An "R"-powered rocket build

Discussion in 'High Power Rocketry (HPR)' started by Rail Dawg, Nov 30, 2018.

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  1. Mar 15, 2019 #1201

    Theory

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    I second this idea, though I believe the entire area will need to be sanded as the inside of the main airframe will receive coupler assemblies that will run the entire length.

    I wonder of you could fab up a sanding flapper with a long dowel and some 220grit. say cut a slit in the end and slide the paper in that then secure the other end to your drill via a hole bored down the center that is filled with a piece of steel rod. doesn't need to win a beauty contest, jut needs to work
     
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  2. Mar 15, 2019 #1202

    Rockyt

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    I saw this posting start with 'wiping'...

    then had to ask myself... "Is bottom thrust plate a new term for 'toilet seat?" :D

    true story, no ill will intended. Truly
     
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  3. Mar 15, 2019 #1203

    Rail Dawg

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    I like the flap sanding disk idea. Learn something new every day!

    Chuck C.
     
  4. Mar 15, 2019 #1204

    djs

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    Don't you have a small child you can give a dust mask and some sand paper to? :)

    I just do the "sand paper taped to a stick" method, although that sucks...
     
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  5. Mar 15, 2019 #1205

    Rail Dawg

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    This idea could work too. A dowel would fit nicely into a drill chuck.

    The main thing is being able to get a little pressure on the sandpaper. It doesn’t have to work perfectly as there is plenty of surface area on the roughened-up coupler/tube interface.

    Thanks!

    Chuck C.
     
  6. Mar 15, 2019 #1206

    GalantVR41062

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  7. Mar 15, 2019 #1207

    Ez2cDave

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    Chuck,

    Make a "hone" . . .

    Remember than piece of Blue Tube coupler you had laying around ?

    Peel ( if you can) the outside layer ( sand it down, if you can't peel it ), so that you can attached a sheet of 220 sandpaper ( double-sided tape ? ) . . . Put a bulkplate in each end with a hole in the center for 3/8" - 1/2" All-Thread ( secure with double-nuts ) . . . Chuck in up in a drill ( preferably a 1/2" variable-speed drill . . . Spin it up and start "honing" !




    Dave F.



    pirate-talk-clipart-1.gif
     
  8. Mar 15, 2019 #1208

    Pyropetepete

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    Small child.
     
  9. Mar 15, 2019 #1209

    MClark

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    I have a friend's daughter peel the waxy layer from a 12 foot length of 16" sonotube.
    When she was in the middle I started rolling it.
     
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  10. Mar 15, 2019 #1210

    rcktnut

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  11. Mar 16, 2019 #1211

    Rail Dawg

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    Of course you did lol!

    Chuck C.
     
  12. Mar 16, 2019 #1212

    Ez2cDave

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  13. Mar 16, 2019 #1213

    warnerr

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    Last edited: Mar 16, 2019
  14. Mar 16, 2019 #1214

    TonyL

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    Chuck,

    by the time you have fabricated a deluxe sanding stick/wheel/etc or fancy custom honing cylinder you could have been done already with an orbital sander taped to a broom handle. Heck by the time you get done reading all this discussion you could have been done already. I would suggest just mark the depth on the handle and have at. Always remember to change your paper often :)

    br/

    Tony
     
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  15. Mar 16, 2019 #1215

    Wallace

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    Agreed, don't overthink it. A simple stick or rod with a slot cut in it in a drill will happily hold a piece of sandpaper or scuff pad. Ball hones are perfect (and pricey) if you actually need 'em,and cylinder hones even more, but almost always end up being single use unless you're into production since they're somewhat size specific.You only really need a hone if you're attempting to true the I.D. I've got dozens of simple home made and they always work.
     
    Last edited: Mar 16, 2019
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  16. Mar 16, 2019 #1216

    Wallace

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    Example. GetAttachmentThumbnail.jpg
     
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  17. Mar 17, 2019 #1217

    Wallace

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    Those 3 stone hones are great in concept but suck to use. I've had way better results with Flex (ball type) hones. But...That's been for automotive motorcycle applications where shooting for improved surface/I.D.'s. If you want to spend the dough, this'd be your friend. Just remember that you'll likely never need it again so 300 bucks for single use. Clear as mud right?https://www.amazon.com/305MM-Flex-H...+hone+12+inch&qid=1552831435&s=gateway&sr=8-3
     
  18. Mar 17, 2019 #1218

    Rail Dawg

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    Definitely the way to go but like you said for single-use hard to justify. Am thinking of getting a dowel that will fit into the drill chuck and cut a slit in it. See if that will do the trick.

    Got a couple days here where I can do some build will find out if it works.

    Chuck C.
     
