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  1. #1
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    A neil_w inspired design...

    I have always loved Neil_W's designs, but I don't typically like just building other people's designs. Therefore, I decided to put together a build with a Neil "look" to it while still being my own design. I will probably have access to a laser cutter soon, so I need to come up with something with crazy fins... I also love gap staging, so staged it is. I have lots of BT-50 lying around, so that gives me a tube size... Papered fins to support crazy shapes, etc.

    Combining all of these aspects, I present...

    ...

    ...err, it doesn't actually have a name yet.

    But it has a design!
    Click image for larger version. 

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    The square crossfins are actually fintabs with no fin, so they don't sim. Additionally, they're the "wrong way", so they have to be square. The actual crossfins will interlock, like this:
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    The gap is intentional- I never do anything precisely, so I don't want to have to align them. Thus, an intentional 1/4" gap.

    The booster borrows liberally from the Biohazard, but it has plates rather than a ring, so it has a different feel to it - more angles than curves.

    The whole thing is so anti-3FNC that OR flatly refuses to sim it. No, really!
    Click image for larger version. 

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    Therefore, I have two .ork's, one that sims but is ugly and one that doesn't but looks nice.

    The paint scheme is definitely not set in stone, so feel free to suggest something else! Same with just about everything else, for that matter...

    Attached Files Attached Files
    NAR #104043

    crmrc.org

  2. #2
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    1) NICE!!!
    2) Get OR 15.03dev and you can do the fins the way you want to... kinda

    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

  3. #3
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    12th September 2013
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    I like the two stage stealth photon disruptor vibe.


    Sent from my iPhone using Rocketry Forum
    Charles McGonegal
    Ciderwright at AeppelTreow Winery & Distillery
    www.appletrue.com
    NAR #103560 L1 6/25/17 Estes Leviathan CTI H175-SS
    Ad Astra Tabernamque!

  4. #4
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    Quote Originally Posted by K'Tesh View Post
    1) NICE!!!
    2) Get OR 15.03dev and you can do the fins the way you want to... kinda
    Does it save now? I heard it was having problems with that before.

    Sent from my LGL44VL using Rocketry Forum mobile app
    NAR #104043

    crmrc.org

  5. #5
    Join Date
    14th July 2015
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    Very nice, like it a lot!!! I've been wanting to do a 2-stage design for a while and this really hits a lot of the points I would have been trying for. You can definitely tighten up that 1/4" gap though.

    The new OR would be able to handle this design, since your pods are in groups of 3 and symmetrical.

    When I get a chance I'll have a look at the ORK files.

    (not sure I really need credit in the thread title)

  6. #6
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    Quote Originally Posted by LithosphereRocketry View Post
    Does it save now? I heard it was having problems with that before.
    Depends... I'd guess not... well, not as you'd hope. To do the fins, you'll need to have pods set to 1 more than likely. Once you've got the fins and everything where you like, make a note of the location in either the comments, or the name of the component on the offsets, and angles. OR will probably set your pods to 2 by default, and zero the offsets and angles when you save, close, and reopen the file again. Flight characteristics will be highly suspect.

    Oh, and you'll not be able to scale a fin (after importing it from an image). I suggest using the older version of OR to import the fin shape, and scale, then copy it, and paste it into the developer's version.
    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

  7. #7
    Join Date
    15th October 2016
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    Huntsville AL
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    The new rocket chic......Neil-Scale!

    I wonder how Rocksim would handle this form.
    "I'm at least 70% confident about whatever I say (90% of the time)"- college me

    NAR 101195
    Level 1: Big SAM, 9/10/16

  8. #8
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    14th July 2015
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    Played with the design in new the new OR today, indeed it doesn't handle the angles of fins on pods correctly, so you'd need to do three separate individual pods, which is totally not worth the trouble so I dropped it there.
    For what it's worth, I found it a bit more pleasing to my eyeballs to move the transition back a couple of inches.

    I have to say I am totally digging this design. Look forward to seeing the build!

  9. #9
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    Quote Originally Posted by neil_w View Post
    Played with the design in new the new OR today, indeed it doesn't handle the angles of fins on pods correctly, so you'd need to do three separate individual pods, which is totally not worth the trouble so I dropped it there.
    For what it's worth, I found it a bit more pleasing to my eyeballs to move the transition back a couple of inches.

    I have to say I am totally digging this design. Look forward to seeing the build!
    Thanks!

    The main tube length is pretty much fixed - it uses exactly one 18" tube. I'll try stretching the fore tube next time I'm at a real computer though.

    Sent from my LGL44VL using Rocketry Forum mobile app
    NAR #104043

    crmrc.org

  10. #10
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    Click image for larger version. 

