Hi folks,

I've done several flights with my TRex500 Flybar + Spirit Pro.
(Note @ZeXx86, with a shunt ratio to 195% with my HW Platinum 80A, the consumed mAh Vs. charged mAh is between 1% and 4%. Finally, I'm happy of the Hobbywing ESC current capabilities ).

My heli skills are very low. So, I don't do 3D flight. Just hovering and flying a bit around the field (Normal & Idle-Up modes, no 3D mode).
Thanks to the Rescue mode, I think I will be more confident, thus I'll be able to increase my pilot's skills.

My radio gear is a FrSky X9D+.
The gain ratio is 65%.

Now, here are my questions:
1. If I push the collective pitch to the maximum (+12° @2300rpm), the tail move to the right (I'm facing the back of the TRex during this maneuver). Do I need to tune some parameter? If yes, which one? I didn't try to increase the gyro gain, since the user guide said that around 55% it should be fine. My setting is already 10% over this default value.
2. When hovering, the TRex has a slow up and down movement on the longitudinal axis (to be more precise, on the elevator servo). Any idea why? Which parameter can I try to tune, to cancel this parasite effect? When the heli is moving nothing weird is happening. However, as mentioned, I'm a beginner so my observation can be incorrect. Off course, when the heli is not flying, the servos are perfectly static.

Thanks,
Seb

Hi,

thank you for great message!

1. Yes, Gyro Gain should be always tuned specifically for the model. 50% is fine for the maiden flight but it is always needed to change it. So the easiest thing to try is to increase Gyro Gain first.
Increase it by 2-5% until you will observe tail oscillation in a fast forward flight or turns or pitch pumps.
If it will still not help then Pirouette Consistency and/or Rudder Delay should be changed. You can find optimal Rudder Delay value in our Servo list.

2. This is in the most cases result of bent main shaft or less likely feathering shaft. It could be also result of some other blade imbalance.
If these things are fine, you can try to reduce Advanced/Elevator Filter parameter. Maybe to 0-1.

_________________
Spirit System developer

Hi Tomas,

1- OK, I will increase the gain. I was anxious to setup a too high gain (currently, it is 65%).
2- I don't think the main shaft is bend. My Rex has never crash. However, I never balance the main blades.... I will check this point.

Again, thanks a lot for your great support.

I know this is an old post, but just catching up

Trex 500s are renowned for "nodding" - a fore-and-aft movement if the headspeed is too low, 2300rpm is below what most people would use for a 500. To test try with a higher headspeed and see if that solves your proble.

Hi Mike,

Thanks a lot for this tip !
I'm a beginner, so I'm scare to use higher rpm (even if I didn't setup a very high pitch angle).
I checked the telemetry log of my last flight, it is indeed around 2300rpm.
What would be your recommendation for a beginner?

Thanks for your help.

Seb

PS: I checked the user guide, in fact the recommend rpm is 2400rpm for hovering and 2800rpm for Idle flight!!
OMG!