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  1. #1
    Join Date
    3rd August 2014
    Posts
    494

    "Tubestack" mid-power scratch build thread

    You know, sometimes there exists sentimentality where you least expect it. In my new workshop / lounge area I have a nondescript wooden box. There are two things special about this box you don't know at first glance. The more important one is that Dad built this for me close to 40 years ago, it's my childhood toybox, my sister had a matching one. I have a lot of memories attached to this box, and one of my oldest memories was seeing the two matching toyboxes in the corner of our den acting as walls, holding a puppy. That little schnauzer was one angry little a-hole, and he's been gone for decades. Anyway.... that's too much of a tangent.



    The other special thing about this box, is it's my rocket box. I keep all my un-built kits in here, as well as all my leftovers and spares. It's incredible how just a few repairs and clones can build up a big pile of body tubes you weren't expecting to have.



    And this is my next build right here, it's a stack of tubes. So let's call this build "Tubestack". Original name? Yes. Good name? who cares, let's build a rocket!!!!!


    NAR # 99851 / Tripoli # 15833
    NAR Chapter 785 - The South Dakota Rocket Jockeys - SDRocketJockeys.com

    L1 - Estes Scion - CTI 168H133 - 1802ft
    L2 - Blastcap Painkiller 3 - CTI 1281K360 - 6951ft

  2. #2
    Join Date
    3rd August 2014
    Posts
    494
    So, what all do we actually have here, anyway?
    Mostly a selection of BT-60, BT-80, 3" and 29mm.

    ....... 29mm motor tubes.......



    Thought #1 that occured to me is how nicely a trio of 29mm motors fit into BT-80.
    But I'm not exactly cluster experienced and a triple motor set really can ONLY fly as a triple motor set.
    Can't fit 4 in here, which would have been nice because I could do a pair or a quad.
    Good warmup for that 4-29SS I still need to finish.



    Another thought I had was tube fins. Lots of 38mm tubes here, and they kinda stack up nicely against that 3" tube.



    So, why not combine those ideas, shall we?
    Quad 29mm's in a 3" tube. But that 3" is a weeeeeee bit short, and my brain screams 'stability margin, stability margin, stability margin.'


    NAR # 99851 / Tripoli # 15833
    NAR Chapter 785 - The South Dakota Rocket Jockeys - SDRocketJockeys.com

    L1 - Estes Scion - CTI 168H133 - 1802ft
    L2 - Blastcap Painkiller 3 - CTI 1281K360 - 6951ft

  3. #3
    Join Date
    3rd August 2014
    Posts
    494
    Ahhhh yes, I have a rather good length of BT-80, don't I?
    I'll need to figure out a transition and some centering rings, and there's no doubt in my mind it'll need more fin area for sure.
    But I think we've got ourselves a rocket. My head is full of ideas now to build off this base pattern.

    Time to start burning some time in openrocket and see what it'll take to make this guy safe.

    NAR # 99851 / Tripoli # 15833
    NAR Chapter 785 - The South Dakota Rocket Jockeys - SDRocketJockeys.com

    L1 - Estes Scion - CTI 168H133 - 1802ft
    L2 - Blastcap Painkiller 3 - CTI 1281K360 - 6951ft

  4. #4
    Join Date
    3rd August 2014
    Posts
    494
    Ok, OpenRocket gets me stability, but weeeeeeeee doggy does it get me some altitude with even mild 2-motor clusters.
    I've got my high fliers, and have some even-higher fliers in mid-build. I want a bit more field friendly of a design here.
    The last thing I want is another fantastic rocket hiding in the corner because I can only fly it with a road trip.

    So let's dial back to a single motor, shall we? A single Aerotech F23 gets me a good 600ft flight and almost over-stable.
    Or I can run a 24mm adapter and CTI 6-grain G65 and a really beautiful looking profile up to 1500ft.
    Honestly I really like the flight profiles I'm getting in the F-G motor range.
    That and I really like the fin pattern too. Just some basic trapezoids really, but I like the look.

    I think I found my rocket.

    NAR # 99851 / Tripoli # 15833
    NAR Chapter 785 - The South Dakota Rocket Jockeys - SDRocketJockeys.com

    L1 - Estes Scion - CTI 168H133 - 1802ft
    L2 - Blastcap Painkiller 3 - CTI 1281K360 - 6951ft

  5. #5
    Join Date
    27th March 2013
    Location
    Has Changed
    Posts
    9,558
    Quote Originally Posted by HHaase View Post
    I think I found my rocket.
    The SPEV 2017!

    Looks interesting!
    Dreaming of making the rockets I dreamed of as a kid (and then some).


    NAR L1 Cert flight: Sheridan, Oregon, USA. Sept. 19, 2015. Flew Deep Space OFFl on an I357T-14A Blue Thunder

  6. #6
    Join Date
    3rd August 2014
    Posts
    494
    I'm going to impose some FUN rules on this build for myself, to keep it in the spirit of using up things I already have.
    So purchasing components must be kept to a bare minimum. At current I think I can get away with ONLY buying a chute and some thin ply stock for the fins.
    I'm also going to 3D print as much as possible. Again, because it makes this build more fun to me, your mileage may vary.

