3GX vs 3GX MR is there any difference in performance?

[chrisleematt21]

I currently have a Trex 450 plus DFC and a Trex 550 Pro, the 550 uses a 3GX and the 450 uses a 3GX MR. I was considering buying another 3gx and installing it on to the 450 along with 2 spectrum satellites so that I could then use the same transmitter for both heli's which has a couple of advantages to me. I was wondering if the 3GX " fly's " any better than the 3GX MR? Has any one had the chance to compare the two side by side?

[coolice]

Hey buddy.

You will be able to make the 3GX fly better as you can alter its parameters using the PC software. The MR version is programmed at the factory and cannot be altered outside of the basic gain settings.
You can pick up 3GX's quite cheap so it would be a simple upgrade for your 450 and the Tx and MR sale will most probably pay for it to.
.

[chrisleematt21]

Cheers, that was what I was thinking as well, just setting my 3gx up now for the first time and there are a LOT of options, some I have NFI what they mean.

I've seen a lot of threads where people seem to slate the 3GX, are other flybarless units that much better? I've only ever used the 3GX and it seems ok although a bit complicated to setup for a beginner like myself, but I guess that's the downside for all the options.

Do people buy the 3GX MR and T6 Transmitter then? I got the impression that No one liked them so as going to thro them in a cupboard and forget about them. Result!

[coolice]

Cheers, that was what I was thinking as well, just setting my 3gx up now for the first time and there are a LOT of options, some I have NFI what they mean.

I've seen a lot of threads where people seem to slate the 3GX, are other flybarless units that much better? I've only ever used the 3GX and it seems ok although a bit complicated to setup for a beginner like myself, but I guess that's the downside for all the options.

Do people buy the 3GX MR and T6 Transmitter then? I got the impression that No one liked them so as going to thro them in a cupboard and forget about them. Result!

Hey Buddy.

No problem, you're welcome.

There is a lot of options with the 3GX, but compared to some other makers FBL unit's there isn't so many. Initially you think it's quite complicated, but once you get used to the DIR setup steps, it's actually very simple and quick to get a 3GX'd model in the air.
The main stumbling block comes later one when you can start to use the PC settings to alter how the unit feels & behaves in the air, this is even harder if you've not had fly barred experience and can relate the electronic options to the old mechanical and weight changes we used to do with fly barred models to achieve the response we wanted.

Unfortunately the 3GX never really got rave reviews due to people not understanding it and bad reviews never go away. While it is not the best FBL unit out there and has the odd flaw, once setup it can perform well and in the right hands do the book. There are better FBL unit's out there, I fly Vbar and the model does feel much better, however it's a unit that is 2.5 times the price so I'd expect it to be good.

Best thing I can suggest to do it follow the instructions through, there are video's online that have essentially taken the manual, what they have learnt from forums and made it into video for anyone to follow. Personally, the manual does work but sometimes backup from the video's helps if you have doubts.
I'm always around so any questions fire away, I can almost setup a 3GX blind folded now

With the Align branded T6J, yeah there are people that want them I'm sure, for the very reason they came with your kit originally and that is as a good started set or for the sacrificial 450 model
.

[trexsteve700]

Im in the same boat as you, converted from the align t6 to dx8 and 3gx,but not had chance to test it yet. Most of the learners at our club have gone to 3gx from flybar and are getting on really well and ive found them easy to set up by eye although the pc stuff has me stumped sometimes lol.

[tomatwalden]

I've seen a lot of threads where people seem to slate the 3GX, are other flybarless units that much better? I've only ever used the 3GX and it seems ok although a bit complicated to setup for a beginner like myself, but I guess that's the downside for all the options.

No - one of the main reasons why I ditched 3GX on my Trex in favour of the AR7200BX (BeastX) was the ease of setup in comparison to the 3GX. It's a doddle in comparison. I've since started using the Vortex VX1n across most of my helis and find it almost as easy, but with even more configurability.

The 3GX is probably the cheapest non-clone/mainstream FBL unit you can find though, and if you are comfortable with it - happy days!

[electricsceadu]

[QUOTE=coolice;1121846]Hey Buddy.


The main stumbling block comes later one when you can start to use the PC settings to alter how the unit feels & behaves in the air, this is even harder if you've not had fly barred experience and can relate the electronic options to the old mechanical and weight changes we used to do with fly barred models to achieve the response we wanted.

very well put Ian
I've found the experience of flying flybared models helps no end trying to get a fbl model to fly right
I've even when stumped with a fbl model is to take a flybared heli up to remind myself of what I need to tinker with on the fbl unit

[tourerjim]

For those that are wanting to go 3GX & want to keep within a comfort zone I would with pc software 'parameter window 2' lower the flip/roll rates & aile/elev travel limits to 20%, can also be set from the 3GX itself.
These settings will give you swash angle of about 8 degrees which is ample for fbl & the flip/roll will allow for getting into mild 3d.