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    I like it! Thanks for the suggestion, Neil! You definitely get credit for this design... It steals liberally from just about all of your recent designs!
    NAR #104043

    crmrc.org

  11. #11
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    So... I might actually build this thing...

    I got fins laser-cut today. No pics yet, I'll post them later.

    Yes, laser cutting is amazing. But these could've turned out better. I'm not sure if it wasn't focused correctly or what, but it cut a fairly large groove in the wood compared to what I've seen in the past. Of course, this is the one model where parts actually have to fit together well. It'll work fine.

    The other problem is that the fan that clears the smoke away from the cutting area started blowing the already-cut fins around. Not a good time. A few fins got a little scorched when they flopped too close to the laser. No biggie, just annoying.

    The one really disappointing thing...

    I just realized I forgot the little nose strakes in my laser file.

    Again, not anything horrible. They're simple and mostly along the grain, so they shouldn't be hard to cut by hand.

    I already have plans for a BT-70 upscale as an excuse to get into electronic staging... Don't know if/when that'll actually happen.

    In other news, I thought up a bit of backstory... This is a commercial spaceliner based on a standard LH2 engine in the first stage and a horrifically toxic but efficient nuclear sustainer. The first stage gets it up to a high enough altitude so that those on the ground aren't harmed... Then it drops away and SpaceX-es itself using three weak but efficient airbreathing engines on its fins. How does the sustainer get back? No clue. I'll get back to you on that one.
    NAR #104043

    crmrc.org

  12. #12
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    Picture time!

    Aforementioned laser cut fins, sans nose strakes:

    Also some tubes and the Tomahawk's cone for scale...
    Click image for larger version. 

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    I decided not to paper the fins- they felt strong enough as-is. They're also extremely light and easy to sand, so I decided to airfoil them. How did I trick myself into that?

    Being the idiot I am, I of course rounded several spots where the fins will eventually glue together.
    Click image for larger version. 

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    Next step will be brushing off the Xacto knife- those tubes and fins won't cut themselves!
    NAR #104043

    crmrc.org

  13. #13
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    That is a fine looking load of lumber ya got there. Look forward to seeing this come together!

  14. #14
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    So I got a bunch done but my thread updating is behind schedule.

    First step was to start fabricating a few parts. Rummaging around in my parts box, I realized that I didn't have any BT-50 couplers. So I repurposed a bit of tube that got a "hook zipper" when a booster didn't tumble quite as much as I would have liked. I glued a strip of scrap paper to either side of the seam and let it dry inside a tube. Came out nicer than I expected. I also made an engine block from a motor casing. 29mm retainer for scale.
    Click image for larger version. 

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    Next thing I forgot to check if I had: Centering rings. Luckily I had about a million (alright, 6) 5-50 CR's, so I just tore out the middles. One even came out nice enough for another engine block! I was already epoxying for another build so I also glued the shoulder onto the NC.
    Click image for larger version. 

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    Then I glued the strakes onto the main booster fins- the other booster fins have strakes too, but they're too thin to stay on before I glue the fin to the BT.
    Click image for larger version. 

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    I also did a bit of work on the MMT/stuffer system. Both stages will use homemade engine hooks, which I thought I got a picture of- apparently I didn't. You can see them OK in these pictures. The front end of the booster stuffer is notched to accept the hook.

    Yes, someone is going to complain that I put finger tabs on my engine hooks. I personally like finger tabs, especially with wiper-blade hooks that are stiffer than standard. The sustainer hook has a low-profile tab to fit better in the stuffer.
    Click image for larger version. 

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    One more small step- put together the transition/upper BT assembly.
    Click image for larger version. 

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    NAR #104043

    crmrc.org

  15. #15
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    Good progress, I like the way the two motor mounts fit together. But donít forget to vent the booster motor mount, since youíre gap-staging.

  16. #16
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    Quote Originally Posted by neil_w View Post
    Good progress, I like the way the two motor mounts fit together. But don’t forget to vent the booster motor mount, since you’re gap-staging.
    My plan is to drill a 1/8" hole through the entire diameter of the booster once I get the MMT installed. Any reason not to? I've gap staged 18mm with 2 1/8" vents before... Admittedly, the booster CATOed. But it still lit the sustainer!
    NAR #104043

    crmrc.org

  17. #17
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    Just remembered, I still need a name. I'm open to suggestions!
    NAR #104043

    crmrc.org

  18. #18
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    Quote Originally Posted by LithosphereRocketry View Post
    My plan is to drill a 1/8" hole through the entire diameter of the booster once I get the MMT installed. Any reason not to? I've gap staged 18mm with 2 1/8" vents before... Admittedly, the booster CATOed. But it still lit the sustainer!
    That seems fine, sounds like you have it well in hand.

