What is Chad Staging?

Discussion in 'Low Power Rocketry (LPR)' started by slim_t, Oct 1, 2003.

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  1. Oct 1, 2003 #1

    slim_t

    slim_t

    slim_t

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    Hope this doesn't come off as a dumb question, but could someone explain Chad staging to me?
    I saw it on a video of a Space Shuttle model project and it was just awesome.
    On the model, the 2 SRB's had motors in them and they boosted the rocket first. They then seperated, then a motor in the shuttle ignited seperating it from the tank and boosted the shuttle into a cool glide. I'll find the link again and post it later.
    It said they were chad staged and that's new to me.
    I knew someone here could explain it easily.

    Thanks,

    slim
     
  2. Oct 1, 2003 #2

    jetra2

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    CHAD. CHeap And Dirty.

    Simple...there is is no booster stage with fins, the booster motors just hang off the ends of a standard motor. You have to be careful that your rocket is really stable when you do this, because it shifts the CG pretty far back!

    It works great with a snitch, though!

    Jason
     
  3. Oct 1, 2003 #3

    spacecowboy

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    chad is generally bending the engine hook out of the way, and using a ring of masking tape to tape 2 motors together, like a
    b6-0 booster and a b6-4 sustainer (2nd stage), and stick the combo in the roc and let 'er rip. It generally either puts a roc into orbit, or catastrophically destroys it.

    tongue in cheek, I tried a triple chad once, and watched that roc go up come back down, bounce off the ground, repeat twice. It was kind of funny. Some of my other chad shots are just cool.
     
  4. Oct 1, 2003 #4

    shockwaveriderz

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    heres a pic I found somewhere on the web showing chad staging....wish I knew where I got it so I could give credit..

    shockie
     
  5. Oct 1, 2003 #5

    Justy

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    The upper end of a 24mm motor (eg. D12-0) fits snugly over the business end of a 18mm motor (eg. C6-5), and I believe this also qualifies as CHAD staging. Again, careful with the CG/CP balance, though.

    But I have never seen a CHAD staged rocket fly successfully.
     
  6. Oct 1, 2003 #6

    jflis

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    :) That would be from me and FlisKits. Someone was asking about CHAD staging in another thread and I did that drawing as a modification of our "multi-staging hints sheet"
     
  7. Oct 1, 2003 #7

    jflis

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    Here is a photo of the FlisKits Corona kit CHAD staged (you can see the CHAD motor extending well below the fins.)

    http://fliskits.com/photo_album/cmass_102002t/images/P1010037.JPG

    The *trick* is to use a rocket that is very stable (over-stable), so that the added weight rearward doesn't make it unstable.

    Good candidates are long thin rockets and/or rockets with large and/or swept fins.

    jim
     
  8. Oct 1, 2003 #8

    spacecowboy

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    Jim is right, taller rox with massive, swept fins account for all my successful chad launches. It's a real kick-in-the-pants when it works. Also, the launch rod needs to be sticking as straight up as possible (amazing how many times I'm at the pad and notice how off center my launcher is). And little or no wind. Even the smallest wind weathercocks, and then the rocket goes waaay unstable because of the extra engine weight. Estes Polaris and Nova payloader were good chad flights, all the E2X birds I tried got buried , , , ,usually under a LOT of power.
     
  9. Oct 1, 2003 #9

    jetra2

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    Uhh....I think I have QUITE the interesting idea...... anyone care to take a guess???

    richter recker........

    Jason
     
  10. Oct 1, 2003 #10

    jflis

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    let me know how *that* one goes... would be most interested in how it works and what motor combination you use.
     
  11. Oct 1, 2003 #11

    maddogdelta

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    I think the shuttle link you are looking for is here:
    http://members.aol.com/GCGassaway/gcghome.htm

    George Gassaway is a veritable RG diety, in my book. The July - August Sport rocketry has a simple balsa sport scale shuttle that looks easy enough to build and fly (pretty amazing, considering how complex the shuttle is) which was based on a Gassaway design.

    You are right...WAY cool video!
     
  12. Oct 1, 2003 #12

    Fore Check

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    I just rocksim'd (on the 5.0 freeware) a scratch model I have in mind with a chad stage. Stable by Rocksim (1.08) and Marginally by the other (.98). Chad d12-0 to a d12-7. Busted off to 2100 ft!

    Design is a 9" BT55 with a PNC-55AC. 6 fins made of 1/8" balsa 1" strip, with the root edge and tip edge 45 degrees to the parallel leading and trailing edge. Leading edge is 4". No nose weight (so root edge length is 1.414", sweep angle is 45 degrees)
     
  13. Oct 1, 2003 #13

    Fore Check

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    Now I'm going to have to build this thing.

