Replies to This Discussion

Permalink Reply by Wessie on August 2, 2011 at 11:04am

Mine (A Hexa) is EXACTLY this on monday. Tracked the problem down to a bad connection in the cheap chinese deans that came pre-soldered from the factory.

 

new blades, and a decent deans connector fixed it!

 

Solo, looks like XT60 Connectors are going to be the way forward....

 

 

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Permalink Reply by Kristian on July 29, 2011 at 4:06am

Same thing happened to me, twice. The reason was aggressive flying, pulling stick to zero throttle and full left yaw, causing disarming of the controller in mid air. Very frustrating watching the thing fall from the sky, trying to arm it before it hits the ground.. :-)

 

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Permalink Reply by u4eake on July 29, 2011 at 4:42am

Set dual rates on rudder, so that you have 100% and 90% rudder. When flying switch to 90% rudder so that you cannot disarm motors. Granted, you'll have slightly less rudder control but I think that's a small price to pay for not crashing due to disarmed motors. Furthermore you might be able to compensate for the 90% rudder by increasing yaw P value.

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Permalink Reply by Kristian on July 29, 2011 at 7:53am

Thanks. I've been thinking about doing it this way too, I was just too lazy to set it up.

Both times this happened, the quadcopter actually starts autorotating on the way down, causing minimum damage. Very surprising because the height was about 150feet+. After falling 50 feet or so, the propellers start to spin from the air flow and the quad levels by itself. Sounds like this ....ssssshhhhhwoooooeeeeiiiiiBUMP. With a lot of "NO! NO! NO!" from me at the ground. Fascinating sport! :-)

 

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Permalink Reply by Chase Hall on August 2, 2011 at 7:10am

I read this whole thread just to see if autorotation was mentioned.

 

I love since quads are fixed pitched collective they auto-autorotate. I hypothosise that at a certian altitude the quad can be turned completely off a make a free fall to a soft "normal" landing.

 

I just haven't had too many volunteers for testing.

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Permalink Reply by Kristian on August 2, 2011 at 7:39am

Yes, it works. But on a helicopter you would change the pitch of the blade just before hitting the ground, to slow down further. On a fixed pitch quad this is not possible, so the speed is still high on impact. I bent a couple of arms and broke a landing leg both times, but it was up and running again after 15minutes. The prop size is probably also important. I use 11x4.7, smalle props will probably mean more speed.

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Permalink Reply by mc_don on July 29, 2011 at 4:59am

have you check your remote?

in my JR when fail safe active, same time trotle is loss.

so, now i set my all chanel to hold mode in failsafe setting.

hope can help your problem

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Permalink Reply by Kristian on July 29, 2011 at 7:55am

You really should think about setting throttle to a little less than hover, so your quad makes a slow decent instead of flying away.

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Permalink Reply by Hyon Lim on July 29, 2011 at 8:21pm

That's possible. Thanks!

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DeveloperPermalink Reply by Olivier ADLER on July 30, 2011 at 6:54am

 

Jason, this gives me an idea. On the AVR chips it is possible to detect the cause of a reboot condition.

 

Would it be possible to implement a fast reboot, checking for the brownout detector reboot flag ?

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Permalink Reply by Owen Booth on August 4, 2011 at 1:38am

I just had the same thing happen on mine too, still unsure of reason. Broke three legs (custom units), probably from around 100ft.

modified Quad kit, with 5000mAh battery, 10x45 props, 2.0.38 firmware,

Attachments:

• UAVCrash.mpg, 6.3 MB

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Permalink Reply by Todd Hill on August 4, 2011 at 3:40pm

Sounds like a brown out.  Just Curious, but does the Arducopter power distribution board utilize all of the BECs' from the ESCs', or does it just use one?  I have been making my own PDB for my multirotors with a customized PCB board.  I have been plugging my servo connectors from the ESCs' directly to the APM.  Since using this method I haven't had any brownouts like I was having in the beginning.  My APM gets anywhere from 8-12 amps if it needs it.  

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