one click rudder difference, really?

[arborvision]

The tail on my b4503d drifts left.....I have the servo 90 degrees from tailboom, the travel is set on gyro, slider is smoothed,gyro rate is 73.5%......I've checked all this multiple times.......even swapped the servo out for a new one. If I try and trim it while hovering one click will get it to drift the oppostie way....so its close but one click difference from a left to right drift?....now its not real bad....maybe every 6 to 10 seconds I have to correct it with a opposite rudder input to keep the tail in, I only let it drift a couple inches before I correct it.
I probaly only have 15 batteries of hover threw it about five to six feet off the ground. It's a brand new rtf with no crashes. I have my hands full learning stable hovering, is correcting the rudder normal, while hovering.

[arborvision]

I have also tried increasing gyro to 74.5%....with no change in tail drift.

[mcalder]

I know mine was drifting after a rebuild and it drove me nuts for the longest time. Everyone says you shouldn't have to trim the tail. Turns out my "slider" wasn't exactly centered with servo at 90 degree it was off just a bit. I adjusted the servo rod to get it as close to center as I could eye it and the problem was solved.

Mike

[arborvision]

Any suggestions on possible fixes would be greatly appreciated.

[arborvision]

Originally Posted by mcalder

I know mine was drifting after a rebuild and it drove me nuts for the longest time. Everyone says you shouldn't have to trim the tail. Turns out my "slider" wasn't exactly centered with servo at 90 degree it was off just a bit. I adjusted the servo rod to get it as close to center as I could eye it and the problem was solved.

Mike

I have centered and re-centered the servo a couple times with same result.....maybe I'm not getting it perfect.

[mcalder]

My servo was perfect at 90 degrees, the slider on the rudder itself wasn't centered. I checked it before and after it powered up, if I remember correctly it would move after power up, I adjusted it till it was centered no power and powered up.

[arborvision]

Originally Posted by mcalder

My servo was perfect at 90 degrees, the slider on the rudder itself wasn't centered. I checked it before and after it powered up, if I remember correctly it would move after power up, I adjusted it till it was centered no power and powered up.

That's same thing I'm doing, I guess I'm just not getting the slider perfectly centered........I'm about to buy a micrometer and measure distance on both sides of the sliders furthers travel points and split the difference.

[mcalder]

Hmmm beats me then, I didn't measure it. I've had another complete tail rebuild since the first time I "figured it out" and just eyed it this time too, and it was good enough for no drift.

[arborvision]

Originally Posted by mcalder

Hmmm beats me then, I didn't measure it. I've had another complete tail rebuild since the first time I "figured it out" and just eyed it this time too, and it was good enough for no drift.

I'm going to go over it again....hopefully it goes away...if not ill have to take video of it and hopefully someone can point out what I'm missing or doing wrong.

Thanks for your help.

[mcalder]

NP hope it helps, I just re-read your post, and for what it's worth, yes depending on wind and such I'm still having to correct the tail on a hover. If it is dead calm it will hold but any wind and I have to correct it. Of course I'm switching back and forth from my SR to my 450 and compared to the SR the 450 is solid

[Skidpad]

If you rotate the tail blades toward each other so the tips touch, get them perfectly aligned...the moment they do so will be zero tail pitch, and the slider should be centered. Try it.

Regarding your tail wag....what TC are you running? Remember that the tail has more authority too, as TC and rpm increase along with main rotor rpm. If you are running tame settings for training, I wouldn't get too worried about how the tail is performing until you start turning your TC up.

As you run higher TC settings, the heli behavior changes immensely...a gyro setting that works at 60% TC may turn into significant tail wag at higher TC.

Something to think about...

[arborvision]

Originally Posted by Skidpad

If you rotate the tail blades toward each other so the tips touch, get them perfectly aligned...the moment they do so will be zero tail pitch, and the slider should be centered. Try it.

Regarding your tail wag....what TC are you running? Remember that the tail has more authority too, as TC and rpm increase along with main rotor rpm. If you are running tame settings for training, I wouldn't get too worried about how the tail is performing until you start turning your TC up.

As you run higher TC settings, the heli behavior changes immensely...a gyro setting that works at 60% TC may turn into significant tail wag at higher TC.

Something to think about...

I'm using a dx6i with the preprogrammed intermediate settings.

[arborvision]

Originally Posted by Skidpad

If you rotate the tail blades toward each other so the tips touch, get them perfectly aligned...the moment they do so will be zero tail pitch, and the slider should be centered. Try it.

Regarding your tail wag....what TC are you running? Remember that the tail has more authority too, as TC and rpm increase along with main rotor rpm. If you are running tame settings for training, I wouldn't get too worried about how the tail is performing until you start turning your TC up.

As you run higher TC settings, the heli behavior changes immensely...a gyro setting that works at 60% TC may turn into significant tail wag at higher TC.

Something to think about...

Tc is 0, 56.5, 72.5, 72.5, 72.5,

[jdFin]

I'll throw my hat in:

1. You have drift of (very roughly) 1 degree per second. That might be the best you can get. I don't think I was ever driftless with stock gyro; some guys have better luck than others.

2. One more thing you can do to try to make it better is look for vibration - that can confuse a gyro. Does the vertical fin vibrate? The tail boom struts? Shouldn't be much blur at all in those two parts. Have you checked blade tracking? Just stuff to check. Less vibration tends to help everything.

3. Go ahead and play its game. When you correct, move it past center a bit, then continue hovering as it drifts.

(Wait 'till it gives you a 90* jolt for no reason and you find yourself side-in. That was my first crash.)

[InFocus]

Originally Posted by Skidpad

If you rotate the tail blades toward each other so the tips touch, get them perfectly aligned...the moment they do so will be zero tail pitch, and the slider should be centered. Try it.
...

?? This is incorrect.

When the slider is perfectly centered, the tail blades should have some pitch. 0 pitch on the tail would actually allow CCW rotation of the heli.

Be sure you have 0 trim on the rudder. Any amount of trim is a command to the tail gyro that you want the heli to move in that direction.

If you have drift:
a. be sure to eliminate any vibration in the heli. Checking main blade balance, bent feathering shafts, and other things that cause vibrations.
and/or
b. Check your main blade tracking. I know, sounds weird, but when tracking is off, it can be a source of vibration.

and/or
c. increase the gain of the tail gyro.

[buddha2490]

I didn't see someone mention it, so will.

Do not use transmitter trim on your rudder, ever. If you do, your gyro will not work. Set it up the best you can, but if there is still tail drift you will only make things worse with transmitter trim.

Edit: Now I see InFocus said the same thing.

[aaronbru]

I agree with the comments on checking for vibration. centering servos shouldn't have an effect on drift. The gyro's job is to eliminate drift. Stock, I had a lot of stability issues with the tail. Mostly, it was sharp right piros, but had considerable drift too.

I fixed by adding another layer of double sided foam tape under the gyro. After that i had minimal/no drift. Raising gain only made it drift 'differently'.

[arborvision]

Originally Posted by aaronbru

I agree with the comments on checking for vibration. centering servos shouldn't have an effect on drift. The gyro's job is to eliminate drift. Stock, I had a lot of stability issues with the tail. Mostly, it was sharp right piros, but had considerable drift too.

I fixed by adding another layer of double sided foam tape under the gyro. After that i had minimal/no drift. Raising gain only made it drift 'differently'.

I've got it as good as its gonna get it drifts very little after getting my tail slider perfectly centered....only vibration is probaly from main gear...having wobble switched it out twice and it still wobbles...but not as bad.