Flying over water? - Tips

Discussion in 'CineStar FAQ - Tips and Tricks' started by Chris Newman, May 2, 2013.

  1. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Ja, sure, you betcha. :)

    I'll be happy to test it for you -- I'll do it the day after I receive your Cinestar. ;)

    Andy.

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  2. Tyler Olson

    Tyler Olson Member

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    You could also plug the booms with cork or foam and leave a tight little hole for the wire to go through. It probably wouldn't be water tight but would certainly slow down the sinking... You might get 10 minutes to fetch your copter ... maybe??
     
  3. Tyler Olson

    Tyler Olson Member

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    Or... I like the ping pong ball idea quite a bit... if it was tied onto heavy fishing line you could use it to pull up your quad.

    Ping pong ball in a cup on top of the copter, perhaps closed with toilet paper. When it sinks, the paper disintegrates and the ball rises and is attached to the copter via heavy fishing line, which you can then pull up your copter with. Just don't let it fall out when flying or your rotors will get strangled.
     
  4. Casey Van Nyhuis

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    Hey,

    It's been a while for me as well but i just did the math for a cinestar 360 and i'm getting 7166cm3 which comes out to 15.795lbs (ish). My original math way back then was only for a cinestar 8 without a 360 gimbal. For volume of a cylinder it's pie r squared. Did you accidentally use the diameter the boom? Looks like you might have.

    I may be an idiot and missing something though ;)
     
  5. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Hi Casey:
    Nope -- you're not the idiot. I am. I did use the diameter. Sigh. That's what happens when you don't remember how to do something and just grab a calculator off the Internet. I'll edit the original posting to warn off people!

    A.
     
  6. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    OK. Now that Casey has shown me the error of my ways, let me try that again. Underscoring shows the different results

    My calculation goes like this:
    1. Internal diameter of booms: 2.32 cm and thus the radius is 1.16 cm.
    2. CS8 boom length = 50 cm
    3. Internal volume of one boom: 211.45 cc and change.
    4. Total internal volume of all booms: 1,691.6 cc.

    5. Gimbal booms: 20.0 cm side booms (x 2).
    6. Front transverse boom: 20.0 cm.
    7. Rear transverse boom : 21.0 cm.
    8. 3-Axis gimbal top boom : 20 cm (x 3).
    9. Thus total length of boom in gimbal = (20x2) + 20 + 21 + (20x3) = 141 cm.
    10. Total internal volume of all booms in gimbal: 596.29 cc.

    Grand total of internal volume of frameset booms and gimbal booms: 2,287.89 cc.

    Weight of 2,287.89 cc of distilled water: 2.28 Kg (5.04 pounds).
    If the water is not distilled water, it only gets better, depending on the dissolved salts.

    The calculators I used were:
    1. Volume of a cylinder: http://www.online-calculators.co.uk/volumetric/cylindervolume.php
    2. Google's built in calculator.
    3. Weight converter for water: http://www.csgnetwork.com/h2oweightconv.html

    Bottom line: Cap all the booms and make them waterproof and it will float only 5.04 pounds.

    Anybody see anything wrong with the above (and thanks Casey!) :)

    Andy.
     
  7. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Hmm. I'm still getting very different results from yours Casey....
    Can you lay out how you get to 7,166 cc?

    Andy.
     
  8. Steve Maller

    Steve Maller UAV Grief Counselor

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    5.04 pounds? Looks like I'll need a lot of pool noodles to make up the difference.
     
  9. Casey Van Nyhuis

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    Whoops! Yep, somehow i multiplied 211.45 by 8 and came up with 5306.....guess i needed to slow down a little bit with the button pushing on the calculator ;)

    2287 sounds close enough to me!

    Although my math also confirms if you fill all your booms with helium and cap them then it'll float 4 times more! Plus extended flight times!!! Problem solved guys!!!
     
  10. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Yeah...Helium. No problems with sparks near copters, eh? ;)
    By the way, as I recall you need around 430 liters of helium to lift one pound. Could make for an interesting design....

    Thanks for correcting your math -- you know how to get me worried, Casey! I think between the two us we have come to our sink/float answer: SINK!

    Just as well we figured it out now before I tested my theory on Gary's Cinestar, isn't it? ;)

    Andy.
     
  11. Casey Van Nyhuis

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    Haha hey every little bit when we're talking about flight times! ;) Bet it would make hitting power lines even MORE exciting!!

    But...i think Gary's cinestar would be a worthy sacrifice. It would be for science after all ;)
     
  12. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Oh...by the way. Helium doesn't burn! (At least not in the Earth's atmosphere and not unless you play molecular tricks on it.) I got my wires (or gases) crossed. Hydrogen bad. Helium good!

    Andy.
     
  13. Gary Haynes

    Gary Haynes Administrator
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    Casey no water nearby. But don't you live next to a pretty nice lake. Jaws anyone......
     
  14. Jose Luis Ocejo

    Jose Luis Ocejo Active Member

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  15. Steve Maller

    Steve Maller UAV Grief Counselor

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    "Anything under 2.2 pounds"? Nothing on my copter would float. :confused:
     
  16. Casey Van Nyhuis

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    ...for anyone mindless enough to watch the show "Archer" (like me! Season 1: Episode 7 if your feeling left out) they will know the irony of me forgetting helium isn't flammable. Guess i'm still missing the core concept haha. Andy i think as long as we are around to keep each other in check we can figure anything out ;)
    And yes although we're far from any oceans....we've still got plenty of water to park kopters in!
     
  17. Shane Moore

    Shane Moore Member

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    Sadly I can say from personal experience that eight standard sized pool noodles floated a Cinestar 8, a CS 2-axis mount and a GH2 in saltwater very nicely. The foam was cut to the length of the booms.

    I was wondering if it was enough flotation and in the terrible moment of pulling up to it in a boat I remember thinking "wow it's actually floating really high, I probably could have used the smaller pipe insulation." The whole rig was in the water for about one minute. We immediately rinsed it with fresh water several times and blew all of the water out with compressed air from a scuba tank. I still use the motors one year later and have about 800 flights on all but one of them. Amazingly, the battery was fine too and I just recently retired it. I ended up losing only the flight control, camera, servos and pots, so it was definitely worth it. It's very non-scientific, but now I use the pipe insulation or four pool noodles and hope I never need to report if it's enough flotation.

    Shane
     
  18. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    I'd love to see an image of the bird in "floatation collar mode!"

    And thanks for sharing the story on the forum. I think there are several folks who have had questions answered by what you wrote.

    Andy.
     
  19. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    It's a deal Casey -- after the great flight training you gave, it's the least I can do.

    I think we're both going to be needing to figure out the Synapse, Movi, and HL when they come on the market!

    Andy.
     
  20. Chris Newman

    Chris Newman Member

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    Thanks for sharing your experience Shane! I will do the pool noodle method. So you think 4 is enough for the cinestar?

    Also does anyone have any tips for launching and landing from a wake-boarding or fishing boat? Use a sheet of plywood as a launch pad? Any issues initializing the heli in choppy waters?
     

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