Estes Pershing 1A Clone

Discussion in 'Scale' started by Leo, Feb 3, 2019.

Help Support The Rocketry Forum by donating:

Tags:
  1. Feb 3, 2019 #1

    Leo

    Leo

    Leo

    Well-Known Member

    Joined:
    Aug 19, 2009
    Messages:
    1,774
    Likes Received:
    44
    Gender:
    Male
    Location:
    Germany
    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.
     
  2. Feb 3, 2019 #2

    rharshberger

    rharshberger

    rharshberger

    Well-Known Member

    Joined:
    Oct 13, 2014
    Messages:
    8,473
    Likes Received:
    824
    Gender:
    Male
    Location:
    Pasco, WA
    Looks good so far Leo. I will be following this thread.
     
  3. Feb 3, 2019 #3

    Brent

    Brent

    Brent

    Well-Known Member

    Joined:
    Jan 19, 2009
    Messages:
    1,503
    Likes Received:
    24
    Looks great Leo!
     
  4. Feb 4, 2019 #4

    James Duffy

    James Duffy

    James Duffy

    Well-Known Member

    Joined:
    Jan 19, 2009
    Messages:
    780
    Likes Received:
    82
    Wow, that looks fantastic! How much does it weigh?

    James
     
  5. Feb 4, 2019 #5

    Leo

    Leo

    Leo

    Well-Known Member

    Joined:
    Aug 19, 2009
    Messages:
    1,774
    Likes Received:
    44
    Gender:
    Male
    Location:
    Germany
    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.
     
  6. Feb 4, 2019 #6

    burkefj

    burkefj

    burkefj

    Forum Supporter TRF Supporter

    Joined:
    Jan 27, 2009
    Messages:
    2,856
    Likes Received:
    178
    Thats much better than i expected.
     
  7. Feb 4, 2019 #7

    neil_w

    neil_w

    neil_w

    When in doubt, add more rocket TRF Supporter

    Joined:
    Jul 14, 2015
    Messages:
    6,712
    Likes Received:
    995
    Location:
    Northern NJ
    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.
     
  8. Feb 4, 2019 #8

    Leo

    Leo

    Leo

    Well-Known Member

    Joined:
    Aug 19, 2009
    Messages:
    1,774
    Likes Received:
    44
    Gender:
    Male
    Location:
    Germany
    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.
     
  9. Feb 5, 2019 #9

    Gary Byrum

    Gary Byrum

    Gary Byrum

    Overstable By Design

    Joined:
    Aug 4, 2011
    Messages:
    6,318
    Likes Received:
    182
    Gender:
    Male
    Location:
    Lincolnton NC
    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.
     
  10. Feb 7, 2019 #10

    Leo

    Leo

    Leo

    Well-Known Member

    Joined:
    Aug 19, 2009
    Messages:
    1,774
    Likes Received:
    44
    Gender:
    Male
    Location:
    Germany
    I've uploaded the nose cone for print. Will work on other parts within the next couple of weeks.
    If you have questions concerning the nose cone then post them here.

    https://www.thingiverse.com/thing:3411256
     
  11. Feb 9, 2019 #11

    Leo

    Leo

    Leo

    Well-Known Member

    Joined:
    Aug 19, 2009
    Messages:
    1,774
    Likes Received:
    44
    Gender:
    Male
    Location:
    Germany
    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?
     
  12. Feb 9, 2019 #12

    Leo

    Leo

    Leo

    Well-Known Member

    Joined:
    Aug 19, 2009
    Messages:
    1,774
    Likes Received:
    44
    Gender:
    Male
    Location:
    Germany
    and hot of the press or printer in this case the fin of the 1st stage:

    Pershing_Fin_1st_Stage.jpg
     
  13. Feb 9, 2019 #13

    cwbullet

    cwbullet

    cwbullet

    Obsessed with Rocketry Staff Member Administrator TRF Lifetime Supporter Global Mod

    Joined:
    Jan 24, 2009
    Messages:
    22,512
    Likes Received:
    1,380
    Gender:
    Male
    Location:
    Glennville, GA
    Pretty nice.

    Gary: do you have a printer?
     
  14. Feb 9, 2019 #14

    Gary Byrum

    Gary Byrum

    Gary Byrum

    Overstable By Design

    Joined:
    Aug 4, 2011
    Messages:
    6,318
    Likes Received:
    182
    Gender:
    Male
    Location:
    Lincolnton NC
    No, but I wouldn't mind having one of those around. Problem I have is space. Especially now that I sucked up another portion of my house with new musical equipment.
     