  19. Mar 17, 2019 #1219

    Wallace

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    Yup, pretty stiff price for something that just ends up taking up space. Maybe try a broom handle cut down at the shank to fit in a drill? A centering ring or 2 as a guide. Shouldn't be overly difficult to make it work. Oh, and thanks for sharing since all of us would love to attempt this type of project but probably never will.
     
  20. Mar 17, 2019 #1220

    rcktnut

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  21. Mar 17, 2019 #1221

    Rail Dawg

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    It goes both ways on the sharing because I pick up ideas I hadn't thought about.

    I've got to cut a coupler down to 24" today or tomorrow. Haven't had to cut G12 before because I always used tubes that were pre-cut. However some good ideas were posted to this thread so it should go smoothly.

    I've got a diamond blade on the table saw and will use a block of wood as a brace. Should be able to make a good clean cut.

    After sanding the inside of the coupler I'll start putting in the vertical stringers. Those will then be carbon-fibered in place. Should make for a very strong assembly. The motor is going to put out upwards of 3 tons of thrust so you have to provide strength all the way up the rocket. Any weak area will crush like an aluminum can.

    Since we're not going for altitude there's more leeway to overbuild the insides. This will be the proving grounds for the 16" "S" rocket that is being planned for next year.

    I'm always learning and this is a big project. It's fun to share the journey. I'll post more pics soon.

    Chuck C.
     
  22. Mar 17, 2019 #1222

    Rail Dawg

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    Lowes has these in stock! That's a great idea. It's worth a shot. I want to be able to get some oomph into the sanding and am not sure the spinning paddle idea will do enough. There's only 2-3 feet in the middle I can't reach but want to make sure it has a good bonding surface area.

    Chuck C.
     
  23. Mar 17, 2019 #1223

    rcktnut

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    Why sure! I was thinking a sponge under the paper could be shaped a bit or just tighten the sandpaper enough to get a bit of curvature. You could sand it vertically or lay the tube down,(work bench height) secure it somehow or have someone hold it and sand it horizontally.
     
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  24. Mar 17, 2019 #1224

    Wallace

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    The pole sanders with U joint actually work fairly well, bit hard to control at times though. You can also get pole sander heads with just a right angle.The sponge is a good idea too. The "stiffer" you can get the backer the better off you'll be. I suspect you'll revert to power tools rather quickly though..
     
  25. Mar 17, 2019 #1225

    Rail Dawg

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    I might go to power tools quickly. There’s only 3 of the 5 ft tubes to get in the middle of so maybe after the appropriate amount of cussing and swearing with the manual paper I’ll be done.

    The first couple of feet in each tube will be done with a disc sander.

    Chuck C.
     
  26. Mar 17, 2019 #1226

    blackjack2564

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    I have 2 12inch tubes sitting out back.....to sand interior I just bit the bullet and reached inside with folded sandpaper and did it all by hand. Wet sanded and hose by my side. Went quick...wet sand it.
    Some times the easiest way is right there all along. I can reach past 1/2 way from each end.

    It's a cylinder within a cylinder, once glued, nothings going anywhere. I really believe you are overthinking this. lol:cool:
     
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  27. Mar 17, 2019 #1227

    Rail Dawg

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    I think you're right lol.

    Chuck C.
     
  28. Mar 17, 2019 #1228

    blackjack2564

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    Some ideas for Av-bay; we did this "floating" bay to cut down interior space needed to pressurize ejection charges.
    Jig for cutting tubes on my ancient table saw. You probably have a nice large table so spacing will be easy.
    Set blade so it barely extends out of cut and rotate slowly.
    Insert bay where you want it....use shoplight or flashlight to illuminate interior.
    We bolt in place for easy prep and removal as a unit.
    Mark and drill first hole.Insert bolt to hold in place, then continue around exterior. we used 8 -1/4in. bolts staggered.
    4- 5/16th tie rods holding everything together and 5/16 U-bolts with 2in. seatbelt harness for Y-harness on each side extending out end of tube.[ hopefully prevent zippering lol]
    Recovery attached to these.
    Nutz epoxied in place with JB Weld.
    Charge Holders curtesy of Rocket Junkies..they made custom 16 gram holders for us. We only ended up using 8 grams per side with 6 number 6 shear-pins.

    DSCN0310.jpg DSCN0589.jpg DSCN0590.jpg DSCN0591.jpg DSCN0593.jpg DSCN0597.jpg DSCN0600.jpg
     
  29. Mar 17, 2019 #1229

    Rail Dawg

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    That's really nice work Jim. And a good explanation too.

    It's appreciated.

    Chuck C.
     
  30. Mar 17, 2019 #1230

    Rail Dawg

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    Cut my first 24" coupler tube on the table saw using a diamond blade.

    Using the fence and simply taking my time it came out perfectly.

    Woo hoo! This is fun.

    Chuck C. IMG_4894[1].JPG
     
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