ActingLikeAKid
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This should be an easy one
Working on a Blue Tube rocket. I've attached a sled to the (solid) nose cone. Sled is plywood, holds an Eggfinder and small lipo.
I want to secure the sled/NC inside the tube (the whole top ejects, so there's a bulkhead and eyebolt below this).
I'm thinking 2 #6 screws through the shoulder of the NC, one through the bottom of the sled.
(the top 2 go into solid urethane; the bottom one into 1/4" plywood).
These will only be to secure the nose cone and eggfinder during recovery - on the way up, the top of the airframe pushes against the nose cone. During ejection and chute deployment, though, the tube will want to pull away from the nose cone, so the screws are to stop that from happening. And with a nice long shock cord, most of the energy of the ejection should be dissipated.
So the (loaded) sled and nose cone weigh about 190g. If my math is right, that means each #6 screw would be supporting 64g while gently drifting down under chute; even if it experienced 10Gs during a really hard deployment, that's still about a pound and a half of force, which a #6 screw ought to be able to hold, especially if it's only for a minute.
Thoughts? Is my math right on this?
Working on a Blue Tube rocket. I've attached a sled to the (solid) nose cone. Sled is plywood, holds an Eggfinder and small lipo.
I want to secure the sled/NC inside the tube (the whole top ejects, so there's a bulkhead and eyebolt below this).
I'm thinking 2 #6 screws through the shoulder of the NC, one through the bottom of the sled.
(the top 2 go into solid urethane; the bottom one into 1/4" plywood).
These will only be to secure the nose cone and eggfinder during recovery - on the way up, the top of the airframe pushes against the nose cone. During ejection and chute deployment, though, the tube will want to pull away from the nose cone, so the screws are to stop that from happening. And with a nice long shock cord, most of the energy of the ejection should be dissipated.
So the (loaded) sled and nose cone weigh about 190g. If my math is right, that means each #6 screw would be supporting 64g while gently drifting down under chute; even if it experienced 10Gs during a really hard deployment, that's still about a pound and a half of force, which a #6 screw ought to be able to hold, especially if it's only for a minute.
Thoughts? Is my math right on this?