    Admittedly, it seems to me like making the holes in the MMT before itís installed would be easier, and anyway the holes in the MMT and outer BT donít need to be aligned. But if youíre comfortable drilling through the whole assembly then go for it.

  19. #19
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    Quote Originally Posted by neil_w View Post
    That seems fine, sounds like you have it well in hand.

    Admittedly, it seems to me like making the holes in the MMT before it’s installed would be easier, and anyway the holes in the MMT and outer BT don’t need to be aligned. But if you’re comfortable drilling through the whole assembly then go for it.
    I might go for the drill-separately option. The only issue I would worry about is catching the fore CR with the drill hole.

    Seriously, though. This thing needs a name.
    NAR #104043

    crmrc.org

  20. #20
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    14th July 2015
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    Names are Hard. I have a better feel for names for my own designs because I know what I was thinking during the design (still not always easy). But I shall ponder.

  21. #21
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    4th October 2014
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    I like the interlocking tip fins on the interstage.

    For the booster tumble recovery, can you check c.g. and c.p. of the booster alone? Might have to balance that after built with a spent engine casing to make sure you get a good tumble rather than a lawn dart. Or, go Black Widow style and trim that thing for glide!

  22. #22
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    Quote Originally Posted by GlenP View Post
    I like the interlocking tip fins on the interstage.

    For the booster tumble recovery, can you check c.g. and c.p. of the booster alone? Might have to balance that after built with a spent engine casing to make sure you get a good tumble rather than a lawn dart. Or, go Black Widow style and trim that thing for glide!
    I've already learned to do that the hard way... I'd attach a picture but my phone won't upload images for some reason.

    Long story short- I built a gap staged Boosted Arcas but didn't tumble check my booster. Shoved the stuffer/lattice assembly up the tube. D12-0 made a nice zipper via the engine hook, giving me lots of free coupler material. The booster lived to fly again- with rear ejection.

    Sent from my LGL44VL using Rocketry Forum mobile app
    NAR #104043

    crmrc.org

  23. #23
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    [posted to the wrong thread, darnit]
    Last edited by neil_w; 3rd November 2017 at 05:53 PM.

  24. #24
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    For hard-to-explain reasons, the name "Splinter" has been stuck in my head for this rocket.

  25. #25
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    Quote Originally Posted by neil_w View Post
    For hard-to-explain reasons, the name "Splinter" has been stuck in my head for this rocket.
    What will happen when those booster fins hit the ground?

    By the way, I noticed a mistake I made with the fins on this rocket. A big round of applause to anyone who can figure out what it is... I'll give you a hint- you can't figure it out without using the OR renderings in the OP or post #10 (revised fore section).
    NAR #104043

    crmrc.org

  26. #26
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    A bit of progress... Got the fin lines marked on the BTs.

    Click image for larger version. 

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    Still no takers on the stupid mistake in post #12 (easier to see in post #14)?...
    NAR #104043

    crmrc.org

  27. #27
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    5th January 2015
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    Staging coupler in aft end of sustainer MMT? No way to insert/secure sustainer motor?

    Sent from my SM-G920V using Rocketry Forum mobile app

  28. #28
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    Quote Originally Posted by dmgrime View Post
    Staging coupler in aft end of sustainer MMT? No way to insert/secure sustainer motor?

    Sent from my SM-G920V using Rocketry Forum mobile app
    Nope, try again. Good idea though.

    Sent from my LGL44VL using Rocketry Forum mobile app
    NAR #104043

    crmrc.org

  29. #29
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    Lotsa progress, complemented by thread updating laziness...

    Installed the MMTs and drilled vents. Could've gone better, but it worked OK.
    Attachment 334490
    Attachment 334491

    Attached strakes to the sustainer. Pretty easy.
    Attachment 334492
    Attachment 334493

    Glued the tubefins onto the main booster fins. I took pictures of all 3 but they all pretty much look like this.
    Attachment 334494

    So important life lesson here: Don't Titebond on aluminum.

    I was gluing the T fins together, so I started with Elmer's wood glue since I'm trying to get rid of it in favor of TBIII. That worked fine. But on one, I already had the Titebond out, I decided to use that instead.
    Attachment 334495

    News flash- TBIII sticks to aluminum. Not well, but given the amount of surface area touching the angle, it was enough to make pulling the fin off a nightmare.

    I have a picture of the slight damage but I can't attach it for some reason- I'll try again later.

    Long story short- attached the sustainer T fins.
    Attachment 334496
    Attachment 334497

    Starting to look llike a rocket!

    Sent from my LGL44VL using Tapatalk
    NAR #104043

    crmrc.org

  30. #30
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    More progress- attached the T fins to the booster.
    Click image for larger version. 

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    Still looking for a name for this thing...

    Sent from my LGL44VL using Tapatalk

    NAR #104043

    crmrc.org

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