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Originally Posted by flybynight55
Any books , videos, or tech articles on thermoforming a home-made bubble canopy.. This is for a non-Vans aircraft i am working on.. thanks
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Some friends did this a long time ago making molded canopies for a Duster homebuilt sailplane.
It involved a homemade, oversize pizza style oven, many sheets of plexiglas, much experimentation, many swear words and many cans of beer...
I believe they did finally get one out, but then took the mold to a canopy place in S. Cal (Aircraft Windshields?) and many more Duster canopies were made professionally...
It became the default kit canopy.
When they delivered their mold, they were surprised at how poor the other molds were in professional outfit... apparently the proprietary molding techniques involved some sort of interface that smoothed out the mold imperfections. Al's mold was just about optically perfect, since he was one of the original Ca surfboard shapers...
IIRC, the biggest problem was the very narrow temperature range in which Plexiglas could be draped (or blown)... higher, and it bubbled/melted, lower, and it would be too stiff to form. This temperature also had to be very uniformly distributed in the plexi blank to get optical uniformity.
They did write an article in Soaring magazine about their antics. Try looking in the 1975 time frame. It's old, but I don't think Plexiglas properties have changed much since then....
Given that they can use a pretty poor mold (a male mold, not female), and the cost of large sheet of plexiglas, this might be more cost effective being done professionally....
gil A
PS.. the two instigators of these antics went on to design the Dragonfly canard homebuilt...
blow molding canopies,,books, videos????
Other folks efforts
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