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Old Feb 22, 2012, 05:52 PM
Registered User
United States, MA, Sturbridge
Joined Jun 2008
1,002 Posts
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Random power loss - HawkSky

Dynam Hawksky
Stock Brushless outrunner motor / ESC
2200mah
72mhz Esky 4chan TX/RX
Esky gyro on aerolons

So flying today in very high winds the motor on my hawk sky would cut out of like a second or less. sometimes slightly longer. Controls also seemed to cut out also.

At one point I lost complete control engine died no controls and it hit the ground and I could hear the ESC restarting once it was on the ground.

any ideas?
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Old Feb 22, 2012, 06:44 PM
An Ordinary User
United States, VA, Fluvanna
Joined Jan 2011
1,177 Posts
This sounds like a power loss to the reciever. Could be brownout or a loose connector on the battery. I'm guessing your battery and ESC came with the red 4mm banana plug. These are pretty sturdy but it's possible a solder joint has gone bad. Wiggle the battery wires and ESC battery wires around to see if it does the same thing on the bench.

A brownout will have very similar symptoms (electrical outage, receiver rebooting). The Rx might have a signal that something went wrong such as a blinking LED. My Spektrum receivers have a LED which is solid under normal conditions and blinks to indicate a loss of signal. A good test of this is to turn on Tx and then plug your battery into your plane. Then disconnect the battery and reconnect it again. If the Rx is blinking it indicates that the Rx was restarted but the Tx wasn't.

The fact that the Rx rebooted when it hit the ground makes a case for a bad battery connection, but if it hit hard enough it may have broken the battery connection due to the impact alone.

SB
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Last edited by GooberSB; Feb 22, 2012 at 06:45 PM. Reason: brownout and battery disconnect both cause a blinking led
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Old Feb 22, 2012, 07:21 PM
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United States, MA, Sturbridge
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Is it possible a bad ESC would cause total power failure?
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Old Feb 22, 2012, 11:27 PM
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I think you were right about the plug. It appears I was not plugging the plug in completely. My mistake! If you want to see video of me flying and crashing it should be done uploading soon
Hawksky flight in wind with crashes (6 min 40 sec)
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Old Feb 23, 2012, 09:27 AM
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seattle, wa
Joined May 2008
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I lost my GWS Corsair twice to similar symptoms. I swore up and down it was a Rx issue and even sent the Rx to Horizon for evaluation. They were like " yer Rx is fine but here's a new one anyway." So I tracked the problem down to a bad Deans plug. Sure miss that Corsair...
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Old Feb 23, 2012, 07:49 PM
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Quote:
Originally Posted by shafferama View Post
I lost my GWS Corsair twice to similar symptoms. I swore up and down it was a Rx issue and even sent the Rx to Horizon for evaluation. They were like " yer Rx is fine but here's a new one anyway." So I tracked the problem down to a bad Deans plug. Sure miss that Corsair...
Yeah you can see in the video the thing loses all power at the end of the flight.
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Old Feb 23, 2012, 08:37 PM
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Great video for forensic purposes.

I watched the crashes several times and here's what I could tell from the video. The audio is very good and you can hear the servos twitch right after the motor cuts off. I get this exact same thing when I don't make a good JST connector on my 2S lipos. The receiver reboots due to low (or no) voltage and the servos twitch. The throttle is momentarily disabled as it boots (so you are basicly flying without a battery for a few seconds) and the ESC arms right after it hits the ground. That's easy enough to fix - I think you already figured it out.

There are other interesting pieces of audio that I noticed. As you are flying along, I clearly hear the motor cut off for half a second or so at random times. But these happen faster than the receiver can reboot so it's a completely different issue. It sounds like you also have a bad connection to your motor. Lots of things could cause this, but lucky for you, one of them is a bad battery connection. Maybe the connection is vibrating and every so often the connection isn't so good and the voltage drops. When the voltage drops, the ESC "misfires". Then it vibrates back into a good connection and the motor picks up again. This could happen and not cause the receiver to reboot.

Secure your battery, wiggle the battery/esc wires around on the bench (no throttle needed)and see if it reboots. If it does, redo your connectors. Hopefully when you stop the power loss to the receiver, you'll stop the motor cutoff as well.

SB
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