[coolice]

very well put Ian
I've found the experience of flying flybared models helps no end trying to get a fbl model to fly right
I've even when stumped with a fbl model is to take a flybared heli up to remind myself of what I need to tinker with on the fbl unit

Hey Buddy.

Thanks.
As you say, past experience of tuning a fly barred model greater helps your understanding of FBL setup. As you say the same tweaks and changes are all there, but they are replicated in the digital world rather than mechanical as in the old days.
I suppose a good manual also helps
.

[chrisleematt21]

Hey Buddy.

No problem, you're welcome.

There is a lot of options with the 3gx but compared to some other makers FBL unit's there isn't so many. Initially you think it's quite complicated, but once you get used to the DIR setup steps, it's actually very simple and quick to get a 3GX'd model in the air.
The main stumbling block comes later one when you can start to use the PC settings to alter how the unit feels & behaves in the air, this is even harder if you've not had fly barred experience and can relate the electronic options to the old mechanical and weight changes we used to do with fly barred models to achieve the response we wanted.

Unfortunately the 3GX never really got rave reviews due to people not understanding it and bad reviews never go away. While it is not the best FBL unit out there and has the odd flaw, once setup it can perform well and in the right hands do the book. There are better FBL unit's out there, I fly Vbar and the model does feel much better, however it's a unit that is 2.5 times the price so I'd expect it to be good.

Best thing I can suggest to do it follow the instructions through, there are video's online that have essentially taken the manual, what they have learnt from forums and made it into video for anyone to follow. Personally, the manual does work but sometimes backup from the video's helps if you have doubts.
I'm always around so any questions fire away, I can almost setup a 3GX blind folded now

With the Align branded T6J, yeah there are people that want them I'm sure, for the very reason they came with your kit originally and that is as a good started set or for the sacrificial 450 model
.

When you have been setting up the 3gx have you ever come across a bounce when using right rudder? I dont get it with left rudder only right its really annoying but does only happen with fast piros. Just wondered if there was an easy cure as ive tried a lot of different options but havent managed to cure it yet.

[coolice]

When you have been setting up the 3gx have you ever come across a bounce when using right rudder? I dont get it with left rudder only right its really annoying but does only happen with fast piros. Just wondered if there was an easy cure as ive tried a lot of different options but havent managed to cure it yet.

Hey Buddy.

Yes I have, it became a problem in V4 firmware.

The fix I found is to make sure you setup the tail in rate mode, in this case once initialised switch into rate mode and hover the helicopter. If tail trim is needed adjust the tail pushrod length to achieve a hands off hover, better to do this step on a calm day to avoid the weather cocking effect.
Then readjust the tail travel limits within the 3GX to avoid any binding.
Also we need to remove all delay in the tail gyro parameters within the 3GX. To do so it's made easier to have the 3GX on and connected to your PC/laptop with the 3GX software on the display tab. Once here, press and hold the 3GX button when powered to enter the tail gyro setup menu and press the button to go across to the delay LED. Now move the rudder stick to select large or small heli delay and let the stick return to centre, checking on the PC screen we should see zero or a very small percentage (2~3%) of delay which is what we're after.
Now go fly and have no bounce back.
.

[chrisleematt21]

Hey Buddy.

Yes I have, it became a problem in V4 firmware.

The fix I found is to make sure you setup the tail in rate mode, in this case once initialised switch into rate mode and hover the helicopter. If tail trim is needed adjust the tail pushrod length to achieve a hands off hover, better to do this step on a calm day to avoid the weather cocking effect.
Then readjust the tail travel limits within the 3GX to avoid any binding.
Also we need to remove all delay in the tail gyro parameters within the 3GX. To do so it's made easier to have the 3GX on and connected to your PC/laptop with the 3GX software on the display tab. Once here, press and hold the 3GX button when powered to enter the tail gyro setup menu and press the button to go across to the delay LED. Now move the rudder stick to select large or small heli delay and let the stick return to centre, checking on the PC screen we should see zero or a very small percentage (2~3%) of delay which is what we're after.
Now go fly and have no bounce back.
.

Brilliant thanks i'll give this ago, hopefully tonight.

[chrisleematt21]

Hey Buddy.

Yes I have, it became a problem in V4 firmware.

