Swedish yoke

Smack

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694
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Kitfox IV / F1 Rocket / Magni M-16 / Beech 18
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'Ol Otto probably used bamboo because..... that's the best material he had from which to choose.
If he had aluminum available...... I bet he would have used it. Heck, maybe Otto would have used a 3D printer.
Bamboo is not homogeneous; you're right, no 'aviation grade'.
 

kolibri282

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Aluminum is probably not the best choice for small aircraft. There are several foot launchable gliders and none of these so far (as far as I know) is made from aluminum. There are some wooden ones (ULF-1, Hall Vector 1) and the rest is FRP. The problem with aluminum for small aircraft is, that, to be light enough, you have to use tubes with very low wall thicknesses which makes them very prone to fatigue failure. I would feel very uncomfotable in an aluminum glider. For gyros things are a bit different, they are so draggy anyway that the additional weight you need with aluminum does not matter. There are some projects using aluminum tubing but I think these will turn out to be inferior at least to the FRP gliders. Even for "real" soaring aircraft the aluminum Pilatus and Blanik aircraft are the odd ones out.
 

dinoa

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Apr 3, 2007
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florida
Bamboo has nodes so the fibers are not all continuous. It may have been used for millenia, but it's not optimal.
 

kolibri282

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The nodes might be weak spots but they are thicker than the segments in between, so my guess is that a bamboo rod has an equal strength all the way down. Don't forget that mother nature has had a few million years to optimize this and she never wastes anything. The main problem is, that there are not enough data and design codes. You will probably be able to come up with a better (lighter) design using FRP but you'll need a very careful design and manufacturing process. For the Pietenpol Aircamper there is a choice of using wood or welded steel for the fuselage. The wooden variant is a few percent heavier than the steel tubes, I made a comparison just for the fun of it, but if you'd use wooden parts slightly thicker, cut them in half, mill a channel along the center line and glue them together, giving you a sort of tubular wood section, you'd beat the steel variant hands down for lightness and any time if we start to talk fatigue. There is a good reason why the Cap series of aerobatic airplanes is a wood designed.
 
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