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  1. #1
    Join Date
    16th May 2011
    Location
    Central California
    Posts
    941

    38mm build "Spare Parts"

    I've been wanting to fly the new J316 pink from CTI and also been wanting to use my new cable cutter from Archetype Rocketry so with our big 3 day October skies launch coming up I figured I'd build something to accomplish this. The rocket will be called Spare Parts because I have everything but the nosecone laying around. The airframe will be G12 glass 20-3/4" long, fins .062 carbon fiber with proline fillets, nosecone will be a FWFG from rocketry warehouse and will houses raven, a raven AV bay and a CSI tracker. Shock cord will be 1/8" Kevlar and the chute will be between 14-18 inch and will be deployed at 800' by the cable cutter.without final weights I'm expecting 15,400ft for the flight. I went with a space cowboy type fin shape because I love the look. Mine aren't airfoiled just beveled.


  2. #2
    Join Date
    16th May 2011
    Location
    Central California
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    941
    First I layed out the fins on a piece of carbon fiber, cut them out, and beveled them. I then sanded the faces of the fins with 320 to accept paint then the root edge 3/8" or so with 80 to accept epoxy. Next I sanded the area around the slots with 80 then did a little scoring with a razor blade at about 45 degrees to the slot. Click image for larger version. 

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  3. #3
    Join Date
    16th May 2011
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    Central California
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    941
    Next I tacked the fins in with JB quick.Click image for larger version. 

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  4. #4
    Join Date
    16th May 2011
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    Central California
    Posts
    941
    Here's a pic of all the fins tacked in. Next up will be the Proline fillets.Click image for larger version. 

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  5. #5
    Join Date
    16th May 2011
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    Central California
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    941
    I got the fillets all pulled and the fillets came out great but beside the fillet got a little messier than I like but nothing a little sanding wont fix.Click image for larger version. 

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  6. #6
    Join Date
    13th February 2012
    Location
    Central Jersey
    Posts
    5,663
    How did you cut out the fins and the fin jig? I imagine the fin jig could have come from another project, I guess.
    Several rocket motors burned this year.

  7. #7
    Join Date
    16th May 2011
    Location
    Central California
    Posts
    941
    I cut and bevel all my carbon fiber and G10 with a grinder with a metal cutting cut off wheel. The jig came with my blackhawk 38.

  8. #8
    Join Date
    4th September 2012
    Location
    Portland, OR
    Posts
    884
    Sweet! Take some pictures of that Pink, I really want to see it. I'd have flown one by now if I had a rocket for it.

  9. #9
    Join Date
    1st April 2011
    Location
    Utah / UROC
    Posts
    3,478
    Quote Originally Posted by maxvelocity View Post
    carbon fiber...... to accept paint
    no.

  10. #10
    Join Date
    16th May 2011
    Location
    Central California
    Posts
    941
    I will try to catch it. I really want to get a good shot of it but usually they are too fast. But I will post if someone catches it.

  11. #11
    Join Date
    20th August 2011
    Location
    Windsor, Connecticut
    Posts
    2,332
    Quote Originally Posted by Aksrockets View Post
    no.
    Agreed.

  12. #12
    Join Date
    16th May 2011
    Location
    Central California
    Posts
    941
    I received my nosecone yesterday and it needed a few modifications to work so I figured I would get right on it. First off the tube I used is a lightweight version which has a thinner wall than the standard tubes. Because of this the nosecone diameter didn't match the tube so I needed to take some material off the OD at the base. For this I machined a piece of AL that would fit in the end of the cone with the AL tip removed and center the cone in my lathe.Click image for larger version. 

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    Next I learned something: You don't machine G12 with HSS tooling, the G12 machines the tool... Anyways I got the cone in the lathe and ended up using 80 grit to turn down the OD.Click image for larger version. 

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  13. #13
    Join Date
    4th September 2012
    Location
    Portland, OR
    Posts
    884
    Quote Originally Posted by maxvelocity View Post
    Next I learned something: You don't machine G12 with HSS tooling, the G12 machines the tool...
    I tried to part a G12 tube with a HSS parting tool; that ended poorly for the parting tool...

  14. #14
    Join Date
    19th November 2009
    Location
    Brooklyn, NY
    Posts
    855
    Great work so far! I think this method of min. dia. fin attachment is underrated but it must add at least some strength, not to mention improved alignment.

  15. #15
    Join Date
    16th May 2011
    Location
    Central California
    Posts
    941
    The next issue is that because the coupler of the nosecone will be used to house the Raven av bay I needed it to be 2" long. The coupler would then only stick out of the cone by about an inch which I don't feel comfortable with as a long enough shoulder so I needed to trim the cone down so the 2" long coupler would stick out at least 1-1/2". So I found a piece of coupler I had that was 2" long stuck in in the cone as far as it would go and I needed to trim off apprx. 7/16" from the base of the cone. I did this in my chop saw then sanded it square with sandpaper on a steel table. Now it looks like a rocket. Click image for larger version. 

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    next up I'm going to secure the coupler in the cone, a few other small details and then paint and she will be ready to fly next Saturday.

