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Old Dec 07, 2012, 10:07 AM
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Portugal, Lisbon, Cascais
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Discussion
SECURITY / Risks / Laws / etc...

Hi, I'm starting this threads to put together our concerns about all those topics...

But today, my first concern is...
I would need to fly in a urban area and, there is a certain range on the floor that is completely secure away from public and cars.

My question and idea, maybe a very dumb one this is why I'm asking and won't do it if you guys think it is stupid to do it, would be to put a light metal cable secured by a crew member with the range safety...? so if something goes wrong with can avoid the mutlirotor to run away and hurt somebody.

Question is how the multirotor (in my case a WKM - DJI) would handle / behave once we pull the cable? will it fall? will it get crazy? I thing not if GPS is off...

Any thoughts?

thank you.
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Old Dec 07, 2012, 10:22 AM
I never finish anyth
United States, TX, Houston
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The issue with connecting a rope/cable to the bottom of a multi is weight. As you climb you are adding more and more weight, eventually you will overload the multi and make it more dangerous than it was before.

To the question about pulling it, look at the Naza-GPS videos online. People put it in GPS and then grab it by hand and walk it away... the Naza fights them and then eventually returns to the same space. In GPS mode it would fight you to get back to the same spot... in ATTI mode it will fight you to get to the same altitude. If something goes wrong typically it will start falling, if you yank an cable it might change it's course but not by much. That is assuming you can pull it, if it falls 5ft and you haven't pulled (it will happen in 1second) then you have 5ft of slack to overcome before you make the multi move.

Worried about a fly away? How often does that really happen? I think you are making the mutil way more dangerous with the extra weight for something that has less than a 1% chance of happening.
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Old Dec 07, 2012, 10:35 AM
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I understand your comments and thank you for replying, but I've seen mutlirotors going away for several reasons, several times. So the cable would prevent this. I prefer a fall and crash than a multirotor of 8kgs running away and hurt somebody. Not a risk I want to take. About the weight, I would assume that the total weight of the rope is possible to be add as a payload.
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Old Dec 07, 2012, 10:36 AM
Manual will not flyaway :D
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Ask this guy!

RC QUADCOPTER Pulls Kid on LONGBOARD (1 min 27 sec)
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Old Dec 07, 2012, 10:39 AM
I never finish anyth
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Yeah I too have heard about fly aways a lot on the forums. You need to realize that when bad things happen they are almost always posted here. If every successful flight was posted you'd NEVER notice the fly aways. I would guess there is maybe 1 flyaway in every 5000 successful flights and they are often cause by user error.
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Old Dec 07, 2012, 10:46 AM
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Humans error is 60% the root causes of crashes I'm human, anything can happen even when everything seems well controlled . I think I will try it on the Naza first...
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Old Dec 07, 2012, 01:56 PM
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So I made a test, I went to a fishing store bought a cheap set, but a strong line - 50 Kg's for about 50 meters, and an extra weight to hang under the multirotor...

The first attempt in ATT crashed :P and I forgot to record... but I think it happen because I wasn't expected the reaction, it start to drift a lot and I didn't try to correct anything.

Changed the broken propeller and back in action... in ATT if you correct it while it start to drift, it is OK, but while in GPS it’s even better... more easy to control.

Video:
Safety cable test DJI Naza (2 min 39 sec)


one thing for sure, when it crashed, it crashed at the cable maximum range... so it is not easy to handle, but could safe someone.

Anyway, I’ve refused the job due safety reasons.
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Old Dec 07, 2012, 02:01 PM
I never finish anyth
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You can't fly with it at the end of the cable, it needs a touch of slack. The FCC can understand weight, it can't understand being tied down.

Good on you for making safety a priority over money, it's hard to do but worth it in the long run. Your customer will respect that you are looking out for his best interests.
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Old Dec 07, 2012, 02:05 PM
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Yeah, the cable should be lose all the time, but we don't see it, and if in color it can be bad for the editing.... so I'm already working on another idea let's see if someone else come with an idea.
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Old Dec 07, 2012, 02:33 PM
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Don't forget about wind. If the cable is long it will drag quite a bit. Also be careful not to get the cable tangled in something...
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Old Dec 07, 2012, 03:03 PM
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Maybe a kill switch with a totally separate radio to control it could be a solution. The Switch could be a servo pulling out the power connector.
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Old Dec 07, 2012, 03:49 PM
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hmmm this will be a kill for sure, while with the cable you might eventually control back and land...

I was thinking in solution with a rolling cable full of small weights... enought for the cable to stay down...
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Old Dec 07, 2012, 05:50 PM
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As has been said before - big respect for making safety the major concern. I see too many vids that would end in tears if a motor died and the craft came down unexpectedly.
As for the fly-away danger (or damaged craft thrashing around on the ground etc) I have set my Rx failsafe as a kill switch. Kill the transmitter and throttle goes straight to zero, AH and PH are turned off (if I could think of a way to kill main power without sacrificing a channel I'd do that too). This may be a bit drastic, but I don't do long range or fpv and if the RC link goes down something bad has happened and I want the flying chain-saw decked ASAP.

Just my paranoia talking

Charles
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Old Dec 07, 2012, 07:01 PM
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Why not attach a parachute or weather balloon? Seems simple enough.
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Old Dec 07, 2012, 07:10 PM
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Quote:
Originally Posted by voidunknown View Post
Why not attach a parachute or weather balloon? Seems simple enough.
This guy did it:
parachute recovery system - RC helicopter - heli view (0 min 41 sec)


Model rocketry guys do it (I used to be one).

Also look at this:







Granted, these are not multicopters, but if you really want to you can make it work.
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