Author Topic: just can`t get it right (Read 2830 times)

ron young · « **on:** July 16, 2018, 04:31:10 PM »

Well my set up is as follows

rtf ringmaster from brodak
arrowind 40 a esc brodak
fm-oc timer as above
arrowind 2810/12
apc 10x5e
didn't really check rpm but lap time 4.9 on 60 ft .015 lines
timer set for between 2and 3 minutes
I have maybe a dozen cycles like that and I had smoke coming from motor already so I have some how managed to fry this awfully quickly ,I shut it of immediately and went home later for kicks I fired it back up and it seemed to run fine although the motor smells burnt.I won't run it again but any thoughts ,anything glaringly wrong here.This in no way a reflection on Brodak .I orderd another to replace but it seems something may be amiss i'm not getting.
Thanks
Ron

Jim Mynes · « **Reply #1 on:** July 16, 2018, 05:08:48 PM »

Seems to me my electric ARF Ringmaster has a 9” prop on it. It’s 1600 miles away otherwise I would check.

Get one of those in-line watt meters and see how many amps you’re drawing. They come in real handy at times.

John Rist · « **Reply #2 on:** July 16, 2018, 05:12:24 PM »

Quote from: ron young on July 16, 2018, 04:31:10 PM

Well my set up is as follows

rtf ringmaster from brodak
arrowind 40 a esc brodak
fm-oc timer as above
arrowind 2810/12
apc 10x5e
didn't really check rpm but lap time 4.9 on 60 ft .015 lines
timer set for between 2and 3 minutes
I have maybe a dozen cycles like that and I had smoke coming from motor already so I have some how managed to fry this awfully quickly ,I shut it of immediately and went home later for kicks I fired it back up and it seemed to run fine although the motor smells burnt.I won't run it again but any thoughts ,anything glaringly wrong here.This in no way a reflection on Brodak .I orderd another to replace but it seems something may be amiss i'm not getting.
Thanks
Ron

How many cells LiPo?

Fred Underwood · « **Reply #3 on:** July 16, 2018, 07:09:50 PM »

In addition to other questions asked, what battery pack and what amp draw? Or what amp replacement on the charger for what actual time run?

ron young · « **Reply #4 on:** July 17, 2018, 04:17:30 AM »

Battery pak 4s 2200 mah

ron young · « **Reply #5 on:** July 17, 2018, 03:49:56 PM »

I don't know how to figure amp draw.
any help there ?
looking at the list your set up most seem to be using similar set ups em I wrong?when the new motor arrives I will try to figure amp draw ,I will also compare with 9 in prop
Thanks

Fred Underwood · « **Reply #6 on:** July 17, 2018, 04:10:10 PM »

You can get an in line RC type Watt meter and get a reading once you adapt the ends to fit in line. Or fly the plane for a known number of minutes starting with a full battery and then note the number of milliamps to get it back to full charge. You then have average ma/minute of actual flying. Some ESCs have datalogging and you can get a readout, with appropriate computer attachment, for several parameters during a flight.

Jim Mynes · « **Reply #7 on:** July 17, 2018, 04:46:22 PM »

I had another thought.

Sometimes parts fail. Even new parts can fail.

That’s two thoughts in two days!

I would try the new motor with a 9” prop, see how many amps it’s pulling, and go from there. Without my Ringmaster nearby, I’d venture a guess that it pulls between 20 and 30 amps. Probably closer to 20 than 30.

I have the same setup in my Ringmaster, but I would bet money I’m running a 9” prop.

Tim Wescott · « **Reply #8 on:** July 17, 2018, 06:00:40 PM »

Quote from: ron young on July 17, 2018, 03:49:56 PM

I don't know how to figure amp draw.

One way is to run the current through a resistor and see how hot it gets. In this sense, the motor is a resistor. You could get a wattmeter, but if you've just got one electric plane that's a lot of extra cost.

Is the motor stiff when you turn it? If you flip it like you're starting a slime engine it should make several rotations before it stops. You should feel the cogging from the magnets, but not friction, and you shouldn't hear any grinding or rubbing noises from it. I'm wondering if you got one with bad bearings or a loose magnet or something.

