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BruceS

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My son printed this dragon nose cone. I figured I should do something with it.
Body BT-60, 24 mm engine mount,
Planning on D12-3 for first flight, then E of some sort.
Putting the this into Open rocket is going to be a bit of a challenge. IMG_20211128_112147.jpg IMG_20211128_112207.jpg IMG_20211128_112147.jpg IMG_20211128_112207.jpg
 

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jqavins

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First and foremost, my compliments to your son. That is an awesome nose and will make for an awesome rocket.

I like the double arc fins with one pointed forward and another back. I've had a similar theme in mind, non dragon related, for a long time.

I assume OR has a fin type that uses arbitrarily specified points. What I've done for fins like this in RS is to compute a series of points, along with some points just assigned, in a spreadsheet. Graph them to make sure they are right. Then concatenate them, along with whatever punctuation is needed.

Next, model the rocket in OR with a custom planform fin placeholder that only needs to have a couple of points. Save the file. Open the file in a plain text editor and paste in the point list from the spreadsheet. Save then reopen in OR, and Bob's your uncle.

Looking forward eagerly to progress.
 

green dragon

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Very nice so far.. kudos on the cone work.

of course, we might have to steal it as our namesake when done :)
 

GlenP

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Rear eject, with small holes for a bit of venting through the dragon nostrils!
 

BABAR

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Rear eject, with small holes for a bit of venting through the dragon nostrils!
Excellent idea, although with through the wall fins as shown may be a bit challenging.

Another option is an external shock cord attachment at the tail end (basically a small Kevlar loop or some other inconspicuous attachment point.) Run a thin piece of Kevlar line with a snap swivel on the end attached to this, the other end to the "real" shock cord. For display purposes, leave the line unattached (remember to put attaching it on your checklist.) At launch time, attach the snap swivel, run the line along the body (say put it on the launch lug side so even at launch it is kind of "hidden" from spectators), run the line BETWEEN the cone and the tube. May need to cut a notch in the base of the nose cone, otherwise it may make the cone too tight.

Really nice work on this, I think it's gonna look great on the pad no matter how you do it.
 

BruceS

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IMG_20211208_125514.jpg Passed the swing test. After rough calc of CP, looks like 2 calibers of stability. Priming complete. Now for the detail painting.
 

BigMacDaddy

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Very cool!!!

If you think you need a bit more fin area / CP in back (probably do not but...) you could hang an additional pair of leg / claw fins from the bottom rear of rocket. Depends on where you fall on the debate about whether dragons have 2 legs or 4 (i.e., do the wings replace a pair of legs or are they extra).

Great use of 3D printing!
 

SirNomad

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Hey, where did he find the STL for that nose cone? Or did he design it himself? Because resin and FDM printed objects tend to be a bit thicker than the blow-molded, etc., commercially made nose cones, you might not even have to add clay for that! SWEET! :)
 

BruceS

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Very cool!!!

If you think you need a bit more fin area / CP in back (probably do not but...) you could hang an additional pair of leg / claw fins from the bottom rear of rocket. Depends on where you fall on the debate about whether dragons have 2 legs or 4 (i.e., do the wings replace a pair of legs or are they extra).

Great use of 3D printing!
This is a wingless dragon, similar to the Chinese dragons. Based on swing test and old school CP approximation it has between 1.5 and 2 calibers of stability. We'll see.
 

jqavins

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Mindsim says your fine. Really, it's more or less al 3FNC; it's just that the Fs and the NC have funky shapes. Those are good size fins, and a 3D printed nose cone is probably heavier than a molded one (that is, you've got intrinsic nose weight) so you've really got no problem.

Now if only you could get the nose to spit fire. Or smoke, at least.
 

BruceS

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Mindsim says your fine. Really, it's more or less al 3FNC; it's just that the Fs and the NC have funky shapes. Those are good size fins, and a 3D printed nose cone is probably heavier than a molded one (that is, you've got intrinsic nose weight) so you've really got no problem.

Now if only you could get the nose to spit fire. Or smoke, at least.
Next iteration 😁
 

GlenP

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Just watch out for any archers on the field if it has a missing scale on the next launch.
 

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