Cherokee E build thread

Discussion in 'Mid Power Rocketry (MPR)' started by Lukun7, Sep 28, 2019.

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  1. Sep 28, 2019 #1

    Lukun7

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    Hello rocketeers, today I decided to make my first build thread. I will build the Estes Cherokee E, which I plan to launch on E9, E12, and possibly E6 if I can get my hands on one. This rocket comes with a Fin Jig that you can build, the first one I'll have used, so It will be a learning experience for me too. 1569704805329.jpeg
     
  2. Sep 28, 2019 #2

    K'Tesh

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    I'm in...

    Now the Cherokee-E is basically the same rocket as the Estes Magician. I forgot about the fin guide until you mentioned it here. My Magician's guide was (for me) underwhelming. I'd recommend checking your alignment before committing to use it.
     
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  3. Sep 28, 2019 #3

    Lukun7

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    Update #1: 9/28. Building the booster, part one.


    The first step I took in building the Cherokee-E was to start building the fin jig. I will likely not be using it until towards the end of my build, after making the recovery system. However, I decided to do it today because it was convenient. The pieces were very loose, so I had to lay it down to glue.



    IMG_20190928_160915095.jpg
    IMG_20190928_162150138.jpg



    This is a picture of the jig holding a tube.



    IMG_20190928_161220309.jpg



    Next, I built the motor mount tube. I will not be using a retainer, just the stock engine hook because I don't intend to fly it on bigger motors since it is a small kit. I used all purpose glue for the same reason. I made fillets with my fingers.


    IMG_20190928_165306285.jpg


    Then, I realized that the centering rings were snug already even with the glue still wet, so I decided to glue it into the booster section.


    IMG_20190928_165858846.jpg


    I also glued the coupler into the tube after scuffing it up.



    Next update, I will make the upper section and recovery system. Until next time!
     
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  4. Sep 29, 2019 #4

    prfesser

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    Making mine with the short white tube as a payload section. Bulkhead in the coupler, glue coupler into payload, not into main airframe.
     
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  5. Sep 29, 2019 #5

    Mugs914

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    That's what I did too, Prfesser...

    And I will second what K'Tesh said about the fin guide thingy. I didn't find it particularly useful for gluing on the fins, but it was great as a cradle to hold the rocket while fillets were applied.

    Hmmm... I guess in a sense it WAS actually useful for gluing fins, then. o_O
     
  6. Sep 29, 2019 #6

    Lukun7

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    Yes, I guess it might be helpful in some ways. I drew lines on the booster with the guide but they weren't evenly spaced out so I may have to find another way to make fin lines. Maybe just some math.
     
  7. Sep 29, 2019 #7

    Wallace

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    A flexible tape measure or ruler is your friend.
     
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  8. Sep 29, 2019 #8

    John Taylor

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    Payloadbay.com
    Printable fin guides very easy to use.
     
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  9. Sep 29, 2019 #9

    KILTED COWBOY

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    First coat of paint is drying on mine.
    Built it stock.
    I like the reverse body tube idea.
    May have to hit HL and get another one to customize
     
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  10. Sep 30, 2019 #10

    Lukun7

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    Or I could just use a piece of paper. I will probably do that.
     
  11. Sep 30, 2019 #11

    kuririn

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    +1 to Payload Bay. Here's the link to the fin wrap tool:
    https://www.payloadbay.com/index.php?page=Tools&action=FINWRAPS
    Easiest way, first click on the circle in front of body tube. Use the pull down menu to select the mfgr. and tube size. Then enter the # of fins. Click submit, a .pdf will be generated that you can open and print. Then just cut out the wrap. Easy peasy.
     
  12. Sep 30, 2019 #12

    prfesser

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    That's the only way I'll mark fins. Of the half-dozen or so kits I've bought over the last year or so, not a single one had a fin-marking guide that actually fit properly around the tube. Most were too short.

    When you've marked your paper and gotten out your ruler, use the metric side. Much easier to divide 232 mm by three (or four) than to do the same with 2 5/16"...
     
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  13. Sep 30, 2019 #13

    John Taylor

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    I am also building my own. Fabricated 1/8th" birch plywood fins with thru the wall construction. Also used the reverse tube build style but used the divide for a mid frame deployment separation point. Replaced the rubber band shock cord with a long piece of thin nylon elastic. Replaced the plastic chute with a proper nylon one. Other than that used epoxy on the motor mount and fin attachment along with the fin filets. It is some added weight but with this model it could go out of site with most 24mm motors. I will be flying first flight on an Estes D12. I am painting it florescent pink so I can see it better.
    I love the building almost as much as the flying.
     
