Hi I´m designing a scale amphibian-airplane, Osprey2, escale 1/5, Wingspan 60" , weight 6-7 Lbs average, to .56 or .60 four stroke engine. I don´t know how main spars to use, 2 spars of...1/4 x 3/8 balsa or 1/4 x 1/2 balsa or hardwood. have examples plans, but ihave doubt.I am afraid that it is fragile. Anyone know any standard form for that weight?

Thanks and best regards vansenair

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