This is the only design gothca that would concern me. I have seen several large diameter projects with a tube in a tube coupler/shear plates.
Originally Posted by Feckless Counsel
They have a tendency to buckle at that weak point under wind shear or off vertical flights under higher thrust motors. Once it starts, ain't no going back, they break right there. The smaller inner tube cannot handle the load, even though the outer is capable. there is a leverage effect.
You might consider a rod & tube receiver set up . rods on on BP & tube receivers on the other. Double up on the bp's several inches apart with the rods mounted in both. Same for the other side with tubes. Glass, carbon fiber for rods. Aluminum for tubes or whatever you consider stress worthy.
By the way... I have stood on fin cans when RSO' ing. If the fincan cannot take me standing on it or the flier is not confident enough the building skills, I don't give it a prayer withstanding high thrust motors. Usually a minimum diam. with a M or N stuck in it.
I always bounce on mine to test, they better be able to handle more than 200lbs of shear.
Last edited by blackjack2564; 8th November 2011 at 02:46 AM.
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