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Midland Helicopters . HeliProz . Ron’s HeliProz South

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e-Century Hummingbird - Swift > GY401 with ELECTRON 80/100 in gov mode
 
 
HarveyR
Heliman
Location: France - North

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My setup (standard Century 6S combo):

# SWIFT 620SE CARBON KIT (CN1043)
# OUTRUNNER 600A PLUS, 1100kV BRUSHLESS MOTOR (CNE274)
# ELECTRON 80/100 BRUSHLESS ESC (CNE480)
# MOTOR GEAR - 9T, 5mm, 1.0 MODULE (CNMG509)


+ GY401/s9254 in Heading Hold mode.

Before I always used ESC mode 1 (non governor mode).

I tested the governor mode (mode 2) this lunch time, but the tail was wagging (like once every 2 seconds for a fraction of a time, I'd say you hear it more than you see it). I had to reduce gyro gain to 30% for this to stop, but then the gyro wasn't very efficient anymore.

Is there something I should do with one of the two settings on the GY401 (limit and delay I think, but I'm not sure of their names) to be able to use the ESC in governor mode?
10-27-2009 02:33 PM
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oldfart
Elite Veteran
Location: Vancouver, Canada

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Seems like the ESC may be giving off some extra RF in the governor mode. What receiver and how far is it from the ESC and Gyro?
10-28-2009 12:53 AM
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Ben-T-Spindle
rrProfessor
Location: Central Illinois

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Sometimes you get into a situation where the governor and gyro fight each other at a particular gain setting. Try running the GY401 at a much higher gain setting with about 50% delay and see if that helps.



... BTS
10-28-2009 11:40 AM
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HarveyR
Heliman
Location: France - North

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oldfart, are you suggesting it could be a radio interference problem? I have a Futaba 10CG 2.4GHZ TX with the receiver that comes with it (R6014HS). I bought this purposly for my EP hoping I wouldn't be bothered with interference problems.

The RX is in between the two trays near the front. The LiPo is above the top tray, at the front. The ESC in under the bottom tray below the main shaft (with the BEC there too). The gyro is at the back on the gyro plate.

Given this, do you think interferences could be the problem?


Ben-T-Spindle, I was hoping something along this line. I'll probably test tomorrow (messing around with the delay).

Thanks for the ideas.
10-28-2009 04:21 PM
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oldfart
Elite Veteran
Location: Vancouver, Canada

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Not interference with the RX, but the RF from the ESC may be interfering with the Gyro.

I always keep my RX/ESC/gyro as far from each other as possible.
10-28-2009 05:58 PM
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HarveyR
Heliman
Location: France - North

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Well, as my setup is, I think they are as far apart as possible (the ESC is approx halfway between the RX and gyro). I'll check the Delay setting to see what effet that has..
10-28-2009 06:06 PM
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HarveyR
Heliman
Location: France - North

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Great flight! The Gov mode is working fine now without messing the Gyro up. It just needed a bit of delay (30%) on the 401. I like the constant HS feel. My IDL1 curve is now a constant 75%.

Just a question: Does someone know how it works technically? I mean, there's no sensor (like on NP) for the ESC to know the motor RPM. So how does the ESC measure the "real" speed?
10-29-2009 03:21 PM
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oldfart
Elite Veteran
Location: Vancouver, Canada

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Glad to see you have it all working now.

What rotor speed are you getting at the 75% setting?

I calculate that you should be getting about 1600 with the 9T pinion on the 1110KV motor.
10-29-2009 04:39 PM
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Ben-T-Spindle
rrProfessor
Location: Central Illinois

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Brushless ESC’s use a back-EMF sensor to detect the motor’s rotor position.

... BTS
10-29-2009 04:39 PM
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HarveyR
Heliman
Location: France - North

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With a 90% efficiency ratio I calculate about the same (1559 RPM). I'd be really curious to measure but I know no one with a tool to measure.

I know most people would think it's slow, but I like slow turning heads, it matches my current soft flying style. Most of my training is "training flight configurations". I absolutely want to be 100% confortable in all positions and movements (upright, inverted, forward, backwards, sideways, nose in, tail in, lateral, ...). I currently spend much of my flights training inverted backwards flight (fast and slow, circles, eights, squares, ...).

Anyway, I find even with this slowish HS, the 620SE is quite nervous, rolls and flips are fast, and it doesn't bog down (thanks to gov mode I suppose).

Thanks for the EMF hint, I've read about it on wikipedia. Quite interisting.
10-29-2009 10:45 PM
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HarveyR
Heliman
Location: France - North

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At what frequency does the ESC measure motor speed and correct throttle? Because, before adjusting the delay, I was getting the tail wag, about once a second I'd say.

Would you think that that's the frequency at which the ESC is switching to "back EMF" (from what I gather, to measure motor speed, the ESC stops sending voltage and instead measures the voltage generated by the spinning motor)?

If it is it seems like a low frequency, although in practice, the HS was nice and constant. But for people doing hard 3D, wouln't that be to slow.
10-30-2009 12:46 PM
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Ben-T-Spindle
rrProfessor
Location: Central Illinois

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Most ESC’s run the motor in the 8KHz to 16KHz range. This is called the PWM frequency. The high end ESC’s have this adjustable can run at a higher frequency if required depending on the motor.

Your 1 Hz oscillation if just a combination of the inertia of the helicopter interacting with two separate control systems. Delay just gets the response of the gyro below that of the power system. The Power system also has from motor and rotor system inertia so it’s a complex electro-mechanical phenomenon.




... BTS
10-30-2009 03:51 PM
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e-Century Hummingbird - Swift > GY401 with ELECTRON 80/100 in gov mode
 
 
HarveyR
Heliman
Location: France - North

My Posts This: Topic  Forum
Another question. I've noticed that depending on the LiPo I'm using (my new one or my old one) the HS seems different. With the new LiPo it spins faster than with the old one.

I have gov mode on and a flat idl1 curve at 75%.

To me this means that the speed you set on the ESC (my 75%) isn't "absolute", it is relative to the power coming in or something...

Any idea about this?
11-09-2009 09:06 PM
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Midland Helicopters . HeliProz . Ron’s HeliProz South

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e-Century Hummingbird - Swift > GY401 with ELECTRON 80/100 in gov mode
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