Octavius

Runs fine up to about 1/2 throttle and then it starts to sputter. You can see the motor wires bouncing around as well. Any reason for this? Thanks.

- ElectriFly SS-25 25A ESC. This is the ESC that came with the motor. UltraFly SU-27 combo.
- APC 4.2x2 prop.
- 1750mha 3S 25C.

Edit: Using Audacity I was able to count the revolutions from the wave form and came up with 27150 RPM.

<embed type="application/x-shockwave-flash" allowfullscreen="true" allownetworking="all" wmode="transparent" src="http://static.photobucket.com/player.swf?file=http://vid70.photobucket.com/albums/i94/Razorfish3000/RCPlanes/UltraFly-D-13-32-Test.flv" width="600" height="361">

Larry3215

Sounds like its loosing sync. Have you tried different timing settings? Smaller prop? What is the amp draw?

Wouldnt hurt to look inside the motor and be sure one of the magnets hasnt moved or been broken, rubbing on a winding etc.

Any of those can cause that as well.

The prop also may be a tad out of balance but it doesnt sound all that bad.

JustGoFly.com

Could be a bad solder. Typically a bad solder, or broken power wire, will work well at low amps, but not able to handle providing the current as the amp draw increases - at higher throttle settings. If solders are rock solid, then try different timing, and then different ESC.

Vinnie

Octavius

Thanks.

I'm pretty sure the ESC is not programmable except for optional brake. I have another ESC to try but it's 50 amp. Is it generally OK to go way over size on the ESC? If that fixes it I can buy a more appropriate size ESC of the same model.

I just soldered all the connectors/wires and pretty confident, but I'll double check.

JustGoFly.com

You can go WAY over on the ESC. The ESC amp value is the "max" it can handle. As you go up in amp capacity the weight of the ESC goes up so becomes undesireable. If the larger ESC weight doesn't bother you - then give it a try. Check all the connectors to make sure they are making a good contact between motor and ESC too.

You'd be surprised how often the issue is the solder joint.

Vinnie

CHELLIE

try a bigger esc like 40 amp plus, and a bigger lipo too, look at all the solder connections, bet your esc is too small, and not giving enough amps to the motor, hope that helps, Chellie

Larry3215

Turning that prop at 27000 rpm should take less than 80 watts or so. If thats the 1/2 throttle rpm, then full throttle should still be not much over 100-130 watts or so or around 10-15 amps max on a 3S pack.

That should be well within the esc spec.

Id run a watt meter to check though.

That sound its making - cracking sound - is loss of sync.

The esc may be defective or it could be the motor or you could be turning more rpms than the esc can handle.

I doubt a larger esc will help. A better esc almost certainly would help

CHELLIE

Also the wires from the esc to the motor look very long, how long are the battery wires too, may be something to look at for a problem. How many Amps/Watts are you drawing, we need Numbers That motor is designed for a gear drive, it may not do well direct drive.

http://www.modelflight.com.au/manual..._32_manual.pdf

Ultrafly D/13/32

Brushless, Sensorless Motor

A Bargain for Quality and Performance.

Designed for gear drive applications, Ultrafly’s D/13/32 brushless, sensorless “outrunner”
motor is a unique and affordable option for park flyer models weighing below 1kg (2.2lb). Its
high-quality construction and precise CNC tooling enable this motor to operate at higher RPM

without serious vibration. The D/13/32 fits in many 300/400 size

Octavius

Thanks all for suggesting the ESC or timing. Looks like a different ESC worked. After 20 minutes trying to program this 50/60A ESC I finally remembered it doesn't have a BEC and I hooked a rx battery. hahaha. Even though it ran fine with the default timing (2-4 poles) I changed it to 10-14 poll "high RPM outrunner 30 deg". I did get a slightly higher RPM for the 30 deg timing. 31950 (30 deg) vs 31700.

Kind of annoying since the Electrifly ESC came with the motor and since I was running it geared it might have been doing this all along and I never noticed.

Battery wires and motor wires are about 6 inches. I also have a vibration at low RPM but probably just need to go back an check the prop balance.

<embed type="application/x-shockwave-flash" allowfullscreen="true" allownetworking="all" wmode="transparent" src="http://static.photobucket.com/player.swf?file=http://vid70.photobucket.com/albums/i94/Razorfish3000/RCPlanes/UltraFly-D-13-32-Test2.flv" width="600" height="361">

Octavius

Just for fun, here's the audio waveform for 1 deg vs 30 deg timing. I kind of like the look of the 1 deg timing but the 30 deg did produce higher RPM.

CHELLIE

Well, That sounds better Take care and have fun, Chellie

CHELLIE

The 25 amp ESC was fine with that motor being gear driven, not direct drive, direct drive will draw a whole lot more amps Glad you got it going, Take care, Chellie

Octavius

Really? If I go with a larger ESC my next concern could be cooking the motor. Specs say 160 watts max.

Larry3215

Do you have a watt meter?

You really should check to see how many amps you're drawing. Higher timing will sometimes give more rpm but it almost always causes more heat. Also, that extra rpm will come at the expense of more amp draw. You need to see how many more amps its costing to get those rpms.

They may not be worth it in therms of heating and reduced flight times

As far as geared vrs direct drive - the amp draw depends on the load. Geared down the motor will be able to spin a larger prop but at a lower rpm. Small prop at hi rpm direct drive = same load and same amp draw as a larger prop at lower rpm with a geared drive.

A note on motor and battery wire length. Long motor wires are usually not a problem unless they are too small and so add too much resistance. I have one setup now with motor wires that are 49" long. Bob Boucher of Asro flight fame ran motor wires up to 50 FEET long in blimps with no issues.

Its long battery wires that will kill your controller but they usually dont cause starting or running problems. They just burn things up - usually the input caps - in the controller.

Octavius

Thanks for the info. The motor is only slightly warm to the touch, but yes you're right, I need to get a watt meter.

How long is too long? The reason I'm getting this motor going is to put in a new 25" span XB-70, and the motor to battery separation could be up to 18". Is that too far? You're saying to keep the ESC close to the battery? In this case the motor wires are pretty small but I'll have to extend them and can use a much larger gauge.

Larry3215

Yeah, use a larger size wire and extend the motor leads where ever possible. Your esc will like it much better

CHELLIE

You can push your motors a little, 200 Watts wont hurt that motor in a 10 sec burst, but only in burst, I love to push my motors alot Look what I do to Micro Motors, and they are still going strong this motor only cost like $6.95 its a 1800KV motor, that will spin a 7x4 to a 7x6 apc e prop on 3 cells, your 3700kv motor is a heater, it will not spin to big of a prop with out getting hot and drawing a lot of amps direct drive, so be careful, this micro brush motor is rated at 6 to 11 amps, I am giving it 20 amps and 210 Watts, its fun, and does not get real hot, its one of Koshs favorite motors, and i see why now, lots of power from such a little package, here is a video of Kosh flying this motor in a delta, Take care, Chellie

[media]http://www.youtube.com/watch?v=MgV17GlLMlI[/media]

AX-2308N-1800
Micro brushless motor
Comes with stick mount, as shown.

Factory Spec.
Kv: 1800rpm/v
Lipo Range: 2-3 cell
Suggested prop: 5x3 ~ 8x4
Best current range: 6~11A
Weight: 44g

Stator: 23 x 8mm

Test Data.
Battery: 11.5v
Current: 6.3A
Propeller: 5x3
Thrust: 326g
Speed: 18454rpm

shaynew

like what i see