DX8 Gyro Settings (Please Help)

[Ponchota]

Hellooo everyone, I have had my DX8 for a few months now actually just got it back from HH for RF repair service. I have a Trex 250 with a GP750 gyro. my problem is I bought the 250 off another member and he gave me his settings from his DX7 which seemed to work well, but I had a minor crash and replaced some tail parts. It wasn't quite right so I messed with the settings and now I can't get the tail to not spin. When I spool her up in normal mode it holds for a few seconds but when I give it more throttle (enough to slightly lift) the tail just goes into an uncontrollabe spin. If I try to counter it I have to go full rudder in opposite direction which just makes it spin in that direction! The gyro is set up correctly, I quadrillianth check it over and over. If you go into main menu on Tx and go to gyro I have CH: at gear, Sw is gyro and currently POS is 70% across the board. I have tried everything from 0-100% only thing that changes is that 100% the tail twitches a little and then lets loose. Any ideas would be greatly appreciated. Thanks

[1004ron]

As a test, change your TX from a Rate gain value, to a HH gain value and confirm the the gyro status LED changes color show the change in mode, just to confirm that the gain channel assignment is correct.

Typically uncontrolled yaw is a result of the gyro compensation being the wrong direction.

https://www.helifreak.com/showthread...77#post3069277

Originally Posted by 1004ron

With the DX8 0 to +100 is HH, and -100 to 0 is Rate mode.

[Ponchota]

Forgive my ignorance as I'm pretty new to setting up a radio. I changed the settings per your pic. and Rate is no longer there, so I assume it is in HH now. The gyro still has green light, but it was green when my display showed rate as well. Long story short, still spins.

[JoeW]

You're on to something there.

On the dx8, most gyros will have rate from -100 to 0 and HH from 0 to 100

If the light isn't changing colours, you're not changing between rate and HH, you're only switching between two HH values likely.

In his example the only value that would be in rate is the TH value.

Either your radio values are wrong, or you don't have the remote gain wire hooked up to the right channel.

[1004ron]

Originally Posted by Ponchota

Forgive my ignorance as I'm pretty new to setting up a radio. I changed the settings per your pic. and Rate is no longer there, so I assume it is in HH now. The gyro still has green light, but it was green when my display showed rate as well. Long story short, still spins.

You can use the picture example, but just make sure that you set the output channel to "Gear", if you have the gyro gain lead plugged into Gear on the RX.

Using the example pic, when you flick the TH switch ON/OFF you should see the gyro status LED change color, and that will confirm that you have the gain channel correctly assigned.

[Ponchota]

I've confirmed yellow wire from gyro is in gear spot on Rx. But the light on gyro does not change color when I give it throttle. It just stays green

[1004ron]

Originally Posted by Ponchota

I've confirmed yellow wire from gyro is in gear spot on Rx. But the light on gyro does not change color when I give it throttle. It just stays green

It won't change when you give throttle - it will change when the gyro gain value switches between a HH and a Rate mode value.

If the LED is not responding to gain changes, then it's likely that the gain channel hasn't been correctly assigned.

[Ponchota]

It will change to red if I go to aux 1 or 2 instead of gear. I was watching the tail slider when it was spooling up and I noticed that slowly creeps inward toward the boom, if I correct it it will slowly creep back again.

[1004ron]

Originally Posted by Ponchota

It will change to red if I go to aux 1 or 2 instead of gear. I was watching the tail slider when it was spooling up and I noticed that slowly creeps inward toward the boom, if I correct it it will slowly creep back again.

You need to establish a degree of confidence that the gain channel is correctly assigned, and that the gyro correction direction is correct.

When in doubt, I spool up on a smooth surface without the skid rubbers, and that way the heli is free to spin if you give small rudder commands and you can gauge the gyro reactions.

[Ponchota]

When you say gain channel do you mean where the gyro is plugged in on the Rx? I am spooling it up on my Hwood floor, and I can say for sure that if I wiggle the tail the servo reacts properly and that when I spool it up and the tail breaks loose into a fast spin I can counter it on the rudder stick with little reaction until I am just about at the stick limits then it shoots into the other direction. Sorry for being such a newb, I appreciate your patience

[1004ron]

Originally Posted by Ponchota

When you say gain channel do you mean where the gyro is plugged in on the Rx?

