L3 Build

Discussion in 'High Power Rocketry (HPR)' started by mperegrinefalcon, Apr 16, 2019.

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  1. Apr 16, 2019 #1

    mperegrinefalcon

    mperegrinefalcon

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    Hello all, here is my plan for my L3. I have a limited time to build this as I have a specific date I need to launch by. I ordered all the components today, I also have a Loki M2550 on order for the flight.

    The launch will be the first weekend of June, so I will need to work quickly but thoroughly. This is a fairly simple build, so I have no worries about getting it done in time. For those interested my proposal is attached.

    L3 Certification Proposal

    Matthew Slater, NAR 103600

    For my level 3 certification I would like to make a 4” diameter rocket with a 3” motor mount made out of filament wound fiberglass. It has 3 fins and 3 strakes, and is 110” long. I will have an on-board Mobius camera, and it will be held on the rail by two 1010 rail buttons screwed into weld nuts. Minimum rail length: 72”

    Cover Image.png

    The motor I am choosing for this flight is the Loki M2550

    Loki M2550 16,022 feet 449 m/s NCR North Site standing waiver is 20,00


    Fins and mounting:

    The fins have a 25” root and are 4.2” tall. They are also 3/16” thick. The FinSim data also reports that this design is capable of this flight.
    Finsim Sqr(x).png
    Finsim U vs G.png

    I plan to epoxy the fin root in place, then inject West Systems epoxy mixed with fiberglass dust and fumed silica as internal fillets. Rocketpoxy will be used for the rest of the construction.
    The fins would be beveled and mounted through the wall. I would inject epoxy and pull the fillets inside the rocket body. Rocketpoxy will be used for 1" diameter external fillets


    Shear Pins:

    I will use three #4-40 shear pins to hold the nosecone to the payload section, and the Av-Bay to the booster. LumaDyne Aluminum Tube Fasteners will be used to hold the paylod section to the Av-Bay.


    Recovery:

    Recovery will be carried out by an 84” Fruity Chutes Classical parachute. The predicted final weight of the rocket is about 20 pounds. With the case it is predicted at 24 pounds after the propellant has burned. The predicted decent rate is 19.5 FPS with this parachute.


    Electronics:

    The main deployment will be carried out by an RRC3 altimeter with the backup being an Telemetrum. I will have separate batteries, charges, and switches. I will use rotary switches for both electronics. All of this will be mounted on a 1/16” thick G10 sled with ¼” launch lugs epoxied on to it. The batteries will be zip tied to the sled and the electronics mounted with 4-40 nylon standoffs. Note: The raven has been replaced by an RRC3.

    I will use aluminum charge cups to hold the black powder. I will use two, 1 cell, 250 milliamp batteries for power.


    UPDATE:

    The switch wire terminals on the Telemetrum will be jumped with some wire and the switch will be added between the battery and the device.


    Tracking:

    I will use the Telemetrum in the Av-Bay and a TeleGPS in the nosecone for tracking. This way I have redundant systems for tracking the flight. I will talk to Bdale about how I should set this up.


    Launch date planned:

    I am hoping to be able to fly this at Mile High Mayhem, 2019. The first weekend of June.



    Let me know what you guys think of this plan for an L3.

    -Matthew
     
  2. Apr 16, 2019 #2

    Ben Martin

    Ben Martin

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    I would suggest using 1515 rail guides due to the weight, but 1010 would probably be fine. It just depends if you want the longer rails that are normally associated with 1515.
     
  3. Apr 16, 2019 #3

    Steve Shannon

    Steve Shannon

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    It doesn’t matter what we think. The first thing you need to do is get an L3CC and discuss this with him or her.
     
