Violent tail kicks on 700E

[gergob@gmail.com]

This 3G gyro is killing me. I first mounted it with zeal tape, then foam + metal plate. After reading up on how others mount theirs i used a single align foam tape and strapped it down tight with the supplied velcro tape. The heli hovers like it was just floating. No wags, no weird tendencies. I can do a 100 feet climb out and back down and the tail doesn't move. Then suddenly halfway through the flight i get a 120 tail kick. This happened throughout my last 10 flights, basically every flight since i bought the heli. Today i had 1 good flight with maybe a minor tail kick, then during the second flight the tail started going back and forth so hard and so fast that i couldn't even tell if i was right side up anymore. I was getting ready to hit throttle hold to ease the crash when the heli just stopped. It went in a perfectly level hover, tail smooth as butter and i landed. Basically everything works perfect, heli flies like it should, and out of nowhere i get 1 violent tail kick on every flight and it just goes back to normal after that. My 3G came with the silicone mod. If there is anything else i can do please let me know, otherwise the 3G is coming off the heli for good.

[danyl]

Your tail servo may be going bad. Are you running the correct voltage? If the gyro holds at all then it is fine. Gyro technology in general should not have intermittant failure. It's solid state all the way.

I know someone will jump on me about this, but I have had 10 years experience with hundreds of analog and digital servos and some of them do exhibit seizure activity in thier last hours of life.

Please make certain your torque tube or belt is also tight. Intermittant skipping of gears or teeth will also cause your kick

[jondabear]

+1 Very good analysis above.

Vibes also cause this.

[gergob@gmail.com]

Thats something i have not though of, thanks. Voltage is correct and i don't think there is a whole lot i can do about vibration. The heli is 2 weeks old.

[nightflyr]

Might try to isolate the trouble,
Try installing a separate gyro to control the tail and see if the same issue occurs...
If it does you need to look at your servo..
If not.. welcome to the 3G twitch club

[Coolice]

Hey.

Are you running any delay and also what servo are you using?
On all my 3G models running even V2.1 I get the odd tail kick in flight buys its very sporadic and sometimes I don't even get one for many flights, it is a known quirk with the 3G unfortunately.

Some tail kicks can originate from the ESC's governor mode if its not smooth, also one thing to check is your auto unit as if the one-way slips this can give the sane effect.
.

[gergob@gmail.com]

I was borrowing an 8900 from a friend. ESC is in rate mode with flat throttle curve. Today i tried the stock Align 650 tail servo and it worked better. Flew only once, and no real 3D just flips and piros. No kicks so far. Could be that the servo i was borrowing had an issue. I have a WR Hercules feeding 6v into an AR 7100 (i think) the receiver has a 5.1v step down built in for the tail servo. Voltage is not the issue here i think. One way doesn't slip, mechanically everything is sound. I'll fly it harder tomorrow to see how it's doing. Little tail kicks are fine, but loosing site of the heli while its doing a chicken dance in the air is not cool. Hopefully it was the servo...

[Mystic3D]

Originally Posted by gergob@gmail.com

I was borrowing an 8900 from a friend. ESC is in rate mode with flat throttle curve. Today i tried the stock Align 650 tail servo and it worked better. Flew only once, and no real 3D just flips and piros. No kicks so far. Could be that the servo i was borrowing had an issue. I have a WR Hercules feeding 6v into an AR 7100 (i think) the receiver has a 5.1v step down built in for the tail servo. Voltage is not the issue here i think. One way doesn't slip, mechanically everything is sound. I'll fly it harder tomorrow to see how it's doing. Little tail kicks are fine, but loosing site of the heli while its doing a chicken dance in the air is not cool. Hopefully it was the servo...

If an 8900G starts kicking, ground the heli, send back to Horizon, they are great on warranty work. I have had a couple fail, Running one now on my 700E, at some point will replace with a BLS251.

Should be ~ 17mm on Servo Tail Servo Horn. and a few degrees of pitch to counteract
torque is the proper setup on this heli. Make sure the tail has no binding. If you installed the KDE Tail Mod likely it is binding.

[Coolice]

Hey.

I'm running an 8900G on my 700E 3G also, which I transferred over from my 700N. I have read that when they start to show signs of age they do let go regularly so it could be the culprit.