The fix I found is to make sure you setup the tail in rate mode, in this case once initialised switch into rate mode and hover the helicopter. If tail trim is needed adjust the tail pushrod length to achieve a hands off hover, better to do this step on a calm day to avoid the weather cocking effect.
Then readjust the tail travel limits within the 3GX to avoid any binding.
Also we need to remove all delay in the tail gyro parameters within the 3GX. To do so it's made easier to have the 3GX on and connected to your PC/laptop with the 3GX software on the display tab. Once here, press and hold the 3GX button when powered to enter the tail gyro setup menu and press the button to go across to the delay LED. Now move the rudder stick to select large or small heli delay and let the stick return to centre, checking on the PC screen we should see zero or a very small percentage (2~3%) of delay which is what we're after.
Now go fly and have no bounce back.
.

Right I gave it ago and it got rid of about 80% of the bounce back which is fantastic. I just wanted to go through what I did to make sure I did it correctly. I put the heli into rate mode by lowering the gyro gain on my DX9 to -70, it was + 70 in HH. I then flew it and it started to spin so I adjusted the length of the rudder servo rod until the rudder would stay in place so I could do a hands off hover which it did very nicely. I then re did the limits to prevent binding. I already had the delay on zero.

When I set the heli up originally, to get the rudder servo arm at 90 I had to use some subtrim, about 8 clicks. Did I miss anything? or should I expect some bounce back?

I'd like to cure it if I can as I have another 3gx for my 450.

Thanks for the help, so far yours is the only advice which has worked.

[coolice]

Right I gave it ago and it got rid of about 80% of the bounce back which is fantastic. I just wanted to go through what I did to make sure I did it correctly. I put the heli into rate mode by lowering the gyro gain on my DX9 to -70, it was + 70 in HH. I then flew it and it started to spin so I adjusted the length of the rudder servo rod until the rudder would stay in place so I could do a hands off hover which it did very nicely. I then re did the limits to prevent binding. I already had the delay on zero.

When I set the heli up originally, to get the rudder servo arm at 90 I had to use some subtrim, about 8 clicks. Did I miss anything? or should I expect some bounce back?

I'd like to cure it if I can as I have another 3gx for my 450.

Thanks for the help, so far yours is the only advice which has worked.

Evening Mate.

Ah brilliant news, we're on the right path.

Ok, you've done all the right steps. I'd perhaps double check the zero delay, as by default Align add 30% which used to work well but from V4 onwards doesn't.

Sub trim on the tail servo isn't a good idea, this side of the FBL unit doesn't work like the cyclic gyro's whereby it remembers the added sub trim and use's the new values as the centre/neutral position. The tail will take sub trim as a command to move and so could be adding to your problems.
Ideally you need to find the arm which sits on the servo at 90 degrees to the casing without the use of sub trim, I usually use one of the small round disks on my 450's which sets the control ball about 6mm out from centre. To do this you may have to fit the servo to the holder from underneath to allow the control ball to sit on top of the servo horn rather than under it, I'd need to look at my own 450L to see if this model needs this trick or not to run shorter control arms.

What length servo arm are you currently using on the tail servo?

You're very welcome, glad to help and pleased you're having some good success.
.

[chrisleematt21]

Evening Mate.

Ah brilliant news, we're on the right path.

Ok, you've done all the right steps. I'd perhaps double check the zero delay, as by default Align add 30% which used to work well but from V4 onwards doesn't.

Sub trim on the tail servo isn't a good idea, this side of the FBL unit doesn't work like the cyclic gyro's whereby it remembers the added sub trim and use's the new values as the centre/neutral position. The tail will take sub trim as a command to move and so could be adding to your problems.
Ideally you need to find the arm which sits on the servo at 90 degrees to the casing without the use of sub trim, I usually use one of the small round disks on my 450's which sets the control ball about 6mm out from centre. To do this you may have to fit the servo to the holder from underneath to allow the control ball to sit on top of the servo horn rather than under it, I'd need to look at my own 450L to see if this model needs this trick or not to run shorter control arms.

What length servo arm are you currently using on the tail servo?

You're very welcome, glad to help and pleased you're having some good success.
.

Currently I'm setting up my 550 im using the four point ones which gives about 16mm I think and I have them on the third hole from the centre. Does it matter which type of arm you use? what difference does using a different hole make? sorry if the questions get annoying but its all new to me. The one I'm using is the one the manual says to use, I had four to pick from and this was the closest to 90 I could find.

I've just double checked the delay and it is definitely 0. I also have the Rudder Lock Gain on the 3gx set to 30 (As low as it would go as this seemed to help).

Thanks again.