Estes Pershing 1A Clone

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Leo

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After being inspired by this thread: https://www.rocketryforum.com/threads/can-we-save-this-estes-pershing-1a.150649/
and finding scale data here: https://www.rocketryforum.com/threads/scratch-built-5-25-pershing-1a-built-with-foam.120203/
I decided this was a perfect time to use my old BT-101 body tube that has been lying around from the mid eighties.

First thing was to create 3D files of the nose cone:

Pershing_Nose_Cone.png

I then printed all 3 parts. Total print was 12h45min. They turned out fantastic.
Pershing_Nose_Cone_Parts.jpg


Before I glue the nose cone together I will need to find out how much nose weight will be required.
Parts stacked together:
Pershing_Nose_Cone_Together.jpg


Next step is to create the vanes, vane pads, cable covers and charge retainer as 3D files.
 

James Duffy

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Wow, that looks fantastic! How much does it weigh?

James
 

Leo

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The bottom part weighs 54.21 grams, the mid part 36.30 grams and the top part 25.15 grams = 61.45 grams in total.
 

burkefj

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Thats much better than i expected.
 

neil_w

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Those parts look ridiculously clean. Is it PETG? Do you do anything special to get them so smooth?

I don’t have a printer but have had some parts printed by services; none have ever come out anything close to that nice.
 

Leo

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This was done with PLA but PETG or ABS will look same, at least with my printers. Nothing special done, just single wall 0.8 mm thick.
Of course the printers need to be setup perfectly mechanical wise and well calibrated.
 

Gary Byrum

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The bottom part weighs 54.21 grams, the mid part 36.30 grams and the top part 25.15 grams = 61.45 grams in total.
That's a boatload lighter than the original cone that was used on the BT-101 version. I still have the bottom portion of my old nose cone.
 

Leo

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I came up with this result using the dimensions found in the first post.
Pershing_Fin_2nd_Stage.jpg


Looking at many pictures of the Pershing it doesn't really seem to look the same. Did the Pershing 1-A have different variants in fin design? How does this compare to the Estes designed version?
 

Leo

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and hot of the press or printer in this case the fin of the 1st stage:

Pershing_Fin_1st_Stage.jpg
 

cwbullet

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Pretty nice.

Gary: do you have a printer?
 

Leo

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After searching a lot I finally found pictures showing the fins in very good detail. Still keeping to the scale data sheet I modified the objects and now they look as they should.

Fins on the printer:
Pershing_1-A_Fins Plate.jpg


Pershing_1-A_Fins.jpg


Question now is will the model fly with these scale sized fins?
 

Leo

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Next items designed and printed are the cable covers for the Pershing:

Pershing_Cable_Covers.jpg
 

burkefj

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What is your root/height dimension on the fins now?
 

Leo

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The up-scaled fin has a root length of 64.60mm and a height of 50.40mm.

Pershing_Fins_1st_Stage.jpg


I think this should be enough for stability. I will be using the scale fins for the second stage to bring the center of pressure to the rear.
 

burkefj

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I meant what are the actual scale Fin dimensions of both the upper and lower
 

Leo

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1st stage fin (root = 54.4mm, height = 42.4mm)
2nd stage fin (root = 45.6mm, height = 49.6mm)
 

burkefj

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Ok, based on those, here are the dimensions I used for my versions, I'm sort of all over the place, not sure why as I started from the same basic openrocket drawing, but something must have happened when moving from templates to cutting out etc.... The 4" and 7.5" are closest to scale, some of mine actually have my upper fins oversized slightly more than the lower fins, but they all fly just fine and I don't think they look bad.

Capture.JPG




1st stage fin (root = 54.4mm, height = 42.4mm)
2nd stage fin (root = 45.6mm, height = 49.6mm)
 

Brent

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Any chance on printing the parts for me?
 

Leo

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Any chance on printing the parts for me?
I've had requests but had to turn them down.
The Pershing has big parts that take a long time to print. The nose cone alone nearly takes 13 hours to print. The fins 1 1/2 hours each....
At the end of the day it just takes too much prep work and time for me. Then add shipping costs from Germany....

Sorry
 

rlhatcher

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Hi - this looks great! I'm curious about .8 thickness in spiral mode. Are you using multiple perimeters or setting the extruder width to .8? Also, do you have a rocksim or .ork for this?
 

Leo

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I'm using 1 perimeter and nozzle set to 0.8 or whatever is recommended.

I'm working on a model in Openrocket as I need to determine how much nose weight will be needed.
 
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