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Old May 11, 2012, 02:44 AM
Flying Free
erashby's Avatar
Utah
Joined Aug 2001
1,938 Posts
Quote:
Originally Posted by Whomprat View Post
I've done 8 successful rewinds just grabbing two next to each other, not worrying about where I started or ended. (after I have the winds on of course). I just rewound one last night. I"ve got the wires twisted up. I'll test it with s1 connected to s2 and see if it really matters or not.
Just a word of caution-- don't twist those pairs up too tightly. I did and I just had a wire break at the twist junction because it began to double twist (the twisted pair began to twist) where it comes off the stator. I thought I had a bad ESC because another ESC spun the motor up (but I was testing without a prop) and also probably had somewhat of an intermittent conection.

Thankfully, there was barely enough wire to solder the broken ends together and slide shrink tubing on it so it doesn't short out to the stator. I tested it, and it all works.

So don't twist the pairs too tightly.
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Old May 11, 2012, 11:06 AM
Flight Enthusiast
Ferndale WA
Joined Dec 2006
137 Posts
Assassin electrical problem

Here is a description of my problem.
I am flying my Assassin in a farmerís field of one acre or less. My style of flying at this stage is like someone flying a trainer plane, just lazy circuits around the field to get the feel of the wing and some stick time in, and adjust trims if necessary.
The first battery used is a Turnigy Nano Tech 1300 mah 3S 25Ė 50C discharge rating.
The second battery is a Common Sense 1250 mah 3S 10C discharge rating.
The ESC is an Exceed Proton 30A protected by a 25A auto fuse in line in the red lead.
The motor is stock Emax CF 2812 from Heads Up.
The prop is an APC clone 7 x 6E from Hobby King.
The Rx is a Power Up 6 channel from Heads Up.
Bind is successful with the transmitter, a new DX7s.
The ESC parameters are all default values.
Brake = Off
Battery Type = Lipoly
Cutoff mode = Soft-Cut
Cutoff threshold = Medium = 2.85v per cell or 8.55v for the pack
Start mode = Normal
Timing = Low
After about 2.5 minutes of this lazy flying with no WOT or high speed at all, the wing lost power and fell to the grass field. This was not a soft cutoff because I had no control during its fall to the earth.
So I put on another fresh battery. This time I made one trip around the field before I turned on the timer but the time was approximately the same. After 1.5 minutes plus the initial trip around the field the power to the motor quit. No control on the way down.

When it quit the first time, I tried the power and had to disconnect and reconnect the battery and after doing that the motor ran. I tried flying it right then and it only flew 50 yards before it quit again. Then I put on the second battery.

When I got home the 1300 mah battery (the first one I used) read 12.15v on the Watts Up power meter and the charger concurred with the voltage reading and said its charge level was at 84% before charging.

The second battery (1250 mah) read 12.27v and was at a charge level of 89% before charging.

During boot up of the power system I have experienced a power failure while holding the plane in my hand. I would boot up the system try the control surfaces, run the motor, all seemed well and then a few seconds later before my toss, the power system would quit. I attributed this to being too close to the Tx but I really donít know the cause.

The transmitter was fully charged reading 5.4v when I left for the field.
Last night when I got to the field the Tx read 4.9v when I booted the system and got ready to fly. I wondered if that might have been part of the problem last night, but I checked the manual and it says the low voltage alarm for the DX7s goes off at 4.3v.

Because I have no control on the way down, it looks like it is not a soft cutoff. It looks to me like the ESC is shutting off on its own as if the Tx is out of battery, but the Tx is still on.
Do any of you have any ideas as to what is going on?
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Old May 11, 2012, 11:38 AM
Planes in flames,,,
jetpackninja's Avatar
Gravity Sucks
Joined Aug 2010
3,501 Posts
Sounds like possibly a problem with the receiver?
This kind of problem can be really hard to track down.
If it rebooted while it was in your hands with no drain on the battery, I'm leaning toward the RX...
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Old May 11, 2012, 11:41 AM
Planes in flames,,,
jetpackninja's Avatar
Gravity Sucks
Joined Aug 2010
3,501 Posts
Check all of your connections and solder joints while you are at it
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Old May 11, 2012, 12:21 PM
Hit Me! Please!
jwjohnson's Avatar
Provo, UT
Joined Jan 2005
3,974 Posts
I've had a couple of combat planes do that after they've been whacked around a bit. Has turned out to be a bad solder joint both times. Good suggestion Ninja.
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Old May 11, 2012, 12:26 PM
Registered User
Joined Jul 2010
208 Posts
Quote:
Originally Posted by jetpackninja View Post
Check all of your connections and solder joints while you are at it
I agree with jetpack, if Lipos are still charged you have a fault in power leads or a dud ESC > no juice to servos

