rocket sled build question

Discussion in 'The Watering Hole' started by mbecks, Jan 13, 2016.

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  1. Jan 13, 2016 #1

    mbecks

    mbecks

    mbecks

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    Hello, Id like to build a rocket sled again and one that doesn't require a guide as the end result. I want to do it safely though. My question is does anyone know of a way to test my sleds before going unguided to have a better idea if they will in fact go strait and not airborne. I understand people don't like this idea and your concerns are noted.
     
  2. Jan 13, 2016 #2

    KidRockET

    KidRockET

    KidRockET

    Epstein didn't kill himself

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    Micromeister is the resident...

    Expert on all rocketry matters...

    A close second is gassaway...

    If you pm them, they probably...

    Will send you plans from...

    Their sooper secret underground bunker...
     
  3. Jan 13, 2016 #3

    mkadams001

    mkadams001

    mkadams001

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    Since you have already pissed of Micromeister I doubt that you will get much help.

    Otherwise, build a wind tunnel and test in that.

    Or, make the guide so sloppy that you would be able to tell if it is stable before it interacts with the guide.

    Or, don a hard hat, safety glasses, face shield, hearing protection, steel toe boots, maybe some welding chaps, Lexan shields, head out to the middle of nowhere and build a bunker, disable all video equipment and test what you have. Do not share any information of what you are doing with this forum. Or you could request a special locked thread that will keep out the safety police. Then, you could share with those of us who won't tear you a new one because you are using a rocket motor as a form of propulsion for a sled. (this paragraph was in fun for those who cannot tell if I am being serious or not)


    BTW, I like what you have been doing. I find it refreshing to see someone build from stuff they have around the house and make fly.
     
  4. Jan 13, 2016 #4

    mbecks

    mbecks

    mbecks

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    Thanks for enjoying what I do, Ill have some new videos up soon. I'm trying to work on my production value but I'm very new to video editing and posting so your seeing the work in progress.
     
  5. Jan 13, 2016 #5

    H_Rocket

    H_Rocket

    H_Rocket

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    But if he actually tries it someone will see and it will inevitably result in the federales banning rocketry everywhere, it may well finish off space travel as nothing will ever be allowed to have a rocket motor again.


    All hail the safety code!

    (And yes following safety guidelines is important. It's just that the MPR/HPR safety codes do not necessarily apply in every instance where a model rocket motor is involved.)
     
  6. Jan 14, 2016 #6

    mbecks

    mbecks

    mbecks

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    I guess ill be pioneering this because it does seem to be a common thing.
     
  7. Jan 14, 2016 #7

    H_Rocket

    H_Rocket

    H_Rocket

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    Has it occurred that there has never been (to my knowledge) a rocket sled that did not have some sort of guidance?
     
  8. Jan 14, 2016 #8

    TRFfan

    TRFfan

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    Maybe put large, reverse airfoiled "wings" on the side of the sled so that enough downward force would be generated to keep the sled on the ground?
     
  9. Jan 14, 2016 #9

    mbecks

    mbecks

    mbecks

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    It has been done...remarkable...haha watch the video you will get it.


    Not all are successful here but this looks like just a good time.
     
    Last edited: Jan 14, 2016
  10. Jan 14, 2016 #10

    MCriscione

    MCriscione

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    As has been mentioned repeatedly, pursuing this activity is most assuredly not a risk-free activity, and it could potentially reflect poorly on the hobby and enthusiast community as a whole. However, in the interest of pursuing this line of though in a relatively safe manner I've decided to post the following.

    The idea of a 'sloppy' tether seems like a reasonable one to me. Something that is an effective 'hard' tether but allows for some significant play along the length of the run. I can envision a type of tether system that has a significant amount of slack or excess length taken up by a very low tension. This type of system would appear at first glance as a normal guide wire, with a direct path between two points, but one of those points would allow for additional line to be released, extending the tether should the sled track away from the direct path. The overall tether length would have to be restricted with a hard stop, keeping the sled within a restricted volume and thus safe (so long as no one is inside that volume) but allow for freedom of movement beyond the direct point-to-point path between the terminal points. An adjustable friction fitting at one end, for instance, a fishing rod reel with adjustable tensioner, might provide exactly this type of 'sloppy play'.
     
  11. Jan 14, 2016 #11

    bill_s

    bill_s

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    To some extent, you might be able to find a way to use Open Rocket to simulate your "flight" ... or even RASP, use zero weight to simulate air drag without lifting. I was thinking originally this could estimate the space required.

    One thing good about the sleds is it's easier to find a suitably large, private space to do it. Drag cars on, say, a driveway would definitely need a guide line.

    For a launch guide, it might work to use something like 2 pieces of wood, one on each side, rather than a rod. The sled would need to be long and skinny and not something that produces friction. To get it moving in a predictable direction at least. And don't stand/sit directly behind the rocket, nozzle ejection has happened. Use more wire too.
     
  12. Jan 14, 2016 #12

    mbecks

    mbecks

    mbecks

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    Thanks for the ideas. I was thinking about the slack line idea, I like it because I could get an idea of if it would have flown off in some direction but the line would stop it from going to far. I got to figure out how to stop the line from getting bunched up in front of the rockets guide tube first. Another idea I have is a line that is about 4 feet up then a rope on a tube that attaches to the rocket. that ways its completely free to move unless it goes crazy.
     
  13. Jan 14, 2016 #13

    Charles_McG

    Charles_McG

    Charles_McG

    Ciderwright

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    Wire hoops and thin mil sheeting, or netting. Like grape vine bird netting. (Which comes in long rolls).
    If she stays on the ground and straight, no interference. If she lifts, flies and tumbles, she gets netted.
     

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