Canopy Adjustment after bonding

bugsy63 · #1 10-28-2013, 05:38 PM

I am seeking advice or thoughts on adjusting the bows of the canopy frame after bonding with Sika. Although I thought I'd made sufficient allowance for frame spread following the attachemnt of the canopy, it is now around 5/8" too wide.

The Vans instructions suggest adjustments can be made after attachment but there are no guide lines for doing this, with the obvious concern being cracking the canopy while bending.

Aside from ensuring that the canopy is warm, has anyone any experience or caveats in acheiving this?

Thanks in anticipation

BSwayze · #2 10-28-2013, 06:12 PM

Michael, I assume you're doing a tip-up, correct? Where is it too wide? Forward? Aft? Middle? One side, or both? Any pictures?

bugsy63 · #3 10-28-2013, 07:27 PM

Hi Bruce,

thanks for your reply. It's a slider. The spread had occurred principally on the front bow resulting in noticeable binding of the rollers when sliding.

The profile of the side rails will, I assume, return to their correct position when the front bow is adjusted.

RV7AJeremy · #4 10-28-2013, 08:19 PM

Michael,
I was able to adjust my canopy quite a bit after bonding, however I live where it is very hot and I let the canopy bake out in the sun before I made any adjustments. I adjusted my rear canopy bow about 3/8" but to get there it had to stretch quite far. I didn't have any issues at all but I would not try this in cool temperatures. Get it hot and start pulling. Good luck!

scrollF4 · #5 10-28-2013, 09:15 PM

Bruce, Jeremy!
Will this also work for a tip-up? My plexi is sikaflex'd onto the frame, but I have almost 1/8" of inward indentation on each side about a foot back from the forward ends. I'd like to bend it out but am afraid I might crack the plexi.

RV7AJeremy · #6 10-28-2013, 10:53 PM

Scroll, get it HOT! I was amazed how much I could pry on the canopy system after it was glued and cured. But I live in Tucson AZ, and it was about 105 that day, and I let it bake in the sun for about 20 minutes. I am not too familiar with how much steel in in the tip up frame, the slider has some stout bars that took the bend. I really think the key is the heat. I did some test with the scraps, when it was 105 out and the pieces were in the sun, I could really bend the heck out of the pieces, when I had the pieces in the house at 70 degrees, the broke quite easily.

Quote:

Originally Posted by scrollF4

Bruce, Jeremy!
Will this also work for a tip-up? My plexi is sikaflex'd onto the frame, but I have almost 1/8" of inward indentation on each side about a foot back from the forward ends. I'd like to bend it out but am afraid I might crack the plexi.

Pmerems · #7 10-29-2013, 07:45 AM

I found that after about 2 yrs after I mounted the tip-up canopy to the frame (screwed), I had approximately a 0.05" underlap (the canopy frame was narrower than the fuselage) on one side. I already had the fibeglass faring glassed in so I didn't want to chance bending the frame and damaging the plexiglass or faring. Additionally I know from building the fame that if I wanted to increase the width I needed to expand quite a bit. So I bit the bullet and added some fiberglass to the offending side. It came out great.

Sometimes you have to do things you wished you really didn't have to.

The TU canopy is flexible and constantly changing in shape a bit. During the cold season it fits slightly differently then in the summer.

Quote:

Originally Posted by scrollF4

Bruce, Jeremy!
Will this also work for a tip-up? My plexi is sikaflex'd onto the frame, but I have almost 1/8" of inward indentation on each side about a foot back from the forward ends. I'd like to bend it out but am afraid I might crack the plexi.

scrollF4 · #8 10-29-2013, 08:44 AM

I'm at that point, and have the epoxy filler, so I believe I'll stick with the filler plan. Autumn is here and I won't see 100-degree days in North Texas for 9 months.