I'm starting my L1 cert. research

Discussion in 'High Power Rocketry (HPR)' started by Cmac, Feb 17, 2020.

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  1. Feb 17, 2020 #31

    Cmac

    Cmac

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    Thank you for that info.
    I've scoured their website for the motor code explanation. Are you able to link it for me?
     
  2. Feb 17, 2020 #32

    Cmac

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    Yes, I see that now. Thank you.
    Where can I see a good organized description of the characteristics of all of these propellants?
     
  3. Feb 17, 2020 #33

    gna

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    Not sure what you mean by "step up" from reloads, but I'll take a stab at it.
    "Composite" is not how the motor is put together--it's the propellant. Estes motors use black powder, but Aerotech and Cesaroni et al use a rubbery composite made of APCP: https://en.wikipedia.org/wiki/Ammonium_perchlorate_composite_propellant

    You can buy single-use motors, which are one and done, or you can buy a case and put reloads into it. In between is a LMS, which is in between: you assemble the motor parts, but it's essentially a single-use motor. It's cheaper and gets around HAZMAT charges.

    For simplicity, I'd stick with a single-use motor. One thing that is different is the range. Most Estes black powders are essentially at the top of their power scale, but when you get to larger motors, there's more room for variation. So you can get H motors from 161 Newtons all the way up to 320 Newtons.

    So try to find an H motor that's a single use, at the lower end of the power scale for Hs.
     
  4. Feb 17, 2020 #34

    Nytrunner

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    If you go to the Motors part of the Apogee store, and click on Aerotech and Cesaroni motors, you'll see the pages below. Scroll ALL the way past the bottom of the motor table and you'll see the information blurbs, along with a listing of the propellant types and their suffixes
    https://www.apogeerockets.com/Rocket_Motors/AeroTech_Motors
    https://www.apogeerockets.com/Rocket_Motors/Cesaroni_Propellant_Kits
     
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  5. Feb 17, 2020 #35

    David Schwantz

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    Thanks Nyt, I was looking for that and could not find it.
     
  6. Feb 18, 2020 #36

    Cmac

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    Seconded!
     
  7. Feb 18, 2020 #37

    mg444

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    I'm also doing research for my L1. This thread is very helpful. Thank you to all.
     
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  8. Feb 18, 2020 #38

    dwightr

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    Apogee Zephyr is a great kit. I did my L1 then built an AvBay to convert it to dual deployment and did my L2.
    Be careful to build light if you want to be able to fly without a waiver.
    I made some modifications to the nosecone (added a removable bulkhead to allow a tracker to fit inside later) and did fillets on the fins that are probably overkill and too many coats of paint trying to get a perfect finish and I wound up around 1600 grams with an Aerotech G80NBT ready to fly.
    It's big and easy to see, mine did about 1400' on an Aerotech H135 and 3400' on a J270.
    Stayed in sight the whole way.
    About 700' on a G80 but I do need a waiver because of the weight.
    I'm currently working on a 3" scratch build that looks a lot like a downscale Zephyr, it should end up around 950 grams with a G80 for flying without a waiver but only goes about 2500' on an H135, probably about the upper limit for seeing a 3" rocket.
     
  9. Feb 18, 2020 #39

    HVArcas

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    take your fav mid power rocket and put an H128 in it..
     
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  10. Feb 18, 2020 #40

    Cmac

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    Ha ha... You mean like my Estes Big Daddy!?
    Sounds a little iffy to me.
     
  11. Feb 18, 2020 #41

    HVArcas

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    Kinda joking, mostly not - how else do you find limits, right? I dunno about a big daddy but a leviathan built properly with mere wood glue will take motors like that for ages. Realistically an H128 is not all that much more than the typically popular G motors, only it burns quite a bit longer.
     
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  12. Feb 18, 2020 #42

    Cmac

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    Well... I don't own a Leviathan.
    I'm not looking to find limits.
     
  13. Feb 18, 2020 #43

    Cmac

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    Thank you for the great info.
    I think I'm getting my head around this now.
     
  14. Feb 18, 2020 #44

    Nytrunner

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    The secret of L1: There really isn't one way to do it.

    Have fun! Make a flight that you want.
    A lot of H motors aren't much more stress than a G80. If you can fly and recover a rocket on that, you can do L1 real easy.
    Or if you want to try something new and challenging, there are punchy Warp-9 motors and I motors.

    Cardboard and plywood can take a real load and come out just fine. Due to the lack of material data around, it's easy to overbuild, but the more you spend time with the materials, the more you get a feel for what they can handle.
     
  15. Feb 18, 2020 #45

    Earache

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  16. Feb 18, 2020 #46

    HVArcas

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    Sounds like an impedance mismatch here, nevermind.

    Good luck with your certs.
     
  17. Feb 18, 2020 #47

    Cmac

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    Yup.
     
  18. Feb 18, 2020 #48

    Cmac

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    Thank you! I'll take that.
     
  19. Feb 18, 2020 #49

    Cmac

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    Why doesn't this forum have stickies like other hobby forums?
    This should be a sticky!
    I have it bookmarked into my "Certification" folder now.
    I'll scour it tonight. Thank you!
     
  20. Feb 19, 2020 #50

    Steve Shannon

    Steve Shannon

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    It does have stickies. [emoji106]
     
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  21. Feb 19, 2020 #51

    Cmac

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    Yeah, I see a few but there are several subforums without any. Mostly the beginner, MMX and low/medium power groups.
    I'm not criticizing. I'm getting lots of good info here by using search and asking questions.
     
