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  #1  
Old 08-27-2020, 10:47 PM
Jack Hydrazine Jack Hydrazine is offline
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Default Estes PNC-50CA Nose Cone

I'm interested in designing the Estes PNC-50CA nose cone as a 3D model posting it to Thingiverse. It was used for the following kits.

1281 Alien invader
1343 Torellian Invader
1358 F-61 Star Fighter
1383 Hyperion

Does anyone know what the nose cone might be designed without the attached bulges 180 degrees opposite one another?
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  #2  
Old 08-28-2020, 02:53 PM
DavidQ DavidQ is offline
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I just measured my two out-of-box 50CA nose cones, and excluding the shoulder, they are 4 13/16 long. My records of BT50 nose cones indicates that there isn't another ogive that is the exact length to serve as the base.

My eyes may be tricking me, but I'm not 100% sure that it really is an ogive, because it seems that the ogiviness doesn't start in earnest until it gets past those bumps. Of course, an ogive with a tiny point would be very close, and might even be exact if my eyes are deceiving me. Some measurements would help confirm it, if that level of precision is needed.
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Old 08-28-2020, 05:14 PM
Jack Hydrazine Jack Hydrazine is offline
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Could you measure the dims of the two bulges for me? I'm trying to figure out how I'm going to design those. I'll probably end up making a profile of one and then turning it into a round object. From there I can merge it into the main nose cone.

Any and all help is very much appreciated.
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  #4  
Old 08-28-2020, 08:26 PM
DavidQ DavidQ is offline
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I wanted to help you with a 3D model, but the 50CA is one that I didn't draw up. So, I'll send take measurements and see you well you do.

Each bump is kind of a tear drop shape. Measuring along the ogive (not parallel to the long axis of the nose), the bump is 1.845" long.

With the nosecone pointing up, and a bump facing you, the bump is 0.822" wide where it intersects the ogive. The widest part of the bump is about 0.68" to 0.7" up from the base, where it makes contact with the ogive.

With the nosecone pointing up, and the bumps facing left and right, the nose has a greatest width of 1.350". The widest point is about also 0.68" to 0.7" from the base of the bump, as measured parallel to the long axis of the nose.

If I were to eventually try it, I would probably try the bottom half of the bump as an ellipsoid. The top half might match up better as a longer ellipsoid, or maybe as an ogive. One possibility may be to scan it, and trace the profile in some 3D Modeling app, and then rotate the shape. To my eyes, the bump looks to be rotationally symmetric when rotated around it's long axis. Heck, it might be that that ellipsoid has one diameter of 0.822", with a center of rotation about (1.35"-0.822")/2 = 0.264" off center of the ogive.
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  #5  
Old 08-29-2020, 11:14 PM
Jack Hydrazine Jack Hydrazine is offline
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Thanks for your help. Those dimensions help me a lot.

I think I'll do some editing of the picture I have and use it to make the main nose cone and the tear drop shapes separately. It's just a matter of getting the dimensions correct.

It looks like the tear drop shapes are about as wide in diameter as the nose cone itself.

Is it possible for you to post a pic of the nose cone's profile with the tear drop shape facing the camera?

Thanks!
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  #6  
Old 08-30-2020, 01:02 AM
DavidQ DavidQ is offline
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My photo of the teardrop bump.

I'm holding it in a heavy-walled 50H tube, because that's what I happened to grab. I mention that, because I don't want it to look like the nose is skinnier than a typical BT50 tube.
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  #7  
Old 08-30-2020, 06:12 AM
Jack Hydrazine Jack Hydrazine is offline
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That's a perfect photo! Thanks so much for that! That really helps me a lot!
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  #8  
Old 08-30-2020, 02:50 PM
Jack Hydrazine Jack Hydrazine is offline
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I have now created a 3D model of the Estes PNC-50CA nose cone along with some variants. It's been uploaded to Thingiverse that you can download for free and print on your 3D printer.

https://www.thingiverse.com/thing:4583948
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  #9  
Old 08-30-2020, 03:23 PM
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Flash Flash is offline
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Awesome, thank you so much for your hard work and making that available to all rocketeers free of charge with easy access to but
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  #10  
Old 08-31-2020, 07:35 PM
Jack Hydrazine Jack Hydrazine is offline
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It wouldn't have been possible without DavidQ's help.

Thanks, Dave!
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