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Forward fit of canopy

RVG8tor

Well Known Member
I have some questions on fitting the canopy for those of you who have gone before me. I have the frame fit to the fuselage and the initial holes drilled for the side tracks. I looking at my fit I see that the hook (rear track) engages the block with about a ?? between the forward bow in the frame and the roll bar. I can snug it up and get roll bar and frame to within ??. I thought I should see how the latch fits so I put that together and the latch will not go to the full closed (horizontal on the handle) position. The frame and roll bar touch before the handle goes to the full lock position. It looks like I will have to trim the latch for a better fit.
Well this got me to thinking, shouldn?t the frame be in this most forward locked position for fitting the canopy bubble. If I fit the bubble with the frame in the just hand tight position then after the canopy is cut in two, if you move to the locked position then the two halves will interfere. Do you make another cut to match the radius of the forward part of the frame thereby giving room for the two halves to not interfere when locked? Also if I camp the canopy frame full forward so it is nearly touches the roll bar the side rollers roll up onto the foot of the roll bar (part attached to the sides). This raises the canopy just a bit so this would throw things out of alignment.
So am I missing something? Did you guys clamp the frame in the locked position when cutting the canopy to fit the fuselage? Pictures show latch fit and how rollers come up onto roll bar foot. Thanks for any help.

Cheers

1z7zgx.jpg


av1jzr.jpg
 
Nemo - did you apply a good amount of force when attempting to fully latch the slide assembly forward? I just went through this myself a few weeks ago and it does take a good bit to engage the latch fully. I probably have about a 3/8" gap between the two canopy bows at the top when latched. I'll measure exactly and get back to you. I have not fitted my canopy yet so I'll be interested in the answers you receive from those who have...

cheers,

Spank
 
Mike,
This is how mine came together.

When shut and not locked, I have about 1/4 gap at the bottom of the two canopy bows. This gap widens to about 1/2 inch at the top of the bows.

The latching mechanism needed to be trimmed. You do not want the latching mechanism to pull the canopy frame forward when latching, as this will distort the frame & plexi.

I did not latch the frame when placing and cutting the canopy. I made sure that the canopy frame was in the full forward position. Remember that the latch should not move the frame forward. It should just secure it.

I used Sika to glue the canopy to the frame. I'm not flying yet, but I am pleased with the end result.

Mike
finishing, finishing, finishing, ....
 
Hits roll bar

Nemo - did you apply a good amount of force when attempting to fully latch the slide assembly forward? I just went through this myself a few weeks ago and it does take a good bit to engage the latch fully. I probably have about a 3/8" gap between the two canopy bows at the top when latched. I'll measure exactly and get back to you. I have not fitted my canopy yet so I'll be interested in the answers you receive from those who have...

cheers,

Spank

Spank,

The cam action of the latch tries to pull the canopy forward just a bit, the frame hits the roll bar before the handle can get to its over center locked position. I do have more of a gap at the top, with the canopy clamped to almost touch at the bottom I have about 1/8" gap at the top. I was concerned about this and when I spoke to Van's on another issue they said that the frame and roll bar did not have to be parallel.

It looks like I will have to take a good 1/4 inch off the hook part of the latch arm to make the handle lock without pulling the canopy forward.

Did your rollers move up onto the roll bar footer?
 
Mike,
The rollers should not go up on the roll bar brace. Roll the canopy frame forward until the rollers touch the base of the roll bar mounting flange. The aft pin should be almost fully seated in the UHMW block. This is now the fully closed position. The gap between the canopy frame and roll bar is insignificant. Whatever gap there is will not change. The latch mechanism needs to be trimmed alot, so that it has a very small amount of resistance and slight over center type feel to it when you fully engage it, if that makes sense.
On the 3 RV8's that I have done, the only adjustments I have made to either the canopy front bow or the roll bar (bending wise) is, spreading the front canopy bow so that the rollers are centered in the tracks.
When I'm trimming the canopy, I usually start trimming at the front windscreen area, gradually lowering the canopy with successive cuts until it rests on the top of the roll bar. This is usually what happens, then, if you get inside you can push up on the canopy frame to see how much you might have to shim (add a large diameter washer) between the roller and the canopy frame tube. If you got lucky and the canopy contacted both the roll bar and canopy bow you are ready to make the split.
If it contacts the canopy bow first, then you would trim the tubes that the rollers go into, until the canopy frame is lowered enough so that the canopy touches both frames at the same time or the roll bar first.
Once the aft and sides of the canopy are trimmed enough so that the canopy can be clamped securely along the sides I go ahead and make the split cut.
I then drill the canopy to the frame. I put masking tape on the frame, then starting at the top, I firmly press down on the canopy and a little dark line appears on the masking tape, drill perpendicular to the surface of the canopy and hit that line. That line is where the canopy is contacting the frame. Clecoe as you go working down both sides.
Then I drill the windscreen. Again, starting at the top, I drill the first hole. Then I lay a straight edge across the clecoed on canopy and windscreen, they should be level with each other( due to the previous trimming or shimming at the rollers). I then move down and drill the next hole, usually the straight edge will reveal that the two surfaces are level to each other again.
If not, it usually requires that I slip a washer underneath one of the offending surfaces. It is usually the windscreen that requires a washer. I use AN960-3's and -3L's. What I shoot for is, the canopy riveted to the bow with no washers. Then I drill and shim as I go from the top center of the windscreen down the sides. I mark on the windscreen at each hole how many full and how many half washers are at each position. I also make a drawing that depicts each position and washer call out in case the marks on the windscreen are inadvertently cleaned off. On my RV8's I usually wind up with 0 to 1 and a half washers around the upper circumference of the roll bar and as many as 4 or 5 full washers at the very bottom. This leaves me with a very level (to each other) surface to lay fiberglas cloth across, for the eventual fairing that covers the gap. You will then see the washers from inside the plane unless you put a fillet of something(micro/epoxy?) between the roll bar and inside surface of the plexi.
To make inserting the washers easier get one of these from Cleveland.

