3GX Collective and Cyclic Pitch Question

mstenbo · 05-03-2012, 04:06 AM

Hi all.
I recently bought a Trex 450 with 3gx and am really enjoying it.
I have set it up a number of times and am becoming familiar with how to do this.

The problem I am having is that when I do the collective and cyclic pitch settings while going through the setup I set both collective and cyclic max. to 10 deg. But when I am finished and initialize the unit I get about 18 deg from the cyclic. The collective is still 10.

I am using a DX7s and my swash settings are:
Ail -71
Ele +70
Pit +42

The simple answer would be to reduce the Ail and Pit settings to around 40. The manual says I can alter the swash settings without having to reset the 3GX but I wonder if I am doing something wrong?

The heli was very twitchy around mid-stick but I fixed this with around 30% expo on cyclic.

Has anyone else experienced this problem?

Does anyone have any ideas for me?

Thanks in advance.

Coolice · 05-03-2012, 07:04 AM

Hey.

What firmware are you running? We need to know this to offer advice on why you're seeing the pitch range you are.

On the newer V2 firmware, you set the swashplate mix values while in DIR mode to give 8 degrees of cyclic pitch. The 3GX then stores this information so that it knows where 8 degrees is along the travel range.
Outside of DIR mode there is still more cyclic pitch available for the 3GX to use to control the roll and flip rates, however if binding is observed then using the PC software you can reduce the overall travel limit of the swashplate to stop any binding.

On older firmwares it works a little differently, hence the need to know.
.

bad007 · 05-04-2012, 06:35 AM

Why would you set everything ot the max and wonder why it's twitchy?????
1.* set cyclic 8-9 depending on your skills and 12-13 pitch, dido.
for 2.0 8 cyclic is a must like coolic mentioned and then in FM settings, set your limits linked up with the cyclic in a corner incremently and use cyclic expo in the software instead of in the TX

scoio · 05-04-2012, 07:22 AM

Quote:

Originally Posted by mstenbo

Hi all.
I recently bought a Trex 450 with 3gx and am really enjoying it.
I have set it up a number of times and am becoming familiar with how to do this.

The problem I am having is that when I do the collective and cyclic pitch settings while going through the setup I set both collective and cyclic max. to 10 deg. But when I am finished and initialize the unit I get about 18 deg from the cyclic. The collective is still 10.

I might be wrong, but you do not have an accurate mesurement when the unit is not is DIR mode.Whit the control loop on you cannot measure any pitch or cyclic as the c.l. keep correcting the swash.

Chris

mstenbo · 05-05-2012, 03:08 AM

Hi all,
Thanks for the responses.

Bad007 - Firstly the manual states I should set the collective between 9 and 13 deg. I have set it at 10. That is not "the max". Secondly I am not wondering why it is twitchy, if you read my original post again you will see that this was something I noticed and found a solution for.
Really... 5 question marks? And I'm not really into Dido.

Coolice - I'm not sure what version I have, I bought the heli used a month ago and have not upgraded the software, so I assume it's running 1.2
You have answered my question anyway with the 3GX responding to my set endpoints and then having further travel. There is no servo binding so it's all good.

Chris - you are right about incorrect measurements when not in DIR mode. For the reason Coolice talks about. I have a digital pitch gauge but it's not fast enough.

05-03-2012, 04:06 AM	#1
mstenbo Registered Users Join Date: Apr 2012 Location: New Zealand	3GX Collective and Cyclic Pitch Question Hi all. I recently bought a Trex 450 with 3gx and am really enjoying it. I have set it up a number of times and am becoming familiar with how to do this. The problem I am having is that when I do the collective and cyclic pitch settings while going through the setup I set both collective and cyclic max. to 10 deg. But when I am finished and initialize the unit I get about 18 deg from the cyclic. The collective is still 10. I am using a DX7s and my swash settings are: Ail -71 Ele +70 Pit +42 The simple answer would be to reduce the Ail and Pit settings to around 40. The manual says I can alter the swash settings without having to reset the 3GX but I wonder if I am doing something wrong? The heli was very twitchy around mid-stick but I fixed this with around 30% expo on cyclic. Has anyone else experienced this problem? Does anyone have any ideas for me? Thanks in advance.

05-03-2012, 07:04 AM	#2
Coolice Registered Users Join Date: Jun 2004 Location: Northants, England	Hey. What firmware are you running? We need to know this to offer advice on why you're seeing the pitch range you are. On the newer V2 firmware, you set the swashplate mix values while in DIR mode to give 8 degrees of cyclic pitch. The 3GX then stores this information so that it knows where 8 degrees is along the travel range. Outside of DIR mode there is still more cyclic pitch available for the 3GX to use to control the roll and flip rates, however if binding is observed then using the PC software you can reduce the overall travel limit of the swashplate to stop any binding. On older firmwares it works a little differently, hence the need to know. . __________________ Ian Contessa Team Robbe SchluterUK / Midland Helicopters / Align To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

05-04-2012, 06:35 AM	#3
bad007 Registered Users Join Date: Nov 2009 Location: New Brighton, PA	Why would you set everything ot the max and wonder why it's twitchy????? 1.* set cyclic 8-9 depending on your skills and 12-13 pitch, dido. for 2.0 8 cyclic is a must like coolic mentioned and then in FM settings, set your limits linked up with the cyclic in a corner incremently and use cyclic expo in the software instead of in the TX __________________ Align 450Pro 3GX, Align 500 3G Align 550 3g, Velocity 50 Vbar

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05-05-2012, 03:08 AM	#5
mstenbo Registered Users Thread Starter Join Date: Apr 2012 Location: New Zealand	Hi all, Thanks for the responses. Bad007 - Firstly the manual states I should set the collective between 9 and 13 deg. I have set it at 10. That is not "the max". Secondly I am not wondering why it is twitchy, if you read my original post again you will see that this was something I noticed and found a solution for. Really... 5 question marks? And I'm not really into Dido. Coolice - I'm not sure what version I have, I bought the heli used a month ago and have not upgraded the software, so I assume it's running 1.2 You have answered my question anyway with the 3GX responding to my set endpoints and then having further travel. There is no servo binding so it's all good. Chris - you are right about incorrect measurements when not in DIR mode. For the reason Coolice talks about. I have a digital pitch gauge but it's not fast enough.