Bad day at the ole flying field for me today.  When I started to take off on my second flight with the electric T-Rex today, there was a lot of smoke and a very loud squeeling noise.  I tried to nose the prop into the ground so we could shut the motor off but only suceeded in knocking the cowl off on the first try and the second try resulted in a line hanging up in the grass with the plane leaving the ground and turning in at me.  Fortunately, the motor stopped at that point and the plane fell several feet to the ground breaking the fuselage off just behind the wing.  There were a lot of flames and smoke pouring from the plane when trying to stop the motor but the wood did not catch on fire.  The Castle ICE-50 Lite ESC had completely melted and all of the wires had melted off of it.  There was smoke damage but no fire damage to the plane.  I only had about a dozen flights on this setup and things were going very well.  My brother Ron also had his Castle ICE-50 regular ESC burn up a couple of weeks ago.  I really don't have any idea why these ESCs failed but I am beginning to wonder if they are suited for our control line use.  I am using a Turnigy 42-50 650 kv motor on a Hubin FM-2a timer with a 4000 mah, 5S, 20C battery.  In all of the checks I have done on my computer, I have never seen an over voltage or over current condition on these ESCs.  Has anyone else had any experience with failed ESCs?  I am returning my Castle ICE-50 Lite ESC to Castle hopefully as warranty work but we will see.  My brother returned his and the sent him a refurbished unit at no charge but did not provide any answers or explainations.

My first flight of the day was excellent.  I was very pleased with my plane and setup but now I am not so sure and I may have to go back to the drawing board.

Best wishes and good safe flying.

Roger Anderson

Hello Roger,
Bummer.
The squealing noise is what is interesting. This strongly suggests that the motor was somehow mechanically jamming against the airframe, Shorting between windings internally, or that a bearing was seizing.
Any of these would cause a dramatic and sustained overcurrent condition. Everything else may simply be collateral damage.
Was the squealing at the same note as the ESC chopping frequency? Was it at some other note? The SHEFTSB investigators (Stunt Hangar Electric Flight Trans[portation Safety Board) need to know.
Were both failures using the same type motor?

Hope we can help,
Dean P.

On my electric bird, I used an inline watt meter and found that I was drawing 45 amps or better static. This with an AXI  motor turning a 12x6 E prop. The Trex is a MUCH larger airframe. did you do an amp check on this setup? I really dont think you were using enough ESC. I would have thought something more like the ICE 75 would be more appropriate, or a 60AMP setup at least. That just seems like a lot of airplane to fly on a 50 AMP ESC to me.

Hi Guys, I have had this problem with Turinigy motors in dark side models,Usualy from being overproped, Just a thought, your problem may be different. Noel.

Hi Dennis,

I did not save the data but I did record some of it.  The highest amps spiked on my records for this motor were 35.5 amps and the average was 25.7 amps.  These numbers should be well within the capability of a 50 amp ESC.  The resonance theory seems more reasonable but I really don't know yet if the battery, motor and/or timer were also damaged.  I have not had a chance to check these items yet but I will ASAP.  The motor leads were damaged so it will take a bit of effort to test the motor.  A visual look at the componets seems OK.  I can't detect any damage to the battery, timer or motor other than they are covered with smoke.  The motor turns freely and I can't see any damage to the windings of magnets.

Roger

Hi Gang,
The dying screech that Dennis described a few posts ago was likely caused by an internal short as a result of the overheating.
Internal shorts then lead to goofy scenarios like one of the three windings having, in effect, a much higher Kv than the other two. 
This causes ridiculous spike currents, screeching and sudden ESC failure. It could even shake the nose of the plane apart!
A good 4-terminal milli-Ohm meter can be used to compare all three windings to each other, but even this does not catch all internal short related failures.
I bought mine on Dovebid for $100, but new it would have been $1000, so this is not a normal shop tool.

The point of this is that failures like this can often be a string of cause and effect failures. The culprit may not be what you think ...
later,
Dean P.

Easiest way to find internal shorts is measuring no load current.

But still - it can be contact which apears only at some vibrations, so the best is to measure and compare data every flight, especially if it needs more mAh than usual, or if it goes hotter than before etc.

I received a replacement refurbished ICE-50 Lite ESC from Castle yesterday at no charge.  I also received an e-mail and telephone call from the folks at Castle.  Their opinion is that the failure was probably caused by the motor or battery but they can't be sure.  According to them, the ESC was not under sized or abused and should have been adequate for our use.  They said they have not done any testing on Turnigy motors or the brand battery I was running so they have no data on which to base any conclusions of reasonable guesses.   I repaired the T-Rex today and did a static test run using all of the same componets (except the ESC of course) and the package ran perfectly.  I will give her more extensiive practical testing by flying probably on Sunday.  At any rate, it seems I am back in business.  I can't say for sure what went wrong either, but all of the componets except the ESC were installed and work just fine.  I guess only time will tell.

Best wishes and good safe flying.

Roger Anderson

Definitely good news that you are flying again - but a head scratcher too.  You might want to get/keep a data log flight or two to use as a baseline.  I guess LITE #1 must have had some kind of flaw in its construction?