  14. Sep 30, 2019 #14

    John Taylor

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    Forgot to mention I did not use the engine block but extended the motor tube aft 7mm for tape secure-meant. And moved the centering rings to align with the fin root edges. I believe all of these steps will make the model more robust and reliable.
     
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  15. Sep 30, 2019 #15

    rharshberger

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    my favorite method of motor securement in LPR's and minimum diameter rockets.
     
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  16. Sep 30, 2019 #16

    Lukun7

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    These are all really cool ideas!I didn't know that Payload bay was as easy as making a PDF, so maybe I'll try it out.
     
  17. Sep 30, 2019 #17

    John Taylor

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    If you do modifications to the aft end adding weight to the model be sure to check the CG compared to the CP. I had to add nose weight to bring the CG forward. The CP I found is 25.2" from the front. Please correct me if I'm wrong.
    I used plywood fins and used epoxy, both add weight.
     
  18. Oct 2, 2019 #18

    Lukun7

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    Update #2: 10/1. Nose cone and Recovery system built.

    Today since I had time to build, I decided to start the recovery system. I had one slight problem, but it was an easy fix.


    The original plan was to use my quick links and small chute to link the parachute, but we had a problem.



    Doesn_tfit.jpg


    The quick link didn't fit into the nosecone. This was a problem I'd never had before, so I made up an impromptu plan.


    Loop.jpg


    I don't know if this is safe or not, but it seems to be okay. I created a loop and used a knot to ensure that the loop doesn't enlarge unnecessarily. Please tell me if you see any problems with it!


    Layout.jpg


    Newthingy.jpg


    Finally, the parachute paper mount thingy is by itself. I hated having to cut out part of the instructions.


    Last.jpg


    Yeah. That's it for now, just a short update. I will keep the nose cone separate until painting time.
    I expect to launch it on the 12th at Tripoli Houston. Later!
     
    Last edited: Oct 2, 2019
  19. Oct 2, 2019 #19

    Nytrunner

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    Your loop will be fine. The plastic of the nosecone will snap before the shock cord most likely
     
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  20. Oct 2, 2019 #20

    John Taylor

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    Yes the plastic loop is the weak link. Depending on the shock cord choice and length and how energetic the ejection charge is it could fail.
     
  21. Oct 2, 2019 #21

    Lukun7

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    I'll try to stick with smaller motors. One possible problem is that the shock cord is now a little shorter, which could increase stress on it.
     
  22. Oct 2, 2019 #22

    Nytrunner

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    A rocket that size will be fine. The hollow nosecone will slow down real fast as it's shot out and won't give a crazy jolt to the shock cord
     
  23. Oct 2, 2019 #23

    DAllen

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    You really do not need that quick link FYI. Think about it, you are gluing a small piece of paper to anchor the recovery, you are using 1/4" wide rubber band for shock cord with a nylon chute. Throwing a steel quick link into that recovery system is way overkill because that link is likely hundreds if not thousands of times stronger than any other component. Feel free to leave it in there for whatever reason you want but that seems like a waste of propellant to me.

    Other than that rather nick-picky item lol...this is looking good so far.
     
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  24. Oct 3, 2019 #24

    BRS Hobbies

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    I agree with DAllen, the quick link is overkill for this size rocket. Quick links are very useful but are best used in larger rockets.
     
  25. Oct 3, 2019 #25

    Lukun7

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    I've already made the loop, and the link is small, but I suppose I could try without it. The main reason I want to use it is because I don't want to use the very bad chute Estes makes. I have two removable nylon chutes for my larger rockets that I could use, because one of them fits into the body tube.
     
  26. Oct 3, 2019 #26

    Nytrunner

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    Tie a small loop in the cord a few inches back from the nose cone. You can loop your parachutes on that
     
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  27. Oct 4, 2019 #27

    Lukun7

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    Is it okay if I tack the fins with super glue and then do fillets to secure them?
     
  28. Oct 4, 2019 #28

    Nytrunner

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    Totally fine. If I go that route, I'll put a small drop at each end and wood glue along the rest of the root
     
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  29. Oct 4, 2019 #29

    kuririn

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    +1. This is my standard procedure cuz I'm an impatient son of a gun. Hold the fin in alignment for one or two minutes until the CA grabs, move on to the next fin. After the wood glue dries, come back with full fillets.
     
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  30. Oct 5, 2019 #30

    Lukun7

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    Thanks. Update should be tonight.
     

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