TAROT 3 axis gyro

[clough42]

Originally Posted by Emurzion

Where did you find that the roll and pitch gain should be at 10.

It was mentioned in the posts on RCG announcing the firmware. Here's the official Tarot download page. It just says to reduce D gains if you get hunting, but doesn't give a target number. Other posts suggest the new firmware can cause "violent oscillations" with high D gains. That sounds hard to land, so I followed the advice and just set them to 10.

www.0577mx.com/news_view.asp?clsid=15&id=268

[Emurzion]

Thanks DR M.

What are the recommend tweaks we need to make with the new firmware?

A list should be good.

Deadband = 10
D gain = 10

And....

[Dr. M]

Originally Posted by Emurzion

Thanks DR M.

What are the recommend tweaks we need to make with the new firmware?

A list should be good.

Deadband = 10
D gain = 10

And....

Fly first tweak later.

[Rahulgaba]

My bird is acting wierd .... Please help if this is a tarot issue... (I don't think so )


But please let me know!

Man. I replaced every freaking gear shaft , bearing on it. New everything. I am so frustrated. Low head rpm doesnt show it.. But idle up 85 percent throttle or up as you can see in the video goes crazy... Tail fin , carbon boom supports, tail push rod all go crazy!!!!!!! Blades are tracking.

I am stuck!! Help!!!

YouTube

YouTube

[Dr. M]

Originally Posted by Rahulgaba

My bird is acting wierd .... Please help if this is a tarot issue... (I don't think so )


But please let me know!

Man. I replaced every freaking gear shaft , bearing on it. New everything. I am so frustrated. Low head rpm doesnt show it.. But idle up 85 percent throttle or up as you can see in the video goes crazy... Tail fin , carbon boom supports, tail push rod all go crazy!!!!!!! Blades are tracking.

I am stuck!! Help!!!
http://www.youtube.com/watch?v=l0OyWyK_7pQ

Holy cow! That is the most massive vibration I've ever seen on a 450. I'm totally surprised the ZYX didn't freak out and flip the bird over right as you set it down.

I'd say it more than likely it's got something to do with your tail hitting some resonance frequency with your chassis. Check the follwoing items and make sure they're not bent or broken:
- tail shaft
- tail hub
- torque tube (if applicable)
- tail bearings

If those check out, make sure your tail blades are balanced. Even better try a different pair of tail blades and make sure those are balanced.

Dynamically balance your tail blades: remove main blades and tail push rod from the servo end (keep it attached to the tail pitch level. Spool up on the bench to your highest HS you'd be using in flight and watch the tail blades: they should be tracking perfectly. If you spot them out of track or if you see vibes in the tail fin, add a piece of tape to the leading edge of one of the tail blades. Repeat the spoolup test and observe if the vibes got better or worse. If worse, move the tape to the other blade, otherwise, keep adding small bits of tape until you see the vibes diminish and start to increase again, then remove the last piece you added. On a 450 I've never had to add more than 3 bits of tape to even the worst tail blades: clear scotch tape about 5mm wide, 15-20mm long.

[Rahulgaba]

Thanks for the input.

The things mentioned first are all new like brand new never flown new. Bearings shafts and torque tube.

Torque tube is not hard in on both sides has wiggle room. The tail blades are new I'll check as you said, but without tail and main blades I saw some vibes in the tail fin on the bench. The whole helis seems to be in sort of a constant hummm.... Like its not reaching that resonating frequency where things can be in harmony. Even replaced the motor mount. Lol

I'll check more things. Will update y'all.

Thanks for the reply dr. M

[dna001]

Originally Posted by Rahulgaba

Thanks for the input.

The things mentioned first are all new like brand new never flown new. Bearings shafts and torque tube.

Torque tube is not hard in on both sides has wiggle room. The tail blades are new I'll check as you said, but without tail and main blades I saw some vibes in the tail fin on the bench. The whole helis seems to be in sort of a constant hummm.... Like its not reaching that resonating frequency where things can be in harmony. Even replaced the motor mount. Lol

I'll check more things. Will update y'all.

Thanks for the reply dr. M

Had first maiden on my friends 450 4cell at 80% throttle yesterday and it did the same thing, we lowered the d gain from 30 down to 15 and lowered tail gain and it went away even though we later found out it had a bolt missing from the anti rotation are.
Have you tried lowering the d gain ?

[Cap231ex]

Originally Posted by Rahulgaba

Thanks for the input.

The things mentioned first are all new like brand new never flown new. Bearings shafts and torque tube.

Torque tube is not hard in on both sides has wiggle room. The tail blades are new I'll check as you said, but without tail and main blades I saw some vibes in the tail fin on the bench. The whole helis seems to be in sort of a constant hummm.... Like its not reaching that resonating frequency where things can be in harmony. Even replaced the motor mount. Lol

I'll check more things. Will update y'all.

