Upscale Estes Bullpup AGM-12D Build

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bigone5500

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Well I finally finished it. I upscaled my Estes Bullpup to a BT80 tube size. The only thing that isn't upscale is the nosecone. The PNC-80K is the only one I had and I couln't really afford the $$$ for a custom made one at the time. I probably have around $45 in this rocket as is.

It has a 11" Sunward 29mm MMT with three lite ply CRs. I used US Composites #150 fast thick epoxy throughout the build. The only thing I wish I had used was a thicker body tube. But I can add some couplers if I want more rigidity.

I used 1/8" basswood for the fins. The rear fins are TTW. The leading edge of all fins are rounded. I summoned the great skills of our very own sandman for the balsa tailcone. I must say it was a beauty! I used two sections of #8-32 threaded rod for the motor retention which is held in place by locknut and washer which is then epoxied in place.

Launch guidance is via series 1000 nylon rail buttons. The rear button is threaded into the shoulder of the tailcone and the forward is 'almost' threaded into the forward CR.

Recovery is attached to the forward CR via 400# braided kevlar. The kevlar is threaded into one hole, around the MMT tube, then out another. The kevlar is then tied and the knot secured via two drops of thin CA. A large barrel swivel connects the 9' of 3/8" poly/elastic and the kevlar together. A 24" TopFlite X-Form parachute completes the assembly which is connected to the nosecone by a forged 1/4" eyebolt.

Motors ranging from an E18 to an H128W will be used in this rocket which is why I have incorporated a removeable noseweight system. I constructed this using 1/8" aircraft plywood. Two bulkheads were used in the assembly; the forward one epoxied at ~midpoint, and the other is removeable but is positioned at around 3/4" from the base of the shoulder of the cone to prevent axial movement which could cause epoxy adhesion failure. #8-32 threaded rod is epoxied to the forward bulkhead by locknuts and fender washers. Two #8-32 nuts are jammed together about 1 1/2" from the forward bulkhead and the removeable weight is then installed. Another nut is threaded down to secure the weight in place. A fender washer is slipped onto the rod followed by the aft bulkhead and another fender washer. The 1/4" forged eyebold is then screwed onto the threaded rod and tightened down. I made the eyebolt by cutting off the threads then drilling and tapping the remaining stud with #8-32 threads. Removeable weights are made from 1" cold rolled round stock.

I hardened the tailcone with thin CA then sanded with #400 grit. Afterward I filled it with a thinned out Elmer's wood filler. I could have taken more time with it and gotten better results but didn't. Finishing was done with Krylon white primer and Krylon Industrial Tough Coat gloss white. The decals are from Ray of InFlight Rockets...and I must say they are top quality. Final finishing will be done with Krylon crystal clear.

BT80 Bullpup AGM-12D Comparison_resize.jpg


Fins and templates.jpg


Tailcone size comparison.jpg


Kevlar leader installed.jpg


Motor Mount epoxied in place.jpg
 

sandman

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Real nice!

Do you mind if I use one of the pics on my web site?

That nose cone looks just fine the way it is. The Estes model isn't that scale anyway.

agm-12-all.jpg
 
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