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  1. #1
    Join Date
    18th November 2014
    Location
    Somewhere in Ohio
    Posts
    867

    29mm MD rocket "The Minute Man" (Build Thread)

    Here is my build thread for my MD 29mm rocket.
    Here is how everything will work:
    DIMENSIONS
    20 inch long rocket
    14 inch long body tube
    6 inch long conical nose cone
    29mm diameter
    ______________________
    AERODYNAMICS
    (3) 1/8 inch plywood fins
    ______________________
    RECOVERY
    200 LB test Kevlar
    12 inch mylar (sparkly) parachute
    possibly some flower, as in the white stuff that you use in cookies, (for tracking purposes)
    ______________________
    ELETRONICS
    PerfectFlite APRA altimeter
    ______________________
    LAUNCH
    motor: AT DMS H195T (OR) AT DMS H135W
    Launch pad; not sure yet
    ______________________


    TECHNIQUES:
    I glue the fins to the tube with STRONG CA. Then fillet with 30 min epoxy
    Click image for larger version. 

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    4/3/2017 - I have a name for the rocket. "The Minute Man"
    4/18/2017 Here is the finished product!
    Click image for larger version. 

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    SO LET'S BUILD!

    Thanks,

    Andrew - 14 year old rocketeer who loves to watch and fly model rockets all year long!!!
    2018 - 41.69 Ns _ Biggest motor, CTI G106, highest flight around 3,500' - TRA Member #17056
    Owner, Andrew's Rocketry Shop - andrewsrocketryshop.blogspot.com

  2. #2
    Join Date
    18th November 2014
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    LETS BUILD!!!!!!I glued the fins to the tube with STORNG CA.
    Tomorrow I will fillet the fins with 30 min. epoxy :-)
    Click image for larger version. 

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    The fins are decently straight. Straight enough!! I'll get pictures later.
    Thanks,

    Andrew - 14 year old rocketeer who loves to watch and fly model rockets all year long!!!
    2018 - 41.69 Ns _ Biggest motor, CTI G106, highest flight around 3,500' - TRA Member #17056
    Owner, Andrew's Rocketry Shop - andrewsrocketryshop.blogspot.com

  3. #3
    Join Date
    18th November 2014
    Location
    Somewhere in Ohio
    Posts
    867
    I know the fins don't look very good. But, it should be a cool flight!
    Today hopefully I can fillet the fins!
    Thanks,
    Andrew - 14 year old rocketeer who loves to watch and fly model rockets all year long!!!
    2018 - 41.69 Ns _ Biggest motor, CTI G106, highest flight around 3,500' - TRA Member #17056
    Owner, Andrew's Rocketry Shop - andrewsrocketryshop.blogspot.com

  4. #4
    Join Date
    30th June 2015
    Location
    Palmyra, NY
    Posts
    46
    You might want to consider chalk instead of flour. Flour dust is pretty flamable.

  5. #5
    Join Date
    13th June 2014
    Location
    Cocoa Beach, FL
    Posts
    3,550
    Quote Originally Posted by DGBrown View Post
    You might want to consider chalk instead of flour. Flour dust is pretty flamable.
    Or even baby powder.
    Tim
    L3 NAR 98225

  6. #6
    Join Date
    30th January 2016
    Location
    US > OK > NE
    Posts
    3,474
    Baby powder, leak tracing powder are also decent choices. Chalkline is pretty stain-y, but that's better than a flour bomb.

  7. #7
    Join Date
    13th June 2014
    Location
    Cocoa Beach, FL
    Posts
    3,550
    This is what happens when you put a 2 pound bucket of flower on the launch pad!

    Click image for larger version. 

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    Tim
    L3 NAR 98225

  8. #8
    Join Date
    26th June 2016
    Location
    Mobile, AL, USA
    Posts
    1,236
    Red Tempera paint powder is a great tracking powder also.
    NAR # 37682

    All the weird kids are doing it!

    If at first you don't succeed... You're about average.

  9. #9
    Join Date
    25th October 2016
    Location
    Texas, United States
    Posts
    1,697
    Try Creamola or whatever it's called - powdered coffee creamer - chock full of fats and sugar - they it to make fireballs in pyrotechnics. Also maybe have a concave bowl or bucket of sorts so it sprays the powder out.

