My 550 farted !!

[mjdee14]

I just got a new set of 3300's (7th set) and I planned to hover in the front yard a few times to cycle them .....well it got dark, etc, so I set it up in my empty bonus room and bring up the rpms just under 1/2 stick...so maybe 40%....it's humming along for about 3 mins and

wham...it's farts...:badair: I see a puff of smoke.....I can smell it...it sounded like the motor was freewheeling like the OWB let go, but when I bring it down and back up again...everything seems normal....

Now I know and can a smell heli :badair: when see/hear one, but I'll be damned if I can find out where it came from....I have the 20t OWB, fairly new, the ESC was warm but not hot...I just don't know....

I'm going to have to be very careful next time I fly, it may be the OWB is going and slipped and it was plastic burning......it didn't have the distinct odor of electrical but it was similar....

Anyone have any thoughts...(that are worth anything) ( or you can just vent if you feel the need)....

I hate things I can't figure out, but all things come to light eventually....glad Ive been practicing my autos...:YeaBaby:

[mysticmead]

hmm... could be the plastic starting to melt.. I'd check the OWB to make sure it was working correctly.. either that or you need to stop feeding the hurri burritos

[mjdee14]

OK....I downloaded my ET and it looks like maybe the OWB unloaded and the motor rpm went nuts.....i was only humming along at about 10,000 rpms and it shot up to 62,000:WOW then the:BSS:Fan. I'm running the brushless rpm sensor so it tells me the same thing for the blades....but I know the blade rpm didn't go from a 1,000 to 10,000.

So I'm guessing the OWB.....I just hope the smoke wasn't a motor bearing or anything..

before it farted...it burped...like a slight tail wag...I wonder if it unloaded the OWB and it couldn't hook back up and spun.....I probably shouldtake it apart, but maybe I'll hover it in the front yard and see what happens...

[mysticmead]

I say.... take it out and fly the piss out of it...if it fails, you'll get some good auto practices in :D

[mjdee14]

Took everything aprt...the OQB looked good, no melted plastic, the lower motor bearing Z20....felt a little ratchety....not smooth like the top one.....Ebay has them for about $3 but it doesn't look like it's easy to get out.....if you heat the aluminum too much you could melt the wiring.....

I lubed it and will fly the "piss" out of it mystic suggests....autos are nice when planned....but we'll see what happens...may have to get the CF version done and in the air....

If you look at the graph just before the spike in rpms, it had a little dip....I'll bet it was just enough for the OWB to unlock and then slipped like crazy...maybe the smell was some oil on the shaft burning....:thinking

[helvetic]

What I don't understand is the motor RPM's . Guess you have a 6S Lipo, and your Z20 is 980 KV. So this brings your motor to a max of ~ 25000 RPM. 62000 sounds really too high. Are you sure your motor and ESC are ok after this? IMO, the puff smoke is a result from a electric problem!?
I'm not sure if the OWB may heat up itself so fast to puff.
What HS did have while hovering? Only 1000? Maybe the motor/ESC cannot handle this partial load?
Hope you can figure it out and fly safely with her again!

[mjdee14]

I have found that the Eagle tree is not always as acurate as you might think.....when you just plug in the last lipo you get a spike that shows RPM or a huge amp surge....

I wasn't even hovering, it was just sitting on the floor spinning about 40% throttle....maybe 900-1000 rpms...

I think the OQB unloaded and slipped and burned some oil on the shaft.

I don't how or what would have made the motor "actualy" go to 62,000....rpms.

I think that is just another ET misrepresentation...since the motor surely can't operate at 300% of it's rated capacity.

The only thing the grapg was good for was to show it did spin up...

I still need to beed down the new packs...so I'll try and hover in the front yard in normal mode and we'll see what happens over the nice soft grass....

[mysticmead]

am I the only one that plugs both packs into the series connector and the the series connector into the ESC?? everyone keeps saying they get a spark plugging in the second pack... am I doing it wrong or just different?

[mjdee14]

am I the only one that plugs both packs into the series connector and the the series connector into the ESC?? everyone keeps saying they get a spark plugging in the second pack... am I doing it wrong or just different?

I have my Y adapter already plugged into my Eagle tree so I leave that alone....

It just seems natural to place both batteries on the heli...then plug in one plug at a time.

never thought about doing any other way....

Do you not get a spark when you plug in to the ESC?

[mysticmead]

I have my Y adapter already plugged into my Eagle tree so I leave that alone....

It just seems natural to place both batteries on the heli...then plug in one plug at a time.

never thought about doing any other way....

Do you not get a spark when you plug in to the ESC?


I get no more spark than if I were plugging in a single 3s for my 450...which means.. yes, I get a spark... all because of the deans design.. that's been a complaint of mine from day 1.. and others have the same complaint. have though about switching to bullet connectors like the motor uses.. could even eliminate the Y cable in the process

[mjdee14]

I don't think you eliminate it....you might just not see it...


Mike

[kgfly]

I plug my packs into the Y-lead first and then the Y-lead into the ESC as the final step before flight. I get a decent spark most times (8S A123 = 28V).