APM 2.6 in T-rex 250 set up


I am working in an autonomous control design for a Trex 250 (PRO DFC) using the APM 2.6 for my thesis. I made some adjustments in the helicopter, I replace the landing skid for a 450 size to have enough space to place all the components on it (among other things), I set up the 3gx gyro that comes with the helicopter and I connected the APM 2.6 signals between the receiver and the 3gx (input/output respectively).

I did the set up mentioned in the official page and adjusted the PID gains using the values found for a 450 size helicopter in this forum. I made some fly test but the results are still not satisfactory, The helicopter can lift but bounces a lot and turns counterclockwise, I don’t have control on it ( I am using it in governor mode). So I am wondering if you can suggest me a set of values for the PID gains for this type of helicopter?

And also, do you suggest to keep using the 3gx gyro system included in the helicopter or only use the APM 2.6 to control the helicopter?

Thank you in advance for your help.

I have been recently working on 250 as well, however haven’t got to installing APM yet.

I noticed that the flybarless gains for the 250 are much lower for a 3d flybarless controller (tarot). So my guess would be to reduce the gains which you used in 450 ( assuming the servo hole etc were same ) and try.

My main question is why are you using a 3GX on top of the APM? The Helicopter software does a really good job flying helicopters. Even the tail can be rock solid if setup right. I would remove the 3GX and only use the APM to control your heli. Once you established that I would go through the Helicopter tuning guide “read it multiple times” it will be a lot of ups and downs to get your heli dialed in right but when it’s done you will love the way it flies. I figure if the helicopter doesn’t fly like a standard FBL helicopter then your PID setting are not right and take it slow!

Yeah, the system is not designed to control the heli through a Flybarless controller. It is supposed to drive the servos directly. I don’t think you’ll ever get it working right that way.


I have a Mikado Logo 500, with a Agusta A109 body where I want to use a HKPilot Mega 2.7 Master Set With OSD, LEA-6H GPS, Power module, Telemetry Radio (433Mhz) (XT-60). But before trying it on the BIG THING, I would like to fly it first on my TREX250 to see how it works and to learn how to setup.

Did you have success with this project? Can you share the details or usefull links?