Hey, no fair!

You jumped 21 years into the future to snap that photo!

What did you use, RockSim v15 to draw it? And you didn't bother to bring us back a copy, either!!!

Now, let's see...

That's gotta be at least an 8" tube, probably fiberglass or carbon fiber nose cone...

Punching the numbers now...

This'll take awhile...

Craig

I did a 2.6" (BT-80 body tube) upscale of the Goblin about 15 years ago and it's still going strong today. It is an awesome demo model for schools because of it's slow and firey launches. I used 1/4" balsa for true scale and a single 24mm motor mount for D/E engines. It flies perfectly with D12-5's in calm air, and with D12-3's in moderate winds where weathercocking comes into play. It recovers with an 18" chute, but I cut the center out of it for faster decent. With the thick balsa through the wall construction, it would probably recover just fine with a 12" chute.

Wow, that's a great upscale, Thor!

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That BIG one I found on another rocket forum,it certainly is not mine! I am only at the 2X level, never fired anything over a D engine yet. I am having a great time. Hey tbzep, that sounds great, I had wondered if the Ds were enough, I am probably going to configure it to fire both Ds and Es. I appreciate the help and reports. These guys are talking about a 2X DOUBLE stage with 4 Es on each stage! No wonder it is listed in the HIGH POWER section.........crazy!!!Goblin 2X Two STAGE

The 2X is finished except adding decals and after looking at the "decal" threads I think I will buy them from Tango Papa rather than making them myself with an inkjet printer. I have not tried this but it does intrique me. After weighing the rocket in its final form I was astonded to see it went 13.5 ounces, egads. I finally decided NOT to shoot it with an E engine but go to an F. Probably an Aerotech F21-4W I had originally wanted a larger Goblin I could shoot with E engines so I might have to build a 1.5X one with a 2" tube and give a try to making my own cone. The one I bought for the 2X was a little too conical in shape so the next go round I may try making one. This was really fun and a good rocket to get back into rocketry. I have just finished the construction of a 1X clone with a BMS cone that looks right. I was astounded this little D Engine rocket only weighs 1.5 ounces. MAN.......what a screamer!!!

WOW! Did you build it out of lead?

My 2X weighs in around 7.5 oz without the motor. That's with 1/4" thick balsa fins and a lengthened PNC-80 nosecone.

I built a 2.6" diameter Red Max with 1/4" balsa fins also, but I turned the nosecone for it instead of modifying an existing plastic cone. It's unpainted and is only around 4.9 oz right now. I'm sure it will be close to the Goblin's weight after painting and detailing.

Well, obviously I am not good at building them light. Thickened plywood fins, I think they are 5/32 thick, a 8" BT 50 stuffer tube with THREE plywood centering rings and lots of glue I guess. I has a BT52 stiffner tube over the 50 Engine section. Built much like the Der V-3 construction with an extra centering ring. I was a bit shocked when I weighed it the last time. Perhaps I should call it the Fat Albert Goblin! lol I am interested in how you made your cone? Who makes the PNC 80 nose cone? Thanks! Obviously I have a long way to go to correct construction, but I am having fun. THANKS!

Your rocket should withstand F and G motor flights easily.

If you want to build light enough for D and E motors, just build it with standard BT-50 motor mount/stuffer tube, and use regular cardboard centering rings. Three cardboard centering rings on the mount/stuffer tube will handle composite E motors with ease.

I used 1/4" through the wall fin construction just for scale reasons. The original Goblin had 1/8" fins, so a 2X would be 1/4" thick. The fins are plenty strong to handle a composite E15, but I always fly it on a black powder D12. Considering the size of the rocket, 1/8" inch balsa fins would be strong enough for Estes D and E motors as long as a decent size chute is used. An 18" would be plenty.

The PNC-80K was offered by Estes when they actually sold parts out of their catalog. It's the same nosecone that was in the Phoenix kit. I have no idea if you can buy them seperately now. I've started turning my nosecones for scratchbuilts, so I'm not too worried about availability.

Edit: I used cardboard from the kids' boxes of Corn Flakes, Frosted Flakes, etc. to make my centering rings, including the BT-80 sized Goblin, Red Max, and Big Bertha. I just laminated a couple of rings together to make a thicker ring that was still thinner than the cardboard that Estes uses for 2.6" diameter kits. The Goblin has flown with Aerotech E15's so three of these rings with a long motor tube is plenty strong until you get to bigger motors.

Hey tbzep! THANKS for all the good info, looks like I used a double thick wall BT-80 which looks a bit overboard too! I am interested in how you turn your cones. Do you do it on a lathe or use a drill press? Do you start with balsa blocks and cut off the corners to start. I made tranverse measurement on the the original Goblin cone every 0.5" so 10 measurements total to get the profile of this cone. Any sugguestions on making your cones would be appreciated. I am very interested in making my own. Thanks!

I usually just measure the length, shoulder diameter, (the max diameter will be the same as your body tube) then eyeball the smaller nosecones. If I'm doing an upscale, I just use the multiplying factor for the new dimensions and start turning.

For larger ones, I do profile measurements the way you mentioned also, but I find that when I have the smaller original cone to look at, I can get the shape pretty close.

I have a Harbor Freight lathe and tools. I wish I had better, but they do a good enough job on nosecones. I bought my balsa blocks from BMS. I don't fool with cutting off the corners of balsa, but I do run hardwood stock down the bandsaw to knock off corners. I'm no expert on turning. I didn't read any books or watch anybody, so I imagine I do everything backwards. Your best bet would be to find somebody local that does woodworking and get advise from them. Lots of cities have woodturning clubs with members that love to help newbies. I live in a rural area, so that didn't help me.