I've seen several cracked bubbles caused by people trying to stretch the bubble into a pre existing frame and trying to attach it with through hole fasteners (screws, rivets, or bolts). The successful ones I've seen on RV's and other metal planes were fastened with no preload to the plexiglass bubble and with slightly oversized holes (to allow for expansion) with the holes properly deburred and some sort of cushion between the plexiglass and steel tube frame. Those bubble canopys aren't cheap. You shouldn't try to work with them unless the weather is warm. Happy gluing!
Joe Scappoose, Ore. Message: 5 List-Post: krnet@list.krnet.org Date: Fri, 24 Dec 2010 22:49:53 -0800 From: "BadBob" <badbob0...@embarqmail.com> Subject: KR> RE: Canopy Gluing- Epoxy To: <kr...@mylist.net> Message-ID: <574CAC0890AE49DAAF96BF8BB9B69D34@BadBobPC> Content-Type: text/plain; charset="iso-8859-1" Joe stated; "Any holes drilled around the edges make for a potential stress riser. Drill no holes." I would have to respectfully disagree, to a point, with Joe on this one. (I don't find myself in that position often as he is a wealth of good information!). The canopy on my Thorp T-18 was drilled and had screws holding it on with no glue. The canopy on my Cassutt is also bolted on and has seen 250 MPH+ without an issue. Now, having said that, Joe brings up an important point. A stress riser is to be avoided on a plastic canopy. You do not drill a canopy the way you drill other things. If so inclined to drill please research the subject thoroughly or you will be buying another canopy! Also you must mount, through the hole, without binding the canopy. You can, however, drill a canopy and bolt it or cotton flox it for added strength, however, heed Joes warning and be careful. Bob Johnson Willamina, OR 971-645-9491 *******
