Battson
Well-Known Member
Hi team,
How many layers of fibreglass will I need to get enough strength in my custom-made wingtips?
They are a standard hoerner shape for the Bearhawk Alpha wing, NACA 4412, depth about 10" and span about 15". I estimated they will see about 90N of lift each at 1.0g.
Obviously I want to use the least material necessary, to save weight. On advice from the aircraft's designer, I have started with 4 layers of 6oz cloth and used the stronger epoxy resin, including a heavy resin layer with mircoballoons instead of gelcoat. They have sanded up really nice and smooth. There's an extra layer of 2" glass tape around the edge to add strength where the screws will go through.
They are just slightly more flexible than I expected, so I wondered about strength.
If I need to add strength I can add chop strand mat, cloth, or foam plus cloth to create some structure on the inside. But I can't decide whether or not that's necessary. Advice appreciated.
How many layers of fibreglass will I need to get enough strength in my custom-made wingtips?
They are a standard hoerner shape for the Bearhawk Alpha wing, NACA 4412, depth about 10" and span about 15". I estimated they will see about 90N of lift each at 1.0g.
Obviously I want to use the least material necessary, to save weight. On advice from the aircraft's designer, I have started with 4 layers of 6oz cloth and used the stronger epoxy resin, including a heavy resin layer with mircoballoons instead of gelcoat. They have sanded up really nice and smooth. There's an extra layer of 2" glass tape around the edge to add strength where the screws will go through.
They are just slightly more flexible than I expected, so I wondered about strength.
If I need to add strength I can add chop strand mat, cloth, or foam plus cloth to create some structure on the inside. But I can't decide whether or not that's necessary. Advice appreciated.