    Just rsim'd the rocket above, but downsized the bt to a BT50 (minimum diameter) with a same shape PNC. Extended the length of the body tube to 12". Fins stayed the same. Added 2 grams of nose weight, and chad staged an E15-0 to a E15-7. Sim'd to 3750! And stable. Recovered at 17 fps on a 3x30 mylar streamer.

    I think I'll call it the "CUL8R"
     
  14. Oct 1, 2003 #14

    slim_t

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    The link Maddogdelta posted is correct. From there, click on movies link and check out the shuttle video.
    Evidently I got the stories mixed up though, it was a different rocket that was Chad staged, not the shuttle. But watch the shuttle video and see if you can tell me how they ignited the shuttle motor later in the flight. Maybe the shuttle was Chad staged so that the first motor burned with the SRB's, then the 2nd stage lit in the shuttle???

    Apparently George is a member of the same rocketry club I'm in, as I got to his site through the club site. Maybe I'll get to meet him at a launch sometime and he can tell me all about the shuttle.

    Thanks for all the info.

    slim
     
  15. Oct 2, 2003 #15

    eugenefl

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    Here's a successful CHAD staged rocket! The great Estes Snitch! Jason (jetra2) and I flew it CHAD staged twice - once on a C6-0 to B6-0 and a 2nd time on a C6-0 to C6-0.

    Here's a picture of it on the pad.
     
  16. Oct 2, 2003 #16

    eugenefl

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    Here's the Snitch on a C6-0toB6-0 liftoff.
     
  17. Oct 2, 2003 #17

    seo

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    I did a quick check on Rocksim and it looks like the Praetor might also be a good candidate for CHAD staging. C6-0/C6-5 sims to just over 1000 feet and the CG is still more than 2x the diameter in front of the CP.

    Scott
     
  18. Oct 2, 2003 #18

    jflis

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    hhhmmmm, now *that* wouild be intersting... ...a Praetor, eh??
     
  19. Oct 3, 2003 #19

    teflonrocketry1

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    Fore Check,

    Is the attached RocSim version 5 file close to what you had in mind?

    Bruce S. Levison, NAR #69055
     
  20. Oct 3, 2003 #20

    PGerringer

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    The Snitch is a perfect rocket for CHAD. You don't really have to worry about stability because they are way over stable. But why stop at Cs? We would go D -> C. Course, since it was a saucer it wouldn't go but about 100' but it as a cool ride.
     
  21. Oct 3, 2003 #21

    seo

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    Yes..............

    But I need to finish it yet. Just need a few spare hours....

    I won't CHAD stage it right away, I am going to fly it on single motors at first. I'll wait til it loses a bit of the new car smell before I attempt a CHAD staged flight..

    Scott
     
  22. Oct 3, 2003 #22

    Fore Check

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    Pretty close!

    Try decreasing the number of fins to 3 and increasing the delay on your sustainer to an Estes E15-7. Sims to 4200 ft. with calibers of 1.28 and 1.41

    I think I'll build one and not bother painting it, knowing full well that I'll never see it again. It sure would be cool, though!
     
  23. Oct 4, 2003 #23

    teflonrocketry1

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    Attached is the updated RockSim5 file for the CUL8R
    I get 4300 ft AGL on that motor combination!

    If you put a beeper in it and use a long evough reflective streamer you might have a chance at getting it back.

    Bruce S. Levison, NAR #69055
     
  24. Oct 4, 2003 #24

    Fore Check

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    I wonder if the long skinny fins would survive an E staged flight.........
     
  25. Oct 16, 2003 #25

    flashgc

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    .... 'cheap and dangerous' which refers to the practice of staging without building any sophisticated interface fittings between the stages. Just thought you might like to know.
     
  26. Oct 16, 2003 #26

    powderburner

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    I believe 'CHAD' is an acronym for 'CHeap And Dirty'

    The dirty part is in reference to the sloppy design approach and less-than-minimal booster stage construction
     
  27. Oct 16, 2003 #27

    jflis

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    powderburner, you are correct on the origins of CHAD. It's been around since the 60's. There isn't anything *dangerous* about it. The assumption is that the person has verified stability befor launching, but then this is true of any scratch built. So I wouldn't say a CHAD staged rocket is any more dangerous than a scrtatch built model.

    As for the engine casing droping out of the sky, while this violates competition rules (see the Pink Book), it is not uncommon in sport model rocketry (see the Mosquito, Gyroc. Sprite, etc)

    jim
     
  28. Oct 18, 2003 #28

    flashgc

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    ... an yer right. It's no more dangerous than you let it be.
     

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