K'Tesh's OpenRocket Nosecone Library

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Speaking of Semroc... I was working on my .ork files for the Binder Design Raptor and Velociraptor, and realized that I hadn't uploaded their nosecones yet... A true downscale of the nosecones would have been 6.56 inches long (plus shoulder), but Semroc had a 6.6 inch nosecone that looked the part. So, with that, here's the Semroc BNC-60G4:

 

Attachments

  • Semroc BNC-60G4 6.6 inch Ogive.ork
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Just posted an updated .ork files for the PNC-60AH and the PNC-60RL in the original post. I did a lot of these before I was able to buy a digital caliper. I'm now updating my files accordingly.
 
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Ok, today's additions are all based on the Semroc BNC-60BB.

Semroc BNC-60BB



Here's the same nosecone with the parts needed to represent an upscale of the Estes PNC-50BB or PNC-50V (same nosecone, the 50V lacks the tailcone portion as a raw part).

Semroc BNC-60BB (with assembly to upscale the Estes PNC-50BB/PNC-50V)



And again, with the parts needed to represent an upscale of the Estes Black Brant II (1958) nosecone assembly (w/antennas).


Semroc BNC-60BB (upscale of Estes Black Brant II nosecone assembly with antennas)
 

Attachments

  • Semroc BNC-60BB.ork
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  • Semroc BNC-60BB (with assembly to upscale the Estes PNC-50BB).ork
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  • Semroc BNC-60BB (upscale of Estes Black Brant II nosecone assembly with antennas).ork
    1.4 KB · Views: 70
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This Very Important Issue has been bugging me for a while (hey, I never claimed to have a life). Putting a small blunt nose tip on top of a transition to create an Estes rounded nose cone was a great idea, but the execution always seemed just a bit... off. Because the nose tip is approximately (or exactly) semicircular, there is a slope discontinuity between the tip and the rest of the nose, and it is noticeable in the rendered images. Once I noticed it the first time, I immediately saw it all the time, and can't unsee it.

So I fiddled and came up with what I think is a good solution. Instead of using an ellipsoid as the nose tip, use a secant ogive with the shape parameter set around .75 (actual values need to be fiddled depending on the shape of the rest of the nose.) Even though this yields a slightly pointed tip, it's less noticeable (and bothersome) than the problem it is solving.

Here's an example of the fix applied to the Solar Warrior/QCC Explorer nose cone (one near and dear to me):
attachment.php


New OR file is also attached below. The new version is not perfect but the transition between the two parts of the nose looks much better to me, eliminating the apparent "bulge" in the old version.

better_rounded_nose.png

View attachment Estes PNC-60(Unk) Pt# 072665_new.ork
 
And here's an update to the Semroc BNC-50XP, which was a particularly bad offender:
attachment.php


The smaller the aspect ratio of the nose cone, the sharper the slope at the junction, and the greater the discontinuity. Note that OR still shows a small "ridge" at the junction of the two pieces, which I've been unable to get rid of no matter what I try. If anyone can find a trick to eliminate it then please share.

semroc_nose_update.png
 
Ok... I figured out how to sim this w/o actually having a sample in hand. I used an image from Semroc, and the Estes Custom Parts Catalog to create this... The BNC-50J (Part No. 70256) nosecone.

Estes BNC-50J (Part No. 70256)


It might not be perfect, but it'll allow me to do some work on some designs I've wanted to tackle for a while... Again... (Stupid Hard drive crash. :hot:)

This is the nosecone used in the currently in production Estes Comet Chaser (3202), and the Airborne Surveillance Missile (7257), as well as one of the many nosecones used on the Trident (K-33/1233) and the Trident II (3033).

Unlike previous nosecones in this library, I figured out how to simulate the different color of the shoulder, while allowing the sim to be fully useable (I used an "Internal Tube" for it. A nice side effect of this is that it also increased the weight closer to the average weight indicated in the Custom Parts Catalog (.08 oz).

For giggles, I'm also including an image of the BNC-50J from OR, as its "default" BNC-50J (I added an inner tube made of "Air" to show the shoulder). I think mine looks a whole lot closer to the real thing... Although, the default does have a strong resemblance to the nosecones of actual Exocet Missiles... Hmmm...


OpenRocket Default Estes BNC-50J.png
 

Attachments

  • Estes BNC-50J (Part No. 70256).ork
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Good point on the... points, Neil! I'll have to check what I've done in mine.

I've also tried to get rid of that visible ridge. However I've come to the conclusion that the ridge is unavoidable. It's part of the 3D rendering attempting to apply a shine to a sharp edge like that. Seems to be there on the narrower end of transitions regardless.

And for the perfectionist in all of us, another option for tweaking the rounded tips is to try other profiles. For example, the BNC-50XP, you can also try "power series" with a shape parameter of ~0.4

Capture123.PNG

Capture122.PNG
 
I'm designing & building a mid-power rocket. I wanted the nosecone to look somewhat like the ones SpaceX uses so I followed your tutorial and came up with this. Thanks for posting these tutorials. I'll be making it out of balsa.
 

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  • SpaceX Nosecone.ork
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Simming up the Super Neon (7242) and I found a new nosecone for the library... Here's the 72703 nosecone with the 72654 nosecone insert



The nosecone insert is actually clear, but I opted not to represent that as OR 15.03 doesn't support clear parts. Also, for the image, I added the attachment point for the shock cord, but deleted it for the .ork file.
 

Attachments

  • Estes Nosecone (PN 72703).ork
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This isn't perfect, but when I read about the A20 Demon NC, I was reminded of the Ramjet type of nosecones (PNC-55D). I don't have one to measure from, but I did find an image. I know that this is not accurate, but for the info I have, it shows what is possible with the method I've found for recreating designs.



UPDATE 3/9/2023: With the release of OR 22.02 and my completion of the Estes Red Nova, I've created a sim for the Red Nova's Nosecone (PN 67171)(W/Clay). I have yet to get my hands on an actual PNC-55D (my sample is awaiting me in the US).



Thanks to Starfire73 and Alan Sinclair for the help on this sim.
Did you ever get any accurate dims on the PNC-55D nose cone by any chance?

-Jack
 
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