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Building Tips and technical articles. => Building techniques => Topic started by: James Mills on May 08, 2013, 07:44:20 PM
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I am building a Junar and have looked at several different plans of planes in the same size range and noticed some do not show a doubler under the stab (nothing shown on the Junar plans) but others do. Randy's Tempest shows a 1/8" balsa doubler and I think Paul's Impact shows 1/32 ply. Is the doubler necessary? Is it for added strength or more glue area for the stab?
Thanks,
James
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If it makes any difference, I generally use a 1/64" ply support on the fuse sides under the stab.
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If it makes any difference, I generally use a 1/64" ply support on the fuse sides under the stab.
Is the purpose added strength?
Thanks,
James
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Yes &yes. Do what is needed to make the plane strong enough to last. Many times on small classic models I add a doubler under the stab on the outside sanded in so you will not notice it. Ball links take up a lot of room.
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I've used doublers there hit or miss over the years but never noticed any difference either way. Now I carbon the fillets anyway so don't bother with doublers.
Dave
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I've used doublers there hit or miss over the years but never noticed any difference either way. Now I carbon the fillets anyway so don't bother with doublers.
Dave
Dave,
What do you mean by carbon the doublers?
James
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Use the balsa doublers, they do not weigh much at all and results in a much better glue joint and way stronger, it also helps add stiffness to the stab, a balsa fillet on the outside works well too
Randy
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Use the balsa doublers, they do not weigh much at all and results in a much better glue joint and way stronger, it also helps add stiffness to the stab, a balsa fillet on the outside works well too
Randy
Thanks Randy.
James
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James,
Years ago I had a fuselage split along the horizontal grain line beginning at the leading edge of the stab. I now glue a 1/2" wide strip of 1/16" balsa running vertically along the inside of both sides of the fuselage just in front of the stab leading edge. I've never had a problem since.
Paul
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Dave,
What do you mean by carbon the doublers?
James
James, a little misunderstanding, I carbon the fillets and don't use doublers. Actually I'm using .5 carbon tissue strips doped at the joint to create the small radius fillet which becomes like steel with a few coats of dope. Also this completely stopped fillet blisters and lifting. This (I feel) is a bunch stronger than whatever doubler I might add.
Dave