I would try running it on the ground, without a prop. If it doesn't get hot, that tells you the motor by itself is OK. If it does get hot, something's wrong. This'll work better if you also fly RC and can just hook it up to a receiver, but it'll work OK with a timer (if you get antsy and want to shut it down, disconnect the ESC -- don't pull a motor wire or the battery).

Dane Martin · « **Reply #9 on:** July 17, 2018, 10:58:16 PM »

Quote from: ron young on July 17, 2018, 03:49:56 PM

I don't know how to figure amp draw.
any help there ?
looking at the list your set up most seem to be using similar set ups em I wrong?when the new motor arrives I will try to figure amp draw ,I will also compare with 9 in prop
Thanks

Ron, if you have dean's plugs, I can mail you my watt meter to check this. If not dean's, I might be able to make up adapters. Let me know if you need to borrow it. I think it's an important measurement.

ron young · « **Reply #10 on:** July 18, 2018, 04:51:27 AM »

This motor still spins freely,also I restarted it and it seemed fine but I didn't try to run more than a few seconds .
In response to Dane motor has bullet plugs and esc has deans I don't know how meter would hook up ,but would take you up on your offer im happy to pay shipping
Thanks all for responses
Ron

Tim Wescott · « **Reply #11 on:** July 18, 2018, 01:28:23 PM »

Quote from: ron young on July 18, 2018, 04:51:27 AM

This motor still spins freely,also I restarted it and it seemed fine but I didn't try to run more than a few seconds .
In response to Dane motor has bullet plugs and esc has deans I don't know how meter would hook up ,but would take you up on your offer im happy to pay shipping
Thanks all for responses
Ron

Basic problem solving, if we want to approach this as 'divide and conquer'

Everything about the motor and electronics is OK, but you have the wrong prop
The motor has mechanical problems (you've eliminated this, unless it's really oddball)
The motor doesn't have the advertised Kv. Unlikely
The motor has an internal short -- it won't show (much) just spinning it, but would make it get hot running without a prop
The ESC is faulty. Symptoms could be a lot of different things, but may show as heat when running without a prop
Too many cells (did you say how many?). It'd take way too many to really heat the motor, and then your ESC would likely get cranky, too
Something I haven't thought of

Measuring current draw with and without a prop would help pin this down -- Dane's offer is a solid one.

Dane Martin · « **Reply #12 on:** July 18, 2018, 01:50:46 PM »

I sent you a PM Ron. Just send your address. I'll get it right to ya.

Dennis Adamisin · « **Reply #13 on:** July 19, 2018, 06:21:52 AM »

Hi Ron
As Jim mentioned the "normal" prop for this set-up is a 9x4.5, typically running around 10,800 rpm to deliver around a 4.9 lap which is good for a Ringer. Even still, the 10x5 should be OK - the airplane will flu better on a 9" tho... Frankly if I had a stack of 10x5's for my Ringer I would clip them to 9"

The motor has kv=1100 so it is meant to spin up using a lower pitch prop like the 9X4.5. In this case the 9x6 prop is too "pitchy".

The highest load is with the motor running on the ground, so minimize the spooled-up time on the ground. For that reason I also avoid taking the current measurements on the ground - the loads you measure on the ground are meaningless anyway.

Jason Greer · « **Reply #14 on:** July 19, 2018, 12:53:08 PM »

I ran your setup through MotoCalc (an electric system simulator) and it complains about the motor overheating at full throttle with the 10 x 5. I wasn't able to find the resistance constant for the Arrowind motor, so I looked at several similar motors and averaged them. How accurate this is, who knows, but it should be in the ballpark, I think. The attached image shows the results of the simulation for both the APC 10 x 5 and the APC 9 x 4.5. Everything looks to be much happier with the 9 x 4.5 as Dennis suggested. The efficiency of the system is higher and the watts lost to heat is almost cut in half, which should make your motor generate less smoke.

