"Starship" - L3 Build Thread

Discussion in 'High Power Rocketry (HPR)' started by Ben Martin, Mar 4, 2019.

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  1. Mar 26, 2019 #61

    Nytrunner

    Nytrunner

    Nytrunner

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    Ah, that makes sense. Does your sled not fit the RRC3 or 2 planform? If there's room there's always drill and tap!
     
  2. Mar 26, 2019 #62

    Ben Martin

    Ben Martin

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  3. Mar 27, 2019 #63

    jd2cylman

    jd2cylman

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    Still not Carl... ;-)

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    It fits, you just have to be creative. Missileworks don't have to be perfectly square to the sled or each other. Pick the set of holes that are closest and screw them down.
     
  4. Mar 27, 2019 #64

    Ben Martin

    Ben Martin

    Ben Martin

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    Switching to an RRC3 and RRC2+ combo. Similar price and it's actually available. For mounting, I will check to see what screw holes are the closest and drill out new ones if needed.
     
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  5. Mar 28, 2019 #65

    Ben Martin

    Ben Martin

    Ben Martin

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    Update #11

    Photo #1: Added fillet on the rear centering ring, this thing is built like a tank.

    Photo #2: Applied JB Weld to motor tube for retainer.

    Photo #3: Installed motor retainer, ensuring that the tailcone sits flush with the tube.

    Photo #4: Another view of the motor retainer. 20190327_223404.jpeg 20190327_232031.jpeg 20190327_235438.jpeg 20190327_235453.jpeg
     
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  6. Apr 2, 2019 #66

    Ben Martin

    Ben Martin

    Ben Martin

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    Update #12

    It's been a while since the last update. Tons of school work came up and I was planning a lot of the rocket out.

    Photo #1: Taped the airframe for the external fillets. They will be around 6% of the fin span, which I heard is within the proper range.

    Photo #2: Finished taping the airframe and the fins. Pretty fillets are a must.

    Tomorrow I will be drilling holes through bulkheads, cutting down the 1/4 stainless all thread I picked up, working on the exterior fillets, and finalizing the design for the modular noseweight system. The plan for the nosecone is to epoxy an 5/16 all-thread into the nose and then using nuts to secure the bulkhead. This would allow me to add weight the without any permanent mounting. 20190401_234753.jpeg 20190402_001226.jpeg
     
  7. Apr 3, 2019 #67

    Ben Martin

    Ben Martin

    Ben Martin

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    Update #13

    Photo #1: Cut down the 1/4 stainless all thread for the electronics sled.

    Photo #2: Drilled holes through the nosecone bulkhead for the stainless steel ubolt.

    Photo #3: Drilled holes in the electronics bay bulkheads for the two threaded rods.

    Photo #4: Completed first exterior fillet. It turned out smaller than I expected due to me removing too much of the epoxy. However, this size should do the job and I'm pretty happy with the results so far. Not bad for my first time doing exterior fillets with RocketPoxy.

    Photo #5: Another view of the exterior fillet. Not perfect, but not bad. 20190402_195653.jpeg 20190402_195703.jpeg 20190402_195722.jpeg 20190403_005830.jpeg 20190403_005901.jpeg
     
  8. Apr 3, 2019 #68

    Ben Martin

    Ben Martin

    Ben Martin

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    View of electronics bay components and nosecone bulkhead. 20190403_004818.jpeg
     
  9. Apr 4, 2019 #69

    Ben Martin

    Ben Martin

    Ben Martin

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    Update #14

    Booster is complete!

    Picture #1: All of the exterior fillets were completed today. I'm quite happy with how they turned out.

    Picture #2: Another view of completed booster.

    Picture #3: Close up shot of one of the fillets.

    20190404_003408.jpeg 20190404_003420.jpeg 20190404_004618.jpeg
     
  10. Apr 4, 2019 #70

    Nytrunner

    Nytrunner

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    Neat work. Did you wait a bit before pulling the tape? I thought I spy a bridge of epoxy on the edges
     
  11. Apr 4, 2019 #71

    Ben Martin

    Ben Martin

    Ben Martin

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    Indeee I did. I waited a bit before pulling the tape off. It was my first time doing exterior fillets with RocketPoxy so it was a learning experience.
     
  12. Apr 4, 2019 #72

    chuck5395

    chuck5395

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    Nice job. Guess I should start on mine soon.
     
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  13. Apr 5, 2019 #73

    Ben Martin

    Ben Martin

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    Ordered 2 ejection charge mount kits from Doghouse and a package of JST connectors from Amazon. I've heard some good things about using JST connectors for wiring and could not justify spending $30 more for Doghouse connectors.
     
