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Jul 07, 2013, 06:48 PM
Registered User
"BillBlair"

Noob or not, now, as a result of this thread, you know what the hazards are. And as a result, I doubt you will ever "get bitten". Your careful assesment and quest for knowedge is indicative of a methodical, studied, approach. It's this mindset that makes it safe to persue these unique aircraft. And, as far as "jesolins" spectacular effort, don't just subscribe, riffle through the 30 odd pages of stuff he has typed up over the past few, print it out, and read it, you'll be so far ahead of the noobs, you'll be an expert right out of the gate. It's a virtual bible of the dos and don'ts of multis.
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Jul 08, 2013, 02:24 PM
Foam Wrecker
BillBlair's Avatar
Quote:
Originally Posted by Electro 2
And, as far as "jesolins" spectacular effort, don't just subscribe, riffle through the 30 odd pages of stuff he has typed up over the past few, print it out, and read it, you'll be so far ahead of the noobs, you'll be an expert right out of the gate.
Thanks, I will definitely read it. Reading as much as I can on a subject is what I always do, in most cases simply to find out what parts to buy and what mods to make, but in this case more than others in order to avoid getting hurt.
Jul 23, 2013, 09:20 PM
Registered User

My Injury


Check out my one guys. I was holding it when it went off. Lucky my arm headed perfect.
Jul 24, 2013, 10:25 AM
Forever WTTM Pilot #7
Buzz's Avatar
Quote:
Originally Posted by raddavo
Check out my one guys. I was holding it when it went off. Lucky my arm headed perfect.
Nasty cuts! What do you mean you were "holding it when it went off". What caused it to do that?
Jul 24, 2013, 11:33 AM
Tri-Quad-Hexa-Octo-copters!!
Gents,
Please read and heed!:
Safety dulling props 101
Consider that a safety backup plan in the event of senior moment failures of appropriately removing props, tying it down, and throwing a towel on an uncontrolled multicopter.
Cheers,
Jim
Quadrocopter and Tricopter Info Mega Link Index
Last edited by jesolins; Jul 24, 2013 at 06:21 PM.
Jul 24, 2013, 01:20 PM
Forever WTTM Pilot #7
Buzz's Avatar
We need foam rubber props!
Jul 24, 2013, 01:59 PM
Registered User
Today I wanted to see if reinstalling the Dji Naza 3.12 fw might fix a bug. The Assistant program admonished me to disconnect the motors or remove the props. The props were already off.

The upgrade began and at one point the motors came to life seemingly at full throttle. It startled me. They shut off after 5 seconds. I now seem to remember the same thing happening the first time I upgraded. Also without props, fortunately.

It was a reminder to never forget how dangerous these craft can be.
Last edited by RobertsUp; Jul 25, 2013 at 12:15 AM.
Jul 24, 2013, 02:25 PM
Mmmmmmm!
WiseDuck's Avatar
That's why I put a towel over all the props/motors when I updated my Phantom with props on the other day. I've seen it happen on my hexacopter. One motor twitched during a firmware update. I won't let it do that again.
Jul 24, 2013, 04:58 PM
Registered User
If the props had been on during the upgrade, the craft would have shot up like a bullet. It would have taken my face off. What might have happened still scares me.

I've read about putting towels over the props. My LiPo connectors are XT60's and they're very snug and hard to pull apart. I noticed that I have to put my arms in the path of the blades for me to get enough leverage to disconnect the battery.

I'm going to take towels with me from now on.
Last edited by RobertsUp; Jul 25, 2013 at 12:33 AM.
Jul 24, 2013, 05:57 PM
http://youtube.com/c/Fastgixxe
Fastgixxerlv's Avatar
Quote:
Originally Posted by raddavo
Check out my one guys. I was holding it when it went off. Lucky my arm headed perfect.

Wow!
Funny (0 min 17 sec)
Jul 24, 2013, 07:02 PM
Registered User
Quote:
Originally Posted by jesolins
Gents,
Please read and heed!:
Safety dulling props 101
Consider that a safety backup plan in the event of senior moment failures of appropriately removing props, tying it down, and throwing a towel on an uncontrolled multicopter.
Cheers,
Jim
Quadrocopter and Tricopter Info Mega Link Index
Nice idea, but I really cannot see how dulling the propellers will change anything with the motors rotating at around 10000 rpm, it will still mangle any piece of human that gets in its way..
Jul 24, 2013, 08:53 PM
Tri-Quad-Hexa-Octo-copters!!
A,
It is about the same difference as being whacked by either a stick or a knife. Ask me how I know this
For most multicopters, it is actually closer to 5-6K RPM at full throttle.
Dull the props. Remove sharp edges to improve last chance safety.
Fly safe!
Cheers,
Jim
Quadrocopter and Tricopter Info Mega Link Index
Quote:
Originally Posted by Alekoy
Nice idea, but I really cannot see how dulling the propellers will change anything with the motors rotating at around 10000 rpm, it will still mangle any piece of human that gets in its way..
Jul 25, 2013, 02:03 AM
Mark Harrison
Quote:
Originally Posted by jesolins
A,
It is about the same difference as being whacked by either a stick or a knife. Ask me how I know this
For most multicopters, it is actually closer to 5-6K RPM at full throttle.
Dull the props. Remove sharp edges to improve last chance safety.
Fly safe!
Cheers,
Jim
Quadrocopter and Tricopter Info Mega Link Index
Has anybody ever done some tests on this? I've thought about a Mythbuster's style test on a pork shoulder with the skin still attached.
Jul 25, 2013, 06:13 AM
Tri-Quad-Hexa-Octo-copters!!
Hi M,
I've ops tested it accidentally a few times over the last 10 years of building and flying multicopters and the results are no slices and only whacks and a bruise. The flashing on the edges of most new props is like a razor blade and unnecessarily dangerous. Again dulling the prop edges and rounding the tips for safety is the difference between getting whacked with a knife or a stick...It takes a couple of minutes to do this and then balance them. Besides being common sense, both are multicopter best practices. Feel free to test it on some pork
Cheers,
Jim
Quadrocopter and Tricopter Info Mega Link Index
Quote:
Originally Posted by marhar
Has anybody ever done some tests on this? I've thought about a Mythbuster's style test on a pork shoulder with the skin still attached.
Jul 25, 2013, 09:48 AM
Registered User
Quote:
Originally Posted by jesolins
The flashing on the edges of most new props...
Even when I was brand new to flying I removed the flash just because I knew it was a molding 'residue' effect and shouldn't be there. I also knew that when I bonked it it would bend/deform/break off anyway.

At first I was in the habit of using the back side of a hobby knife to scrape the edge all around, because I my best intuitive guess was that a sharp leading edge was the best way to leave it, which worked fine.

Until I heard the story as related below, after which I got into sanding the edge all around with 'worn out' 220 sandpaper.

Folks may be wondering about efficiency as regards messing with leading edges. This story was related to me by a an aero-guru, about a test that another guru friend of his did.

The friend wanted to test the effects of different -shape- leading edges, and a few other aspects of prop surfaces as related to efficiency. He made props (this was in the days before prefab commercial props) with round, knife edge, and even square/flat leading edges. He found that there was essentially no variation in efficiency. The shape of trailing edges had a slight effect, but mostly only as related to stall characteristics.

The most important thing he found was that efficiency was -most- effected- by the smoothness of the -top- -surface- area of the prop. Roughed up or nicked/gouged top surfaces drastically degraded efficiency.

Bottom line being that since it doesn't hurt anything and can help in the event of an accident, then yes by all means round off the leading edges and tips.


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