    -Hans
    NAR # 99851 / Tripoli # 15833
    NAR Chapter 785 - The South Dakota Rocket Jockeys - SDRocketJockeys.com

    L1 - Estes Scion - CTI 168H133 - 1802ft
    L2 - Blastcap Painkiller 3 - CTI 1281K360 - 6951ft

  7. #7
    Join Date
    18th January 2009
    Location
    Maryland
    Posts
    11,663
    Quote Originally Posted by HHaase View Post
    Again, because it makes this build more fun to me, your mileage may vary.

    -Hans
    And, that is the only reason to build any rocket as far as I'm concerned. I like this kind of build, although I usually don't have that many actual rocket parts
    Dick Stafford
    The member formerly known as the Pointy-Haired Moderator.
    The Original Rocket Dungeon
    Volunteer compiler of product news for ROCKETS Magazine

  8. #8
    Join Date
    26th January 2010
    Location
    Northern California
    Posts
    13,154
    Very cool design!
    NAR 91107, Level 2

    I really, really hate bugs.

  9. #9
    Join Date
    3rd August 2014
    Posts
    494
    Did I mention how much I love doing 3D printed stuff? First try at these centering rings had a slightly under-sized hole for the motor tube, but 2nd try was spot-on.
    The motor retainer came off thingiverse, and is very similar to Estes retainers.
    Normally I buy the Estes ones, but keeping with the theme of the rocket I decided to print this time.




    Add it all together and I've got me a motor mount ready to epoxy together and into the lower 3" tube
    This is all ABS plastic. In the past I probably wouldn't have used plastic for motor mount centering rings.
    But after all the flights I've done with the plastic Estes retainers I'm pretty comfortable with the material in this build.
    Lots of examples out there on the web of people flying extensively 3D printed designs.

    NAR # 99851 / Tripoli # 15833
    NAR Chapter 785 - The South Dakota Rocket Jockeys - SDRocketJockeys.com

    L1 - Estes Scion - CTI 168H133 - 1802ft
    L2 - Blastcap Painkiller 3 - CTI 1281K360 - 6951ft

  10. #10
    Join Date
    30th January 2016
    Location
    US > OK > NE
    Posts
    3,477
    Quote Originally Posted by HHaase View Post
    Did I mention how much I love doing 3D printed stuff? First try at these centering rings had a slightly under-sized hole for the motor tube, but 2nd try was spot-on.
    The motor retainer came off thingiverse, and is very similar to Estes retainers.
    Normally I buy the Estes ones, but keeping with the theme of the rocket I decided to print this time.




    Add it all together and I've got me a motor mount ready to epoxy together and into the lower 3" tube
    This is all ABS plastic. In the past I probably wouldn't have used plastic for motor mount centering rings.
    But after all the flights I've done with the plastic Estes retainers I'm pretty comfortable with the material in this build.
    Lots of examples out there on the web of people flying extensively 3D printed designs.

    Hrmm, 3d-printed I-beam supports for stock paper rings would actually be pretty interesting. Weight should come in under ply.

  11. #11
    Join Date
    18th January 2009
    Location
    Maryland
    Posts
    11,663
    Quote Originally Posted by HHaase View Post
    Did I mention how much I love doing 3D printed stuff? First try at these centering rings had a slightly under-sized hole for the motor tube, but 2nd try was spot-on.
    The motor retainer came off thingiverse, and is very similar to Estes retainers.
    Normally I buy the Estes ones, but keeping with the theme of the rocket I decided to print this time.




    Add it all together and I've got me a motor mount ready to epoxy together and into the lower 3" tube
    This is all ABS plastic. In the past I probably wouldn't have used plastic for motor mount centering rings.
    But after all the flights I've done with the plastic Estes retainers I'm pretty comfortable with the material in this build.
    Lots of examples out there on the web of people flying extensively 3D printed designs.

    Now you're just bragging. But that is pretty cool.
    Last edited by rstaff3; 5th November 2017 at 04:48 AM. Reason: clarification
    Dick Stafford
    The member formerly known as the Pointy-Haired Moderator.
    The Original Rocket Dungeon
    Volunteer compiler of product news for ROCKETS Magazine

  12. #12
    Join Date
    3rd August 2014
    Posts
    494
    I also epoxied a lot of things yesterday.
    I epoxied the motor mount parts together, and installed them in the lower body tube.
    Also epoxied each pair of tubes to each other.

    Still using my favorite epoxy. G-Flex by West Marine, but in this case re-packaged as "Flex-Epox" by TotalBoat.
    Same stuff, going by the datasheets, but cheaper in the off-brand.

    I really like this "no instructions or examples to follow" kind of build.
    I decided it would look better if I moved the tubes and fins forward about 2".
    So I moved the tubes and fins forward about 2".

