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It caught on fire???!!!!!

Old 02-29-2008, 08:22 AM
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pywackit
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Default It caught on fire???!!!!!

Hey Guys, On my third flight of my Cermark DragonFly it caught on fire! I really say flight since I couldn't get it much higher the 5' off the ground before it would start going down but anyway after the third attempt I picked it up and the darn thing started smoking really bad and melted the wires to my Lipo and totally melted the speed controler! The canopy is wasted but other then that I don't think very highly about this plane. I can always get another canopy and electronics but why would this happen? This electric glider seemed under powered right from the start.
Old 02-29-2008, 08:50 AM
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Default RE: It caught on fire???!!!!!

Need lots more information to help prevent a repeat with new parts.

Wing span and weight of plane. Wing area if you can get it from the box or booklet.

Engine make & model ...KV if known. Prop diameter & pitch......Battery make, number of cells or volts, and the amount of amps it was rated at.......
ESC , make model, max amps & volts it was rated for.

With most of that posted we could really help you on the next setup.

Rich


Did you have to modify any parts to finish the plane ? What ?
Old 02-29-2008, 12:56 PM
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pywackit
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Default RE: It caught on fire???!!!!!

Well, I did some checking and called Cermark and they told me you can't have a Lipo battery with a non brushless motor and matching speed control. So I ordered the new upgraded brushless motor and matching speed control plus the new canopy.

I'm calling this lesson number one! LOL!!!
Old 02-29-2008, 01:56 PM
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Default RE: It caught on fire???!!!!!



LIPO can be used with anything. Period.

Brush....brushless......nitro......gasoline....... diesel......rubberbands. ANYTHING.

Hold off on ordering the second set so quickly from the same place. He is wrong.

Some others should verify this.

Rich
Old 02-29-2008, 04:25 PM
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Default RE: It caught on fire???!!!!!

Ditto what cyclops said. More info is needed. And a lipo can be used with any type motor, where you could run into trouble is using too large of a cell count, 2 definitely, 3 max on a brushed motor. And on most brushed motors don't expect a long life running 3 cells on it.

Now only from what you posted, lack of power, and the esc frying, I'll take an educated guess that you had a bad motor and/or somebody didn't have the throttle turned off completly when she touched down. Over amped the esc and it leaked out all it's magic smoke.
Old 02-29-2008, 05:29 PM
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Default RE: It caught on fire???!!!!!

The ESC voltage cutoff has to be right for your LiPo packs, or you may over discharge them and they will puff or explode. If the LiPo pack has a higher voltage than the NiMH/NiCd pack you are replacing, you may exceed the voltage limit of the ESC, and/or the current limit of the motor & ESC. You can use a smaller and/or lower pitch prop to reduce the current draw.

In general, most cheap brushed ESCs don't have the proper cutoff voltage for LiPos. You really need an ESC with a programmable cutoff. Some ESCs have auto-sensing cutoff voltages, the ESC senses your batt pack voltage at power-up, assumes the pack is fully charged, and it guesses what type/cell-count pack you have based on that. If you use a partially discharged pack with an auto-sensing ESC, it may choose a lower cutoff voltage than is safe for your pack.
Old 02-29-2008, 06:05 PM
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Default RE: It caught on fire???!!!!!



PKH.

Thanks for reminding us all about the " Fully charged battery trap ". That probably does in a lot of people who figure.........I will just do a " quicky " flight on the leftover charge. THEN take it home and fully charge it.

I have heard more than 1 pilot say & do it.

Rich
Old 03-04-2008, 08:38 AM
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pywackit
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Default RE: It caught on fire???!!!!!

Ok guys, here's a list of what had in the glider.

1) Lipo 900 mah 7.4V w/jst
2) speed control 5 amp w/jst
3) cobalt cem-130 motor
4) folding prop 6x3

Now there is one thing I did....maybe two.
I did fly with the battery not fully charged before I went....I charged it about 1 week earlier then the weather changed so had to wait for the better day.

Then I'm wondering about when you end a flight and your walking over to your plane I had the throttle control full back along with the trim full down too. I can't turn the radio off before I disconnect the battery in the glider right?
Old 03-04-2008, 04:36 PM
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Default RE: It caught on fire???!!!!!

That is correct that you should NEVER turn off the transmitter before disconnecting the battery. No signal from the transmitter can result in unwanted operation, and potentially cause injury to yourself or others standing in the vicinity. Good luck getting your bird back together and flying!
Trevor

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