  14. Apr 10, 2019 #74

    Ben Martin

    Ben Martin

    Ben Martin

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    Update #15

    Still no luck ordering Stratologger CFs. Apparently they restocked them around a week ago but I didn't notice, bummer. If I'm not able to purchase them within a week or two I'm going to switch to RRC3/RRC2+ as previously mentioned.

    Picture #1: Finalizing design for removable nosecone bulkhead/adjustable weight system. I believe that an 5/16in threaded rod epoxied to the tip should provide enough support for the ubolt/recovery system. The only concern that I have is the bulkhead rotating and dislodging the threaded rod from the epoxy or weakening it. The solution to this could be to design and 3D print a support ring for the bulkhead that would be epoxied above the bulkhead and help to keep it aligned.

    Picture #2: Another view of the nosecone layout. (There will be a washer for the other side of the ubolt, I just only have 2 at the moment)

    Picture #3: Test fit the threaded rods with the sled attached. I plan on adding washers and orings to the nuts in order to distributed the load and seal the electronics bay. I have been mapping out the ubolt and ejection charge mount locations on the bulkhead to ensure that it will all fit. Within the next few days I will receive the ejection charge mount kits and mount them onto the bulkheads along with the ubolts.

    I'm also working on a wiring diagram for further documentation of the build and to double check all the connections before I proceed with the assembly of the electronics bay.


    20190409_000229.jpeg 20190409_000251.jpeg 20190409_000434.jpeg
     
  15. Apr 10, 2019 #75

    jqavins

    jqavins

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    Joseph Avins

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    For the nose cone bulkhead, and your concern about the rod rotating in the epoxy and the tip of the nose, I present this for your consideration: you could put a wing nut on the end of the rod, using a little bit of epoxy as thread locker so it is permanent. Then when the rod is epoxied into the tip of the nose, the nut embedded in the epoxy will prevent any rotation. Of course, one might say that the epoxy in the threads is still not a guarantee, so one could weld the nut on, if one wished. Of forget the nut, and just heat the end of the rod with a torch and hammer it flat. One way or another, keying the end of the rod into the epoxy so that it can't turn.
     
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  16. Apr 10, 2019 #76

    Banzai88

    Banzai88

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    As an avid RRC2/RRC3/RTX user, here's something to note about using a mis-matched set of them if you're intending to use the 3 as a primary and the 2 as a back up. The 3 is usually set for "Deployment Mode 1= Drogue @ apogee, Main at main altitude" as your pirmary electronics with the 2 being relied upon for back up. The 2 can ONLY be set for drogue at apogee +0 or +1.

    This means in theory that AT MOST you have 1 second of delay between the primary drogue from the 3 and the back up drogue from the 2. I personally prefer 2-3 seconds between the two intended events, YMMV. In practice, due to processor variations, barometric sensor variations, and software differences between the two that you OFTEN get 1 highly energetic drogue event as both charges fire together.

    When I first started flying a 3 primary/2 secondary configuration I had TONS of trouble with this, and knew that it wasn't 'ripple fire' caused by any other factor because I ground tested extensively. Every time that I flew my rocket I had an extremely violent apogee event (more so than anyone else's rocket or any of my other DD rockets), and no one on the ground ever saw a secondary charge puff or heard a secondary report, even though BOTH primary and secondary charges were ignited. This happened the same across 5 flights and extensive ground tests to troubleshoot. I've run across several flyers at different fields who've also had the same issue with a mis matched set, so it's definately not an isolated issue.

    I finally contacted Missile Works about my issues, and they passed on the info I've listed above, as they originally designed both the 2 and the 3 with the intent that in a dual redundant scenario that the products would be used as PAIRS of like items, not one of each.

    Suggested solution from MW: fly them in MATCHED pairs, with the RRC3 pair having the greatest flexibility for a dual redundant dual deploy set up. Once I went dual RRC3, no issues at all.
     
    Last edited: Apr 10, 2019
  17. Apr 10, 2019 #77

    Bat-mite

    Bat-mite

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    I use Doghouse wiring and love it. The connectors lock and cannot be pulled apart without depressing a release; the wires are different colors for easy color-coding; the way I wire mine, it is impossible to misconnect my wires. Just my 2¢.
     
  18. Apr 10, 2019 #78

    Ben Martin

    Ben Martin

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    Wouldn't that mean that I could technically fly the RRC2+ as the main and the RRC3 as the secondary due to it being more programmable?
     
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  19. Apr 10, 2019 #79

    Ben Martin

    Ben Martin

    Ben Martin

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    I initially planned on using Doghouse's wiring but changed to JST connectors as the connectors added a considerable cost with little benefits. If I encounter issues with the JST connectors I will be returning them and switching to Doghouse.
     