For me I just setup the tails on my models with 0 pitch and equal movement either side of centre and then let heading hold look after the tail, works well for me.

Just the be safe have you inspected the link cable between 3G sensor and main unit? There have been connector problems which can also lead to erratic behaviour.
.

[gergob@gmail.com]

I tried the stock servo today but i still don't trust the heli. It did a small tail kick today and it didn't stay centered like all my other helis before. I'm done troubleshooting, i'm putting a skookum on it next week.

[wonderd]

I don't think it's the 3G, it sounds more like electric entreference problem - I would make sure all the wires hav good connection and try to re-route them.

[RCMustang]

I have the same tail kick problem with my 700E. I'm flying a stock 3G with a 650 tail servo. My tail was wagging and I blamed prior kicks on vibration. As of yesterday I eliminated the vibration problem (as far as I can tell), and the tail wag is gone. My gyro gain is around 58. Today, during a gentle turn in normal forward-type flight, my tail kicked about 90 degrees. I've seen it happen once or twice before and just blamed it on the vibration.

It was an uneventful, but annoying kick. Happened 5 minutes, 30 secs into my flight, about 25 feet up so I just set it down.

This evening I'll be going over the electrical connections and checking for any binding.

This is REALLY frustrating!

[TTRAPTOR903D]

I have a new 700E 3g Combo kit with align stock servos. (AR 7100, CC160, BEC PRO) I think the tail servo is 650 but not sure. I wanted to add that my tail will also randomly do this almost 60-80 degree kick that scares the &$#%$% out of me , No real pattern other than it seems to happen when I pull out of any circut and start to enter a stable hover .. This has yet to happen in FF but again this is a brand new set up with about ten short dial in flights. I fought the standard tail wag/twitch in the first few flights by making adjustment on the laptop . I reduced stop gain and main rudder gail a little but I think thats all the adj on the laptop I did. I Just today have been satisfied with the 3 min that I flew and liked the tail untill that heart stopping lightning fast kick .otherwise the tail was great !!! LET ME DIGRESS... NO MOD PERFORMED YET!! and no way that you can see mechanical set up issue. SOOOOO, I now wonder if this Is a Voltage spike at the servo or either 3G controller from the CC BEC PRO that is dialed in at 6V. Does any body out there on the 700E 3G have this set up? Although I know all about the MOD , I haven't yet done this because R heliproz will exchange the 3G if I need them to. What about just a 2s lipo as opposed to the BEC . Any kicks out there with that set up? I wish I had a data logger on the voltage feed of that tail servo. I know this is long and this is another eternal 3G thread deluge , but I swear I could be one of the few happy 3G customers If I could at least know why? WHY WHY WHY..??? I think its lose the BEC and then my GY401 stand alone. I caint wait to open that 3G gyro unit and look at these Sensors. Can they stick in place in one position and then let go? Again I will not do the mod untill after I exchange this unit and at least try another one. anyone?

[$teve]

Please get rid of the CC BEC PRO, and go 2S. Then report back. I run 2s on both my 700E's, and I run both with AR7100's. I run the cyclic and will take the 2S voltage, and the tail out the 5.1v side. I started out using CC with a 2S setup at 6v, but the cyclic will take the the voltage just fine, so it's wasted money and I'd never trust it regulating 44.4v


You will experience crazy tail twitches with your GOV gain to high. I ran mine between 7-10, and it is great.

The KDE tail mod does take some work to get it smooth, take the brass bushings out and sand the aluminum down until it's got clearance.

And go with the Align plastic, or the Quick UK tail as they won't come apart in flight.

The Align stock control rod works better than the upgraded carbon control rod as it's miss aligned and binds the tail.

Mounting of the sensor is critical on the 3G also.

[RCMustang]

My 700 uses a 2 cell LiFE pack for the electronics and my radio gear is Xtremelink. The Xtremelink gear has never had a glitch on any of my gear, including my belt drive Trex 500. I agree about the BEC Pro on 12S.

I do not currently run GOV mode on my CC ICE 120. I may have to look into setting that up. It seems like a good idea and I've heard the latest Castle firmware is a big improvement.

