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Old Jul 02, 2012, 03:14 PM
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Originally Posted by MCrites View Post
Added weight = less efficient. Plain and simple.

The simplest way to be safe is to not fly near people. Also know your limits, both mechanical and skill.
Well, the thing that concerns me the most are run-aways and the copter injuring someone where it comes down at.
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Old Jul 02, 2012, 03:16 PM
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Originally Posted by jy0933 View Post
enhance it with some strong plastic ring... cut the ring from button of prot and implant it...
cf is the best.. but customization cost a lot..
I am sure there is a way. I am willing to carry more weight in the interest of safety.
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Old Jul 02, 2012, 03:17 PM
I never finish anyth
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Quote:
Originally Posted by rimshotcopter View Post
Well, the thing that concerns me the most are run-aways and the copter injuring someone where it comes down at.
At that point the props aren't as much of a concern, the 2-6lbs of mass falling from the sky is the problem.
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Old Jul 02, 2012, 03:19 PM
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Originally Posted by chaosdestro0 View Post
Actually in some areas of throttle, ducted fans can increase efficiency.
+1

Quote:
By reducing propeller blade tip losses, the ducted fan is more efficient in producing thrust than a conventional propeller, especially at low speed and high static thrust level (airships, hovercrafts). -wiki
the challenge is the the design of the duct.. you want the margin be small.. also the shape is the increase type ( look at the fig in wiki a bit down)
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Old Jul 02, 2012, 03:19 PM
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Because the thrust multicopters need is mostly static, the most efficient is the largest propeller you can fit!

An EDF reaches its efficiency at high speeds. And yes, a ducted fan is more efficient than a propeller at THE SAME DIAMETER. Since large diameter EDFs are very bulky, the way to go is a propeller.
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Old Jul 02, 2012, 03:19 PM
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I haven't actually heard of runaways on here for a while, I think software side has improved quite a bit.
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Old Jul 02, 2012, 03:22 PM
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Originally Posted by rimshotcopter View Post
I am sure there is a way. I am willing to carry more weight in the interest of safety.
go massive.. but there are just too many variants .... which ones do you choose? or we can design all of them..and get them by demand? I can help with design a bit


Quote:
Originally Posted by MCrites View Post
At that point the props aren't as much of a concern, the 2-6lbs of mass falling from the sky is the problem.
when it drops down..you can avoid the mass by running away... with prop on.. it runs randomly.... and prop cuts first before the mass hits you
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Old Jul 02, 2012, 03:23 PM
I never finish anyth
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Originally Posted by jy0933 View Post
when it drops down..you can avoid the mass by running away... with prop on.. it runs randomly.... and prop cuts first before the mass hits you
No. Run aways come down when batteries can no longer power the motors... props stop.
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Old Jul 02, 2012, 03:30 PM
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Originally Posted by MCrites View Post
No. Run aways come down when batteries can no longer power the motors... props stop.
that's pool skilled/monitored.... batt fail is another thing tho
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Old Jul 02, 2012, 03:55 PM
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Originally Posted by jy0933 View Post
the challenge is the the design of the duct.. you want the margin be small.. also the shape is the increase type ( look at the fig in wiki a bit down)
I am not understanding the meaning of tip losses, can you shade some light upon this please.

Thank you
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Old Jul 02, 2012, 04:11 PM
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I am going to do this and it fact, by doing this will make my Bicopter more attractive. Not saying I am looking for a match for it. Ha!
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Old Jul 02, 2012, 04:29 PM
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http://www.cybertechuav.com.au/-Overview,85-.html

CyberQuad VTOL UAV Demonstrating Urban Aerial Reconnaissance (2 min 38 sec)
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Old Jul 02, 2012, 04:32 PM
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I love it, awesome!!!
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Old Jul 02, 2012, 05:04 PM
James not bond
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@Juggsterbate
pretty stable... the duct is in fact the frame.... it might be a good direction to go for us


@rim
tip loss: at the tip... the air acts a circle alone the tip.. that amount of air instantly comes back to the top of the blade.. unable to contribute to thrust force... when a duct is applied (close margin... again) the air is forced to go downward to contribute the thrust


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Old Jul 03, 2012, 08:59 AM
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Gents,
They are extremely noisy so have a good stock of earplugs handy

From the Project Quads/Hexas/Octos: section in the Quadrocopter and Tricopter Info Mega Link Index

This was posted in 2007:
--Electric Ducted Fan (EDF) Quad: http://www.rcgroups.com/forums/showt...light=edf+vtol

Cheers,
Jim
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