  4. Apr 16, 2019 #4

    Bat-mite

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    Three major considerations for rail button size:
    1. Loaded rocket weight.
    2. Rail length.
    3. Distance from the flight line.
    In more detail:
    1. What size pad will support your rocket's pad weight, and at your club's launch site, do these pads have 1010, 1515, or Unistrut rails?
    2. What length of rail do you need for your rocket and motor to get a safe launch speed, and again, what pads does your club have that can support this. If the answers to #1 and #2 are different, then you have a problem. For example, if your rocket's weight needs a pad with a 1515 rail that is at least ten feet long, but your club's 1515 rails are only six feet long, uh-oh.
    3. Based on the flight configuration you gave us, your pad will need to be at least 500' from the flight line. So make sure that whatever pad you go with is att that distance or greater.
     
  5. Apr 16, 2019 #5

    jqavins

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    Joseph Avins

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    Sure it does, er, strike that, might. I'm not qualified to judge, but someone who is could easily save Matthew some time if the proposal is inadequate on its face.

    Here's a critique, just from an English editing point of view. Take or leave each bit of advice as you like, of course.

    L3 Certification Proposal

    Matthew Slater, NAR 103600

    For my level 3 certification I would like to make a 4” diameter rocket with a 3” motor mount made out of filament wound fiberglass. It has 3 fins and 3 strakes, and is 110” long. I will have an on-board Mobius camera, and it will be held on the rail by two 1010 rail buttons screwed into weld nuts. Minimum rail length: 72”​
    Change "would like to" to "intend to" or "propose to". Be strong and definite.

    "I will have..." and "it will be..." use two different subjects in the same sentence. Make both parts of the sentence refer to the rocket, i.e. use "It will have..."


    'Minimum rail length: 72"' would be OK if you were using this form throughout, such as 'Diameter: 4"', 'Length: 110"', etc. Otherwise, use a whole sentence, such as 'The rocket requires a rail with a minimum length of 72".'

    The motor I am choosing for this flight is the Loki M2550​
    "The motor I am choosing..." would be better as "The motor I have chosen..." Again, be strong and definite. Also, end the sentence with a period, even at the end of the paragraph. Am I picking nits? Yes. To come across as having all your shtuff together you should leave no nit unpicked.

    Loki M2550 16,022 feet 449 m/s NCR North Site standing waiver is 20,00​
    You've already stated what the motor will be, so there shouldn't be any need to repeat it. For the rest of this, either use whole sentences or an actual table, not an unpunctuated string of words and numbers. And, combine it with the previous paragraph (the motor selection) to make either one single paragraph or one single table.

    Fins and mounting:

    The fins have a 25” root and are 4.2” tall. They are also 3/16” thick. The FinSim data also reports that this design is capable of this flight.​
    The "also"s are unnecessary, and the dimensions would be better as a single sentence: "The fins have a 25" root, are 4.2" tall, and 3/16" thick." Also, give the strake dimensions; while I assume they're not really important for stability, when you're giving a description you ought to make it complete.

    I plan to epoxy the fin root in place, then inject West Systems epoxy mixed with fiberglass dust and fumed silica as internal fillets. Rocketpoxy will be used for the rest of the construction.
    The fins would be beveled and mounted through the wall. I would inject epoxy and pull the fillets inside the rocket body. Rocketpoxy will be used for 1" diameter external fillets​
    "I plan to epoxy..." and "I would inject..." should both be "I will..." (At this point, perhaps you are thinking that I'm advising you to use the same words over and over, where some English teacher once told you to avoid doing that. That rule is usually good for creative or academic writing, and sometimes for poetry [but sometimes poets want the effect that repetition gives] but it does not apply to technical writing. In technical writing, stick with one word consistently for one idea, and always be as concise as possible [but not more so].)

    Shear Pins:

    I will use three #4-40 shear pins to hold the nosecone to the payload section, and the Av-Bay to the booster. LumaDyne Aluminum Tube Fasteners will be used to hold the paylod section to the Av-Bay.​
    Typo: paylod → payload

    Recovery:

    Recovery will be carried out by an 84” Fruity Chutes Classical parachute. The predicted final weight of the rocket is about 20 pounds. With the case it is predicted at 24 pounds after the propellant has burned. The predicted decent rate is 19.5 FPS with this parachute.