  20. Apr 10, 2019 #80

    Bat-mite

    Bat-mite

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    That's what I do.
     
  21. Apr 10, 2019 #81

    Banzai88

    Banzai88

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    Yes, but not without some wiring or programming gymnastics. To me, that introduces another failure mode that's very hard to detect on any visual or preflight check.

    You would have to fly the RRC3 in Mode 2, and set your desired drogue delay and the main altitude lower than your RRC2 selection. The RRC2 only allows for 300ft or 800ft for the main, which would make your RRC3 settings 700ft or 200ft. Would that suit your intended flight profile?

    Alternately, you could cross wire which unit controlled the main/back-up charges and program accordingly, but you're STILL constrained by the RRC2 settings.

    You've already spent so much time and effort on this project so far........I would match units, for a project of this caliber and investment, that would mean dual RRC3s.
     
    Last edited: Apr 10, 2019
  22. Apr 11, 2019 #82

    jd2cylman

    jd2cylman

    jd2cylman

    Still not Carl... ;-)

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    I don't know what RRC2 you're using, but the RRC2+ has four main altitude settings. 300', 500', 800', and 1000'. There's a DIP switch you toggle to add 200' to the 300' or the 800' setting.
    I have at least 5 rockets set up with RRC3's as main and RRC2+'s as +1 second backups. Never had any deploy at the same time. You can still set the RRC3 as the backup for apogee deployment and then as the primary for main deployment, if you want more delay at apogee.
     
  23. Apr 11, 2019 #83

    Banzai88

    Banzai88

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    Sorry, you're correct on the +200. Haven't messed with setting one in quite a long time and I forgot about that setting since they're in "set it and forget it rockets" and there's no data to download.

    Glad that they're working for you in +1 second delay configuration. I have 3 distinct sets that, in ANY combination, will NOT fire with any meaningful delay between the RRC3 MAIN and the RRC2+ MAIN with +1 delay. CONFIRMED by sending them back to Missile Works and having them tested in their vacuum chamber. Multiple build dates on them, too. Obviously the sets that you have are working well for you. Mine are not, documented as such, and it's not just me that's had the same issue.

    The fact remains that I was told specifically that they were designed to be used as matched pairs. Not flinging mud, just commenting on my experiences in the field.
     
  24. Apr 11, 2019 #84

    jd2cylman

    jd2cylman

    jd2cylman

    Still not Carl... ;-)

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    Maybe I'm just lucky... :D
     
  25. Apr 11, 2019 #85

    Ben Martin

    Ben Martin

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    Update #16

    Received 2 pairs of 3g election charge holder kits from Doghouse. I'm very impressed by the quality of their work and they even included a pair of 1010 rail buttons for free which will come in handy on a different project.

    Photo #1: Drilled holes for mounting the ejection charge holders and the ubolt. On second thought, I could have certainly positioned the ubolt and charge holders differently in order to get them further away from the edges, but it should not make much of a difference for the functionality.

    Photo #2: Showing the election charge holders mounted and attached to the electronics bay. Only thing that remains to be completed on the bulkheads is drilling out bigger holes for the ubolts and epoxying them on. After this, I will lock down the ejection charge holders and seal them with epoxy.
    20190410_211033.jpeg 20190410_213832.jpeg
     
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  26. Apr 11, 2019 #86

    jqavins

    jqavins

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    Joseph Avins

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    As an aside, can you explain to me the advantage of purpose built ejection charge holders as compared to PVC or copper pipe caps?

    Sometimes typos are a real hoot.
     
  27. Apr 11, 2019 #87

    Ben Martin

    Ben Martin

    Ben Martin

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    Oopsy, and I went with these ejection charge holders as they have integrated terminals and I know that they will work perfectly for my rocket. No reason to possibly mess up the ejection charges by attempting to make them myself for the first time. These are very high quality and I look forward to testing them out in flight.
     
  28. Apr 11, 2019 #88

    Steve Shannon

    Steve Shannon

    Steve Shannon

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    If you remove the 1 second delay from the RRC2+, does it fire 1 second earlier than the RRC3?
     
  29. Apr 11, 2019 #89

    Ben Martin

    Ben Martin

    Ben Martin

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    With all this talk about the RRC3 and RRC2+, it appears that the Stratologger CFs are back in stock. I'm going to pick up 2 but they don't have the data transfer cable back in stock yet.
     
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  30. Apr 11, 2019 #90

    Ben Martin

    Ben Martin

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    Ordered 2 Stratologger CFs and 2 9V battery connectors. Looking forward to receiving them and setting up the electronics bay.
     

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