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- Nov 29, 2018
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Made some serious progress today. I completed the motor mount and secured (epoxied) the piece of 750# Kevlar that will be serving as the shock coard mount. I also remember (thank the good Lord) to measure the location of the forward centering ring stack as this will serve as the mount for the forward rail button.
I then mixed a moderate size batch of BSI 30 min and secured the motor mount in the airframe (no pictures of this, but you can imagine what it looked like)
Next came the fins. It’s really getting exciting now! A test fit led to some final sanding to get everything just right. Then mix a small batch of T88, and “double butter” the root to ensure a good bond to the motor mount. Then, a good coat on the extra thick root edge that bonds to the airframe and tail cone.
Can’t ask for much more here.
As for all the bevel discussions, I opted to leave the trailing edge square. Sanding showed that the balsa was VERY fragile where it tapered gradually to 0 and the thought of repeatedly landing on this sort of edge didn’t excite me. Even with a coat of laminating epoxy (which I will do once the fillets are complete). I toyed with the idea of a smaller bevel, but the lack of symmetry would have driven me NUTS.
As for the fillets, I am thinking of using T88 to pull some very small fillets. I like the look of big round fillet transitions, but I don’t think those will “fit” this build. Given the contact area of a 3/8” wide root and some small fillets, this should be plenty strong, though I do invite thoughts here. So what do you think? Would a small tounge depresser fillet be sufficient?
I then mixed a moderate size batch of BSI 30 min and secured the motor mount in the airframe (no pictures of this, but you can imagine what it looked like)
Next came the fins. It’s really getting exciting now! A test fit led to some final sanding to get everything just right. Then mix a small batch of T88, and “double butter” the root to ensure a good bond to the motor mount. Then, a good coat on the extra thick root edge that bonds to the airframe and tail cone.
Can’t ask for much more here.
As for all the bevel discussions, I opted to leave the trailing edge square. Sanding showed that the balsa was VERY fragile where it tapered gradually to 0 and the thought of repeatedly landing on this sort of edge didn’t excite me. Even with a coat of laminating epoxy (which I will do once the fillets are complete). I toyed with the idea of a smaller bevel, but the lack of symmetry would have driven me NUTS.
As for the fillets, I am thinking of using T88 to pull some very small fillets. I like the look of big round fillet transitions, but I don’t think those will “fit” this build. Given the contact area of a 3/8” wide root and some small fillets, this should be plenty strong, though I do invite thoughts here. So what do you think? Would a small tounge depresser fillet be sufficient?