As some of you know and the rest don't care, I catoed my Formula 200 a few months ago when an EX motor blew the forward closure. The result was that the epoxy bonding the booster, MMT, CRs, etc., completed melted, leaving the booster looking like a mess of spaghetti. If you never knew why they call it "fiber" glass, you would after seeing that carnage.
Well, now, thanks to the government shutdown, I took today off. My wife and kids are out of the house, and I have time to get this build thread going.
This is my rebuild of the Formula 200 (8" D, 124" tall) booster, including MMT and fins.
I will upload what I've done so far, and add as I go.
I intend to make this useful to newbies to fiberglass, epoxy, and large rockets. You more experienced guys may find it boring.
STEP 1 -- Wash the fiberglass parts.
Always wash your fiberglass parts when they are new. They are covered in chemicals that are not good for your skin, nor will they bond well to adhesives.
I use plain old dish detergent and do it in the bathtub.
Dry with a soft towel, or let air dry as you see fit.
STEP 2 -- Sand the parts.
Sand all parts of fiberglass that will be epoxied, starting here with the MMT, fin tabs, and edges of CRs.
STEP 3 -- Measure / mark airframe for rail buttons.
I use a piece of aluminum angle to get a straight edge on a round tube. I wanted my aft button near the bottom of the booster (but above the bottom CR), and my forward button about where the CP will be.
STEP 4 -- Check fit of fins in slots.
Always good to make sure the fins will fit before you start gluing things. In my case, they fit prefectly, so no widening or lengthening of the fin slots was necessary. If it had been, then I would have done it with a Dremel.
STEP 5 -- Prepare to drill CRs for threaded rods and U-bolts.
I used a paper template from PayloadBay.com to get the precise measurements for my threaded rods. Since I already have an aluminum thrust plate that survived the cato unscathed, I needed my CRs to match so that the T-rods wouldn't be bent.
I hand scribbled where the U-bolts would be in the top CR. The U-bolts are recovery attachment points. Simple trace around the U-bolts with a Sharpie.
Why are the U-bolts off-center? I didn't want one to straddle a T-rod, so I offset them. If the MMT is built correctly, it will withstand plenty of force from the harness, so I am not worried about it.
Well, now, thanks to the government shutdown, I took today off. My wife and kids are out of the house, and I have time to get this build thread going.
This is my rebuild of the Formula 200 (8" D, 124" tall) booster, including MMT and fins.
I will upload what I've done so far, and add as I go.
I intend to make this useful to newbies to fiberglass, epoxy, and large rockets. You more experienced guys may find it boring.
STEP 1 -- Wash the fiberglass parts.
Always wash your fiberglass parts when they are new. They are covered in chemicals that are not good for your skin, nor will they bond well to adhesives.
I use plain old dish detergent and do it in the bathtub.
Dry with a soft towel, or let air dry as you see fit.
STEP 2 -- Sand the parts.
Sand all parts of fiberglass that will be epoxied, starting here with the MMT, fin tabs, and edges of CRs.
STEP 3 -- Measure / mark airframe for rail buttons.
I use a piece of aluminum angle to get a straight edge on a round tube. I wanted my aft button near the bottom of the booster (but above the bottom CR), and my forward button about where the CP will be.
STEP 4 -- Check fit of fins in slots.
Always good to make sure the fins will fit before you start gluing things. In my case, they fit prefectly, so no widening or lengthening of the fin slots was necessary. If it had been, then I would have done it with a Dremel.
STEP 5 -- Prepare to drill CRs for threaded rods and U-bolts.
I used a paper template from PayloadBay.com to get the precise measurements for my threaded rods. Since I already have an aluminum thrust plate that survived the cato unscathed, I needed my CRs to match so that the T-rods wouldn't be bent.
I hand scribbled where the U-bolts would be in the top CR. The U-bolts are recovery attachment points. Simple trace around the U-bolts with a Sharpie.
Why are the U-bolts off-center? I didn't want one to straddle a T-rod, so I offset them. If the MMT is built correctly, it will withstand plenty of force from the harness, so I am not worried about it.