I built this 3D version of the Estes Goblin back in the 1971-72 time period. I had been working summers and had placed a large order with Estes when the D engines were newly available. With the order came several Goblins as bonus kits. I do remember that after several CATO's tying to fly a standard Goblin I did not have a lot of faith in the D engines. Over the winter I bashed the remaining Goblin parts into the 3D Goblin. It never flew but did look impressive sitting on the shelf,

Bob

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GOBLIN_3D.rkt (81.6 KB, 57 views)

Darn. I thought we were going to get stereo pictures of the process of a Goblin bash.

I built a sturdy (I thought) 3 x D BT-55 model along these lines. It "kinked" a bit above the main motor mount. Also, the parachute tore off on ejection. . . 7 second delay wasn't enough.

I've since fiberglassed the body tube, but I'm still leery of flying it again.

You need to either get some long streamers for recovery instead of a chute, or do electronic deployment, or pick up some old-stock D11-9's from someone. A while (3-4 yrs) back, someone told me they had a whole case of those that they were willing to sell. Cannot for the life of me remember who though.

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When in doubt, WHACK the GAS and DITCH the brake !!!

Yes, there is such a thing as NORMAL, if you have to ask what is "NORMAL" , you probably aren't !
Failure may not be an OPTION, but it is ALWAYS a POSSIBILITY.
ALL systems are GO for MAYHEM, CHAOS, and HAVOC !

Bob,

Nice bash! Looks like it would be very impressive on the field.

I couldn't help but play around with the design a bit, and found something interesting. If you change the fins on the central core back to the "standard" four-fin cruciform, and eliminate the fins on the pods, the simulations seem to work out better.

I ran at least 10 different combinations of engines, and got reasonably good numbers from 9 of them. See the attachment images below. Surprisingly, they all seem to be able to get in the air safely on a standard 36" x 1/8" rod, but some of those are right to the end of the rod.

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Goblin 3D Mk II.rkt (150.0 KB, 61 views)

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Craig McGraw

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