Sooner Boomer
Well-Known Member
- Joined
- Mar 21, 2011
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I got out this Fall, after having sat out for a couple of years. On the last outing, I flew my Fat Boy^ on an old F39 reload. For some reason, the ejection charge didn't go off in time to deploy the parachute. The rocket core sampled, shattering the nosecone, and crumpling most of the body tube. The only thing salvagable was the fin section.
What was left:
I couldn't easily add on another section of body tube because of the previous coupler/baffle
I used a piece of body tube, and cut out a section to fit into the old body tube, and another section removed to fit new body tube.
It's also lined with a layer of heavy manila paper, painted with a wash of yellow glue to help heat/flame resistance
I decidid to go with a 3-D baffle, built into a coupler. One problem I saw was how much surface area there was, and the need to make sure the baffle didn't get blown out. The second problem was the need to run the recovery harness through the baffle. What I came up with is a series of three "half-moon" sections on a backbone
I coated the aft end of the lower two baffles in JB Weld (yeah, I cut them a bit off - still works)
When I installed the baffle coupler, I used a bamboo skewer to put a ring of glue around the inside of the body tube 1/4 to 1/2 before the seated depth. I also put some lines of glue down the inside of the tube. The coupler was pressed into place with a twisting motion. You can see where the excess glue built up just in front of the coupler. I had previously drilled a set of 1/4" holes for the recovery harness to go through. It's glued in place in the top baffle with a dab of silicone glue.
And what it looks like all put together. Still need to fill gaps and sand, plus primer and paint, and a new nosecone.
^Yeah, this is a Fat Boy.
A friend once told me his family had the exact hatchet that George Washington used to cut down the cherry tree. He told me, "Of course, we had to replace the handle a couple of times, and the head fell off once and got lost so we made a new one. But it's the same exact hatchet!".
It *did* start off as a Fat Boy. Then that one got broke. It was rebuilt with ply centering rings. Then rebuilt with 24mm centering rings. The last rebuild was with ply fins, the bottom 2" fiberglassed, an ejection baffle added. Don't know what I will do for th next rebuild - 29mm engine mounts?
What was left:
I couldn't easily add on another section of body tube because of the previous coupler/baffle
I used a piece of body tube, and cut out a section to fit into the old body tube, and another section removed to fit new body tube.
It's also lined with a layer of heavy manila paper, painted with a wash of yellow glue to help heat/flame resistance
I decidid to go with a 3-D baffle, built into a coupler. One problem I saw was how much surface area there was, and the need to make sure the baffle didn't get blown out. The second problem was the need to run the recovery harness through the baffle. What I came up with is a series of three "half-moon" sections on a backbone
I coated the aft end of the lower two baffles in JB Weld (yeah, I cut them a bit off - still works)
When I installed the baffle coupler, I used a bamboo skewer to put a ring of glue around the inside of the body tube 1/4 to 1/2 before the seated depth. I also put some lines of glue down the inside of the tube. The coupler was pressed into place with a twisting motion. You can see where the excess glue built up just in front of the coupler. I had previously drilled a set of 1/4" holes for the recovery harness to go through. It's glued in place in the top baffle with a dab of silicone glue.
And what it looks like all put together. Still need to fill gaps and sand, plus primer and paint, and a new nosecone.
^Yeah, this is a Fat Boy.
A friend once told me his family had the exact hatchet that George Washington used to cut down the cherry tree. He told me, "Of course, we had to replace the handle a couple of times, and the head fell off once and got lost so we made a new one. But it's the same exact hatchet!".
It *did* start off as a Fat Boy. Then that one got broke. It was rebuilt with ply centering rings. Then rebuilt with 24mm centering rings. The last rebuild was with ply fins, the bottom 2" fiberglassed, an ejection baffle added. Don't know what I will do for th next rebuild - 29mm engine mounts?
