Re: Heat-PROOF engine mount tubing?

Gordon S. Hlavenka wrote:

<edited for brevity - snip>

This scheme has worked nicely, with one problem: I'm using Estes BT20 for the stuffer, and it burns completely through after 4 or 5 flights. Apparently the BP is hanging around too long and frying the tube. I still get a recovery under 'chute, but the bird has to be rebuilt to fly again. This puzzles me, since I have other models with stuffer tubes (albeit not all the way to the nose) and they don't burn through even after dozens of flights :-/

I coated the stuffer with CA on the first rebuild but that burned through also. So I guess I need a stuffer tube made out of something that just plain doesn't burn. Or some way to get the hot stuff out before it starts burning the stuffer. It seems to me this problem must have come up with baffle designs also, so there should be some useful wisdom out there.

Suggestions?


For Estes BP motors only...

I paint the inside of baffle tubes with epoxy. Not a cure, but seems to help. I use a type of Kaplow baffle and spreading the
hot ejection gas/residue over larger internal volumes also helps,
ie, a ported baffle vents into a larger airframe which is also
epoxy painted, or lined with a layer of split body tube. I have
found CA soaked paper tubes to be more susceptible to heat damage
than plain tubes. I "think" the CA structural polymer has a
fairly low melting point which causes the tubes to delaminate
upon heating.

My baffles catch so much particulate matter that I have to
regularly clean them out with a test tube brush. They are fairly
new models, but a few have 10+ flights on them without a burn
through. And my min diameter BT-20 models do not exhibit that
kind of burn through rate, either.

Are you using a particular brand of BT-20 for all the stuffer
tubes so far?

--

Gary

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