electric sander with 120, 220, and 400 grit paper. Smooth as glass, and goes fast. Took less than a week after work to get to this point. An easy mistake to make with the slider would be to postion the frame too far forward in the uncut plexi, thereby stealing from the windshield. The aft end of the canopy will get floppy and come down onto the rear frame bows just fine after the excess is cut off the rear of the canopy. Like most things Van, there is enough material but not a lot extra.
LettersFromFlyoverCountry
Well Known Member
Right, yes, ignore what I said. I keep thinking everyone's building a tip-up... which is silly of me since I think most people build a slider.
Jeff Vaughan
Well Known Member
Cutting the canopy
I used my Souix air drill and the cutting dics from Vans.
Worked real well. You will be surprised at how easy it is to cut.
I used my Souix air drill and the cutting dics from Vans.
Worked real well. You will be surprised at how easy it is to cut.
alpinelakespilot2000
Well Known Member
Steve-Stephen Lindberg said:
My process has been very similar to yours. If you want to use metal skirts, however, there are a couple things you may want to pay close attention to:
1. If you have any sort of "duck tail" or "ski jump" at the aft edge of your plexi glass, it will be very, very difficult to get the alum skirt to sit flat on the aft skin. I trimmed the aft edge of my canopy as close to slider frame as I could (per the drawings) but still have a little upswing just beyond the point where the plexi is riveted to the aft bows.
2. Related, you must make sure that the top surface of your canopy is no higher AND no lower than the aft skin. It really needs to be pretty close to perfect.
Because I was unsuccessful in getting perfect results on #1 and #2, I've resorted to fiberglass. I'll still have a little bit of the duck tail to deal with, but fiberglass at least mitigates that issue pretty well.
The best description of the slider process I've found on the internet is Matt Burch's recent experience at http://www.rv7blog.com/category/fuselage/canopy/ . (Hope you don't mind, Matt.)
Good luck.
Stephen Lindberg
Well Known Member
Steve: I left 3/4 inches of plexi aft of the rear bow (the plans state 1/2 to one inch, so I split it). I could trim off more. I don't see any sign of a ski jump, so maybe metal rear skirts will work. Looks like adjusting the threaded rod on the rear slide will yield 1/16 or better of up and down adjustment to play with. I am still bending the frame to get it to slide well with the canopy on it.