Throttle up in your hand with prop removed and shake it all about to see if it cuts out~~~~~~~~~H
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Old May 11, 2012, 12:33 PM
Registered User
Joined Jun 2009
391 Posts
Time for testing

Quote:
Originally Posted by Ferndale Flyer View Post
Here is a description of my problem.
I am flying my Assassin in a farmer’s field of one acre or less. My style of flying at this stage is like someone flying a trainer plane, just lazy circuits around the field to get the feel of the wing and some stick time in, and adjust trims if necessary.
The first battery used is a Turnigy Nano Tech 1300 mah 3S 25– 50C discharge rating.
The second battery is a Common Sense 1250 mah 3S 10C discharge rating.
The ESC is an Exceed Proton 30A protected by a 25A auto fuse in line in the red lead.
The motor is stock Emax CF 2812 from Heads Up.
The prop is an APC clone 7 x 6E from Hobby King.
The Rx is a Power Up 6 channel from Heads Up.
Bind is successful with the transmitter, a new DX7s.
The ESC parameters are all default values.
Brake = Off
Battery Type = Lipoly
Cutoff mode = Soft-Cut
Cutoff threshold = Medium = 2.85v per cell or 8.55v for the pack
Start mode = Normal
Timing = Low
After about 2.5 minutes of this lazy flying with no WOT or high speed at all, the wing lost power and fell to the grass field. This was not a soft cutoff because I had no control during its fall to the earth.
So I put on another fresh battery. This time I made one trip around the field before I turned on the timer but the time was approximately the same. After 1.5 minutes plus the initial trip around the field the power to the motor quit. No control on the way down.

When it quit the first time, I tried the power and had to disconnect and reconnect the battery and after doing that the motor ran. I tried flying it right then and it only flew 50 yards before it quit again. Then I put on the second battery.

When I got home the 1300 mah battery (the first one I used) read 12.15v on the Watts Up power meter and the charger concurred with the voltage reading and said its charge level was at 84% before charging.

The second battery (1250 mah) read 12.27v and was at a charge level of 89% before charging.

During boot up of the power system I have experienced a power failure while holding the plane in my hand. I would boot up the system try the control surfaces, run the motor, all seemed well and then a few seconds later before my toss, the power system would quit. I attributed this to being too close to the Tx but I really don’t know the cause.

The transmitter was fully charged reading 5.4v when I left for the field.
Last night when I got to the field the Tx read 4.9v when I booted the system and got ready to fly. I wondered if that might have been part of the problem last night, but I checked the manual and it says the low voltage alarm for the DX7s goes off at 4.3v.

Because I have no control on the way down, it looks like it is not a soft cutoff. It looks to me like the ESC is shutting off on its own as if the Tx is out of battery, but the Tx is still on.
Do any of you have any ideas as to what is going on?
First remove the prop and find a suitable area to run the system until the thing quits. Have a DVOM or even a test light and probe for where the circut opens. With it in the failed mode start just passed the battery to ESC connection and on. It has the look of an open circut before the ESC. Thesting circuts until you can identify the cause is what it is going to take. Try with the prop off running the entire system and pull and push and twist the connectors, try to pull it apart, sort of.
My limited experence with something like this was a failed connector between the battery and the ESC. The two piece connector (Deans I think, red) has a spade connector with a spring contact, two piece connector at each spade. When I assembled the connectoirs the spring didn't go inside the connection instead it went 90degrees and outside of the connector. I had a connection but it quickly cut out and I noticed the problem. If that spring had broken off and I continued to fly it could have gone open at any time and the plane of course would have no control.
That's what happened to me anyway.
Good luck.
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Last edited by Chico John; May 11, 2012 at 12:35 PM. Reason: edit
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Old May 11, 2012, 01:02 PM
Flyr John in Floyd VA
United States, VA, Floyd
Joined Nov 2007
542 Posts
Agree with the possibility of bad connection, but also think it might be
the thermal overload on the ESC. Doesn't sound as though you're
actually overloading the system, but could be faulty ESC. If you can't
find a loose connection, try swapping out the ESC.