http://www.cleavelandtoolstore.com/prodinfo.asp?number=WWR4

Sorry about the long response, but this is what works for me, hope this helps others.

6 RIVETED CANOPIES AND NO CRACKS!!!

Regards,
 
Trim and Sika gap?

Mike,
This is how mine came together.

When shut and not locked, I have about 1/4 gap at the bottom of the two canopy bows. This gap widens to about 1/2 inch at the top of the bows.

The latching mechanism needed to be trimmed. You do not want the latching mechanism to pull the canopy frame forward when latching, as this will distort the frame & plexi.

I did not latch the frame when placing and cutting the canopy. I made sure that the canopy frame was in the full forward position. Remember that the latch should not move the frame forward. It should just secure it.

I used Sika to glue the canopy to the frame. I'm not flying yet, but I am pleased with the end result.

Mike
finishing, finishing, finishing, ....

Mike,

It looks like I might have to trim about a 1/4 inch off the hook part of the latch arm, is that about what you had to do. With your canopy closed did the rollers come up onto the roll bar foot or just touch the weld mount part?

I think I may go the sika route, I have a couple of questions I have been asking around about the process; what size gap did you use between the Plexi and the frame? Did you remove the power coating to glue to it? did you use and rivets at all to hold the canopy to the frame?

Any advice you can pass on to me would be helpful. I do have a power point slide show someone posted a while back with a good explanation of the process. The gluing method seems so solid, better in fact than some wind shield in my opinion, with the canopy glued to the frame and then the skirt to the canopy I can't think of how the canopy would come off. About the only issue I can see is year down the road there might be some separation in the glue line but this could be easily fixed. The stories on this site where guys go from semi warm hangers to the cold our doors and get cracks scares the heck out of me. Anything to mitigate that is good in my opinion.

Cheers
 
Crazy question, but are you sure that latch arm is the correct part? I ask because it looks quite different than mine, though mine is about ten years old and Van could have changed the design since then.
 
Super explanation

Mike,
The rollers should not go up on the roll bar brace. Roll the canopy frame forward until the rollers touch the base of the roll bar mounting flange. The aft pin should be almost fully seated in the UHMW block. This is now the fully closed position. The gap between the canopy frame and roll bar is insignificant. Whatever gap there is will not change. The latch mechanism needs to be trimmed alot, so that it has a very small amount of resistance and slight over center type feel to it when you fully engage it, if that makes sense.
On the 3 RV8's that I have done, the only adjustments I have made to either the canopy front bow or the roll bar (bending wise) is, spreading the front canopy bow so that the rollers are centered in the tracks.
When I'm trimming the canopy, I usually start trimming at the front windscreen area, gradually lowering the canopy with successive cuts until it rests on the top of the roll bar. This is usually what happens, then, if you get inside you can push up on the canopy frame to see how much you might have to shim (add a large diameter washer) between the roller and the canopy frame tube. If you got lucky and the canopy contacted both the roll bar and canopy bow you are ready to make the split.
If it contacts the canopy bow first, then you would trim the tubes that the rollers go into, until the canopy frame is lowered enough so that the canopy touches both frames at the same time or the roll bar first.
Once the aft and sides of the canopy are trimmed enough so that the canopy can be clamped securely along the sides I go ahead and make the split cut.
I then drill the canopy to the frame. I put masking tape on the frame, then starting at the top, I firmly press down on the canopy and a little dark line appears on the masking tape, drill perpendicular to the surface of the canopy and hit that line. That line is where the canopy is contacting the frame. Clecoe as you go working down both sides.
Then I drill the windscreen. Again, starting at the top, I drill the first hole. Then I lay a straight edge across the clecoed on canopy and windscreen, they should be level with each other( due to the previous trimming or shimming at the rollers). I then move down and drill the next hole, usually the straight edge will reveal that the two surfaces are level to each other again.
If not, it usually requires that I slip a washer underneath one of the offending surfaces. It is usually the windscreen that requires a washer. I use AN960-3's and -3L's. What I shoot for is, the canopy riveted to the bow with no washers. Then I drill and shim as I go from the top center of the windscreen down the sides. I mark on the windscreen at each hole how many full and how many half washers are at each position. I also make a drawing that depicts each position and washer call out in case the marks on the windscreen are inadvertently cleaned off. On my RV8's I usually wind up with 0 to 1 and a half washers around the upper circumference of the roll bar and as many as 4 or 5 full washers at the very bottom. This leaves me with a very level (to each other) surface to lay fiberglas cloth across, for the eventual fairing that covers the gap. You will then see the washers from inside the plane unless you put a fillet of something(micro/epoxy?) between the roll bar and inside surface of the plexi.
To make inserting the washers easier get one of these from Cleveland.

