450 Tail Kick...

[Rob Lancaster]

Ok guys, here we go, last but not least; the tail kick.
I managed to get most of the tail kick out but not all. Sometimes it kicks more then others. But always after a rudder input the tail will bounce back and forth and then slowly be reduced to a small wiggle, but still would remain oscillating.

Man you jab the rudder and she does the hula when released and then slowly reduces back down to a wiggle. Do you guys know what I mean?
I again have gone from a very low to a very high setting in the gyro. It seems to like it better with a setting around 60/65. But that's the best I can get it. Something else electrical needs to be adjusted.

I'm STILL waiting for Spartan to get back to me. I asked them some questions over a week ago about this problem but so far, just crickets...
A reminder: I have a Spartan Quark gyro and I'm running a Hobbywing Platinum V4 60 amp ESC, with a P-BOX...
Well that's it for now.
What would you guys do next?
Heck, by the time Spartan get's back to me, we all might have it all sorted out by then; ha!
Thanks crew,
Rob...

 

[Geena]

Bad mechanical setup can cause that issue too. Mechanical binding can also cause it. A slow tail servo is another thing that can cause it to bounce and hunt like that. Make sure that the tail slider moves smooth and freely, if all that is good... try going out one hole with the ball on the tail servo horn.

 

[murankar]

Your stop gains sound like they are to high.

Other tail kick issues can come from tail pre comp being to high or low. A poorly adjusted governor. Not enough mechanical gain.

Also check that your blade grips are built right.

 

[D.O.G.]

Recently on my 500 I had problem with my tail acting up. I found out that a very small amount of surface rust, that i couldn't see unless I ran my fingers over it, formed on my tail servo slider rod right where the rod slides through the hole of the tail rod holder. Just enough to mess it up. I also discover while inspecting the tail pitch assembly, my sleeves where worn out which also made my tail act up. I just wanted to throw that out their also. Good luck.

 

[Tony]

What tail servo are you using?

 

[Rob Lancaster]

Ok folks, this may take some time to go over it all. I knew all you guys would be full of ideas..
In the mean time; medic! medic!!!>>> man down! We have an aircraft down some where in the Haiku area!..

Oh man my li'll Blade 130S attacked me last night. I was pirouetting rather fast, the next thing I know the heli was in my lap... The blades cut up two fingers pretty bad. One gash is right across a knuckle and its killing me!

It looked like a crime scene around here. Blood all over my new pants, heli, floor, desk, sink and counter top; awee! Man that little thing can really injure a guy. This event reinforces my belief that my 450 could kill me if I got hit in the neck. Or if it throws a blade and spears me to a fence or something; ha!...

Hey Tony, my rudder servo is a Futaba S9257...….. The servo linkage is a carbon fiber rod. No binding … Tail assembly was recently overhauled and all checks out there...

As for the tail pre-comp and stop gains; I have no Idea what these are or how to set them.

Thanks everyone, I'll see if I can work with one hand but I can't hold and operate TX... DOH!!
Lefty....

 

[D.O.G.]

OUCH!. Sorry to hear Rob. Yeah, that's why you don't call them toys. They can hurt you badly...no matter the size. Your right that a 450 can kill you. My blade had a hair line crack right at the main blade grip holder that I didn't notice. Upon take off, the blade flew off, like you mention and stuck on my back deck about 5' away from the wife. Til this day she doesn't trust the heli and watches from far away. Pre check list is diffidently mandatory just to prevent anything from happening. Good luck on the recovery.

 

[Tony]

Yea, people consider these things toys, but last I checked, a teddy bear doesn't draw blood.

I don't think those things URI mentioned are actually a thing in a flybar helicopter tail gyro. They are pretty simple little boxes. I'm wondering if you don't need to add a little delay to that tail gyro though. Not much, just enough to keep it from over reacting. The 9257 isn't the fastest out there anymore and the gyro could be asking it to do more than it is capable of.

 

[murankar]

I saw Spartan and p box and thought vortex.

If your sure that the mechanical setup is good and spot on then I would look at gains.

If I understand correctly you have a tail bounce after a tail input? Example you do a piro, stop and it bounces till it settles in. Or you jab the rudder stick and it bounces till it settles in.

If this is the case then I would drop the gain a few points and see if it goes away. If not then return your gain back to the start point. I would then look at the ball link on the servo arm.

