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-   -   Mini Ultra Stick - Quad Flap / Motor / ESC Help (http://www.Wattflyer.com/forums/showthread.php?t=72814)

Slappy 12-16-2013 05:46 AM

Mini Ultra Stick - Quad Flap / Motor / ESC Help
Hi WattFlyer community. I'm new to the electric flight world and return to RC flying after a long hiatus. I'm hoping you can help me out with a bit of a conundrum.

I'm flying a Mini Ultra Stick, which I recently converted to the quad flap setup.

I've setup the plane with:
EFlite Park 450
EFlite 20-Amp Brushless ESC (V2)
EcoPower 3S 30C 2200mah
Spektrum A3030 servos

Now when I plug in the battery, everything seems normal. I take off and fly for a bit, then when I land, the motor continues to spin. It's almost like an idle type spinning of a glow engine, when the transmitter throttle lever is fully down. It's not enough thrust to move the plane and the throttle won't advance the speed of the motor.

Is this a sign of an overheating ESC?

I did attempt to fly with all 6 servos, before installing the ParkBEC. I quickly realized the error of my ways when the servos weren't happy. They were jumpy and had bad delays, but I managed to get back on the ground safely. Could that have damaged the ESC?

Thanks for any educated insight...

mclarkson 12-16-2013 06:07 AM

It could be as simple as throttle trim being near, but not reliably at, zero. Try moving the throttle trim down a click or two and see if that doesn't fix it.

Slappy 12-16-2013 06:24 AM

That does sound too easy... And, of course, I never even thought about the trim. I'll give that a try, next time I fly. But that doesn't explain why the throttle won't advance either.

Wildflyer 12-16-2013 08:10 AM

Do some careful ground testing after you remove prop.

You are right, even if the trim was bumped up a little during flight, which would seem right when the prop did not stop. It does not explain why the throttle stick did not speed up the motor. (assuming Tx was on)

I had a smaller plane than yours, jump to life in the middle of a test. These electric props are just a little duller than a good knife, and they are sharper than some of my knives.

Be careful, always remove prop when something doesn't act correctly.

Slappy 12-27-2013 01:14 AM

Well mclarkson, You seem to have been correct. I moved the throttle trim down a bit and the problem of the propeller turning at low speed has been solved. Thank you!

I am still having issues with some servo delays. But, I've narrowed it down to when I mix the flaps & ailerons to operate together. This mix moves all 4 wings servos at one time, essentially making the ailerons full length. Could this just be overloading the external ParkBEC?

fhhuber 12-27-2013 01:38 AM

Its pretty easy to overload some of the low current rated BECs with 6 servos in a model.

hayofstacks 12-27-2013 02:20 AM

if you do track it down to a bad esc, make sure the replacement is a switchmode bec.

I've actually not been able to get a voltage drop on my lesser quality units, even with six full sized servos

mclarkson 12-27-2013 02:38 AM

Glad to hear it helped a bit, at least. :)

Slappy 12-27-2013 07:33 AM

Hmmm... I just noticed on Dimension Engineering's (maker of the ParkBEC, I'm using) website that they say it won't work with digital servos, which I'm using. At least I have a lead.

fhhuber 12-27-2013 08:34 AM

Digitals demand more current at idle (but often less under flight load) and will toast a BEC that is marginal with analog servos.

The little Park BEC expects a max or 4 analog mini or micro servos in a relatively low performance aircraft. Not appropriate for 6 digitals in a your plane at all.

Slappy 12-30-2013 05:38 AM

Thanks fhhuber! You prompted me to do a little more learning about BEC options and I think I'mm just gonna upgrade to a Castle Creations Talon 35. It has a much larger capacity switching BEC built in and I won't need a separate BEC. Hopefully that will do the trick & eliminate the brown outs.

I did get a watt meter and check things out. It seems that when I move all 4 wing servos at the same time I'm right up at the 1.25 amp capacity of the ParkBEC.

hayofstacks 12-30-2013 05:56 AM


here is a switchmode esc heads up sells for $25. it has a 6 amp bec and is the same switchmode style of most higher end esc's. a similar esc will cost you $50-100 for a castle one.I very rarely recommend a part I haven't purchased, but heads up has great customer service and I believe Jeff actually uses his products and knows what works and what doesn't.

you could probably get away with the 30 amp esc, but I pull 26 amps out of my mini ultra stick and I like a bit more wiggle room for my margin of safety.

Slappy 12-30-2013 10:02 PM

Thanks haystacks! For my interest, how do you have the power train of your MUS setup? I started with the recommended setup from Eflite, but I'm also looking for a little more performance. I'm now thinking bigger motor, bigger battery, etc... I'll give the ESC you recommend a try.

hayofstacks 12-31-2013 04:56 AM

I bought my mus used and ready to go. I'm running a suppio(sp?) motor of unknown kv or wattage. im running a 10x10 prop and 2200mah 3 cell. 10-20minute flight times depending on throttle.

it isn't all that fast, but was a good speed envelope and motor stays cool. I propped up to chase one of my flying buddies around with a 480 motor.

if you really want the need for speed and down mind a bit of lead, id try a headsup 480 plus on 4 cells.

there is nothing wrong with the recommended setup though. I originally flew with a 9x6 prop and only pulling 160 watts, it was still fun, just not prop hanging fun.

Slappy 01-03-2014 04:06 AM

So, I just picked up a Castle Creations Talon 35. Thanks for the heads up about Heads Up Hooby, hayofstacks, I'll give them a try on my next model. My LHS had the Castle in stock so, instant gratification & supporting the local guy won.

It's all soldered up and installed. On initial tests, on the bench, it seems that my MUS issues may be solved. I checked the current going to the servos and I was just peaking over the 1.25Amp capacity of the ParkBEC, when I moved all 6 servos at the same time and quickly. The 5amp capacity in the Castle more than covers the servo draw when all 6 digital servos are moving fast.

And simply moving the trim on the throttle has solved the slow rotation of the motor.

Thanks for all the help!

Now to wrap up my Precision Aerobatics Mini Katana build... ;)

hayofstacks 01-03-2014 05:59 AM

nothing wrong with supporting local. I wish I had a decent hobby shop around here.

I use headsup instead of hobby king whenever possible. there at least in Florida.

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