  10. #10
    Join Date
    23rd March 2013
    Location
    Akron, OH
    Posts
    384
    Quote Originally Posted by dhbarr View Post
    Baby powder, leak tracing powder are also decent choices. Chalkline is pretty stain-y, but that's better than a flour bomb.
    +1 to the above. I use baby powder usually.

    What are you using to retain the motor?
    Bill
    Member - MTMA
    Akron, Ohio

    "Rather than cursing the rose bush for having thorns, it is better to thank the thorn bush for having roses."

    Currently searching for that sweet spot between "Paralysis by Analysis" and "Extinct by using Instinct"

  11. #11
    Join Date
    18th November 2014
    Location
    Somewhere in Ohio
    Posts
    867
    Quote Originally Posted by Mr Rocket View Post
    +1 to the above. I use baby powder usually.

    What are you using to retain the motor?
    masking tape. A lot of it!
    I'll use baby powder.
    Thanks for the tips, guys!
    Andrew - 14 year old rocketeer who loves to watch and fly model rockets all year long!!!
    2018 - 41.69 Ns _ Biggest motor, CTI G106, highest flight around 3,500' - TRA Member #17056
    Owner, Andrew's Rocketry Shop - andrewsrocketryshop.blogspot.com

  12. #12
    Join Date
    25th October 2016
    Location
    Texas, United States
    Posts
    1,697
    I would advise, based on my spotty research, to stray away from a conical nose cone.
    https://en.m.wikipedia.org/wiki/Nose_cone_design#
    The chart here summarizes the information: https://en.m.wikipedia.org/wiki/Nose..._general_shape

    Are you are you going to round (or bevel/airfoil, depending on your flight profile and how much you want to optimize performance) the fins? Depending whether the CA is on the exposed surface of the fins and body tube, (where the fillets will go) you might be able to use wood glue for the fillets, which is recommended for paper to wood fins. If there is CA on the surface, though, the wood glue won't be able to form a good bond.

    What body tube are you using? Thin wall or thick wall?

    Have you considered a launch tower?


    There have been many 24-29mm minimum diameter rockets being built and shown on the forum by the young'uns... so peer pressure did me in.
    Wood glue fillets and CA coated body tube and fins, wet sanded to 4000 grit. I don't know why I did that, co sitering tge chances of recovery. I want to recover, of course, but to quote Tom Lehrer('s friend), "always predict the worst, and you'll be hailed as a prophet."
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  13. #13
    Join Date
    5th August 2015
    Posts
    1,180
    Quote Originally Posted by Incongruent View Post
    I would advise, based on my spotty research, to stray away from a conical nose cone.
    https://en.m.wikipedia.org/wiki/Nose_cone_design#
    The chart here summarizes the information: https://en.m.wikipedia.org/wiki/Nose..._general_shape

    Are you are you going to round (or bevel/airfoil, depending on your flight profile and how much you want to optimize performance) the fins? Depending whether the CA is on the exposed surface of the fins and body tube, (where the fillets will go) you might be able to use wood glue for the fillets, which is recommended for paper to wood fins. If there is CA on the surface, though, the wood glue won't be able to form a good bond.

    What body tube are you using? Thin wall or thick wall?

    Have you considered a launch tower?


    There have been many 24-29mm minimum diameter rockets being built and shown on the forum by the young'uns... so peer pressure did me in.
    Wood glue fillets and CA coated body tube and fins, wet sanded to 4000 grit. I don't know why I did that, co sitering tge chances of recovery. I want to recover, of course, but to quote Tom Lehrer('s friend), "always predict the worst, and you'll be hailed as a prophet."
    He cant find any other nose cone apart from a conical one.
    trffan has been retired

  14. #14
    Join Date
    5th August 2015
    Posts
    1,180
    Quote Originally Posted by rockets View Post
    LETS BUILD!!!!!!I glued the fins to the tube with STORNG CA.
    Tomorrow I will fillet the fins with 30 min. epoxy :-)
    Click image for larger version. 