  22. Feb 19, 2020 #52

    wolsen

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    As someone who recently went through this same journey, I would agree with everyone else who has said to keep it simple. Go with a rocket that has techniques similar to ones you are already familiar with and don't rush it. I've seen a few certification flights on the Apogee Zephyr and everyone I talked to thought it was a great kit, similar in many ways to a familiar low power kit. You'll easily be able to see the whole flight.

    If you do get a dual deployment kit (for future purposes), you don't have to fly it dual deployment. Use simple motor eject.

    Other things that come to mind:
    • Make sure to use a simulator such as open rocket (free) or rocksim. Spend some time really understanding what the tool can do and what its limitations are. Use it before its built (heck, before you buy it!), then after its built go back and enter the actual weight and CG positions to see how stable it is and sim your motors. You may or may not need to add weight to ensure the rocket is stable.
    • Consider the flight environment and what kinds of things you might need to consider that is regional. For example, I launch in a desert with a very hard ground so I went ahead and upsized the parachute for a slower decent rate and softer landing
    • build a pvc rocket stand
    • Use a motor retainer... there's all kinds of options, but plan your retention ahead of time and don't start building until you have your retainer in hand. You'll likely need to make some adjustments to the build to allow for the retainer.
    • Practice techniques you aren't familiar with on scrap materials.
    • After built, mark the CP on the rocket and mark one caliber in front of this as the minimum CG.
    • Talk to other people in your local club
    • start a build thread, ask questions there - you'll get tons of advice! its up to you to sort through it and make decisions from what's given
    • practice your parachute folding and packing
    • get a mentor from your local club
    • keep it simple
    When it comes to the flight:
    • Be comfortable in answering a variety of questions the RSO will ask about the rocket. Their job is the most important job at the launch site - to ensure the rocket is safe to fly. As such, they'll ask questions about the rocket (like the center of gravity, how you determined it is stable, what motor, length of shock cord, construction techniques, expected altitude, etc). They need to know its going to be safe.
    • Take documentation you need in a folder with the rocket to the launch
      • the printout of the design from your sim program
      • the simulation data for the motor you intend to fly (this will also remind you of what your delay should be, total mass, etc)
      • the paper work for your certification :)
      • the pre-flight checklist, so you can double check everything - in the moment, its easy to forget stuff
    Lastly, (and I can't stress this one enough) don't rush it. Feel comfortable with saying to yourself, nope - its not ready. If you're rushing on Friday night to get things done so you can get your flight in for a Saturday launch, it's probably time to admit its not ready to fly. And that's okay! The important thing is that you have a safe successful flight... and then another and another.

    Best of luck! Keep us posted on your journeys.
     
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  23. Feb 19, 2020 #53

    tOD

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  24. Feb 20, 2020 #54

    wolsen

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  25. Feb 20, 2020 #55

    58pan

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    Lots of good suggestions here. My two cents.
    As someone else said, get a rocket that the fins do not go below the body tube, preferably angle up. If the rocket comes down swinging when it hits it's to easy for it to crack a fin if the fin hits first.
    Don't mess with dual deploy or chute releases for a cert flight. They just add more things to go wrong.
    Don't know your field but if there are any hazards, trees, ponds, etc. I don't recommend a test flight with a G.
    If your rocket hangs in the top of a tree or lands in a pond on a test flight you have to build a new rocket to do your cert flight. If it happens on a cert flight you will still get your L1 as long as it came down safely under chute.
    I recommend 38mm. Can adapt down to 29mm, and can get 38mm J's to get your L2 with the same rocket. And 54 mm motors cost a lot more.
    And don't stress about assembly and epoxy's and all that. My L1 and L2 was a cardboard tube rocket assembled with wood glue.
    ps. I also like single use motors. Because sooner or later you will lose a rocket and motor hardware is expensive.
     
    Last edited: Feb 20, 2020
  26. Feb 20, 2020 #56

    Ez2cDave

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  27. Feb 20, 2020 #57

    Cmac

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    I've already or will be taking every bit of this great advice, thank you.

    Huh, yeah. I was planning on doing just that. At our local 1000' sq ft soccer fields. Surrounded by trees and playground.
    Great point.

    So we've made our decision.
    We narrowed the list down to:
    Madcow Little John
    Madcow Patriot
    LOC 4" Patriot
    LOC Fantom 438
    Apogee Zephyr

    From what I can tell, any one of them would make a great first high power build. We chose the Zephyr because we are really impressed with the amount of available product and construction info on their website. I have the impression that any needed mid-build help is readily available from them.
    I also noticed that Apogee was the only source for much of any product and construction info for the few of our other choices they sold on the list as well.
    THIS IS NOT a knock on the other vendors. Not at all. It's just that I can tell that they may be used to dealing with more sophisticated and experienced builders that don't need the hand-holding we will feel more comfortable with. I look forward to using some of the kits from these other vendors in the future.

    I've been reading the rocketry bible and my son is reading Modern High Power Rocketry 2. We'll switch when we're done. I have the Mike Westerfield book on order.
    Oh, and watching the 4 Apogee Zephyr build videos. Very well done Tim Van Milligaan.

    Once I get going, I'll start a build thread. I'll have nothing to show off really. I'm just hoping that those that have already been generous with their advice will follow it and chime in.
     
    Last edited: Feb 20, 2020
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  28. Feb 21, 2020 #58

    K'Tesh

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    IIRC... Tim has you tie in the shock cord... I'd recommend against that. If you ever need to replace it, or even want to inspect it, it'll be... Difficult at best. Instead, I'd recommend that you learn to tie the Bowline knot (if you don't know it already), and slip the loop over the line to make it easier to remove/inspect. Or use my U-Loop Method... Don't forget to sleeve the shock cord either.
     
  29. Feb 21, 2020 #59

    Lukun7

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    Disregard
     
  30. Feb 21, 2020 #60

    Cmac

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    Please detail.
     

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