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Old Dec 04, 2012, 05:33 PM
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Hard to say without seeing it. Could be a setup issue or servos
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Old Dec 04, 2012, 11:21 PM
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Originally Posted by Balr14 View Post
That sounds like voltage compatibility problems. Disconnect the motor and exercise the servos.
i just tried this one and it seems to be the servos are working fine with the motor disconnected.

what seems to be causing the servos on throttle up? do u think it's the esc?
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Old Dec 05, 2012, 12:10 AM
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How much vibration is there? If it's FBL, vibrations can mess up the gyro. Even small amounts can mess up the tail hold.
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Old Dec 05, 2012, 02:06 AM
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This only occurs on idle up, not when you increase throttle in normal mode? Do you have to be providing other input, like ailerons or elevators as well, or does it occur with no input? I starting to think rate settings might be too high on idle up.
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Old Dec 05, 2012, 02:18 AM
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This only occurs on idle up, not when you increase throttle in normal mode? Do you have to be providing other input, like ailerons or elevators as well, or does it occur with no input? I starting to think rate settings might be too high on idle up.
nope, i dont use idle up yet. on normal throttle mode is the problem. on throttle hold the gyros are working fine, also when the motor is disconnected gyros are working okay.

it occurs with no input on elevator, aileron or rudder. it is just messed up on throttle up past midstick it's okay below midstick

and oh the esc easily goes hot, is this normal?
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Old Dec 05, 2012, 02:20 AM
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Originally Posted by Hajile View Post
How much vibration is there? If it's FBL, vibrations can mess up the gyro. Even small amounts can mess up the tail hold.
there's vibration but i dont know how u classify it as im new to this type of hobby

but i think it's not that much.
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Old Dec 05, 2012, 04:55 AM
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there's vibration but i dont know how u classify it as im new to this type of hobby

but i think it's not that much.
That's the problem. Neither do i. There's no one else flying helis in my area so i don't have anyone to compare either My observation in my own helis (micros and 450), the more vibration in the frame, the more erratic the tail.

There's a video of a guy on youtube launching his heli from his kitchen counter. The counter is barely wide enough to fit his landing skids, and he was able to spin up to hovering speed and lift off from it. As you probably know, any kind of vibration on a smooth surface will cause the heli to slide across it, his was rock stead the whole way and even his resonance was barely noticeable. My goal on my heli is to get it to spin up like that!
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Old Dec 05, 2012, 07:51 AM
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The ESC should not get hot for at least 5 minutes. That may be the problem. It could also be the receiver is subject to too much vibration as you increase throttle. .
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Old Dec 05, 2012, 08:01 AM
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Originally Posted by Balr14 View Post
The ESC should not get hot for at least 5 minutes. That may be the problem. It could also be the receiver is subject to too much vibration as you increase throttle. .
He is right, the ESC should not get hot on the bench, and should only be warm
after placing significant load on it (more than 50% head speed, with some pitch
in the blades) for at least a minute. My car ESC's (I've owned about 50) behave
in this fashion as well, although most of those were brushed ESC's.

Keep in mind, it could be a problem somewhere else that is causing it to
heat up (such as a damaged servo or wiring) . I just wanted to point out how
abnormal it is for an ESC to get hot on the bench.
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Old Dec 05, 2012, 08:31 AM
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Unless the bec section of the esc is sagging, heat wouldn't effect the servos. I still believe they don't have enough torque for an fbl heli.
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Old Dec 05, 2012, 09:22 AM
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Originally Posted by minbari View Post
Unless the bec section of the esc is sagging, heat wouldn't effect the servos. I still believe they don't have enough torque for an fbl heli.
You know, after thinking about it some more, raising the throttle above center increases pitch, which moves the servos. These are not 3kg servos, so they are going to strain to raise pitch which could heat the ESC. Steve, you know electronics. What do you think?

Try removing the blades and raising throttle to max. Weak servos shouldn't have a problem raising cyclic with no blades.
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Old Dec 05, 2012, 09:44 AM
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Originally Posted by Balr14 View Post
You know, after thinking about it some more, raising the throttle above center increases pitch, which moves the servos. These are not 3kg servos, so they are going to strain to raise pitch which could heat the ESC. Steve, you know electronics. What do you think?

Try removing the blades and raising throttle to max. Weak servos shouldn't have a problem raising cyclic with no blades.
If the servos are stalling out, then the motors in them would be pulling constantly. A DC motor that is stalled will pull 3-4x as much current as a running motor. (good way to burn out motors too) totally possible that is taxing the bec section of the esc.

(btw, I am EE too )
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Old Dec 05, 2012, 09:45 AM
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Pull out a digital voltmeter if you have one, and start checking feeds
to the individual servos. When they have no load (no blades to put
tension on them) they should all be at the same supply
voltage. If one is lower than the others, even by just a little, it is drawing
too much current, and is probably defective.

Of course, all your servos need to be the same for this to have any
meaning, and you should temporarily remove the servo horns.
You don't need a $300 meter for this, a $30 Radio Shack special
will do just fine.

Keep in mind, we are looking for voltage drop... the difference will
be very small, possibly as little as 0.1 volts. But more than likely it
will be around 0.3 volts or more.

Check the feed as close to the servo as you can. Sharpen your meter
probes to a needle point, and just poke right through the insulation of
the servo lead.

Be careful not to short them (on my servos, the positive and ground
wires are right next to each other).

A better way to check would be to use an old servo extension cable,
cut it, and put an amp meter in series.
This way you could monitor current draw directly, even under load.

If I remember correctly, most servo spec sheets include maximum current
draw figures.

I gotta get some work done, be back on later.

Good luck!

**EDIT

To be honest, I think minbari has already figured it out. If the problem only
shows up under load, it makes perfect sense. Many servos freak out when they
can't go to the position you instruct, and that will happen if they do not have
enough torque for the application.


But it does not explain the ESC getting hot on the bench with no load.
If the ESC gets hot with the servo horns removed, I would suspect a
faulty servo or ESC.
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Old Dec 05, 2012, 10:18 AM
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Originally Posted by minbari View Post
If the servos are stalling out, then the motors in them would be pulling constantly. A DC motor that is stalled will pull 3-4x as much current as a running motor. (good way to burn out motors too) totally possible that is taxing the bec section of the esc.

(btw, I am EE too )
Sorry, I didn't know. So you guys are way ahead of me in the electronics area. I'm the guy who used to stick his finger in light bulb sockets and wondering what was biting me and why couldn't I see it, as a kid.
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Old Dec 05, 2012, 10:45 AM
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Originally Posted by Balr14 View Post
Sorry, I didn't know. So you guys are way ahead of me in the electronics area. I'm the guy who used to stick his finger in light bulb sockets and wondering what was biting me and why couldn't I see it, as a kid.
Lol, ossum.

I charged up my dads flash on his camera, then touched wires together on the big cap. Made a huge, blinding spark and welded the wires on there. Pretty much loved electronics after that, lol
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