[TTRAPTOR903D]

Originally Posted by $teve

Please get rid of the CC BEC PRO, and go 2S. Then report back. I run 2s on both my 700E's, and I run both with AR7100's. I run the cyclic and will take the 2S voltage, and the tail out the 5.1v side. I started out using CC with a 2S setup at 6v, but the cyclic will take the the voltage just fine, so it's wasted money and I'd never trust it regulating 44.4v


You will experience crazy tail twitches with your GOV gain to high. I ran mine between 7-10, and it is great.

The KDE tail mod does take some work to get it smooth, take the brass bushings out and sand the aluminum down until it's got clearance.

And go with the Align plastic, or the Quick UK tail as they won't come apart in flight.

The Align stock control rod works better than the upgraded carbon control rod as it's miss aligned and binds the tail.

Mounting of the sensor is critical on the 3G also.

Thanks for the info guys... I will go 2s and loose the BEC. My gov gain is currently 15 but I had it around 4-7 when I first got into diagnosing the tail back and forth problem. After lowering gain and 2 s changeover I will report back. I don't have the KDE tail just stock metal one but its slop free , and I am aware of the tail bolts sheering off and have ordered new high strength bolts for that. Is that what happened to yours? My hopes is that the 44.4 is too much for the BEC and is spiking. but I figured the cyclics would do something similar. What is the best ball link position measurement on the tail servo horn, anybody see any changes by adjusting this? These adj will have to wait a bit cause I just found a nice BB size hole in the top of my 6 month old OS91 HZ ..

[jondabear]

+1....good stuff in here guys!

[$teve]

TTRAPTOR903D,

I never had a tail failure, but after watching a video of one exploding, and reading about others that have failed, I went with plastic until I got my Quick UK's from England.

I've got the ball location where the manual states for now.

Sorry to hear about your OS91 HZ

[RCMustang]

I got two more flights on my 700E today. I made two changes:

1. I strapped down my 3G sensor with some velcro.
2. I tried a few gyro gain changes during the two flights.

Flying today consisted of lots of hovering and side-to-side flying with a little bit of slow forward flight. The tail kicks happen more during this kind of flying than during forward flight.

First I lowered my gyro gain from 58 to 55 since I still had tail wag. This was bad. Any change in head speed caused the tail to move. It was not a kick. It just seemed like the gyro could not keep up. Makes sense. Next I went to 61. This worked much better, but I still could see the tail hunting. Next I went to 64. This made the tail resonate more and I got the sense that a kick was coming.

Finally I backed it down to 62 and flew a few minutes with this gyro setting. It's head hold which is what I'm used to being a non-3D type right now. I did get one 30 to 45 degree kick out of it. It's some kind of strange resonance reaction. I may still have a small vibration, but it's minor. I have to think what I'm going to try next.

Happy new year everyone.

[TTRAPTOR903D]

Originally Posted by RCMustang

I got two more flights on my 700E today. I made two changes:

1. I strapped down my 3G sensor with some velcro.
2. I tried a few gyro gain changes during the two flights.

Flying today consisted of lots of hovering and side-to-side flying with a little bit of slow forward flight. The tail kicks happen more during this kind of flying than during forward flight.

First I lowered my gyro gain from 58 to 55 since I still had tail wag. This was bad. Any change in head speed caused the tail to move. It was not a kick. It just seemed like the gyro could not keep up. Makes sense. Next I went to 61. This worked much better, but I still could see the tail hunting. Next I went to 64. This made the tail resonate more and I got the sense that a kick was coming.

Finally I backed it down to 62 and flew a few minutes with this gyro setting. It's head hold which is what I'm used to being a non-3D type right now. I did get one 30 to 45 degree kick out of it. It's some kind of strange resonance reaction. I may still have a small vibration, but it's minor. I have to think what I'm going to try next.

Happy new year everyone.

what are the settings on your dials on the 3g controller? Mine are at 10 oclock and all the nervousness went away . I was reading a thread somewhere today where they had added some delay through the 3g gyro set up and that it cured the wag. Have you adjusted the rudder stop gain on the 3g link yet. That helped my wag tremendously , but still have that 45 degree kick. also i read if the governor is up to high the tail would do crazy things. Im backing mine down to 3-4 and ill let you know ok. Good luck