Jason

ron young · « **Reply #15 on:** July 20, 2018, 04:18:26 AM »

Thanks everyone for your help I will try new props with new motor and see what happens.
Ron

John Rist · « **Reply #16 on:** July 20, 2018, 08:38:16 AM »

Electric motors are there own worst enemy. If you put too large of a prop on a nitro motor it just gives up and runs slow. If you put too large of a prop on an electric motor it just keeps trying harder to maintain RPMs till it smokes. Too small of a prop on a nitro engine is death due to over RPMs. Too large of a prop on an electric mother is death due to over current.

eric rule · « **Reply #17 on:** July 26, 2018, 05:27:43 PM »

I never comment on any post that involves products that are sold by my competitors but some of the data listed herein is simply wrong. I went to the web and pulled the tech data on the Arrowind 2810/12 motor. Here is what I found:

Arrowind 2810-12 KV=1100

No. Of cells 3x Li-Poly
Max. efficiency 82%
No load current / 10 V 1,5 A
Current capacity 30 A/60s

Dimensions (diameter. x length) 39x31.5 mm
Stator Dimensions 30x10mm
Shaft diameter 5 mm
Weight 86 g/3.03oz.
Recommended model weight 600-1400 g
Recommended prop without gearbox 10"-11"

This motor has a KV of 1100 and it is clearly stated that you should use a 3 cell battery NOT a 4 cell. The prop sizes recommended are for R/C NOT Control line use.

The combination of a 4 cell battery with a 10" prop no doubt will result excessive amp draw plus running at a low rpm (1100 kv X 14.8 volt means the maximum RPM without prop load equals 16,280. With a prop on the motor that equates to somewhere around 13,000) Since the recommended rpm stated by Dennis is 10,800 running that slow would also increase the amp draw.

Pull the 4 cell and replace it with a 3 cell running a 9" prop. I bet you will get an amp draw in the 20-25 amp range which will keep the heat down to where it should be. The Arrowind motors are pretty good units and if run properly should give you years of good service.

TDM · « **Reply #18 on:** July 27, 2018, 08:35:36 AM »

Have you considered a 3536 outrunner motor?
https://www.lindinger.at/en/?sViewport=detail&sArticle=9741917&sSearch=

Mike Haverly · « **Reply #19 on:** July 27, 2018, 09:01:40 AM »

What Eric said. I had a similar problem trying to run 5S on an E-Flite Power 25. It overheated. I have since learned to do the math and follow known set ups. This needs a 3S battery to work correctly, along with the correct prop to match RPM required.

Dennis Adamisin · « **Reply #20 on:** July 28, 2018, 08:23:44 PM »

This isn't a "think piece" - this is a several year old application, with LOTS of very happy electric Ringmasters out there - because this set-up WORKS.

There is no substitute for using the correct equipment; in this case the 4 cell pack with the 1100 kv motor and the 9x4.5 prop generating usable RPM (i.e., at 70%-85% throttle) in the range of 11,396 RPM to 13,838 RPM. The 9x4.5 prop likes to run around 11.400 RPM and at that speed will pull the Ringer at around 5.0 seconds per lap. At that throttle there is plenty of "headroom" for governing.

Put another way, the reason 3 cells CANNOT WORK in this application is that it will not generate nearly enough RPM. With 3 cells the usable RPM range falls to 8,547 - 10,379 RPM. That top RPM is about 1000 RPM short for using the 9x4.5 prop - might work with a 9x6, but at the cost of almost the entire govening range. If you wanted to reclaim the lost headroom with 3 cells then you better find an 8"-9" pitch prop! Better still, with 3 cells and the 9x4.5 prop, find a motor rated at 1500 kv; I know that will work because I have flown those too on the Brodak Super Clown.

About 5 years ago I published a piece in Stunt News on matching props, cell count and KV. I do not remember which issue it was but I attached a PDF of the article below - might help detail some things - or cure your inomnia...

Mike Haverly · « **Reply #21 on:** July 28, 2018, 09:17:16 PM »

OOPS, my bad. I should of looked closer. I thought that motor was a lot higher kV.