3GX MRS PROBLEM?

[SnakesSA]

Hi.

I have just received my 250 Plus BTF.

After binding it to my DX8 the rudder keeps going to the left by itself.

When hovering I need to give constant right rudder to keep it straight.

All settings are as per the manual and sub trims are zero.

Is this a faulty MRS or can it be something else?

The bird came out of the box with a bent main shaft so I do not have any trust in the QC at align, I just want to sort out this problem.

Any help will be appreciated.

[ame]http://youtu.be/oA68NIsL-Pc[/ame]

Thanks,
Morne'

[jmtyndall]

What are your gyro gains set to?

With no power set your tail servo arm to 90* and post a picture of your tail blades


I suspect you're in rate mode or gain is set too low. Though gain too low will usually allow random drift in either direction, not just one

[vtown nick]

You have subtrim or trim in your tx if it is doing that. Go through your tx and check to make sure you remove it and disable flight trims as well so it doesn't happen again.

[mqowen]

Sounds like you are in rate mode. Mine was set per the numbers but ended up having to increase gain way above recommend value.

Need two green LED's on MRS.

[SnakesSA]

Originally Posted by mqowen

Sounds like you are in rate mode. Mine was set per the numbers but ended up having to increase gain way above recommend value.

Need two green LED's on MRS.

Why would rate mode cause it to move when the heli is on the ground?

[mqowen]

Originally Posted by SnakesSA

Why would rate mode cause it to move when the heli is on the ground?

Im a beginner and I Don't know a lot about rate mode, however I've made a lot of beginner mistakes.

This is one. Basically if you don't put it in heading lock mode you have to manually controll the tail. And the tail moves according to pitch and head speed changes. So every move of the throttle requires input to the rudder.

In my case it would move on the ground or in the air. On the ground I believe it tried to move because it was spooling up. Once I got head lock on, two steady green LEDs on, that stopped. However the tail will move during spool up if the tail rotor pitch isn't neutral. Which is fine if you are gradual and can correct it.

[vtown nick]

Check your radio it's nothing to do with rate/head holding modes. You shave trim or subtrim on your rudder I'm very willing to bet.

[mqowen]

Originally Posted by vtown nick

Check your radio it's nothing to do with rate/head holding modes.

It's easy to check if it is in rate mode. Rate mode is steady green for bind and steady red for status. You just flip the helicopter over and look. If it is you increase rudder gain until it turns green on status.

I set mine to align's recommended gain and it was in rate mode. I increased the gain and it changed to heading lock mode.

That's all I'm saying.

[vtown nick]

Originally Posted by mqowen

It's easy to check if it is in rate mode. Rate mode is steady green for bind and steady red for status. You just flip the helicopter over and look. If it is you increase rudder gain until it turns green on status.

I set mine to align's recommended gain and it was in rate mode. I increased the gain and it changed to heading lock mode.

That's all I'm saying.

Rate mode only really holds center, you have to provide input more than in hh but it will not cause the slider to move when the heli is stationary like the op's video. That's the result of subtrim/trim on the rudder channel. The gyro sees that as rudder command and is moving it according and since it's on the bench it will move till it gets a reaction which is impossible on a bench hence why it goes all the way.

[mqowen]

Originally Posted by vtown nick

Rate mode only really holds center, you have to provide input more than in hh but it will not cause the slider to move when the heli is stationary like the op's video. That's the result of subtrim/trim on the rudder channel. The gyro sees that as rudder command and is moving it according and since it's on the bench it will move till it gets a reaction which is impossible on a bench hence why it goes all the way.

Okay. I see what you're saying now. When I looked at the video it was only playing one quarter of the way through. Now it is playing all the way through. I think I understand what you are saying now.

And I definitely agree rate mode does not cause the slider to move like that. I thought OP meant moving while on the ground spooling up.

[SnakesSA]

Thanks Marc and VTown for the replies.

I'll go over all the settings again, it usually is the smallest thing that mess around.

Will check for Rate v HH

Will double check all trims and subtrims.

[vtown nick]

Originally Posted by SnakesSA

Thanks Marc and VTown for the replies.

I'll go over all the settings again, it usually is the smallest thing that mess around.

Will check for Rate v HH

Will double check all trims and subtrims.

Once you get it sorted out and flying, setting up the tail to hold in rate mode for me and a few others helps with tail kick in hh if flying the stock tail servo. I have flown the ds95i and currently 5084mg and they have so much torque it doesn't matter.

[sherman]

I have your exact same problem. the tail slides to one side even it is at the ground and while all my subtrims are set zero.

I then go through the 6 steps gyro setting one more time and set the left and right rudder travel limit. (page 25 of manual) Then it's fixed.

Hope this help.