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#1
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Pershing II Rebuild
About 10 Years ago I built a Pershing II based on the Estes BT-80 body tube. An employee of mine was stationed with the Pershing II for a short period. Knowing I build model rockets he challenged me to build one.
I launched the Pershing II on a D12-3 for the first time. It was a bittersweet launch. Perfect launch and it went up straight as an arrow. Chute deployed fine, but the wind picked up about then and carried it over to the ball field. It slammed pretty hard into the chain link backstop wedging the nose cone in it. Knocked a fin off which is an easy fix, but it shattered the styrene wrap on the nose. It proved out to be a great flyer, but from there is sat damaged for 10 years on a shelf.
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Tim "You know, it, uh, won't fly unless somebody pushes the button." From the movie October Sky. I am SAM # 0167 NAR 98303 Southwestern Ohio Rocketry Association (SORA) #624 https://www.rocketryohio.com |
#2
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I had a hard time finding data on it too. But I did finally find the Pershing II Technical Manual online.
Page 116 of the PDF of the Pershing II Technical Manual has some useful missile data. It’s section 5-1 Table 5-1. First Stage Length = 144.74 Inches Max Diameter = 40 Inches Second Stage Length = 97.3 Inches Max Diameter = 40 Inches Guidance and Control/Adapter Section Length = 61.51 Inches Max Diameter = 40 Inches Min Diameter = 27.75 Inches Warhead Section Length = 64.25 Inches Max Diameter = 27.7 Inches Min Diameter = 20 Inches Radar Section Length = 49.75 Inches Max Diameter = 20 Inches Min Diameter = 0 Inches Missile Length = 417.55 Inches Max Diameter = 40 Inches Min Diameter = 0 Inches Unfortunately, it combines the Guidance and Contol (upper fins mount to this) measurements with the Adapter (first reduction in body diameter). My best guess from studying images at the measurements for these individually are: Adapter Section (Estimates) Length = 17.51 Inches Max Diameter = 40 Inches Min Diameter = 33.1 Inches Guidance and Control (Estimates) Length = 44 Inches Max Diameter = 33.1 Inches Min Diameter = 27.75 Inches There was no data for the fins, so I originally used photos and came up with my best guess. Pretty sure in hindsight the upper fins are larger than my original build, but I think the lower fins are close.
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Tim "You know, it, uh, won't fly unless somebody pushes the button." From the movie October Sky. I am SAM # 0167 NAR 98303 Southwestern Ohio Rocketry Association (SORA) #624 https://www.rocketryohio.com |
#3
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Now 10 years later arrives 3D printing. Time to make a new nose cone! I’ve added in some new details for the upper fins, and I made them larger. Printed in PETG. I'll make an STL available after I get a chance to flight test it and I may tweak it a little.
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Tim "You know, it, uh, won't fly unless somebody pushes the button." From the movie October Sky. I am SAM # 0167 NAR 98303 Southwestern Ohio Rocketry Association (SORA) #624 https://www.rocketryohio.com |
#4
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Quote:
Awesome, Tim! I'll buy one! Allen |
#5
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Out of curiosity, what's the weight difference between the old and new NC? Are you going to have to move up to a composite motor from the D12?
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I love sanding. |
#6
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Old cone weighs 77 grams. New 3D cones weighs 50 grams so far. Keep in mind there is currently no bulkhead for the new cone, it's hollow from the base to the tip, and I don't know if I'll need to add nose weight or not. I've changed the size of the fins a little on the nose (bigger) and they are a wedge shape now. I think the old cone has some small amount of nose weight, if I remember correctly that was more of an assurance than a necessity though.
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Tim "You know, it, uh, won't fly unless somebody pushes the button." From the movie October Sky. I am SAM # 0167 NAR 98303 Southwestern Ohio Rocketry Association (SORA) #624 https://www.rocketryohio.com |
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