loved the 3GX, Gpro feels like a brick

[Drivelayer]

I have a Trex 550 DFC that had an align 3gx on it since it bought it a few years ago. Recently I installed a new GPRo on it and I cannot get it to feel locked in or as agile as it did with the 3gx installed.

the tail does seem to hold well, stops are sloppy at best. the flip and roll rates are slow, fff tracking is poor, seems to want to drift in the roll axis ...

I am looking for any tuning suggestions and guidance.

Thanks in Advance.

[Martinshelis]

Originally Posted by Drivelayer

I have a Trex 550 DFC that had an align 3gx on it since it bought it a few years ago. Recently I installed a new GPRo on it and I cannot get it to feel locked in or as agile as it did with the 3gx installed.

the tail does seem to hold well, stops are sloppy at best. the flip and roll rates are slow, fff tracking is poor, seems to want to drift in the roll axis ...

I am looking for any tuning suggestions and guidance.

Thanks in Advance.

Your swash gain is very high and likely making it feel a little funky/robotic/slow. Your flight response is pretty low and will make it feel sluggish. Your tail is somewhat similar to mine just tuned differently. Is your wiring is pulling on the gyro? My g570 has very nice crisp stops, the flip and roll rates are plenty fast for hard 3d, tracking is good but still tuning the head gain some to make tick tocks more crisp, and it doesn't drift in rolls at all. Overall my setup on my heli is almost perfect for me and I fly hard 3d and fast circuits with 14 degrees of collective. Did you set the gpro to 8 degrees during the setup? Did you check max travel on the setup without any programming on your radio? By your description and looking at your settings I am assuming your physical setup is incorrect and it looks like you are trying to fight that with the software setup. I would suggest going back to the beginning and setting the radio at 100% and making sure the gpro is reading 100% and then go from there. With your parameters the tail should damn near snap in half with how hard your stops are programmed. The heli should flip in the blink of and eye.

[Drivelayer]

Thanks for the response. While, in my mind, I went through the setup step by step and the heli is mechanically true, as I literally pulled off a working 3gx that flew great and popped this one on, it is possible to believe something is off mechanically.
I can say for certain that the wires were not pulling on the unit.
I reset the unit back to default settings and started over trying to get it to fly well, and just couldn't. I've since pulled the gpro off and installed a demon I won at OHB this year and the heli flies great again.

I will use the gpro on a gaui x2 I picked up cause I wanted to try it out.

Thanks again

[RC/DC_5000]

Your Proportional (P) gain is so low, that it's almost turned off.
You want the P and I gains as high as possible.

The elevator precomp should not need to be that high. You should readjust your COG so that the tail does not drop on vertical ascend because the weight is physically balanced fore and aft. With the precomp that high.. the unit will nudge the tail up when it shouldn't.

But the P gain specifically does WONDERS for the overall stabilization of the unit. It's a pretty awesome FBL. Get the P and I gains cranked up just before they induce oscillations. Then spend a day just messing with the P gain. It is very powerful and dramatic.

This is actually and honestly the first complaint I've ever heard about how it flies. I fly it with a Vbar back to back... its pretty good by comparison. Not better... but its comparable.

If it drifts or rolls... you may wanna re-level swash with the tool and recalibrate things. The Gpro is ultra, ultra stable and locked in. Piro comp probably is better than the Vbar.

If you can tolerate the 3GX, then you'll be able to get the Gpro going.

[Martinshelis]

Originally Posted by RC/DC_5000

Your Proportional (P) gain is so low, that it's almost turned off.
You want the P and I gains as high as possible.

The elevator precomp should not need to be that high. You should readjust your COG so that the tail does not drop on vertical ascend because the weight is physically balanced fore and aft. With the precomp that high.. the unit will nudge the tail up when it shouldn't.

But the P gain specifically does WONDERS for the overall stabilization of the unit. It's a pretty awesome FBL. Get the P and I gains cranked up just before they induce oscillations. Then spend a day just messing with the P gain. It is very powerful and dramatic.

This is actually and honestly the first complaint I've ever heard about how it flies. I fly it with a Vbar back to back... its pretty good by comparison. Not better... but its comparable.

If it drifts or rolls... you may wanna re-level swash with the tool and recalibrate things. The Gpro is ultra, ultra stable and locked in. Piro comp probably is better than the Vbar.

If you can tolerate the 3GX, then you'll be able to get the Gpro going.

Even though his total gain is at 90 you still think his p and I are to low? I have to agree that the gpro is a nice gyro even though I want to try a vbar out just to see what the fuss is all about.

[Drivelayer]

Thanks for the detailed advise, I appreciate it. I have a buddy that flies GPro and he loves it, I was certain I would based on my experience with the 3GX and watching his fly.

[RC/DC_5000]

Absolutely... the Gpro doesn't fully lock until you crank up the P and I gains. That goes for a 600 or a 450. The GPro takes a lot of tuning so you have to be patient. Start off with a good physically balanced COG and then start cranking up the gains until you get unwanted movement/oscillations. Then back it down a little bit. I've also seen the IKON need this tuning- so I'm not bashing.

The PID gains control the response of the algorithm. Proportional, Integral and Derivative. So you are turning up the response to the error. On the Gpro- you are specifically tuning the response to the present values of error (proportional) and the past values of error (integral). Having the P gain that low is telling the Gpro not to be responsive to the present value of errors. Thats very bad. The Gpro did not come with that low default P gain.

The Vbar control loop is obviously superior and hardly needs any fine tuning. It pretty much works awesome right from the start. The Gpro needs a lot of fine tuning. It still works.. Just needs more setup.

[Martinshelis]

Originally Posted by RC/DC_5000

Absolutely... the Gpro doesn't fully lock until you crank up the P and I gains. That goes for a 600 or a 450. The GPro takes a lot of tuning so you have to be patient. Start off with a good physically balanced COG and then start cranking up the gains until you get unwanted movement/oscillations. Then back it down a little bit. I've also seen the IKON need this tuning- so I'm not bashing.

The PID gains control the response of the algorithm. Proportional, Integral and Derivative. So you are turning up the response to the error. On the Gpro- you are specifically tuning the response to the present values of error (proportional) and the past values of error (integral). Having the P gain that low is telling the Gpro not to be responsive to the present value of errors. Thats very bad. The Gpro did not come with that low default P gain.

The Vbar control loop is obviously superior and hardly needs any fine tuning. It pretty much works awesome right from the start. The Gpro needs a lot of fine tuning. It still works.. Just needs more setup.

I agree that the Gpro definitely needs a lot of fine tuning. I was completely new to fbl tuning and it took me a lot of trial and error. Even though my setup isn't perfect it is very close to being there and flies great. I have looked at most of the other fbl units pc software and like the Gpro software the most. I would like to try another fbl unit for fun but am getting pretty good at tuning the gpro and don't know what I'd be getting myself into with say a vbar spartan or Ikon. For tuning I just started off with the default gains and raised the overall gain by radio till the tail gets upset in certain maneuvers than back it off till it stops plus a couple points more. From there I start playing with the parameters to get it to behave like I want.