    Electronics:

    The main deployment will be carried out by an RRC3 altimeter with the backup being an Telemetrum. I will have separate batteries, charges, and switches. I will use rotary switches for both electronics. All of this will be mounted on a 1/16” thick G10 sled with ¼” launch lugs epoxied on to it. The batteries will be zip tied to the sled and the electronics mounted with 4-40 nylon standoffs. Note: The raven has been replaced by an RRC3.

    I will use aluminum charge cups to hold the black powder. I will use two, 1 cell, 250 milliamp batteries for power.

    UPDATE:

    The switch wire terminals on the Telemetrum will be jumped with some wire and the switch will be added between the battery and the device.​
    Remove the word "UPDATE". If you have not previously submitted then there is nothing to update; just give the proposal as it stands when you submit it. Likewise, the note at the end of the first paragraph of this section is unnecessary; the proposal is for the use of two RRC3s, and there is no reason to mention Telemetrum. That's just confusing.

    Are the batteries really limited to 250 mA, or do you mean 250 mAh?

    Tracking:

    I will use the Telemetrum in the Av-Bay and a TeleGPS in the nosecone for tracking. This way I have redundant systems for tracking the flight. I will talk to Bdale about how I should set this up.​
    Wait, Telemetrum? Above you said that was replaced by an RRC3? Who is Bdale? (Perhaps that is generally well known, even if not by me.)

    Launch date planned:

    I am hoping to be able to fly this at Mile High Mayhem, 2019. The first weekend of June.​
    Launch date:
    The launch will occur at Mile High Mayhem, June 1st through 3rd, 2019, at the Pawnee National Grassland, Colorado.
     
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  6. Apr 16, 2019 #6

    mperegrinefalcon

    mperegrinefalcon

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    I have been in contact with my local L3CCs and they have both approved of the design and flight. I just want to get others opinions on my plan for this flight.

    -Matthew
     
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  7. Apr 16, 2019 #7

    mperegrinefalcon

    mperegrinefalcon

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    Thanks for the edit! I really appreciate the help! I wrote this quickly to try and get my point accross. It is actually my mother who has helped me extensively editing work throughout high school that ingrained within me to never use repeating terms. I will certainly change that because this is a technical paper.
     
  8. Apr 16, 2019 #8

    mperegrinefalcon

    mperegrinefalcon

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    I have talked to people about this before, I am not too worried about the weight. The rocket is predicted to be about 30lbs on the pad and people have told me that they have done heavier on 1010. I could go to 1515 I just don't think it's necessary. This rocket is similar in size to the Madcow 4" Frenzy and lots of successful L3s I have seen on that rocket finished at a very similar weight and used 1010 rail.
     
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  9. Apr 16, 2019 #9

    mperegrinefalcon

    mperegrinefalcon

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    Here is the paint plan that Mark at Stikershock came up with and the decals he printed for me. I just picked the name and the colors. I will spray the rocket with automotive quality paint and a spray gun. Viper.png

    viper with decals.jpg
     
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  10. Apr 17, 2019 #10

    jqavins

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    Part of his point was that it isn't just the weight. Make sure that there is a 1010 available at the launch in the length you need; if the long rail is 1515 then you have to use 1515.
     
  11. Apr 17, 2019 #11

    mperegrinefalcon

    mperegrinefalcon

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    Oh yeah. The clubs I go to have 8 foot 1010 rails. I won't have a problem with it.
     
  12. Apr 17, 2019 #12

    Steve Shannon

    Steve Shannon

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    Great! Best of luck.
     
  13. Apr 28, 2019 #13

    Handeman

    Handeman

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    Sounds like it should work. It would NOT work at our site. We have plenty of 1010 and 1515 pads, but when you get to the away cell +500 ft out, the only options we provide is 1515 and Unistrut. Also because of our pad designs, we limit the 1010 pads to 20 lbs. with only case by case exceptions.

    You might want to verify the availability of 1010 pads at the safe distance and rocket weight you need. It would be much easier to move to 1515 while building it then after you get to the field.
     
