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PARACHUTE anyone ?

Posted by ARHEXA on March 27, 2011 at 7:50am

3689396321?profile=originalMaybe someone has encountered a small scale parachute ?

I'd like to add a safety parachute to the Arducopter !! help me decide....

 

 

As part of the project is to use an expensive DSLR on the copter,

My GF said i must have some kind of emergency parachute... after joking at it, i thought deeper -

I'd rather feel much safer having a parachute as backup to all electronics (even though i plan on 6 or 8 motors)

 

Just imagine an emergency button that will immediately turn off all motors and shoot a parachute.

 

questions:

as parachute takes some time to open (=some free fall height), the benefits are sure and obvious for a 100m fall.

but if i'm around 5m above ground, (which can still be nasty to the DSLR) - would i have enough "falling time" to open the parachute and having enough braking force ?

 

think i better make one by myself ? is it rather simple as cutting and connecting wires to a cloth,

or it is more complex design that i could hardly achieve and i better get a ready one ?

 

i came across this as the only parachute i could find:

http://cgi.ebay.com/NEW-40-SPEED-RUNNING-POWER-CHUTE-training-parachute-/220760637799?pt=LH_DefaultDomain_0&hash=item33665c0167

 

It looks sturdy and well balanced & stuff... it's totally affordable !

they say the 40" version has 7KG resistance. i'm safe on this side, i dont want a much bigger one.

 

how about the opening technique ?

i could stuff it in a small plastic tube attached to the top of the dome, using a small solenoid or servo to kick it out...

how do i ensure it opens reliably ? i guess it depends on the folding inside the storage tube...

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Comments

  • ip9 March 28, 2011 at 10:56am
    @Zak - slight off-topic, but they do have an airframe is thats something you've been looking for

    http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=...
  • Developer
    Mark Colwell March 28, 2011 at 8:49am
    I am re-purposing a large 50" Golf type umbrella $2 from Bargain  Mart. It has 8 panels, 3 red, 2 white and 3 blue, weighs 74 grams bare . It's now off the frame waiting for sewing on 8 lines, I was planning on using mason's nylon line, but it might be to much, maybe 30# sailplane tow line.  I will use a spring to eject chute upward, chute will have a coiled 1 mm fiberglass rod sewed in that will spring open right after ejection. I don't know how /when it will be triggered yet.
  • ARHEXA March 28, 2011 at 8:25am
    or fatal to a DSLR ;)
  • ARHEXA March 28, 2011 at 8:20am

    but do we realy need parachutes ;)

    YES.

     

  • ARHEXA March 28, 2011 at 5:59am

    @Martin-

    right, but then i have to add 4 small relays (or 2 double pole) to switch the signal off the APM.

    i've seen a warning somewhere to NEVER disconnect an ESC from the APM while running. (that could damage APM)

    I really prefer the electronics disconnecting option...

    i guess i will have to experiment what happens to the ESC in that case...

  • ARHEXA March 28, 2011 at 5:55am

    I think of getting this one.

    http://cgi.ebay.com/48-Red-Model-Rocket-Parachute-Quality-Rip-Stop-...

     

    the description says 'slow descend' for 1.5kg and moderate speed descend with ~2kg...

    my copter will be more than 2kg, so i think there's no chance i'll try some smaller than 48"....

    on the same hand, i hope 48" will be enough...

  • Moderator
    Gary Mortimer March 28, 2011 at 5:39am
    Springs work as well

    http://vimeo.com/8904576
  • ARHEXA March 28, 2011 at 5:36am

    for sending 0% throttle i have to use the copter code, and at the moment of truth i rely on the electronics.

    if the quad fails because of the electronics, i cant use the software to turn off the motors...

    i must have an aggressive and simple way to switch to emergency state, like disconnecting the motors or the APM

  • ARHEXA March 28, 2011 at 5:29am

    Here i found a successful one, @ 0:40

    https://www.youtube.com/watch?v=NbQryfscr-U

  • ARHEXA March 28, 2011 at 5:24am

    exactly,

    this video is exactly the opposite of any common sense design...

     

    now to some experienced user question -

    If i disconnect the power of the APM/IMU/TX all together off the BEC, in the middle of a flight while motors running,

    but the ESC's are still connected to the battery - what will happen ?

    (in other words what happen when you unplug an ESC signal cable while running)

     

    hopefully this will stop the motors, that way i can put a relay to disconnect the 5v electronics, rather than having to use a very high amperage relay to disconnect ESC's off the LIPO....

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