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High Powered Unicorn...perhaps too high powered

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High Powered Unicorn...perhaps too high powered

Old 06-19-2005, 10:27 AM
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cinntax
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Default High Powered Unicorn...perhaps too high powered

Hi everyone,
I got a unicorn core kit for christmas, and since have added the following components to it:

Mega 16/15/2 Motor (Wanted a 16/15/3, but I was antsy and the hobby shop was out of stock on the 3)

9 Cell GP2000 Battery pack

Phoenix 45 brushless speed control

APC 7x5 prop

On the unicorn's maiden flight, it flew very well with this setup. However, after about 5 minutes or so (80% 1/4 throttle, 20% WOT) my motor cut out. When I landed, I found out that 2 out of 3 of my motor wires had broken free, and the heat shrink was starting to melt off. Other than that, I didn't see any other damage. I soldered the wires back on, and all seems well.

I'd like to prevent this from happening again, so I was thinking i should prop down a bit. Does anyone have any suggestions for a prop?
I was thinking about using a 6x4.

Thanks!
-Dan
Old 06-21-2005, 02:43 PM
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edessa
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Default RE: High Powered Unicorn...perhaps too high powered

Use one gauge thicker wire and you should be fine.
Old 06-23-2005, 11:46 PM
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cinntax
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Default RE: High Powered Unicorn...perhaps too high powered

Do you mean on the motor side? The wires didn't seem to be hot at all, and there's still going to be the same size wire going into the motor. What I did do already was use silver solder when I reattached the wires. I don't know if CC used this solder, but that alone will help increase the tensile strength of the joint and raise the melting temp. I'm starting to wonder if the wires shook loose, rather than desoldered.

Thank you for your input!

-Dan
Old 06-25-2005, 06:15 PM
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777
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Default RE: High Powered Unicorn...perhaps too high powered

Have you tried to run those numbers through a motor calc program?

If I'm not mistaken, you'd be pulling way too many amps.

Brad
Old 06-27-2005, 06:06 PM
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cinntax
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Default RE: High Powered Unicorn...perhaps too high powered

No i haven't put them through motocalc, but I bet you're right about it being too many amps.
I'll try and prop down once I get my heatsink installed (thermo tape is really hard to find). I could also take some current measurements to at least see what I'm pulling when the plane isn't moving.

-Dan

Old 06-27-2005, 06:47 PM
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Default RE: High Powered Unicorn...perhaps too high powered

The amp draw is way to high for that set up.--You should use a mega 4 turn and the 7/5 apc.--The 2 turn will not evn work with a 6/4 prop.
It will pull 49 amps static on a 5.5 /4.5 apc on 10 cells.So you can imagine what it is dooin with the 7/5.The 3 turn is still tooo fast the wing wont even fly eficient at the speeds of the 2 or 3 turn.The 2 turn is a ducted fan motor any ways,and is not even close to a good choice to begin with.If you are gona pull 70 amps do it with a wing that will handle 163 mph like the Ritewingrc.com 50' lightning.
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