  15. Feb 9, 2019 #15

    Crawf56

    Crawf56

    Crawf56

    Pig Soooiiieee!! TRF Supporter

    Joined:
    Aug 16, 2016
    Messages:
    1,095
    Likes Received:
    135
    Gender:
    Male
    Location:
    Paragould, AR
    Nice work.
     
  16. Feb 10, 2019 #16

    Leo

    Leo

    Leo

    Well-Known Member

    Joined:
    Aug 19, 2009
    Messages:
    1,774
    Likes Received:
    44
    Gender:
    Male
    Location:
    Germany
    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?
     
  17. Feb 16, 2019 #17

    Leo

    Leo

    Leo

    Well-Known Member

    Joined:
    Aug 19, 2009
    Messages:
    1,774
    Likes Received:
    44
    Gender:
    Male
    Location:
    Germany
  18. Feb 17, 2019 #18

    Leo

    Leo

    Leo

    Well-Known Member

    Joined:
    Aug 19, 2009
    Messages:
    1,774
    Likes Received:
    44
    Gender:
    Male
    Location:
    Germany
    Next items designed and printed are the cable covers for the Pershing:

    Pershing_Cable_Covers.jpg
     
  19. Feb 17, 2019 #19

    burkefj

    burkefj

    burkefj

    Forum Supporter TRF Supporter

    Joined:
    Jan 27, 2009
    Messages:
    2,856
    Likes Received:
    178
    What is your root/height dimension on the fins now?
     
  20. Feb 17, 2019 #20

    Leo

    Leo

    Leo

    Well-Known Member

    Joined:
    Aug 19, 2009
    Messages:
    1,774
    Likes Received:
    44
    Gender:
    Male
    Location:
    Germany
    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.
     
    James Duffy likes this.
  21. Feb 17, 2019 #21

    burkefj

    burkefj

    burkefj

    Forum Supporter TRF Supporter

    Joined:
    Jan 27, 2009
    Messages:
    2,856
    Likes Received:
    178
    I meant what are the actual scale Fin dimensions of both the upper and lower
     
  22. Feb 17, 2019 #22

    Leo

    Leo

    Leo

    Well-Known Member

    Joined:
    Aug 19, 2009
    Messages:
    1,774
    Likes Received:
    44
    Gender:
    Male
    Location:
    Germany
    1st stage fin (root = 54.4mm, height = 42.4mm)
    2nd stage fin (root = 45.6mm, height = 49.6mm)
     
  23. Feb 17, 2019 #23

    burkefj

    burkefj

    burkefj

    Forum Supporter TRF Supporter

    Joined:
    Jan 27, 2009
    Messages:
    2,856
    Likes Received:
    178
    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



     
  24. Feb 21, 2019 #24

    Leo

    Leo

    Leo

    Well-Known Member

    Joined:
    Aug 19, 2009
    Messages:
    1,774
    Likes Received:
    44
    Gender:
    Male
    Location:
    Germany
    Finished the Charge Retainers today:
    Pershing_Charge_Retainers.jpg
     
  25. Feb 21, 2019 #25

    Gary Byrum

    Gary Byrum

    Gary Byrum

    Overstable By Design

    Joined:
    Aug 4, 2011
    Messages:
    6,318
    Likes Received:
    182
    Gender:
    Male
    Location:
    Lincolnton NC
    Hey man, any idea if this build will make it to Camden this year?
     
  26. Feb 22, 2019 #26

    Brent

    Brent

    Brent

    Well-Known Member

    Joined:
    Jan 19, 2009
    Messages:
    1,503
    Likes Received:
    24
    Any chance on printing the parts for me?
     
  27. Feb 22, 2019 #27

    Leo

    Leo

    Leo

    Well-Known Member

    Joined:
    Aug 19, 2009
    Messages:
    1,774
    Likes Received:
    44
    Gender:
    Male
    Location:
    Germany
    It's probably not going to happen because of the size, having to bring it on the plane and all......
     
  28. Feb 22, 2019 #28

    Leo

    Leo

    Leo

    Well-Known Member

    Joined:
    Aug 19, 2009
    Messages:
    1,774
    Likes Received:
    44
    Gender:
    Male
    Location:
    Germany
    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
     
  29. Feb 22, 2019 #29

    rlhatcher

    rlhatcher

    rlhatcher

    Member

    Joined:
    Sep 13, 2016
    Messages:
    11
    Likes Received:
    1
    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?
     
  30. Feb 22, 2019 #30

    Leo

    Leo

    Leo

    Well-Known Member

    Joined:
    Aug 19, 2009
    Messages:
    1,774
    Likes Received:
    44
    Gender:
    Male
    Location:
    Germany
    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.
     

Share This Page