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Disaster_Guy

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We are having some work done on the house so I had to take a half day from work to be here while they were working. Picked up an Estes Big Daddy kit on the way home. I was never that attracted to this kit until I saw it in it's "old school" paint scheme (more on that later). This was a pretty quick and fun build. Not exactly built stock though... This will be built to handle 6 grain motors.

Kit contents. Everything to the right of the fin sheets is discarded to the build box (spacer, block, hook, chute, shock cord...)

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I will be using a 24mm screw-on retainer. Marked where it will sit and measured the centering rings onto the tube. It is going to be tight but should just make it without having to cut another piece of BT-50 for a motor mount.

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Fore centering ring is glued to the motor tube. I used the aft CR from the kit here because it is already notched for a hook and this worked well to pass the kevlar loop through for my recovery harness mount. The kevlar is rated for 200lbs and is attached using the Quest method.

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Fins are installed and internal fillets applied. The entire build through this point has used Gorilla Wood Glue (PVA type)

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Aft CR is installed along with the retainer. I mixed up way too much JB Weld for the retainer installation so I went ahead and spread a very thin film of it on the CR and exposed ID of the body tube. While this may add a tiny bit of weight it may also help a little bit with heat resistance since this thing will without a doubt find skidmark and VMAX loads shoved inside of it.

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Still up will be cutting the bottom off of the nose cone shoulder to accommodate a 6 grain case, external fillets on the fins, likely nose weight, throwing about 8' of 2mm utility cord between the kevlar loop and nose, and deciding on a paint scheme. This will either use the classic black and yellow or become cloned to the design that I did on my Gizmo. Depending on the final weight, this will likely fly with either a 10" or 12" Top Flight chute.
 
Be careful. I wouldn't be so sure that those fins could handle anything more than a middle of the road F. A V-MAX F240 (3G) might find the speed of balsa awfully quickly.

By the same token, you're more than welcome to try it. Who knows? I know I've shredded my fair share of rockets.
 
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I have been considering that... The fins will be sealed and potentially papered. I had given a moment of thought to glassing them or letting some extra thin CA soak into them but.... Based on the sims using stock weight (this thing will likely be much heavier than stock) the max speed I found including the F240VM and G100SK loads was Mach .72. I am open to thoughts on this.
 
Paper would probably be more than enough to quell any doubts if you're looking at M <= 0.72. If you like FG, then .75oz should be more than enough. Most of the problem with balsa is strength in the across-the-grain direction, and either paper or light FG solves that problem. Paper leaves an easier to finish surface and can still be glued with wood glue.

By the same token, you've already glued the suckers on, so I'd just go for it.
 
I decided to go ahead with the paper method and I am pretty happy with the results. I will likely get it in paint in the next few days. I am thinking that I am going to go with the vintage black/yellow.
 
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