Saturday, January 16, 2010

Rocket Materials

In the January-February issue of Sport Rocketrt, which came on Thursday in the mail, there's an article on It's a site with data on failure testing of various high-power rocket materials, with data on everything from shock cords and quick-links to fin materials and motor retention systems.

Two things about the article stuck out for me. First, they tested little tiny 1/8" quick-links rated at 220 lbs. It took over a ton of force (2353 lbs on average) to snap them:

That's over 10 times the rated strength. Pretty incredible, and it means that they're suitable for connecting a nose cone weighing 47 pounds, or connecting a 'chute to a body weighing 47 pounds. (Standard practice says have a 50:1 weight:strength margin for recovery devices).

Second, the author mentions that he built a Level-3 high power rocket with nothing but cardboard and wood parts and wood glue for adhesive, because with a proper joint, wood glue is stronger than the wood and cardboard and is thus an acceptable alternative to epoxy. My use of wood glue as a strength-adder: vindicated!

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