- This topic has 2 replies, 3 voices, and was last updated 14 years, 9 months ago by
Chris LaPanse.
Chris LaPanse.-
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Bret Packard
Is there a resource or rule of thumb for deciding how many layers are needed on a composite airframe tube. I want to try rolling a 38mm carbon tube, 5.7oz cloth, and trying to keep it light. For this exercise, the airframe will not have to survive supersonic flight. Based on my past fiberglass experience, I was thinking 3 wraps. This will be my first attempt at an all carbon airframe. Everything I’ve done before was wrapped over cardboard or phenolic, so the layer count is something of a shot in the dark. Opinions and experiences are appreciated, but please be clear which one your recommendation is based on. Thanks.
Warren B. Musselman
I’ve seen carbon tubes fly that were a single wrap of 5.7oz fabric. You could nearly flatten it with your fingers, but it was rigid enough for an H motor. It is a matter of what you’re trying to do. If you need a single use rocket for an absolute minimum weight altitude project, there you go. However, if you want something a bit more durable, you’ll need to have enough wraps for rigidity in multiple directions. If you’re building a multi-use sport rocket, I’d do 3 wraps and then cover it with a bi-axial sleeve.
One other thing, if you’re using a commercial nose cone, you might consider enough wraps to build up sufficient thickness for the nosecone shoulder. I typically get layer thickness of .01 without vacuum-bagging with 5.7oz fabric. It gets better with v-bagging, about .008″
Chris LaPanse
I’d tend to go with 3 wraps as well. Most commercial composite tubes are thicker than 3 wraps, but honestly, 3 wraps should be more than enough, and it should give you a good, strong, durable tube without it becoming too heavy.
Bret Packard
Warren B. Musselman
Chris LaPanse
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