ORIGINAL: Got RPM
I strongly recommend that you do not use balsa in your build. It is too weak and in a crash is more likely to fail. I know, I used it in a water-prop SAW boat and crashed at 80 mph - the boat broke apart. Use basswood and liteply instead, and don't worry about a few extra ounces of weight, it is meaningless. Strength is far more important. The boat looks way cool so far!
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Where does one buy Basswood and Liteply? Never heard of them before.