3GX Firmware Issues

[Davidehowell]

Hi all, can anybody give me a heads up on the 3GX, I have it in two of my helis, works perfectly OK in my Trex 450 with version 2.1 Firmware, but as my Trex 250 was new I thought I would upgrade to version 4, trouble was with this version cannot get the tail under any control, I've done a full re-setup to check for any errors my end, but all seemed Ok, very strange that on the latest version, no matter how you correct the Tail the link always returns to the central position, I have reverted back to version 2.1 and its now rock solid, any inputs very welcome, cheers Dave H

[coolice]

Hey Buddy.

Almost sounds as if you weren't putting the 3GX into heading hold mode if the tail slider always returned to the centre position after adding a yaw command from the Tx. As you may know, most heading hold gyro's hold in a pilot given tail command until the gyro senses the models fuselage move in response to the input.

V4 is a great firmware, but the tail setup does dictate a different approach compared to V2.1.
With V4 the tail must be trimmed via the tail pushrod to hover hands off while in rate mode and also, with the 3GX connected to the PC to make things easier, on the gyro delay parameter flick the tail stick to choose large or small delay and then let the 3GX time out without setting any delay so it stays at zero delay value. If you press the small 3GX button to advance to the next stage the 3GX does not remember the delay setting, so you need to let it time out to do so.

Also be sure to set the mounting orientation correct for the tail pre-compensation direction, green led for label facing up and red for inverted mounting label facing down.

On the models ESC, are you using the governor mode option for throttle control? If yes change this to slow spool up linear throttle and use your throttle curves to maintain a constant head speed. The governor is known to give tail issues, not that your symptoms sound like this.
.

[Davidehowell]

Thanks for your reply, I am certain I'm in HH,but I am still a novice, so can you confirm that I understand your input, if I do put it into rate mode, do I trim via the TX? For the tail push rod, regarding your further comments on setting delay makes perfect sense, again the orientation is correct.
I will leave it a few days before I have another play, thanks again for your input and taking the time to answer my questions, like everyone else, it seems the more I learn the less I know!!

[coolice]

Thanks for your reply, I am certain I'm in HH,but I am still a novice, so can you confirm that I understand your input, if I do put it into rate mode, do I trim via the TX? For the tail push rod, regarding your further comments on setting delay makes perfect sense, again the orientation is correct.
I will leave it a few days before I have another play, thanks again for your input and taking the time to answer my questions, like everyone else, it seems the more I learn the less I know!!

Evening Mate.

You're welcome, glad to help.

To help you work out if you're in heading hold mode there are two LED's on the top of the 3GX, one is the status LED and shows green when in HH mode and red when in rate mode. The other is for the governor and shines red when the governor is turned off (we need it red) and green when the governor is armed ready for use.

Yes, you need to trim the tail by adjusting the length of the tail pushrod and not using the transmitter trim for the rudder which should be left at neutral.
Just be aware the tail can swing into the direction of wind gusts when in rate mode, also if the tail is out of trim when you go to take off the tail will swing. As a starting point, the tail control arm on the underside of the tail gearbox casing should be parallel to the tail output shaft, this puts about the right amount of tail thrust in to compensate for the torque reaction on the model when hovering.
Also check to make sure you have a gyro gain value set in your Tx for the rate mode side.

Keep us posted and any problems just ask.
.

[Davidehowell]

Thanks again, yes the LED's are correct, as I said earlier, I'm 3GX ed out at the moment, this is my first build and thought I would start small, how wrong could I be, it's all very tight and the 3GX is mounted inverted and is quite difficult to get at for program selection, but I'm working through it, I also have a 450, purchased 2nd hand but has version 2.1 installed and that flys rock solid.
I went back to 2.1 on the 250 yesterday and that's pretty solid as well!! But I will give suggestions a go later this week time permitting.
The other problem for me is my location, Brighton, the nearest serious Heli club to me is about 40/50 miles round trip, so I'm having to virtually teach myself, and ask questions.
thanks again

[tourerjim]

For 3GX V4
Few QA's are you using sats or RX on 250 & 450
On your 250 have you the yellow or blue esc
What tail servo you using on 450.
How old is the esc on your 450.

[Davidehowell]

Hi, just to clear it up, my real concern is with the 250 Trex, the 450 is on version 2.1 and until I can work out the problem with the 250 & V4 with help from all of you, I'll leave that one well alone, but to answer your other queries I'm using Sats on the 250 along with the blue esc, I know there was a issue with yellow one, I think 3GX was pulling to much power causing it to constantly reset itself, Cheers Dave

[tourerjim]

Hi, just to clear it up, my real concern is with the 250 Trex, the 450 is on version 2.1 and until I can work out the problem with the 250 & V4 with help from all of you, I'll leave that one well alone, but to answer your other queries I'm using Sats on the 250 along with the blue esc, I know there was a issue with yellow one, I think 3GX was pulling to much power causing it to constantly reset itself, Cheers Dave

Sorry I meant the 250 servo, when using sats this changes the tail 'Gain' to channel 2 & gov uses the Gear channel so im just thinking this could be the problem.

[Davidehowell]

Hi again, this is where my limited experience comes in!! I thought the tail was on Aux2 & the Gov is inhibited, I'm probably wrong I wait to be corrected, cheers Dave

[coolice]

Hi again, this is where my limited experience comes in!! I thought the tail was on Aux2 & the Gov is inhibited, I'm probably wrong I wait to be corrected, cheers Dave

Hey.

You're correct, tail gyro gain goes onto channel 7 (AUX2) when using sats, not channel 2, Jim's got confused or hit the wrong key. Channel 5 (GEAR) controls the governor.
Depending on what transmitter you're using changes the standard channel assignments for each of the above controlled by the Tx, the DX8 for instance sets the GYRO menu to GEAR (channel 5) by default, you need to change it's assignment and also in the governor menu.
.

[Davidehowell]

Hi all again, here's a update on the situation, I have reverted back to version 2.1, I think I said this before, and its been flying pretty much rock solid, but here's the strange thing, had a little play last night, not touched any settings, but the tai insisted on turning right, on close Inspection the 3GX had dropped out of HH made, I have no idea why?
Cheers Dave H

[coolice]

Hi all again, here's a update on the situation, I have reverted back to version 2.1, I think I said this before, and its been flying pretty much rock solid, but here's the strange thing, had a little play last night, not touched any settings, but the tai insisted on turning right, on close Inspection the 3GX had dropped out of HH made, I have no idea why?
Cheers Dave H

Morning Mate.

Strange one. I would check to make sure you don't have any transmitter rudder trim in any of your flights modes and also that the gyro gain isn't linked to the flight modes as well, as this could be throwing you if it is.
.

[tourerjim]

Hey.

You're correct, tail gyro gain goes onto channel 7 (AUX2) when using sats, not channel 2, Jim's got confused or hit the wrong key. Channel 5 (GEAR) controls the governor.
Depending on what transmitter you're using changes the standard channel assignments for each of the above controlled by the Tx, the DX8 for instance sets the GYRO menu to GEAR (channel 5) by default, you need to change it's assignment and also in the governor menu.
.

Your right Ian must of had 1 to many Guinness that night,

Hi all again, here's a update on the situation, I have reverted back to version 2.1, I think I said this before, and its been flying pretty much rock solid, but here's the strange thing, had a little play last night, not touched any settings, but the tai insisted on turning right, on close Inspection the 3GX had dropped out of HH made, I have no idea why?
Cheers Dave H

When you went V4 did you default your TX for the 3GX to read new model, 3GX has its own memory & stores TX inputs so when going different firmware levels you need to also default TX.