John
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Old May 11, 2012, 01:33 PM
Registered User
Joined Jun 2009
391 Posts
Swap outs

Quote:
Originally Posted by jhark37 View Post
Agree with the possibility of bad connection, but also think it might be
the thermal overload on the ESC. Doesn't sound as though you're
actually overloading the system, but could be faulty ESC. If you can't
find a loose connection, try swapping out the ESC.

John
When confronting things like this, it is impossible to test for trouble codes and I have found that just looking at it doesn't help either.
Having at lest two of everything comes in very handy at times like this. May not be a good time for you jhark but throwing parts at it until it cooperates is eaiser than trying to think it to death.
A CSJ, cold solder joint, or the ESC are the most likely causes here.
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Old May 11, 2012, 03:22 PM
Registered User
Tom Eutsler's Avatar
Asheville,NC
Joined Jun 2002
829 Posts
Esc on Assassin & 2812 Re Wind

With the rewind of the 2812 , anyone have ideas of which esc's to use ?

Right now I have a 30 amp esc on the Assassin and it was mentioned to me to

set timing to "high "........... Thanks .................te
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Old May 11, 2012, 03:37 PM
Slow Flyer
Bombay's Avatar
Richmond, TX
Joined Apr 2008
3,236 Posts
Ferndale:
Be careful in running the motor too long without a prop. I do not know this for a fact, but I have read that the motor is expecting a load and can burn out without one.

It looks like you already confirmed some of the things we spoke about last night. I think you can rule out your batteries and probable the motor. The connections are still suspect...and bad connections can show up in strange ways. But I think at this point...with the additional info you provided...I would swap out the RX first. Second would be the ESC.

My guess is that it is one of those items. Really sounds like a RX issue.

One thing you did not mention is the servos. Which servos are you using? Are they analog or digital?

Rob
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Old May 11, 2012, 03:48 PM
Wherever you go there you are
7oneWo1f's Avatar
United States, MN, Minneapolis
Joined Nov 2011
8,438 Posts
I got a high speed wing scrape the other day. Sadly, camera wasn't rolling. As a consolation, here are some high speed passes from the same day (none of them low enough).

http://www.youtube.com/watch?v=UWtRp62aAaQ
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Old May 11, 2012, 03:49 PM
Registered User
Joined Jun 2009
391 Posts
Check

Quote:
Originally Posted by Bombay View Post
Ferndale:
Be careful in running the motor too long without a prop. I do not know this for a fact, but I have read that the motor is expecting a load and can burn out without one.

It looks like you already confirmed some of the things we spoke about last night. I think you can rule out your batteries and probable the motor. The connections are still suspect...and bad connections can show up in strange ways. But I think at this point...with the additional info you provided...I would swap out the RX first. Second would be the ESC.

My guess is that it is one of those items. Really sounds like a RX issue.

One thing you did not mention is the servos. Which servos are you using? Are they analog or digital?

Rob
Has a range check been done? Set the plane up on something you can view and walk the distance and look at the controls. Move even further out and check the controls again.
Never know.
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Old May 11, 2012, 03:50 PM
Registered User
Joined Jun 2011
123 Posts
Quote:
Originally Posted by Tom Eutsler View Post
With the rewind of the 2812 , anyone have ideas of which esc's to use ?

Right now I have a 30 amp esc on the Assassin and it was mentioned to me to

set timing to "high "........... Thanks .................te
I've run all my rewinds on a 30a esc. We had one setup on a 25A eflite and it caught on fire at SEFF, so if you want to be safe, you can grab a 40A, or go easy at full battery charge. I tend to not to WOT until a minute or so into the flight.

My wattmeter says 36 amps on a fresh battery, so it probably stays until 30 in the air.
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Old May 11, 2012, 03:53 PM
Registered User
Joined Jun 2009
391 Posts
30 amp

Quote:
Originally Posted by Tom Eutsler View Post
With the rewind of the 2812 , anyone have ideas of which esc's to use ?

Right now I have a 30 amp esc on the Assassin and it was mentioned to me to

set timing to "high "........... Thanks .................te
I have a 30 amp Blue H-K ESC and ran 4 batteries in a row without any problems. The motor bell was noticeably warm when I was done but no aparent ESC problems.
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