1.5X Upscale Estes Fat Boy

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Well-Known Member
Jan 17, 2009
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I love the Estes Fat Boy so I decided to build a 1.5X upscale using the Performance Rocketry 4" fiberglass elliptical nose cone and PML QT. This will have a 38mm motor mount and TTW 3/16" birch plywood fins. I plan to fly it on small 38mm and 29mm motors. RockSim predicts about 1,100 ft on a PRO38 1 grain G if I can keep the weight under 3.5 lbs.
I'm using the Aero Pack 38mm motor retainer and their adapter for 29mm engines.
With the help of RockSim I made a cardboard template for the 3/16" birch plywood fins which have been cut and match sanded. More to come...
from Tango Papa. If you look real close you can see the "Fat Boy" in white. The blue is more navy and much darker than the Estes decals but they will still look good.
Looks goodgreat Bruce, can't wait to see it fly !!!

I'm upscaling another Red Max. I'll send you some pictures a little later.

goodgreat?? What was that all about??

Bruce, make sure you get some pictures of the finished rocket and some flight photos.

Originally posted by Rocket Flier VB
goodgreat?? What was that all about??
That's what I call a "senior moment"...:D

This is my first project that I am going to try and document with pictures so I plan to take plenty.
I'm using a stainless steel eye-bolt and U-bolt for the recovery system. Since the nose cone is hollow I am using a bulkhead which will be epoxied inside after I add some nose weight. This also gives me a little more room for the recovery system.
you might want to cut a 38mm hole in the center of that bulkhead, for those long motors that go right into the nosecone
Great build. You are using some fantastic components for this rocket. It'll certainly be a high quality build! I'd like to see some comparison photos with the original once it's done. Looking good.
Next, on to slotting the QT. I've read several posts about slotting QT and we all know what heat does to plastic. But, I'm "tool challenged" and my only realistic option is my Dremel tool. After drawing the lines I drilled a 3/16" pilot hole at the end of each slot.
I will use a diamond cut-off wheel at medium speed to make the slots. I set up my Work Mate to hold the tube in place.
You can see that the plastic "gums up" while cutting. I found that you can just break off the pieces with your fingers after cutting.
With a little patience and some sanding I have finished the slot. Doesn't look as good as you guys with the router tables and what not but it works.
The rear end with motor retainer. Now it is time to start gluing this thing together. May be awhile before I post any more pictures.
Very Very Very nice ! I love the nice clean finslots! I always make them too big :rolleyes: Must fawk out some money for a dremel some day :D
I sanded down the bulkhead plate to fit about 6" inside the nose cone.
I decided to use the router attachment for my Dremel tool and with a 45 degree bit cut a bevel on the fin edges.
Hey Bruce that thing looks great can you post your rocksim? I might to copy your idea I have a piece of 4" tubing lying around and that looks like a good thing to do with it.

Thanks David
This is a picture of 15 oz. of split shot covered in 30 minute expoxy. I forgot how much heat expoxy can generate as it cures and you will notice the nose cone sitting in an ice bath (I almost forgot and came close to ruining the whole thing). The black line is where the bulkhead will be attached.
I've finally started gluing this project together. The bulk plate has been epoxied into the nose cone, the forward centering ring has been glued to the motor tube, the motor mount has been glued to the airframe and the TTW fins have been "tacked" in place (used 5 minute epoxy to tack the fins - longer setting epoxy on everything else).
I finished the internal fin fillets and before I glue the aft centering ring in place I installed the rear rail button.
I glued a self-clinching PEM nut inside the airframe for extra support of the rail button and to allow the rail button to be easily changed if it is damaged.
The aft centering ring has been epoxied in place and now it is on the external fillets. I am using the "tape, popsicle stick and 12-minute epoxy" method for the fillets. I'm not as concerned about strength (because of the internal fillets) as I am about appearance.
The epoxy has been poured and smoothed with the popsicle stick.