  16. #16
    Join Date
    16th May 2011
    Location
    Central California
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    941
    Quote Originally Posted by New Ocean View Post
    Great work so far! I think this method of min. dia. fin attachment is underrated but it must add at least some strength, not to mention improved alignment.
    The fins were incredibly strong with just JB weld in the slots I actually thought about flying it once just like that to see how they would do but it is supposed to hit Mach 2.17 so I figured better safe than sorry and added fillets.

  17. #17
    Join Date
    19th November 2009
    Location
    Brooklyn, NY
    Posts
    855
    Looks like a mean little thing!

  18. #18
    Join Date
    16th May 2011
    Location
    Central California
    Posts
    941
    I got to fly the rocket today at TCC October skies launch. The rocket flew really straight out of the tower very nice big pink flame. The raven beeped out 11226. Later tonight I will download the rest of the days and post. I burned the paint off my fins flew almost 12k and recovered about 200 yards from the pad thanks to the Archetype cable cutter which worked perfect! The J316 is a great motor one of the guys caught a picture of it I will post when he gets it to me.

  19. #19
    Join Date
    15th August 2012
    Location
    Park City, Utah
    Posts
    77
    I have a Raven and the Archetype cutter as well and am anxious to configure & fly it. I'd love to see any specs/pics or details about how your rigged up the cutter and Raven. Great job and congrats on you successful launch!

  20. #20
    Join Date
    16th May 2011
    Location
    Central California
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    941
    So I have decided not to trust what the raven beeps out anymore. Downloaded the data and my baro agl is 13492 which is closer to my sims. It pulled 51 gees off the pad and hit 1445 MPH (mach 1.88) much slower than the Sims but still fast enough to melt paint.
    Last edited by maxvelocity; 22nd October 2012 at 06:17 PM.

  21. #21
    Join Date
    22nd January 2009
    Location
    Palo Alto, CA
    Posts
    2,034
    Quote Originally Posted by maxvelocity View Post
    So I have decided not to trust what the raven beeps out anymore. Downloaded the data and my baron agl is 13492 which is closer to my sims. It pulled 51 gees off the pad and hit 1445 MPH (mach 1.88) much slower than the Sims but still fast enough to melt paint.
    What did it beep out? Usually it's within a few feet of what you figure out from the graph.
    Adrian Adamson
    Featherweight Altimeters LLC
    www.featherweightaltimeters.com

  22. #22
    Join Date
    2nd September 2010
    Posts
    2,458
    Maxx, I'd like to see some pics of your cutter system also if you have some.
    Quote Originally Posted by rheil View Post
    I have a Raven and the Archetype cutter as well and am anxious to configure & fly it. I'd love to see any specs/pics or details about how your rigged up the cutter and Raven. Great job and congrats on you successful launch!

  23. #23
    Join Date
    20th August 2011
    Location
    Windsor, Connecticut
    Posts
    2,332
    Quote Originally Posted by bill2654 View Post
    Maxx, I'd like to see some pics of your cutter system also if you have some.
    Yeah, pics or it didnt happen!

  24. #24
    Join Date
    16th May 2011
    Location
    Central California
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    941
    Quote Originally Posted by Adrian A View Post
    What did it beep out? Usually it's within a few feet of what you figure out from the graph.
    Yea this flight was the furthest from the baro agl I've had so far. It beeped 11226. Its always just a little under but never this much. Any ideas why?

  25. #25
    Join Date
    16th May 2011
    Location
    Central California
    Posts
    941

    cutter

    I didn't take any pics in the field of the recovery setup but I can do some mock up for u guys later. I haven't taken everything apart yet and cleaned it up so it will be easy.

  26. #26
    Join Date
    22nd January 2009
    Location
    Palo Alto, CA
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    Quote Originally Posted by maxvelocity View Post
    Yea this flight was the furthest from the baro agl I've had so far. It beeped 11226. Its always just a little under but never this much. Any ideas why?
    If you post the file I can check it out.

    Thanks.
    Adrian Adamson
    Featherweight Altimeters LLC
    www.featherweightaltimeters.com

  27. #27
    Join Date
    16th May 2011
    Location
    Central California
    Posts
    941

  28. #28
    Join Date
    16th May 2011
    Location
    Central California
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    Here is a picture of the rocket ready for flight and one of the melted paint on the fins after flight.
    Click image for larger version. 

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  29. #29
    Join Date
    11th February 2009
    Location
    Oregon
    Posts
    1,023
    Quote Originally Posted by maxvelocity View Post
    I didn't take any pics in the field of the recovery setup but I can do some mock up for u guys later. I haven't taken everything apart yet and cleaned it up so it will be easy.
    I too would like to see this as I just purchased on of the cable cutter from Archetype Rocketry and would like to see what you've done.
    Did it work well?
    "Keep your charges reasonable and tie the knot..."

    2016 Stats
    *Number of Flights: 20
    *Total Impulse: 40,457.0 Ns

  30. #30
    Join Date
    16th May 2011
    Location
    Central California
    Posts
    941
    Yes the cutter worked perfectly. The best part besides the extremely short walk for a 13K+ flight was being that the chute and shroud lines are all wrapped up tightly with the nomex and held with the ziptie/cutter the chute has a zero chance of being burned and my chute looks like its never been flown. usually i'll get a black mark here or there or a small burn but not with this setup. I am very satisfied with the cutter and will likely use this setup from here on out on all my projects that it will fit in.


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