Its been a long time since I played on a fly bar. So my knowledge is rusty at best.

 

[Rob Lancaster]

Yeah murankar! Exactly! There's still a small kick as I spike the collective pitch too...
I went over all the rod, balls and links and the tail rotor assembly. All is cherry there. However, now I'm not sure about this servo... As I was inspecting everything back there I noticed that the servo wasn't centered. I tried to center it with the sub trim but the sub trim doesn't work right. When I add or subtract sub trim the servo arm won't move until I make a drastic change. Then the arm moves all the way to one side or the other. Oh and the blue LED starts blinking, indicating off center blades.

Tony said this Spartan gyro doesn't like sub trim and I believe him...

Question time: shouldn't I be making rudder sub trim adjustments with the gyro bypassed? And then check or reset the gyros end points.

I also tried another, known good test servo and the problem remains... I know I can center the blades by sliding the servo on the boom but that doesn't center the servo. I'm wondering if this could be part of the problem.
Ok guys, the search continues.
Rster...

 

[Tony]

Yea, try plugging that servo directly into the Rx and set your center. Once you are close, use the rod to do the fine adjust. Make sure to set your endpoints again when you are done. Since it is kicking out on a collective change, delay will actually hurt here. I thought you having a hunting or oscillations while in a static hover.

 

[Rob Lancaster]

Actually there is a tiny, tiny oscillation while in a hover. But again when jabbing the rudder it bounces and then settles back in like murankar said.

Ok I'll bypass the gyro and see what happens.

I already repaired the li'll butcher, (Blade 130S)… She needed a tail rotor, main gear, swash to blade grip linkage. There were also two servos that were damaged. I had all parts in stock except the servos. Fortunately I got very lucky and was able to repair them both, yippy I yo kaya 'A'!!! Even with one hand, fun, fun, fun! HA!
Stay tuned,
Rster...

 

[Rob Lancaster]

Good news...
Yes, yes,,! When setting the rudder servo's center, it's a good idea to bypass the gyro.
The center is dead balls on now...

I redid the end points too, nice!
All that was needed to do to get the final centering was a mere L3 on the sub trim. any more will cause a blade center fault blink on the gyro. Right Tony... Spartan gyro, it truly doesn't like sub trim. Oh I did slide the servo a couple of millimeters up the boom for a better centering.

I hope the wind dies down soon. Now that the major pain has passed, I think I can handle the TX. However I still think that the tail problem will continue. At this point, I'm just glad we now have the all linkages, rods, servos, blades, all squared up much better. I have a feeling digital programming is next. READY!!

Forward! March!!!
Stay tuned,
Rster...

 

[Rob Lancaster]

More good news!
I couldn't wait so I took her up today.

The tail bounce, when jabbing the stick, is completely gone!
All that's left now is to figure out the very, very minuscule oscillation at hover and kick when pouring on the collective pitch.

Note: I did go through the gyro settings again...
It really is way better!
What do you guys say; let's get that last 1.5%
Thanks team!
Rster...

 

[Tony]

No, actually we say hahahahaha.

 

[Rob Lancaster]

You learn something new here all the time.. HA!

 

[Rob Lancaster]

Well I think Spartan's customer service is non- existent. It's been three weeks and three emails with no response.
I hope we can put the cherry on the top of the cake, by resetting the ESC's I/P settings. I figure I'll go up one number on each and see what happens.

What do you guys think? Should I start there?
Rob...

 

[Tony]

It's worth a shot. Just use caution when you test it. It could go out of control.

And I'm assuming you are referring to Proportional and Integral on the PID settings, yes? If not, then I will need you to clarify lol.

 

[murankar]

If this is for the governor in the esc then you will need to track your head speed to see what it is doing while you fly. Now if you are still fighting the tail kick then lower the P gain A few points and see what happens.

If the problem does not go away then restore your setting and increase from start point and see what happens. My guess its an over shoot error so then increasing I gain may be the issue. Again its going to be trial and error.

 

[Rob Lancaster]

Yup, these are the P/I settings in the ESC... (Hobbywing Platinum V4)
What are PID settings? Are we talking about the same thing?

Murankar, when you say track my head speed, do you mean just listening for the ole bogging? Anyway I'm going to reset the P/I settings per your instructions and I'll let you guys know how she goes.
These types of settings are completely new to me so this is very interesting learning what they are for...
Thanks,
Rob...