belem
Squadron leader
Posts: 210
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Post by belem on Sept 13, 2009 5:08:26 GMT 1
So I switched my cub over to 2.4g and added ailerons. Everything was going well....until I lost signal. Not sure what happened, if it was a TX/RX problem or a bad solder. Anyway, she went she went down. Caved in the firewall, snapped the fuse. Picked up a new fuse and cowl this am and back in the air tonight.  Renewed  |
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Post by flydiver on Sept 13, 2009 6:28:06 GMT 1
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belem
Squadron leader
Posts: 210
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Post by belem on Sept 13, 2009 6:36:36 GMT 1
Thanks, that actually makes me feel better. I was worried that it was a problem with the TX as I had some trouble with it before.
So the solution is running a ubec?
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Post by flydiver on Sept 13, 2009 7:21:21 GMT 1
Did you meet the criteria > 3S + 4 (cheap) servos?
Maybe a lipo that wasn't so great (old, low C-rating)?
If so, then you probably had brown out and a UBEC is the answer for that problem.
A bad solder joint or a poor connection could do this also, a crummy/cheap/under spec ESC are other possible culprits. Some folks get the GWS 480li ESC. Looks good on paper, it's not. Tower Pro ESC-ugh. Mystery ESC-don't get me started.
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Post by ginginho on Sept 13, 2009 11:38:57 GMT 1
If available locally to you, I'd recommend a HobbyWing ESC. I have 4 in various installations, all working faultlessly. The 40A version is capable of driving 4 servo without the need for a UBEC (it has a 3A switched BEC).
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Post by flydiver on Sept 13, 2009 16:14:11 GMT 1
There are some new ESC coming out that have 3A SWITCHING BEC built in (usually 40A or larger) compared to the LINEAR BEC that bring the voltage down by making heat. These are more efficient.
FWIW MOST UBEC are switching type. If you find a linear one, keep looking.
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belem
Squadron leader
Posts: 210
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Post by belem on Sept 13, 2009 19:37:48 GMT 1
Yeah, I have 4 of the Hextronic 9gm servos and a 3s lipo. My esc is a cheapo brushed esc because I didn't upgrade to brushless. It's a 30A esc, but the BEC is only 5v/1a.
To change esc I'd need to upgrade the motor too and I was content with the original motor. If I could just add a ubec that would be ideal.
As for the cause- one of my battery wires was disconnected when I found the plane. I could have happened in the crash...or when I was doing loops. But I think I might have been playing around with with using rudder and ailerons together to turn when I lost power. I'll try to brown it out today to see.
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Post by flydiver on Sept 13, 2009 20:02:37 GMT 1
1A BEC with 4 Hextronics is WAY too small.
The Cub can handle a fair amount of weight so an option would be to get a small RX battery and just plug it into the RX. That's what the nitro guys, the glider guys and the larger electric guys do.
A small 5-cell nixx gets you 6v to the servos. That's what that [battery] connector on the RX is for.
RE-disconnected battery. Postmortems can be kind of tough. I had 2 of these kind of failures before I figured it out.
Makes me wonder how the guys puzzle out real plane crashes.
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