Van's Air Force
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Fiberglass canopy
- Thread starter orenjr
- Start date
vernhendershott
Well Known Member
Hi Oren,
You will want to do it all at one time, you first put on the first side piece on each side and then the first strip across the front of the canopy, these go on wet (resin worked into them on the bench) and they are allowed to get tacky (it depends on the resin and hardener you are using, with the West system and the slow hardener at about 80 it takes about 1 1/2 to 2 hours) then each of the other glass sheets can be added by just placing them where they belong and wetting them out in place, keep in mind that there are only four more side pieces and you will have nine more strips across the front so I like to do one side piece and two front strips as a single layer. You do not need to wait between layers after the first is done.
I also like to use the factory edge on 4 inch tape (cut to the correct width) for the first front layer as it makes a very smooth edge to work with when you sand it down. The 4 inch tape is available from Aircraft Spruce and it is much simpler to cut to the correct width than trying to make long strips from large sheet goods. We just lay out a 4 inch wide by 36 inch long strip folded over once to make it 18 inches long, we use a plastic cutting board and the very sharp rolling cutter (pizza cutter) sold by fabric shops and a one yard metal ruler as a straight edge to get very nice uniform strips. We use the same equipment to cut all the side pieces too.
Best regards,
Vern
Canopy Lay up
Hi Vern, What is this 4 inch tape you are talking about? is it a fiberglass tape and do you put it on after the 36 inch strips? I am having trouble trying to figure out how you sand into the top layer of electrical tape to get the crisp edge along the canopy, I think I may be over-thinking this part of the project. Don from Ohio, preparing to fiberglass.
Hi Vern, What is this 4 inch tape you are talking about? is it a fiberglass tape and do you put it on after the 36 inch strips? I am having trouble trying to figure out how you sand into the top layer of electrical tape to get the crisp edge along the canopy, I think I may be over-thinking this part of the project. Don from Ohio, preparing to fiberglass.
vernhendershott
Well Known Member
Hi Lewy,
Yes it is just plain woven fiberglass (about 8 oz.) that comes in a 100 foot roll. It has two factory smoothed edges one on each side, one side has some additional thread stitched on that makes it hard to use but the other edge is very smooth instead of the ruff loose ends you get when you cut fiberglass so if you use the fiberglass tape slid up exactly against the electricians tape you have defined the desired line with you get a very smooth and crisply defined edge line so that when you sand it does not have a raged appearance. Hope this helps.
Best regards,
Vern
vernhendershott
Well Known Member
Have you actually used one or do you know someone who has?
From what I have seen there is enough variation plane to plane that it would be hard to get the fit right. It would also be interesting to know how it is attached as I think it would be hard to get a good bond to the windshield if the fit was not perfect, like you get on a made in place part.
Best regards,
Vern
Hi Vern Not sure on this one but there is information on the Viking engine site .... just click on RV-12 .....
Cheers.
vernhendershott
Well Known Member
I am aware that they are selling them and I wish them good luck, I am just not sure that anyone can make a part that will fit any given aircraft and they also change the method used to attach the Plexiglas so it could not be used on an ELSA it would seem.
I do hope they make the new engine work.
Best regards,
Vern
vernhendershott
Well Known Member
Hi Don,
The reason for folding the tape over is to make it short enough to fit on the plastic cutting surface. So, first cut a 36" long piece of the fiberglass tape. Now fold it in half so that you have a 4" x 18" piece. Most of the cutting boards have lines drawn on then to help you keep things straight so lay the smoothest long edge of the fiberglass tape on one of the guide lines so that both layers are straight and on the line. You then place the metal yard stick on the lay-ed out fiberglass tape so that it will allow you to cut the width of tape you need for the first piece you want to cut, lets say the first layer which is 2.75 inches wide. So you set the metal yard stick so that when you use the roller cutter you will have one side (with the good smooth edge) that is 2.75" wide and a second piece that is 1.25" wide, this second piece can be cut twice again to make the 2 pieces required for layers 4 & 6 and you would have a 0.25" strip of scrap to be discarded.
I find it helpful to use a large (about 24" x 24") piece of cardboard covered with wax paper (to keep the fiberglass tape clean) and on this I layout each strip of fiberglass tape in the order they are to be put on so that it is organized when it comes time to lay each layer on the aircraft.
The pieces you will require are called out on page 34-15
Width Qty Figure 1 Ply #
2 3/4 1 1
2 1/2 2 2 & 9
2 1/4 1 10
2 1 3
3/4 1 5
1/2 2 4 & 6
3/8 1 7
1/4 1 8
Be sure not to use the edge of the tape that has the mono-filament over-stitching on it as it will make a bump in the fiberglass build up that will require a lot of sanding to remove.
Best regards,
Vern
DonFromTX
Well Known Member
OK Vern, got it now, thanks! I had almost figured out part of it while out cutting the paper pieces and trying to acquaint myself with the instructions. Got to get me some sort of cutting machine, I have seen those pizza cutter types, never thought they would be much worth anything, especially with fiberglass cloth.
vernhendershott
Well Known Member
Cheap ones and the plastic cutting board are available at Walmart and other similar stores.
