Estes Goblin Fin Can

thingiverse

I had some spare BT-55 tubes lying around and an extra Goblin nose cone (Check out the thing https://www.thingiverse.com/thing:3073567/files) so I decided I had almost all the parts needed to build my own Goblin. So, I modified the fin can from ellipticaloptician's model rocket kit to make this one.\r\n\r\nA few notes...\r\n\r\n1) I thickened the fins a bit more than the prototype shown in my photo. One of the bottom tips on my prototype broke off (just a little), so I clipped the rest to match. The thicker fins on the included file should work better.\r\n\r\n2) I haven't flown this yet, or checked it for stability. Weight may need to be added to the nose to make it stable. Look up how to do that online if you don't know.\r\n\r\n3) As both Estes and Semroc produce "Goblin" kits now, I'm pretty sure the decals are probably copyrighted, so I didn't include them. Do a Google search, you'll find them just as easily as I did. I added extra bats to the file I found. They're handy for covering up blemishes on the paint.\r\n\r\n4) I used the "best guess" method for scaling the fins. That is to say I looked at a photo of the original, noticed that the fin was about two body tubes wide, and scaled the fins accordingly. I don't own an original Goblin right now so I have no idea how close I got. But it looks good enough to me. They should be the same shape.\r\n\r\nOkay, edit to #4 here as I just talked to my brother, who is making two Goblins from scratch using the original plans. He makes them with plywood fins because he likes to put Es and Fs in them. He's making two because he loses them because he puts Es and Fs in them. According to him, the original root edge on the Goblin fin is 2". Mine are a little over 2 1/4", so they're a bit oversized. I apologize to all the purists out there for this but if you're that much of a purist, go buy the original kit, they still make them.\r\n\r\nEdit to the edit on #4. I had time today so I resized the fins closer to where they should be. I've included them as the "Corrected" fins but left the original in case you want to print the slightly oversized ones for extra stability.\r\n\r\n5) You'll need the nose cone linked above (I used the "Base2" base for this nose) and the retainer from ellipticaloptician's original kit (see the thing this is a remix of) to complete this kit.\r\n\r\n6) Oh, and you'll need a shock cord and chute, naturally. \r\n\r\nEDIT 10/22/2018: Added a notch inside for the shock cord to run through that was missing in the original files.\r\n\r\nEDIT 5/8/2019: Added a version of the "corrected" fins that fit an Estes E-motor. For really high flights.\r\n\r\nFLIGHT REPORT\r\n\r\nFlew the larger of the two on a D12-5 today. The flight itself was perfect, but the nose cone and streamer separated at apogee and fell separately. The body tumbled down and landed smoothly, however, and I was able to recover everything intact. But I may have to use thicker Kevlar shock cord next time.