Thanks for the reply dr. M

Even though it is new you most likely have a slightly bent TT , main shaft , or tail rotor output shaft.
I have had many brand new kits have parts that somehow got bent or messed up in packing or shipping and arrived that way.

If I was you I would remove each item and roll them on glass or a mirror just to double check they are in good shape , it's pretty common to get a bent TT shaft.

[BladeFartz]

out of balance motor maybe?

[Rahulgaba]

http://www.helifreak.com/showthread....52#post4175352


guys I didnt wanna double post.. I made another thread.. please help me there if at all possible! I really appreciate it!

[Rahulgaba]

OK heli is flying like a charm now. The tail block which mounts on the tail shaft , and holds the tail blade grips was out.. so changed that.. vibes went away!

now I am fine tuning my tarot ZYX


I am seeing these issues..
1) stop after a piro any direction gives me a tail wag for about a second.
2) Sometimes when The head unloads , I have elevator and aileron bobble for a second..
3) doing tail slides, or something similar where the blades are zero pitch, tail wants to drift... I would say to the right (nose going right) .. I have no pitch to tail compensation whatsoever programmed in.

What changes do you think I need to to fix this? Apart from that, the heli is rock solid in hover, and flies on rails !

Let me know! Thanks!

[Dr. M]

1) decrease d gain on the tail. Check for binding in the tail grips.
2) set roll and pitch d gain to 10. If it still wobbles, decrease total gains on cyclic a few points.
3) set up your tail in Rate mode to get a steady hover with little or no rudder input.

[Rahulgaba]

Thanks DOC !

Tail grips are smooth as milk.. have been working on the tail for a while, checked that one too many times now

I will do the D gain reduction on ele and aile

Now about that rate mode part. I assume you are wanting me to put the bird in a hover, and see how much input i need, try to reduce that by using the tail linkage and changing that. once I am close, i will go in to the tarot system and redo my servo limits ( travel) for yaw.. right?

Now, I see what you are saying, but why ? I dont understand.. would appreciate if you could shed some light on that.

Thanks!

[Dr. M]

That's exactly right on the tail setup. I'm not quite sure why, it just seems to work best that way and that's how the manual recommends doing it too. I'm guessing that if you've got the mechanics already set up with the correct amount of torque compensation, it takes the idle load off the gyro, leaving its entire dynamic range to handle changes in torque.

[Rahulgaba]

The Tail is setup now and flying around fine. I am not sure what torque compensation I am setting. If I am understanding that correctly, you mean the "center" or "rate mode" position of the tail pitch. Well, right now I am dead center almost on the tail shaft. Means i dont have a whole lot of torque pushing the nose to the right on spool up..

I am guessing thats a bad thing?

[Dr. M]

The tail rotor is there to compensates for the torque reaction induced by the main rotor spinning CW. You should have about 7-8° of pitch in the tail blades at center collective stick in Rate mode, leading edge of the tail blades tilted towards the boom.

As for spoolup, I always do it in Rate mode and hold just enough right rudder input to keep the nose steady. I switch to HH just before lift-off.

[Rahulgaba]

one more question ...

has there been any more updates to the Tarot ZYX software. I bought these systems when they first came out. Did one update on both the systems.. is there any more? any one guide me where to find it ?



also .. has any one experienced a port fail on these gyros. My Ch3 died on one of the gyros. I still have faith in this system, so I have taken off this from other heli and put it on my 450.. but the one that was on my 450 .. CH3 just would respond.. has anyone else seen that. I opened it and no solder was broken. Everything looked in line..

thanks!

[Dr. M]

Firmware v3.50 - highly recommended.

http://www.rcgroups.com/forums/showp...postcount=4014

[clough42]

I have been flying the ZYX-S on my Blade 450 with the Tarot DFC head for nine flights now, and I'm noticing a very slight back bias in the cyclic under certain circumstances. As far as I can tell, the mechanical setup is correct. I'm a perfectionist, and I spent two hours on the bench leveling the swash, adjusting the throws, etc. I'm running +/-12 on pitch and +/-9 on cyclic.

I've got the 3.50 firmware update, and I'm using the mild 3D settings, with the D gains lowered to 10 as recommended.

I notice it most in forward flight. If I get the bird into FF, stable, with maybe 5 degrees of forward tilt and let go of the cyclic, it will gradually tip back to level (or further) over the course of three or four seconds, slowing the forward motion. I have seen this tendency with and without wind.

Has anyone else noticed this? Do I just need to do some gain tuning?

I checked CG yesterday, and it was about a centimeter forward of the main shaft. I moved it back so it was perfectly balanced, and it seemed a little better, but I only had one battery, so I can't be sure.

Could the _backward_ tendency be caused by the FBL unit fighting a CG that was too far _forward_?

[clough42]

Also, I did check to be sure I hadn't bumped the elevator trim. All trims are at zero, and I used subttims and travel adjust during setup to make sure every gimbal was giving -100/0/100 to the FBL controller.