Best regards,
Vern
DonFromTX
Well Known Member
Back from Wal Mart Aviation section, got me a board and a pizza cutter to ty out.
One thing Ihave not been able to quite understand, when making the joint between the sides and the center strip, if you overlap it would appear to make a bump, if not overlapped, a very weak spot. What is with that joint?
One thing Ihave not been able to quite understand, when making the joint between the sides and the center strip, if you overlap it would appear to make a bump, if not overlapped, a very weak spot. What is with that joint?
vernhendershott
Well Known Member
Hi Don,
First you need to study the way Van's would have you do it on pages 34-14 and 34-15.
I use a slightly different system which does the same thing. I put both right and left layers on wet just as they say and I continue on to add the first layer across the too. I let them cure to tacky and then wet the surfaces and apply layer 2 on each side and then layers 2 & 3 across the top. I continue the process until all the layers are in place and then apply the peel ply and let the whole thing cure for two days.
I use about 1/2 inch overlap of the top strip over the bottom side sheets, which would be the first top piece would have 1/2 inch overlap of the first side piece and the second top piece would have a 1/2 inch overlap of the first top piece. The third top piece would have a 1/2 inch overlap of the second side piece and the fourth top piece would overlap the third top piece by 1/2 inch and so on until all five side pieces and all ten top strips were in place. You can start the top strips from one side and cut them when you are near the correct end on the other side or place them from the center working out and cut each end as required, which is what I do most of the time.
It is common to get some sagging between the foam near the front of the canopy frame and the fuselage as that area is not supported and there is an area near the top front of the side pieces that also wants to sag. I just fill these with micro after it is cured and cut to shape.
Good luck.
Best regards,
Vern
DonFromTX
Well Known Member
Well, I just got it all done! Thanks Vern for the guidance, it came in handy as I progressed. Not too bad a job really, just messy as heck. I used black dye on the first two coats so it won't look crappy from the inside when the canopy is open. Now I have to wait a day or two for it to all cure, then hope I can get it unstuck from the airplane!
vernhendershott
Well Known Member
Hi Don,
Glad you got the first part done. The next challenge is separation of the fiberglass from the rest of the aircraft, found that a frosting spreader works best if your wife has one, they are a thin blade with a round tip and work well to slide under the new layup and get it to unzip. Trimming is not to hard, you need to mark it while it is still on the aircraft then remove the canopy and do the trim. I found the most important part was getting the bottom side line straight with the rest of the aluminum skirt. Getting to the front canopy bolts is a little fun. Keep in mind that you can not tip the canopy up very far due to the over run of fiberglass so raise the rear only enough to get the rear bolt on the assist cylinders, then lift the canopy straight up to remove it.
Best regards,
Vern
Jetguy
Well Known Member
Canopy Stuff!
Don see this thread for some Canopy pics that might help.
http://www.vansairforce.com/community/showthread.php?t=68154&highlight=canopy
Don see this thread for some Canopy pics that might help.
http://www.vansairforce.com/community/showthread.php?t=68154&highlight=canopy
vernhendershott
Well Known Member
Hi Don,
I would let it cure, if you pull it before that it may take a set that is not the shape you want.
Best regards,
Vern
I would let it cure, if you pull it before that it may take a set that is not the shape you want.
Best regards,
Vern
DonFromTX
Well Known Member
AFTER ACTION REPORT WITH PHOTOS
Got the canopy off, with some damage. I dug out the pivot bolts and cut a hole around them, and unscrewed the bolts. That led to a pop as the struts broke loose the canopy!. The struts of course pushed it forward, and between that and getting it loose, I bent the panel cover a bit. Also, I had never used that peel ply stuff, did not get along with it too well, could not seem to make it do compound curves or lay down in the epoxy very well. I think using pieces would have worked better.
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Got the canopy off, with some damage. I dug out the pivot bolts and cut a hole around them, and unscrewed the bolts. That led to a pop as the struts broke loose the canopy!. The struts of course pushed it forward, and between that and getting it loose, I bent the panel cover a bit. Also, I had never used that peel ply stuff, did not get along with it too well, could not seem to make it do compound curves or lay down in the epoxy very well. I think using pieces would have worked better.
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vernhendershott
Well Known Member
Got the canopy off, with some damage. I dug out the pivot bolts and cut a hole around them, and unscrewed the bolts. That led to a pop as the struts broke loose the canopy!. The struts of course pushed it forward, and between that and getting it loose, I bent the panel cover a bit. Also, I had never used that peel ply stuff, did not get along with it too well, could not seem to make it do compound curves or lay down in the epoxy very well. I think using pieces would have worked better.
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Hi Don,
Looks like it came out OK, like most of us you will need to use some fill and do some sanding. Keep on trucking.
Best regards,
Vern
