29mm X 24mm, two stage Avenger

[Estesbasher]

This will be the my first mid power two stage. Kind of,Sure I've done the black powder staged rockets. But I never have flown one with AP. motors. I built one once before that I never liked how I set it up for the altimeter. So it fell by the wayside
I just wanted to gain a little better building techniques. This rocket will use the 29mm-120/40 motors for the booster section. the sustainer will fly on the 24mm. pro-motors. I'm going with motor deployment. The timer is a perfectflite mini-4. The booster is the Estes BT-55 tube 1-3/8" od. I'll have one layer of carbon fiber sleeve on the Booster. This makes it so the Od. of the retainer lines up with the Od. of the body tube. Then I have enough room in the estes BT-55 coupler tube for the timer.


This last pic. shows how I did the reducer for the sustainer. I cut a full length coupler tube BT-55 so that when I glass the outside,I'm not taking the chance of crushing the tube with the shrink wrap.

 

[Estesbasher]

I want to go into some detail on how I've been glassing as of lately. For the booster tube I couldn't use a mandrel with the way I had done the reducer for the sustainer. To keep epoxy from socking into the end of the tubes. I socked the inside with CA Then I layed down some blue tape.

I got some shrink wrap from Joanns craft store. Here's a link to what I'm using.
https://www.joann.com/clear-shrink-rolls-3-pk/6659908.html#q=shrink+wrap&start=9

When I epoxy the sleeve I can get a lot of the excess from the cloth just by using the brush. Then I'll take a paper towel and wipe it down.



You could use a hair dryer if you'd like. I went and got a cheap heat gun for 20.dollars. What you have to watch when your heating the shrink wrap is if you stay to long in one place it's going to melt holes into the wrap. So keep it moving and rotate the tube at the same time.

 

[Estesbasher]

Final product with shrink wrap removed.

I'm always cutting fins from card stock and mocking them up just to give me an Idea of what they look like. I kind of like this look. It's going to be about 4" shorter by the time I get done with it. Weight right now is 4oz.

 

[grouch]

That's pretty nice. I can't wait to see the the electronics portion or your build.

 

[Estesbasher]

That's pretty nice. I can't wait to see the the electronics portion or your build.

Thanks Jarrett.
Today so far, I got the retainer and motor mount done for the booster. Cust some small rings from the BT-55 coupler stock. The aft ring I pull one layer of paper from it, makes it where I can slide about 1/16 into the retainer. That way it's centered up with the body tube. I cut a short piece of 29mm coupler stock, this is for the shockcord.
The shock cord is thin enough that it fits between the body tube and coupler. I have a hole drilled through it where I tied a knot and epoxyed it on the inside.
This gives you a Idea of how everything fits.

 

[Estesbasher]

I got the motor mount glued in on the booster. Pic show how I'll take a glue stick and make for where I want the glue for the forward ring.

For the shock cord mount on the 24mm, sustainer I used a motor spacer for the estes motors, I think it's from a E-motor to a D-motor.
Glued some Bt-20 coupler stock to the inside,Then I epoxyed the end of the shock cord to the inside.
Cut a groove on the outside of the motor spacer and glued the cord into that.

 

[Estesbasher]

When I glued the shock cord mount into the tube. I take a short piece of coupler stock. 18mm feed the cord back through the mount it's self. Then feed the shock cord through
the 18mm. stock. Now you have something to push the cord mount up into the body. Glued it in with the same technique as I did on the booster mount. This will keep you from getting glue on the kevlar cord, If you get anything on it like this, thats how it get's burnt through when the injection charge goes off.