I recently trimmed, glassed and made fit against the fuselage skin (pretty nicely) my RV-8 canopy skirt. As is typically the case, the "make it fit" effort was focused mostly along the sides toward the rear of the canopy. I got a nice, clean and relatively tight fit. That was in about the September/October time frame.
Then, a week or two ago I went to slide the canopy closed on the fuse in a cold-ish hangar, in which the propane heater had been on and running for about 25 minutes. When it closed, I saw there was about a 1/8 to 3/16 gap along the sides, basically from the rear seat-back area back a couple feet, in the area where the skirt curves up toward the rear. The right was slightly prouder than the left side. I opened and closed it a few times, thinking maybe it just wasn't seating right. I cussed and stamped my feet and whatnot for a bit. Then I just took a deep breath and started pushing on the skirt sides, and determined that if the "crossbow" portion of the canopy where the slider block attached had just a slightly smaller radius, it would almost certainly fit just right.
The hangar heater's on a timer. It puts out a lot of heat when its running. I kept it running (it was cold out and I'm a cold wimp) and kept messing with the skirt gap, trying to decide if I should grab a pipe bender and tweak that rear bow every so slightly so as to reduce the radius and pull the sides in about 1/8 to 3/16.
Eventually I'd had enough of that and went on to do some other work. The heater shuts off because I let the timer run out and I needed to run up to the restroom (yeah, TMI). When I come back to the hangar, it's a cooled off a bit. I start to walk toward the heater timer and happen to glance at the closed canopy as I walk by. WAIT, WHAT?? It's shrunk back in, narrower gap. Apparently cold means shrinkage. Go figure. I waited a bit, wanting to be sure it wasn't my mind playing hopeful tricks on me, and did the metaphorical opposite of watching water boil: As the temperature dropped, the gap closed up. Once it gets cold enough, it once again fits pretty much perfectly.
So, now I am wondering what (if anything) I should do to tighten things up. If I tighten up the radius represented by that canopy frame bow I can bring the sides in slightly and make it fit tighter. If it's warm, okay fit and if it's cold it would be a bit of an interference fit (fit even tighter) and get sprung out a little. In theory. My canopy is sika glued, and so is the skirt.
Anyone else solve this problem specifically? I searched VAF and found a variety of example posts related to closing up gaps with various materials, and I already have a plan for stopping any errant air. But I do want to get the fit on this expansion/contraction things as close as possible before employing any sort of gap filling materials. Anything else I am missing?
Thanks!
Then, a week or two ago I went to slide the canopy closed on the fuse in a cold-ish hangar, in which the propane heater had been on and running for about 25 minutes. When it closed, I saw there was about a 1/8 to 3/16 gap along the sides, basically from the rear seat-back area back a couple feet, in the area where the skirt curves up toward the rear. The right was slightly prouder than the left side. I opened and closed it a few times, thinking maybe it just wasn't seating right. I cussed and stamped my feet and whatnot for a bit. Then I just took a deep breath and started pushing on the skirt sides, and determined that if the "crossbow" portion of the canopy where the slider block attached had just a slightly smaller radius, it would almost certainly fit just right.
The hangar heater's on a timer. It puts out a lot of heat when its running. I kept it running (it was cold out and I'm a cold wimp) and kept messing with the skirt gap, trying to decide if I should grab a pipe bender and tweak that rear bow every so slightly so as to reduce the radius and pull the sides in about 1/8 to 3/16.
Eventually I'd had enough of that and went on to do some other work. The heater shuts off because I let the timer run out and I needed to run up to the restroom (yeah, TMI). When I come back to the hangar, it's a cooled off a bit. I start to walk toward the heater timer and happen to glance at the closed canopy as I walk by. WAIT, WHAT?? It's shrunk back in, narrower gap. Apparently cold means shrinkage. Go figure. I waited a bit, wanting to be sure it wasn't my mind playing hopeful tricks on me, and did the metaphorical opposite of watching water boil: As the temperature dropped, the gap closed up. Once it gets cold enough, it once again fits pretty much perfectly.
So, now I am wondering what (if anything) I should do to tighten things up. If I tighten up the radius represented by that canopy frame bow I can bring the sides in slightly and make it fit tighter. If it's warm, okay fit and if it's cold it would be a bit of an interference fit (fit even tighter) and get sprung out a little. In theory. My canopy is sika glued, and so is the skirt.
Anyone else solve this problem specifically? I searched VAF and found a variety of example posts related to closing up gaps with various materials, and I already have a plan for stopping any errant air. But I do want to get the fit on this expansion/contraction things as close as possible before employing any sort of gap filling materials. Anything else I am missing?
Thanks!
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