http://www.cleavelandtoolstore.com/prodinfo.asp?number=WWR4

Sorry about the long response, but this is what works for me, hope this helps others.

6 RIVETED CANOPIES AND NO CRACKS!!!

Regards,


Jon,

That was the best explanation I have read yet on cutting the canopy to fit, you should write new instructions for Van's. I have a friend with an -8, unfortunately in an other state, he too has not had problems with cracks. I however think I will go the glued route, not that I don't think the Van's method will not work but the riveted method has a much higher potential for possible cracks due to in use expansion and contraction. Having the canopy glued and sandwiched between the skirt and the frame I can see how this would come apart. Of course no one has 20 years with the glued canopy yet so time will tell how good an idea it was.

Thanks again
 
Double check

Crazy question, but are you sure that latch arm is the correct part? I ask because it looks quite different than mine, though mine is about ten years old and Van could have changed the design since then.

Good point I will take a look at it again, I don't have anyone with an -8 near by so unless someone wants to post a picture I can't be sure. I did have to Emory cloth the shaft of the handle a lot to get the brass bushing to fit over the top, and also the latch are part that goes around the bushing would not fit at first, that was smoothed as well to make them fit.
 
I found this photo on Kevin Horton's site of a latch that looks more like the one I have:

KevinHortonlatch.jpg


The hooked end looks different than the one you have, which made me think yours might be from another model of RV?
 
It had been trimmed

I found this photo on Kevin Horton's site of a latch that looks more like the one I have:

KevinHortonlatch.jpg


The hooked end looks different than the one you have, which made me think yours might be from another model of RV?


His looks different in that the hook part has been trimmed. It look like there is a lot of material to be removed to make it fit. Thanks for the photo.
 
It look like there is a lot of material to be removed to make it fit. Thanks for the photo.

My point was that my latch looks just like Kevin's, and I haven't trimmed mine at all.
 
Mike,

It looks like I might have to trim about a 1/4 inch off the hook part of the latch arm, is that about what you had to do.

Cheers

That sounds about right. I know I had trim off enough to make me nervous

With your canopy closed did the rollers come up onto the roll bar foot or just touch the weld mount part?

With the canopy closed my rollers come up on onto the foot of the roll bar. They do not touch the weld mount part.


what size gap did you use between the Plexi and the frame? Did you remove the power coating to glue to it? did you use and rivets at all to hold the canopy to the frame?

After talking to Sika I took a conservative approach and went with a ~3/16 gap. I went to the local hardware store and purchased a lenght of clear plastic tubing that had a thickness of ~3/16. I then cut slices of the tubing to use as spacers. I also purchased a length of tubing that had a thickness of ~1/8 that I used in a few places on the side of the windscreen.

I did not remove the powder coating.

To fasten the canopy to the frame I drilled through the plexi and spacers into the frame and used a cleco to hold the frame in place. Once the Sika dried I removed the spacers and back filled with Sika

Any advice you can pass on to me would be helpful.

Get the specs and directions from the manufacture. Call the tech line if you have any questions.

Make a stand that will allow you to walk around and inside the canopy. I would consider this a must have. I have two saw horses that are about waist high. Using three dowels I fabricated a stand that will allow you to easily work on the canopy. Below is a rough picture.

canopystand.jpg


Send me a PM if you have any questions or if you want to discuss.

Good luck,

Mike
 
Last edited:
To Glue, Rivet or Screw My -8A Canopy

Hi all, I Need advice! I have my Canopy all trimed and drilled, I chose not to bond but:eek: i am worried about riveting. A fellow -8 owner at our airport has screwed his canopy to the frame. He did this with 6-32 screws and taped the frame. He has about a 100 hrs on it with no problems. It looks good. any input to this?? I was a bit worried about the thickness of the tubing might not give enough threads when taped but with screws every two inches this might be ok.
 
If it fits right

You shouldn't have any problem riveting the canopy on. The screw method should work fine as well, just more work. If I were going that route, I might try and use screws on the rest of the canopy skirt too, making the whole thing removable so if you ever had to replace the canopy, it would be easier. I riveted mine on, the first couple rivets had me worried, but the whole thing came out fine. YRMV

Randy
8A
 
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