Y6 redundancy test (FAIL)

DaveyWaveyBunsenBurner October 31, 2011 at 2:43pm

All, i found thus interesting. Especially pos number 7:

http://www.rcgroups.com/forums/showthread.php?t=1378824

Happy halloween!

W. Thielicke October 17, 2011 at 12:55am

Hi,

I also have a Y6 with a thrust to lift ratio of about 2. When one of the upper propellers is missing, I can still fly almost without problems. But when one of the lower propellers is missing, I crash...

Successful hover with upper prop missing:

http://vimeo.com/20977475 @ 0:33s

And here, I lost one of the lower props, flying seems to be impossible:

https://www.youtube.com/watch?v=7P9tE61GWqI#t=2m03s

I was also a bit surprised, because I never lost a lower prop before...

Did you already try to stop one of the upper motors?

Allen Babb October 14, 2011 at 4:27pm

I'm thinking that control loop speed may be a problem... theoritically, what's the speed of the air coming out of the "pipe" for 2 prop's vs. just 1?

Jose Angel October 14, 2011 at 4:15pm

I can't reply under your message mike :(

Motor info is here.

MK3638 are Pulso 2814/20 840kv rewound to 22 and not 2814/22 re-badged

100KM

u4eake October 14, 2011 at 3:29pm

Try it with the copter in your hand (is your landinggear strong enough to hold it by the landinggear ?), that will be less destructive if you are carefull with throttle and you'll feel how the copter wants to compensate (or not). Take care not to let the props cut yourself though !

Jose Angel October 14, 2011 at 2:48pm

Thanks for the responses.

First, I mean MK3638 motors (2kg of thrust).

For hovering, each motor-pair needs to produce 2.3kg / 3 = 766 gr thrust. Maybe for lift you need a little more... but taking into account the motor is rated at 2kg maximum thrust my thought was one motor per arm would be enough to maintain a hover at least.

I have seen several videos of y6 motor failures without crashing

https://www.youtube.com/watch?v=pjM3sZz5zgE

http://www.rcgroups.com/forums/showthread.php?t=1362884

And some comments (1,2) from seismicwave, a reputated rcgroups user:

I didn't say there is no motor redundancy. I flew mine with both a KK blue board and a MultiWii board and both kept the Y6 flying when one motor went out.

My motor failure has to do with the bullet connectors and they were not gradual. The Y6 just dipped one arm momentarily and the controller board sped up the other motor to compensate. Both times I was only three to four feet off the ground and the controller reacted very quickly.

I have checked that arducopter 2.X y6 motor source code is identical to multiwii code....

So, my only hypothesis is that there are differences between a fail in the air and a fail while lifting.....

Moderator

Michael Pursifull October 14, 2011 at 2:17pm

On paper, traditional octo and sometimes hexa (depending on motor/prop hover thrust levels) are good candidates for recovery from a failure; I don't see the same good prospects for Y6, unless you specifically design it into the propulsion, and I do not see an efficient flight design for Y6 to achieve that redundancy... on paper, that is.

DaveyWaveyBunsenBurner October 14, 2011 at 2:12pm

Wrong

The one good motor on the arm of the failed motor needs to be able to handle the load.

The other four good motors are unafected and cannot lift that arm.

Thats a very different problem.

basshead October 14, 2011 at 2:03pm

That would be my bet, what % throttle do you hover at? The 5 remaining motors need to have enough power and throttle to cover for the 1 motor out.

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Y6 redundancy test (FAIL)

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