Yes - if you you have the gyro yellow wire in the RX "Gear" channel, then that you need to assign the TX gyro output to "Gear" - it should look the same as my pic, except show "Gear" where mine shows "AUX2".

I am spooling it up on my Hwood floor, and I can say for sure that if I wiggle the tail the servo reacts properly and that when I spool it up and the tail breaks loose into a fast spin I can counter it on the rudder stick with little reaction until I am just about at the stick limits then it shoots into the other direction. Sorry for being such a newb, I appreciate your patience

That sounds like your gyro correction direction is wrong - if you view the tail rotor shaft and move it so that it comes towards you, then the tail pitch slider will move away from you and end up against the tail box.

[Ponchota]

If I am looking at the left side of heli with boom on right and I twitch the tail towards me the pitch slider comes to me as well.

[Ponchota]

I reversed the gyro and it is much better. Now I have to tweak the settings. Awesome, thank you so much!

[aerocal]

Hmm.It was ok and then after a crash repair it mysteriously got reversed? If its a belt drive tail are you sure it is spinning in the correct direction and the blades are correct?

[1004ron]

Originally Posted by aerocal

Hmm.It was ok and then after a crash repair it mysteriously got reversed? If its a belt drive tail are you sure it is spinning in the correct direction and the blades are correct?

Very good point, but I suspect it's to do with this:

It wasn't quite right so I messed with the settings and now I can't get the tail to not spin.

[aerocal]

Yes.In another post he referred to possibly having the gain near 70.That kind of makes me suspect the blades may be on backwards.Maybe not.Ive seen this problem though more than once when the belt got put on backwards.
By the time I was asked to look at it gyro and rudder direction were reversed and blades were on backwards because tail was spinning backwards.No offense intended.Its kind of a newb mistake.Just sayin its something to check.

[1004ron]

On second thoughts, if the belt wasn't correct, then the stick direction response would have been backwards, even if the pitch slider was moving in the correct direction ???

[Ponchota]

Originally Posted by aerocal

Yes.In another post he referred to possibly having the gain near 70.That kind of makes me suspect the blades may be on backwards.Maybe not.Ive seen this problem though more than once when the belt got put on backwards.
By the time I was asked to look at it gyro and rudder direction were reversed and blades were on backwards because tail was spinning backwards.No offense intended.Its kind of a newb mistake.Just sayin its something to check.

Well I got the heli used from a member and I used his settings from his DX7 which got me in the ball park then I tweaked it a bit and it was good. After the crash I did take the boom off to inspect cuz the boom could twist in the mount. Come to find out the tab in the mount was gone. When I replaced it I put the belt back on correctly. If you are facing the tail rotor the blades spin counter clockwise. That's correct right? Bye the way thanks for the advice on sending my DX8 back to be repaired. They did it for free as a gesture of good customer service. I'm a big HH fan now. Good new on the 250 is that now I'm down to a tail wag. Hooray!!!

[Ponchota]

Originally Posted by 1004ron

On second thoughts, if the belt wasn't correct, then the stick direction response would have been backwards, even if the pitch slider was moving in the correct direction ???

In my newb stupidity I may have inadvertanly switched it without knowing it. Watching the vids here they say to keep it in normal mode so that is why I didn't think anything of it. Thanks for your help and patience.

[1004ron]

Originally Posted by Ponchota

Well I got the heli used from a member and I used his settings from his DX7 which got me in the ball park then I tweaked it a bit and it was good. After the crash I did take the boom off to inspect cuz the boom could twist in the mount. Come to find out the tab in the mount was gone. When I replaced it I put the belt back on correctly. If you are facing the tail rotor the blades spin counter clockwise. That's correct right? Bye the way thanks for the advice on sending my DX8 back to be repaired. They did it for free as a gesture of good customer service. I'm a big HH fan now. Good new on the 250 is that now I'm down to a tail wag. Hooray!!!

Correct, the tail rotor spins CCW.