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    The fins are decently straight. Straight enough!! I'll get pictures later.
    Thanks,
    The root tip of that fin looks like a little bit is chipped off. The airflow could exploit this weakness and tear the fin off so maybe you could consider making a new fin?
    trffan has been retired

  15. #15
    Join Date
    18th November 2014
    Location
    Somewhere in Ohio
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    867
    Quote Originally Posted by TRFfan View Post
    The root tip of that fin looks like a little bit is chipped off. The airflow could exploit this weakness and tear the fin off so maybe you could consider making a new fin?
    I see what you mean. Hmm, could I take a Dremel® and round the tip off? It's kinda too late becuase I have already filleted. BTW, pictures of that coming soon. :-)
    Thanks,
    Andrew - 14 year old rocketeer who loves to watch and fly model rockets all year long!!!
    2018 - 41.69 Ns _ Biggest motor, CTI G106, highest flight around 3,500' - TRA Member #17056
    Owner, Andrew's Rocketry Shop - andrewsrocketryshop.blogspot.com

  16. #16
    Join Date
    25th October 2016
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    Texas, United States
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    1,697
    Build up more material with epoxy or the filler of your choice and sand to fit of necessary.

  17. #17
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    18th November 2014
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    Quote Originally Posted by Incongruent View Post
    Build up more material with epoxy or the filler of your choice and sand to fit of necessary.
    Good Idea, I'll try it! Now I'm not as worried!
    Thanks,
    Andrew - 14 year old rocketeer who loves to watch and fly model rockets all year long!!!
    2018 - 41.69 Ns _ Biggest motor, CTI G106, highest flight around 3,500' - TRA Member #17056
    Owner, Andrew's Rocketry Shop - andrewsrocketryshop.blogspot.com

  18. #18
    Join Date
    5th August 2015
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    1,180
    Quote Originally Posted by rockets View Post
    Good Idea, I'll try it! Now I'm not as worried!
    Thanks,
    Yeah thats a good idea. But make sure to seal the leading edge of that fin with epoxy to prevent delamination.
    trffan has been retired

  19. #19
    Join Date
    18th November 2014
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    Somewhere in Ohio
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    867
    Oh, boy I think I'm going to need some HELP!
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    The first two fins were good, but the last fin didn't go over too well. I redid the simulation on RockSim with the canted fin. It still was stable. But, I want a second opinion. What are your guys ideas??
    Thanks,
    Andrew - 14 year old rocketeer who loves to watch and fly model rockets all year long!!!
    2018 - 41.69 Ns _ Biggest motor, CTI G106, highest flight around 3,500' - TRA Member #17056
    Owner, Andrew's Rocketry Shop - andrewsrocketryshop.blogspot.com

  20. #20
    Join Date
    1st July 2011
    Location
    Pittsburgh, PA
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    The lean right concerns me less that the front to back is not straight (2nd picture). Going to spin if the fins are twisted! Doubting mach flights and twisted fins are a good combo.
    Kevin Wuchevich
    Tripoli Pittsburgh
    TRA 12238

  21. #21
    Join Date
    24th May 2013
    Location
    Battlground indiana
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    What I would do is redo your fins and use a fin guide to make sure there straight . Small and fast
    Recertification coming soon
    Member of Indiana rocketry joining again

    Tripoli 14704 L2
    L1 mwp 11 XS on a H 250
    L2 mega Hi flyer on J285
    Staring my L3 build a 10" sono tube fin 10.50' tall



    I scratch build .

  22. #22
    Join Date
    20th February 2009
    Location
    Cayuga, Indiana
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    What a hack build.

    Before you start anything that is minimum diameter, high-velocity, do some reading/studying.

    Jeezus!
    L3, TRA #11847
    Tripoli Indiana #132
    Tripoli Central Illinois #59
    Central Illinois Aerospace (NAR) #527
    Chicago Rocket Mafia, "Big Bucks" Dixon
    ___________________________________

    Quiet little voices creep into my head. -- We Were Promised Jetpacks

  23. #23
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    25th October 2016
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    Quote Originally Posted by dixontj93060 View Post
    What a hack build.