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  14. Apr 29, 2019 #14

    mccordmw

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    I'd second (or third or fourth?) the recommendation on 1515 rail buttons. The far away pads are usually all 1515 rails.

    Also, they have 8' 1010? Your front button is probably about what, 5-6' front the base of your rocket? That only gives you 2-3 feet of acceleration before the front button clears the rail. I calculated all my L3 speeds when the front button cleared my rail and when the whole rocket was clear to figure out the safe wind limits.

    You're cutting if awfully close with 1010 when a simple change to 1515 will give you so much more insurance for rail availability and good length.
     
  15. Apr 29, 2019 #15

    Titan II

    Titan II

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    There is no way his top button will be that far up.
     
  16. Apr 29, 2019 #16

    mccordmw

    mccordmw

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    I'm at a bar waiting on carryout drinking Blue Moon, so my math may be challenged.

    He's got a 110" rocket, so a bit less than 10'? What's the CG on the Sim? Should be somewhere close to that. Just spitballng that it's about halfway up the rocket at 5'? Maybe 4'?
     
  17. Apr 29, 2019 #17

    jimzcatz

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    You are out of your mind. 16k for a L3 cert. Ridiculous. Can it be done? Of course? Should it be? No. You will never convince me otherwise, so don't even try. I will wish you good luck though..
     
  18. Apr 29, 2019 #18

    Ben Martin

    Ben Martin

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    Not unheard of for 3in motors in a 4in body tube. Even small Ms put them up to 13-14K.
     
  19. Apr 29, 2019 #19

    Exactimator

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    I won't try to convince you otherwise, but I'm curious why you think 16K on a cert flight is ridiculous and the flyer is out of his mind.
     
  20. Apr 29, 2019 #20

    BF Rockets

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    1010 buttons work on 1515 rails. Problem solved.

    That's how I fly my 3 and 4 inch rockets on K and larger motors.
     
  21. Apr 29, 2019 #21

    OverTheTop

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    Work with your L3CCs as to what is possible and allowable. Fly it like you own it! Enjoy the build and flight. :)
     
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  22. Apr 29, 2019 #22

    mperegrinefalcon

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    I admit I am crazy when it comes to building and flying, but I have flown high a few times already and I feel I can safely return it no problem. I launch in the Pawnee National Grasslands, so we have a crap load of space for recovery.

    Is the channel the same width in 1010 and 1515 with just a larger rail? Is there any extra wobble? I will likely just go for the 1515 because the majority here think it is a better idea. I have the rail available so no issue.
     
  23. Apr 29, 2019 #23

    Titan II

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  24. Apr 30, 2019 #24

    Bat-mite

    Bat-mite

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    All in one place:

    [​IMG]

    1010 rail button (typical)
    A= .3725
    B= .2455
    C= .3
    D= .135

    1515 rail button (typical)
    A= .6265
    B= .3175
    C= .4425
    D= .19


    [​IMG]
    1010 rail


    [​IMG]1515 rail
     
    Last edited: Apr 30, 2019
  25. Apr 30, 2019 #25

    Nytrunner

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    You have the 1515 picture twice.

    I don't like the 1010's .135" inner button height squeezing the .16" thick "ears" of the 1515 rail
     
  26. Apr 30, 2019 #26

    Titan II

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    Curious...are you talking about my link? When I pull it up it shows a whole page of pictures, with several pictures of each size.
     
  27. Apr 30, 2019 #27

    rharshberger

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    I concur, the 1515 rail drawing is showing twice at least for me.
     
  28. Apr 30, 2019 #28

    Bat-mite

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    Fixed ... sort of.
     
  29. Apr 30, 2019 #29

    Titan II

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    41Y5RikgxaL.jpg Strange. Oh well...here is a 1010.
     
  30. Apr 30, 2019 #30

    jbr

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    even the baby M1315 puts a 25 pound 6" diameter rocket to over 11K feet
    if you want to do a 5-10K M motor rocket, you are going to need 8 to 12" diameter
     

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