6250 Sub Trim question! Thanks!

[ss1-2013]

Hello friends,


Can I use sub trim in forward programming in setup menu under swash plate menu under sub trim? The heli drifts backward in no wind. I did the mechanical setup as much as I could. When I use negative 10 degrees sub trim for all 3 channels under sub trim menu in forward programing. I get 0 degree in mid stick.



The heli drifts backward only in normal mode. In idle up 1 it drifts little & in idle up 2 the heli dose not drift at all. So that why I am trying to use the sub trim in forward programing.


Thanks in advance!
Robin!

.

[Keyrigger]

It sounds more like you have the CG giving you problems. Also, try recalibrating the gyro and make absolutely sure that the gyro is level before the calibration routine begins. If the CG and calibration are spot on, then check that your swash setup is in fact, level. You do not want to "trim" the helicopter for level hover if you are doing 3D as it will bite you when you are inverted.

For the CG, move the motor away from the main gear and hold the helicopter by the blades so that they are vertical and the main shaft is horizontal to the ground. If you see the tail drop, then you know you are tail heavy and need to redistribute the weight including moving electronics and batteries. You do not want it tail down at all. Also, put the canopy on and if you are flying without the canopy, put it on. Flying without the canopy screws up setting up a helicopter. Hope this helps.

Don

PS: The helicopter can drift a bit more when the throttle is below your hover setting.

[Deadpony]

Originally Posted by Keyrigger

PS: The helicopter can drift a bit more when the throttle is below your hover setting.

Thats a good point. If the op has his throttle a little higher each stunt mode then maybe lowering the hover throttle point would help. Might be a little to high for his setup? Or too low a head speed.

[ss1-2013]

Thanks folks for your help!

My head speed are, cannot remember from top of my head, I am guessing...
normal mode 1600 to 1700
stunt 1 is 1950 to 2150
stunt 2 is 2400.

The heli flies perfect in idle up 1&2, the head speed is about 2150 & 2400 rpm, I replaced the the swash plate servo linkages all three of them, when you look at it in O pitch in mid stick everything is flat, flat & flat, also arms are 90 degrees, whole 9 yard done, everything looks good, so I will keep on trying, I just dont want to use any sub trim in forward programming. Because I dont know if I use the sub trim in forward programming what will happen while in flight.

Thanks for your help folks!
Thousands of flights to Go! God Bless!
Thanks,
Robin.

[toyracer]

You need to adjust attitude trim for pitch towards a negative value. It can be found in forward programming in the safe menu. These values are dependent on flight mode so make sure you have your radio in normal mode when making the adjustments.

https://www.helifreak.com/showthread...37#post8153277

[ss1-2013]

Hello Folks,


I did calibrate the heli. I will test fly the heli. I will give a try (attitude setup). Thanks for the link, it was very educational....



Thank you Folks!
Thousands of flights to go! God Bless!
Thanks,
Robin!

[brianbremer]

Attitude trim is only for stability and panic modes. If you decide to try stability or panic functions (it does not sound like you are using them now) always test at a safe altitude to make sure everything is working well.

To low of cyclic gains can lead to drift in Normal (non stability mode aka agility mode), with low gains the model would still fly well. What model/servos/gains are you running? I can try to provide some guestimates.

It does sound like your model is tail heavy based on the aft drift in normal mode with no winds as the model should hold well even with low gains, you might have to make a few corrections but the model should not consistently drift in a no wind situation.

After you are sure the gains are correct and the cg is correct the model should remain fairly still in no winds and show some drift in wind (for normal mode only). To further improve the normal mode stability and as long as stick to small corrections on the cyclic sticks during takeoff and landing you can lower the setup->swashplate->decay setting which will improve the stability of the model.

[ss1-2013]

Originally Posted by brianbremer

Attitude trim is only for stability and panic modes. If you decide to try stability or panic functions (it does not sound like you are using them now) always test at a safe altitude to make sure everything is working well.

To low of cyclic gains can lead to drift in Normal (non stability mode aka agility mode), with low gains the model would still fly well. What model/servos/gains are you running? I can try to provide some guestimates.

It does sound like your model is tail heavy based on the aft drift in normal mode with no winds as the model should hold well even with low gains, you might have to make a few corrections but the model should not consistently drift in a no wind situation.

After you are sure the gains are correct and the cg is correct the model should remain fairly still in no winds and show some drift in wind (for normal mode only). To further improve the normal mode stability and as long as stick to small corrections on the cyclic sticks during takeoff and landing you can lower the setup->swashplate->decay setting which will improve the stability of the model.

Brain,
I have a Fusion 480 Smart Super Combo,
Everything is stock.
My gyro gains are:
normal mode: 65
idle up 1 is 65
idle up 2 is 65

I will try to lower the decal.
Thousands of flights to go! God Bless!
Thanks,
Robin.

[brianbremer]

Robin,

In the forward programming menu select swashplate and try these settings to start out;

Agility = 135

Roll ->Deg/S = 290
Roll->P=75
Roll->I=75
Roll->D=7

Pitch->Deg/S = 290
Pitch->P=75
Pitch->I=75
Pitch->D=14

Even if the model feels good don't be afraid to raise the swash P and I by 5% (generally they will be the same values) and evaluate the characteristics. Once your gains are to high you will notice the model bouncing on aggressive inputs.

Normal mode will drift a little in wind, stunt 1 and stunt 2 should hold solid in comparison.

Definitely check the cg on the model, it is easy to check and does make a big difference in the overall performance of the heli in flight.

Let me know if the gains decrease the original drift issue you reported.

[ss1-2013]

Originally Posted by brianbremer

Robin,

In the forward programming menu select swashplate and try these settings to start out;

Agility = 135

Roll ->Deg/S = 290
Roll->P=75
Roll->I=75
Roll->D=7

Pitch->Deg/S = 290
Pitch->P=75
Pitch->I=75
Pitch->D=14

Even if the model feels good don't be afraid to raise the swash P and I by 5% (generally they will be the same values) and evaluate the characteristics. Once your gains are to high you will notice the model bouncing on aggressive inputs.

Normal mode will drift a little in wind, stunt 1 and stunt 2 should hold solid in comparison.

Definitely check the cg on the model, it is easy to check and does make a big difference in the overall performance of the heli in flight.

Let me know if the gains decrease the original drift issue you reported.

Brain,

Once I try this settings, I will let you know! Thanks for your help!

Thanks!