    NAR # 99851 / Tripoli # 15833
    NAR Chapter 785 - The South Dakota Rocket Jockeys - SDRocketJockeys.com

    L1 - Estes Scion - CTI 168H133 - 1802ft
    L2 - Blastcap Painkiller 3 - CTI 1281K360 - 6951ft

  13. #13
    Join Date
    19th February 2017
    Location
    The world, probably
    Posts
    465
    Looks interesting so far! I don't think I've seen too many rockets with the "2 pairs" tubefin approach.

    I like the 3D printed parts! I considered 3D printing retainers but I was worried they wouldn't thread well. Seems to work fine on yours...
    NAR #104043

    crmrc.org

  14. #14
    Join Date
    3rd August 2014
    Posts
    494
    Been struggling a bit with the transition section. First attempt printed beautiful, but I used the ID measurement for the OD, so it was too small and too thin walled.
    2nd attempt I think the dimensions are right but print separated on me. Then I went on a business trip for a week.
    Trying again soon
    NAR # 99851 / Tripoli # 15833
    NAR Chapter 785 - The South Dakota Rocket Jockeys - SDRocketJockeys.com

    L1 - Estes Scion - CTI 168H133 - 1802ft
    L2 - Blastcap Painkiller 3 - CTI 1281K360 - 6951ft

  15. #15
    Join Date
    3rd August 2014
    Posts
    494
    Ok, managed another good print of a transition section, and it's REALLY close to the right dimensions, but not exactly. I was off by about 1.5mm in the ID for the BT-80, I didn't realize there was a coupler slipped in there when I measured the tube.
    Good news is the 3" side fits perfectly and the OD for the BT-80 side matches up very nice as well. So just one dimension to fix and the next print should be good to continue building.

    I can at least mock it up for you all now to show how it's looking, even if this particular transition is going to become a pen holder or something.

    NAR # 99851 / Tripoli # 15833
    NAR Chapter 785 - The South Dakota Rocket Jockeys - SDRocketJockeys.com

    L1 - Estes Scion - CTI 168H133 - 1802ft
    L2 - Blastcap Painkiller 3 - CTI 1281K360 - 6951ft

  16. #16
    Join Date
    18th March 2011
    Location
    Flower Mound
    Posts
    833
    If this is a SPEV, just glue in the coupler and fly what you've already printed.

    Or print another transition. Whatever floats your boat.
    I'm not very smart, but I can lift heavy things...

  17. #17
    Join Date
    3rd August 2014
    Posts
    494
    Thought about that actually, but with the coupler then it wouldn't fit. So I was stuck making another.
    Good news is I DO have a good one now. Just haven't had time to epoxy it all together yet.
    NAR # 99851 / Tripoli # 15833
    NAR Chapter 785 - The South Dakota Rocket Jockeys - SDRocketJockeys.com

    L1 - Estes Scion - CTI 168H133 - 1802ft
    L2 - Blastcap Painkiller 3 - CTI 1281K360 - 6951ft

  18. #18
    Join Date
    3rd August 2014
    Posts
    494
    Ok, 3D printer has been a pain in the behind, but that's all fixed, and I've had rocket time again.
    I'm not going to post another photo with the latest coupler, as it just looks the same as the previous picture.
    But it fits, it's epoxied in place, and I can move on to the next step.

    Nose Cone!

    I need an avionics bay in the nose for my eggfinder, and it mounts on a 29mm sled that I've been using for a while now.
    LHS actually had the Mega Mosquito style BT-80 nose cone in-stock for me. So I grabbed one, and promptly cut the back off of it.
    I also chopped a section of body tube off the rocket, and using a BT-80 coupler, I made a LONG nose cone assembly.
    Throw in a 29mm body tube, more 3D printed centering rings, and another 3D printed motor mount.
    Epoxy it all together, with a recovery harness attachment.

    Once all this epoxy dries, the motor mount assembly will go into the nose cone. Viola! Nose-Bay!
    I'll show the sled in the next post once it's all assembled and ready to go.

    I really love using this style avionics bay for my tracker. Keeps it all rock-solid in place, maintains the Cg/Cp relationship, and is super easy to use.
    I have uploaded the eggfinder sled to thingiverse today, as well as the BT-80 Coupler to 29mm motor mount centering rings.

    NAR # 99851 / Tripoli # 15833
    NAR Chapter 785 - The South Dakota Rocket Jockeys - SDRocketJockeys.com

    L1 - Estes Scion - CTI 168H133 - 1802ft
    L2 - Blastcap Painkiller 3 - CTI 1281K360 - 6951ft

  19. #19
    Join Date
    3rd August 2014
    Posts
    494
    So, here's the 3D printed sled I use for my eggfinder. Fits into a 29mm motor tube, holds a pair of LiPo's.
    Slides into a 29mm motor mount tube, holds it all nice and sturdy, keeps my Cg foward.
    Clean and easy to use.

    Starting to get into the closing stages of this build, really just needs fins, lugs, and finishing.
    Time to start thinking of a color scheme.




    NAR # 99851 / Tripoli # 15833
    NAR Chapter 785 - The South Dakota Rocket Jockeys - SDRocketJockeys.com

    L1 - Estes Scion - CTI 168H133 - 1802ft
    L2 - Blastcap Painkiller 3 - CTI 1281K360 - 6951ft

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