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GY401 Confusion

Old 11-22-2006, 07:11 PM
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Default GY401 Confusion

I have the GY401 with the 9650 digital servo and a Futaba 9C.

I have two questions:

1) It says in the GY401 manual that turning the Limit pot clockwise will increase the servo throw. Mine decreases the servo throw. In fact I have to have it full clockwise to cut down the travel to get it to not bind. I adjust this in normal mode, not AVCS. This is backwards from the manual, and backwards from other advise I have received ***?

2) Bob Whites video says to adjust the gyro sensitivity to 60% on the transmitter, I have heard 30% from others. Near as I can tell 30% is for normal mode and 60% is for AVCS mode. Is that right? How would I know if it is too high or low? What is the behavior of the heli?

Thanks
Old 11-22-2006, 07:52 PM
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Default RE: GY401 Confusion

Issue #1:
Check to see if your servo is reversed or not (In the radio or on the gyro). That's what this sound like.

Issue #2:
Depending on your EPA/ATV channel 5, assuming 0-100%. Normal and AVCS mode are split 1-50% Normal and 50-100% AVCS

[0 50 100] EPA/ATV
[100 0 100] Gyro Gain %
[Normal AVCS] Gyro Mode

So if you want let's say 60% AVCS you need to set your gyro gain to 80% and if you want 80% Normal gain would be set to 10%. I hope this helps. Multiply the gyro gain value by 2 to get actual gain % since the EPA is divided by 2 to split the modes.
Old 11-23-2006, 08:34 AM
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Default RE: GY401 Confusion

Issue #1 - I reversed channel 5 and now the pot moves in the correct direction, increase throw is clockwise. In nomal mode, I seem to get full travel on my slider at about 60% rudder, is that normal?

Issue #2 - I should have clarified that I have a 9C super. I think they set up channel 5 to actually read correctly without all the divide by 2 stuff. It starts at zero, turning one way gives AVCS 0 to 100 turning the other way gives normal 0 to 100. Right now I have it set to 40% in AVCS. So how do I know if that is too high or too low, what is the behavior that this effects? What do you guys have it set to in normal mode, idle1 and idle2?
Old 11-23-2006, 09:09 AM
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Default RE: GY401 Confusion

First ensure you have it connected correctly.

The gyro 3 wire connector should be plugged into channel 4, the single wire should be plugged into channel 5 and aligned with the white wires from the other servos.

Reversing channel 5 should only effect which direction the switch you have selected is Heading Hold and which switch position is Normal (rate) mode and should have no effect on the limit pot.

Make sure you set the gyro sens mix to ACT and the mode to GY.
Then set Rate up = avc 50 and rate dn = nor 50 this will give you 50 percent gain in both modes, adjust from there. If the tail doesnt seem to hold well increase the gain, if it wags or oscilates back and forth you have too much gain.

If you are at 60 on the limit and you can decrease your servo arm length and increase your limit thats a better setup.
Old 11-23-2006, 09:47 AM
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Default RE: GY401 Confusion

"Reversing channel 5 should only effect which direction the switch you have selected is Heading Hold and which switch position is Normal (rate) mode and should have no effect on the limit pot. "

Indeed - this really confused me. Because what you are saying is in line with what Bob Whites video indicates. "You know channel 5 is reversed if in Normal (rate) mode you get a solid light on, Because a solid light indicates HH mode"

However - on mine, in Normal (rate) mode the light blinks, whether channel 5 is reversed or normal. It is very strange.

Old 11-23-2006, 10:07 AM
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Default RE: GY401 Confusion

Ok a blinking light, probably a slow flash, means the gyro isnt getting a signal on the single wire, it wont initialize correctly and I reccomend you dont try to fly it like that.

If its a double flash it means its getting a stick (or trim) input.
Old 11-23-2006, 10:35 AM
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Default RE: GY401 Confusion

I will double check the single wire going into channel 5. But it does turn solid on ACS startup, and the heli flys well and locks its tail.

I did drill a hole as close to the hub as posible on the servo, and double checked all the connections.

Thanks for the reply on the gain. So the higher the gain the more HH behavior will be exibited, if too high it can wag.


Just the facts:

With channel 5 in normal direction, The 401 gave a solid light on AVCS startup.
with channel 5 reversed, The 401 gave a solid light on AVCS startup.

Most strange, perhaps someone with the same setup could try the above experiment for me.

Old 11-23-2006, 11:42 AM
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Default RE: GY401 Confusion

Set channel 5 to the normal direction and set up the gyro sens screen like my previous post.

Power up the system and watch the gyro, the light should come on solid. Flip the switch you have assigned to the gyro gain and the light should go out.

Give left or right rudder input and the light should double flash.

Put it back in avcs and the light should go on solid.
Move the throttle stick up and down and verify that the light remains solid (if this is a trex disconnect the motor), if you get a double flash (make sure you arent bumping the stick left or right) then you have REVO mixing enabled, that needs to be set to INH (inhibit)

Put the flight mode switch in idle up, the light should again, remain solid, if not you have trims enabled for each flight mode, make sure the rudder trim is centered in each flight mode and dont mess with it.

Move the throttle up and down to make sure you dont have revo enabled in idle up.

Do the same test for each flight mode you are using.
Old 11-23-2006, 11:32 PM
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Default RE: GY401 Confusion

Baracuda,

I did exactly as you specified. Channel 5 in normal, Light first goes solid red, then off when I flip the Gyro Sens to Normal. Tested for REVO that is INH in all modes.

Then I did exactly the same thing with Channel 5 reversed, It does exactlly the same thing. Light first goes solid red, then off when I flip the Gyro Sens to Normal.

Seems to me this 9C super is compensating in some way. As near as I can figure it because I have channel 4 reversed I also need channel 5 reversed to get the trimmer pot to move in the right direction.

Any other thoughts or shall we keep it a mystery?

Old 11-24-2006, 08:38 AM
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Default RE: GY401 Confusion

Channel 5 has nothing to do with the trimmer pot.

Do this, go into the AUX CH menu and make sure you have CH5 assigned to the same switch you have it assigned to in the GYRO SENS menu or set it to NULL there.
Old 11-24-2006, 11:24 AM
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Default RE: GY401 Confusion

You may have discovered something.

In the Aux Ch menu, CH5 is set to switch F, but I have assigned Gyro Sens to switch E. (The same one I use for idle-up). Do you want me to change ch5 to switch E or set it to NULL?

I believe you are correct on the Limit Pot. It seems to be working in the right direction now regardless of ch5 direction. So I must have been wrong. So now the only problem I have is:

How do I tell if ch5 needs to be reversed or not? I watched Bob Whites video again and he shows that if it doesn't go into HH mode, solid red, on initial startup, you need to reverse ch5. Mine will go to solid red with ch5 in normal or reversed.
Old 01-04-2007, 06:55 PM
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Default RE: GY401 Confusion

This may or may not help but ,it is what I used to set up my gyro go to" how to set up electronics "in the gyro section read it all...dont forget that this web site is for raptors so disregard all setups that are for that heli...it does tell you step by step how to set up different gyros,I couldnt have done it without this web site...http://www.raptortechnique.com/

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