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  #21  
Old 02-24-2017, 07:33 AM
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K'Tesh K'Tesh is offline
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Quote:
Originally Posted by tbzep
Cut that finger tab off, spin the hook upside down, and you have a classic motor hook. I've done that with every kit I've built that I finished (painted, decaled, displayed), but I have left the finger tabs on a few of the utility rockets I've built.


Too late... However, I was mentioning it just to point out one of the differences between the K-55 and the 7237 kits.
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  #22  
Old 02-24-2017, 07:47 AM
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Quote:
Originally Posted by K'Tesh
Too late... However, I was mentioning it just to point out one of the differences between the K-55 and the 7237 kits.

I meant for your future builds and as a tip for folks new to the board that might see the post. Fly the snot out of your current Goblin and build another with the mod cause you know you want to put a D12 in it and lose it.

BTW, make sure the hook is recessed enough. IIRC, even the old kit's hook is borderline touching when sitting on the fins.
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  #23  
Old 02-24-2017, 08:40 AM
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K'Tesh K'Tesh is offline
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Quote:
Originally Posted by tbzep
I meant for your future builds and as a tip for folks new to the board that might see the post. Fly the snot out of your current Goblin and build another with the mod cause you know you want to put a D12 in it and lose it.

BTW, make sure the hook is recessed enough. IIRC, even the old kit's hook is borderline touching when sitting on the fins.


And I meant too late, as I usually clip the finger tab off and install it backwards to keep the factory edge on the outside of the rocket. However, in this case, I found that you can carefully thread the finger tab into the slot, and it will stay in place nicely. But I can see how future readers of this thread may benefit from the suggestion. My sim of the 7237 however will be stock.

I also am going to have to modify the engine mount to something that isn't quite stock (old or new). Due to damage to the body tube in transportation, I'm reinforcing the back end of the body tube by gluing the aft centering ring flush with the end of the rocket, much like the old Cherokee D kit was. The engine hook will be mounted 1/4" from the end, and not 3/8" from the end. So, it should sit on its fins (or darned close to it).
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Dreaming of making the rockets I dreamed of as a kid (and then some).

"The Guide says there is an art to flying", said Ford, "or rather a knack."
"The knack lies in learning how to throw yourself at the ground and miss."


Launching is Optional... Landing? That Depends on Trees.
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  #24  
Old 02-24-2017, 09:18 AM
jdbectec jdbectec is offline
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Here is the link to Gerry Fortin's page. Unfortunately we cannot see the instructions in the 1255 version. We can see that the fins are 't die cut and the nose cone is balsa.

http://www.seateddimevarieties.com/...torials/k55.htm
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  #25  
Old 02-24-2017, 09:27 AM
jdbectec jdbectec is offline
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Quote:
Originally Posted by K'Tesh
FWIW: My measurements of the modern reissued Goblin (7237) I have here in China shows that the fins have shrunk ever so slightly. The motor has moved back 1/8" and thanks to the finger tab, built stock, the rocket wouldn't be able to sit on its fins.


I know you like to be precise. How much have the fins shrunk? More or less than the width of the laser? I haven't opened mine but I'm going to guess half the width of the laser.
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  #26  
Old 02-24-2017, 09:42 AM
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Quote:
Originally Posted by jdbectec
I know you like to be precise. How much have the fins shrunk? More or less than the width of the laser? I haven't opened mine but I'm going to guess half the width of the laser.


Ok, here's where things can get complicated... Because the fins of the K-55 were not die cut, the fins were hand cut by the builder using the template provided by Estes for them. In my measurements of the fin pattern, I got the root edge of the fin as 2.031" (very nearly 2 1/32"). However, cutting fins by hand can play merry hell with exact measurements. So, I'd say YMMV when it comes to the K-55. If (as it appears to be) the 1255 never came with die cut fins, they'd have the same issue.

My measurement of the 7237's laser cut fin has the root edge as 1.96875" (1 31/32") (Raw, unsanded, and still encased in the matrix it came in). While I haven't had time to measure the other points of the new fins, to see if the results are all smaller by the same percentage, I've managed to sim up the rest of the kit using the parts I have.

One thing to note about Gerry's page, the resolution of the images makes it hard to see if it has die cut fins or not... (though I'm inclined to believe you still have to hand cut them yourself). He also lacks images of the 1981 - 82 version of the kit.
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Dreaming of making the rockets I dreamed of as a kid (and then some).

"The Guide says there is an art to flying", said Ford, "or rather a knack."
"The knack lies in learning how to throw yourself at the ground and miss."


Launching is Optional... Landing? That Depends on Trees.
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  #27  
Old 02-24-2017, 09:52 AM
jdbectec jdbectec is offline
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Thanks that's more than I expected. According to the catalog 1255 never came with die cut fins or a plastic nose cone but, we have both seen part substitutions before.The Estes Flip Flier I just bought has a shorter nose cone than shown on the package and the instructions. So far all of them I have seen have this shorter nosecone.
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  #28  
Old 02-24-2017, 11:24 AM
jdbectec jdbectec is offline
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I've been browsing catalogs at the Ninfinger site. It's interesting to note that the last year the bnc-55AO was offered as a separate part was 1974. They must have made a big batch of Goblin kits! Either that or it was an SPEV. That was also the last year for the K kit numbers. The kit from 1979-80 definitely has a balsa cone,that means they had at least a 5-6 year supply!
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  #29  
Old 02-24-2017, 12:35 PM
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Joe Wooten Joe Wooten is offline
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The one I built back in 1983 had a balsa nose cone.
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