Canopy deja vu

[Timwaiex0146]

Hi everyone ! Well , I'm getting ready to install a new canopy on my Waiex , the first one never made it on the plane, but that's another story. Anyway , I was wondering if anyone had any tips for doing a replacement canopy. I'm wondering how to drill thru the already tapped bows without damaging the threads. Also want to avoid the "dolphin effect ". Any advice will be greatly appreciated. Tim Waiex 0146

[SonexN76ET]

Tim,

For installing a new canopy, here is what I suggest as answers to your questions:

Drill up through the bows into the plexiglass with the appropriate bit for use with plexiglass. This means you use fasteners/clamps/tape whatever to secure the canopy to the bows and then drill from underneath meaning through the bow and then into the plexiglass. After each hole is drilled, remove the canopy from the frame, deburr the hole, reattach the canopy to the frame securely, and drill the next hole. I believe there are videos of this on EAA's Hints for Homebuilders. It is also discussed in one of Tony Bingalis's books.

Forget your previously tapped threads and just use the thinner elastic stopnuts with your screws. It is not worth the risk of trying to salvage the threads at the risk of the expensive plexiglass.

To avoid the Dolphin effect, I believe the key to that is making sure your windscreen and windscreen bow is mounted with the maximum height attainable with your Lexan where it meets the canopy. People get the dolphin effect if they cut the windscreen too narrow and it then does not have a large enough radius and height. The other thing to be aware of is how you cut out your canopy plexiglass. You want to take more or less an equal amount of material off of each side as you start trimming, but you will need to eyeball it based on exactly where your curves are in the blown plexiglass.

Good luck,

Jake

[mike.smith]

Tim,

Forget your previously tapped threads and just use the thinner elastic stopnuts with your screws. It is not worth the risk of trying to salvage the threads at the risk of the expensive plexiglass.

I agree. I've had that arrangement since day 1 and it works like a charm. You'll never have a loose or stripped screw.

[Timwaiex0146]

Sounds like good advice,, let me ask another question . After drilling thru the plexiglass , should you deburr the plexiglass holes ? If so what do you use ?

[Dennis W.]

I had a similar experience with my canopy....never made it to the first flight....slipped when i was removing it to polish the fuselage and cracked it.....but have gone thru therapy and am over it now :). For my first canopy, was diligent with the windscreen install to set the windshield bow high and wide to avoid the dolphin effect with the canopy install. First canopy came out great with good lines from the cowling to the turtle deck. What I found when I replaced the canopy on the existing frame, is that no two canopy blows are the same.....per Sonex they are blown to a laser line and will vary. When I installed the replacement, ended up with some dolphin. I had to use rubber shims on the frame to fill the gaps where before my canopy was flush with the frame. When I installed it, I drilled from the top by eyeballing the existing frame holes. Used my deburring tool to clean up all holes in the canopy. Agree with the previous post to use screws and nuts on the canopy vs. tapped holes......just don't over tighten the nuts....leave enough play so the canopy washers are a little loose. For me, ended up that it worked out well. I'm 6'2" and now enjoy the extra headroom with the canopy closed and can live with the canopy lines.....dolphin is not too bad. Good luck with your re-install.

[mike.smith]

Sounds like good advice,, let me ask another question . After drilling thru the plexiglass , should you deburr the plexiglass holes ? If so what do you use ?

Yes. I used the same deburring tool I used for my aluminum. Just be gentle and don't make it a countersink.