    Before you start anything that is minimum diameter, high-velocity, do some reading/studying.

    Jeezus!
    How do you know it's going to fly minimum diameter and high velocity? Haven't you heard the terms: "You can always adapt down" and "confetti doesn't fly fast"? (Okay, I made the second one up.)

    And rockets, I have picked up a lot of shoddy advice over the years... well, months. Anyways, you can ask me so you have a scapegoat when things fail. Just no lawsuits please!

  24. #24
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    Quote Originally Posted by Incongruent View Post
    How do you know it's going to fly minimum diameter and high velocity? Haven't you heard the terms: "You can always adapt down" and "confetti doesn't fly fast"? (Okay, I made the second one up.)

    And rockets, I have picked up a lot of shoddy advice over the years... well, months. Anyways, you can ask me so you have a scapegoat when things fail. Just no lawsuits please!
    Uh, duh, title of the thread, MD=minimum diameter.

    Flour as fight tracking?? Jeez, please do some research.
    L3, TRA #11847
    Tripoli Indiana #132
    Tripoli Central Illinois #59
    Central Illinois Aerospace (NAR) #527
    Chicago Rocket Mafia, "Big Bucks" Dixon
    ___________________________________

    Quiet little voices creep into my head. -- We Were Promised Jetpacks

  25. #25
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    30th January 2016
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    h195 in naked MMT is maybe not a great plan?

  26. #26
    Join Date
    10th July 2007
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    Melbourne, Australia
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    There is a useful discussion here on fin alignment:
    http://forum.ausrocketry.com/viewtopic.php?t=3510

    You can cut a pair of in alignment guides out of some corrugated cardboard using a steel rule and craft knife. Mark it out with a protractor (use trignometry for bonus points and more accuracy!) and a sharp pencil carefully, and watch your fingers!
    I used the same technique for my 8.25" Nike Smoke (works for small rockets too ).
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    I have also used alignment by eye, assisted with two set-squares on the bench which works quite well. I will try to find a pic...
    Last edited by OverTheTop; 3rd April 2017 at 11:36 AM.
    TRA 13430, Level 3

    "Everybody's simulation model is guilty until proven innocent" (Thomas H. Lawrence 1994)

  27. #27
    Join Date
    18th November 2014
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    I ran a simulation on RockSim last night. I put it at a very canted fin. It was still stable, it lost maybe 200 ft off the simulation, and lost about like 50 MPH. So near the same. It's too late to rip off the fins due to the 30 min. epoxy.
    Thanks,
    Andrew - 14 year old rocketeer who loves to watch and fly model rockets all year long!!!
    2018 - 41.69 Ns _ Biggest motor, CTI G106, highest flight around 3,500' - TRA Member #17056
    Owner, Andrew's Rocketry Shop - andrewsrocketryshop.blogspot.com

  28. #28
    Join Date
    26th June 2016
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    Mobile, AL, USA
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    If I were you, I think I'd start over and pay a little more attention to my craftsmanship; especially if I were going to put some kind of High Power motor in it.
    NAR # 37682

    All the weird kids are doing it!

    If at first you don't succeed... You're about average.

  29. #29
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    24th May 2013
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    Battlground indiana
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    That rocket will not get rso'ed . Not to be mean but MD rocket and a bigger motors is no place to test . And your a teen and your mentor will be on the flight . I would not even let it go to rso table .
    Recertification coming soon
    Member of Indiana rocketry joining again

    Tripoli 14704 L2
    L1 mwp 11 XS on a H 250
    L2 mega Hi flyer on J285
    Staring my L3 build a 10" sono tube fin 10.50' tall



    I scratch build .

  30. #30
    Join Date
    27th November 2011
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    Eastern Canada
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    Quote Originally Posted by TangoJuliet View Post
    If I were you, I think I'd start over and pay a little more attention to my craftsmanship; especially if I were going to put some kind of High Power motor in it.
    +1. Call it an opportunity to learn for your mistakes and do better next time. Fortunately you're using cheap materials, so the cost to rebuild will be minimal (and take the time and effort to cut and shape your fins properly). Here is a useful list of tools including one to make a fin alignment guide you can print out for free.

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