RE: Airplane rudder gyro

RE: Airplane rudder gyro
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All Forums >> Radios, Batteries, Clubhouse and more >> RC Radios, Transmitters, Receivers, Servos, gyros >> RE: Airplane rudder gyro

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RE: Airplane rudder gyro - 8/4/2008 3:13:50 PM

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quote:

ORIGINAL: BarracudaHockey
Ken, wagging the rudder 3x to center it up is a good idea once you're on centerline.

Why, what does it do. I'm am real curious what the purpose is technically speaking. Does wagging the rudder 3x change the memory in the GY401? My question is in no way frivolous. I seriously would like to know what the reason is other than it is just a good idea.

Thanks

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RE: Airplane rudder gyro - 8/4/2008 3:18:48 PM

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Ken,

The manual says it resets the gyro...

Flávio

(in reply to Big_Bird)

RE: Airplane rudder gyro - 8/4/2008 3:27:16 PM

BarracudaHockey

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When the 401 boots it samples the pulse width on the rudder channel. This is whats going on while its fast flashing for 3 seconds. This is why its important to wait 4 or 5 seconds before touching the rudder or moving the model. Once the light is on steady you're all set.

Put your gyro in heading hold and move the stick. The rudder moves and stays there. Why? Because its waiting for the airplane to do what its told. Once you are in heading hold you really dont have a way to center the servo except to bump the stick till you see the rudder is straight. Since thats isn't practical you just reset the gyro.

What resetting the gyro does is force the gyro to re sample the center pulse and center the servo.

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RE: Airplane rudder gyro - 8/4/2008 4:37:38 PM

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Please excuse me for being dense Andy.

Put your gyro in heading hold and move the stick. The rudder moves and stays there. This is where I see the problem. No matter how carefully I do the waggle 3x, rarely does the rudder stop at exact neutral. If I switch to normal at that point, the rudder centers and when I then switch back to HH it is good to go with the rudder centered.
Why? Because its waiting for the airplane to do what its told. Once you are in heading hold you really dont have a way to center the servo except to bump the stick till you see the rudder is straight. Since thats isn't practical you just reset the gyro. What exactly do you mean by reset the gyro?
What resetting the gyro does is force the gyro to re sample the center pulse and center the servo. Is this what I was talking about in my first statement?

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RE: Airplane rudder gyro - 8/4/2008 5:00:42 PM

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Ken

I'm not sure if I'll be too "thin", but what I do and works is to:

1) Turn transmitter on with knob set to AVVS

2) Turn airplane on

3) Turn knob off and taxi.

4) Turn knob back on to AVVS

5) waggle 3x rudder for the Gyro to "zero". WAIT A FEW SECONDS AFTER waggling. It WILL go to center position.

Flávio

(in reply to Big_Bird)

RE: Airplane rudder gyro - 8/4/2008 5:39:57 PM

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5) waggle 3x rudder for the Gyro to "zero". WAIT A FEW SECONDS AFTER waggling. It WILL go to center position.

Flavio, that is where mine is different. If the rudder stops with an offset after the waggle 3x then it never re-centers the rudder even if I wait 10 minutes. It only re-centers the rudder if I switch to normal and then back to heading hold.

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RE: Airplane rudder gyro - 8/4/2008 6:15:46 PM

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Ken,

quote:

It only re-centers the rudder if I switch to normal and then back to heading hold.

That's exactly what I do. Read number 3 on my previous post. I have to turn AVVS off, taxi to wherever I want to, turn back on and then waggle. It WILL center. If I just turn back on and don't waggle, it works, but with smaller volume.

I think the best thing to do it to decide a routine and do it exactly every time you fly. Th's what I'm planning to do.

Flavio

(in reply to Big_Bird)

RE: Airplane rudder gyro - 8/4/2008 6:23:09 PM

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Flavio, I agree with all steps 1 - 5. Now go back and re-read my comments on step #5.

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RE: Airplane rudder gyro - 8/4/2008 6:29:13 PM

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Ken, my man!

I did! I don't know why it doesn't work in case you dont turn it off and back on.

But as long as it does work if you proceed with step # 3, why bother?

Turn it off, back on, waggle and go happily flying!

Flávio

(in reply to Big_Bird)

RE: Airplane rudder gyro - 8/4/2008 6:48:26 PM

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Thanks Flavio,

I've been happily flying my Jungmeister with the GY401 for over a year. This was only a discussion. I will continue to happily fly it with the gyro.

Good luck with yours.

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RE: Airplane rudder gyro - 8/4/2008 7:03:48 PM

BarracudaHockey

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What are your rudder end points?

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RE: Airplane rudder gyro - 8/4/2008 7:13:35 PM

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Rudder end points in ATV are 45/45.

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RE: Airplane rudder gyro - 8/4/2008 7:58:35 PM

BarracudaHockey

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Thats why.

You limit the servo throw with the limit pot on the gyro and set the end points out towards 100 or so. You would set your linkage up so that it limit pot is in the vacinity of 100 as well.

If its working for you, don't mess with it but that is why you're seeing that behavior.

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RE: Airplane rudder gyro - 8/4/2008 9:04:04 PM

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quote:

ORIGINAL: BarracudaHockey

Thats why.

You limit the servo throw with the limit pot on the gyro and set the end points out towards 100 or so. You would set your linkage up so that it limit pot is in the vacinity of 100 as well.

If its working for you, don't mess with it but that is why you're seeing that behavior.

Andy, thanks a lot for your help. That totally corrected the problem. It was not necessary to re-do any linkages. The gyro has total control of the throw even in the off position.

I set the ATV (end points) at 100/100. With the gyro pot at 100 the overall throw of the rudder was the same as it was with the end points set at 45/45. Now, with the end points set at 100/100, when I do the waggle 3x in HH mode the gyro always resets the rudder to neutral. It's sure nice to run across a true expert.

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RE: Airplane rudder gyro - 8/4/2008 9:16:02 PM

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Hi, Ken,

quote:

I've been happily flying my Jungmeister with the GY401 for over a year. This was only a discussion. I will continue to happily fly it with the gyro.

Good luck with yours.

I really didn't mean to be ironic on my previous posts and I apologize if it sounded that way, ok?

Anyway, I'm glad you had the chance to correct the problem with Andy's tip.

I'm really looking forward to try mine on an actual take off. The real deal.

Flavio

(in reply to Big_Bird)

RE: Airplane rudder gyro - 8/4/2008 9:31:26 PM

BarracudaHockey

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No problem.

On a heli, the end points control how fast the gyro will let the helicopter piro. Its called a yaw rate demand gyro, and by setting the end points you can customize how fast the helicopter will spin about its main rotor axis.

I run into this all the time where people turn down the atv's to adjust the throw and end up with all sorts of strange behavior.

Flavio, another thing, you probably want to run your rate mode gain up to about 5 or 6 percent. That area around mid throw is really a dead mans land, from 0 to 3 or 4 percent, and as I said, start small and work your way up with the gain in heading hold.

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