Anyone got a tail wag with the Kosmik installed??

[jamin_00]

2 friends of mine have and think its the Kosmik but Im unsure. They have the identical set up

Servos are the Outrage HV range. Gonna swap the tail out to see if it makes a difference??

Whats your thoughts??

[Luisito]

On my maiden I had a horrible tail wag. Had nothing to do with the ESC (YGE).

Check the following:
1. Tail rotor lever - it needs to travel freely. Absolutely no binding. Check the washer and locktite. You want to make sure the bearing is not binding. Disconnect everything from it and see how she travels. Should fall under its own weight freely.
2. Tail pitch slider (control sleeve) - check the pitch plate hinges. These are the ones you attach to the balls on the blade grips. The hinges are pressed fit with a steel pin. If this hinge is pressed to tight it will cause binding. Just separate the gap enough so that it moves freely.
3. Tail rotor hub - make sure that it moves freely. If not check to make sure the bearings are seated correctly into the blade grips. There's been reports of plastic getting in the way.

When you disconnect your tail control rod, move the tail control lever. Their should be absolutely no binding especially as you approach the endpoints. Typically that's where you will feel binding. The lever with blades should move freely both directions with its own weight with little assist.

I fixed these issues and now no more tail wag.

Hope this helps,

Luis

[Stolla]

Originally Posted by jamin_00

2 friends of mine have and think its the Kosmik but Im unsure. They have the identical set up

Servos are the Outrage HV range. Gonna swap the tail out to see if it makes a difference??

Whats your thoughts??

The silverline is sensitive to a certain type of frequency vibe, if the helis are new give them a couple of flights, something as simple as slightly too tight mesh can be the cause, loosen mesh slightly for starters, what motors? The kosmik is not the cause im sure

[robbarnes1098]

I have set the mesh on the main gear as best I can , in some place there is no play in others there is some. I will be stripping the tail tonight and rebuilding it and will come back with the results later this week !


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[robbarnes1098]

I will look at all options tonight if I can as this is my problem ! On my 700 Xxtreme


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[robbarnes1098]

I have looked at the tail and there isn't any binding at all ! The gear mesh is free and not binding, however another pilot who has the same set up has the identical problem so he's slackened off his mesh but wouldn't do 3d with it as its too loose just to prove a point.
I did reduce my tail wag yesterday by increasing the P gain and reducing the i gain on the vbar ! But it was still there to an extent.
When I get chance over the weekend we are going to experiment a little more with both the parameters on the Kosmik and the vbar and should have some logs of both to see where the problems lies !

[notorious_benny]

I too had persistent wag.

I completely pulled apart my tail hub and re seated the bearings in the grips. I also checked the tail slider and pushrod guide for any binding, oiled them and reassembled..... doing the above and dropping my tail gain to 73 seems to have cured the wag.....

Mine now has about 50 flights. ....

[robbarnes1098]

I have yet to take mine apart and rebuild it, but it funny how three of us in the uk have the same issues running a Kosmik yet the other 2 models we know too run the YGE and there's is fine ?


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[LOGO800]

Guys……I don’t say that this is a solution…but it was for my LOGO700.
I use FUTABA HV servos and I use KOSMIK 160A. first flight I had very bad tail wag. I did everything but nothing helped…I did change my tail servo to a new one(futaba HV)still tail wag.
What I did, I ordered programming disc for kosmik and I changed 5,6 volts witch is standard on kosmik to 7,4 volts. I use Vbar that came with a kit….ALL my problems with tail wag gone now.
Usually(or as my experience)FUTABA HV servos(or other brand HV servos)they don’t give maximum effect with 5,6 volts. Even in manual for FUTABA HV servos they don’t mention 5,6 volts but 6.0V-7.4V
I am a happy owner of LOGO700 and I love this heli. I don’t say it works for you,,,,,, it definitely did for me. Good luck.

[rcmarty]

Futaba does scec more than 5.6v

RH comments

SPECS:
Speed: 0.055 sec/60° at 6.6V
0.050 sec/60° at 7.4V
Torque: 61.1 oz/in (4.4 kg/cm) at 6.6V
69.5 oz/in (5.0 kg/cm) at 7.4V
Size: 1.57 x 0.79 x 1.45" (40 x 20 x 36.8mm)
Weight: 2.15oz (61g)
Power Supply: 6.0 - 7.4V DC

ADDITIONAL COMMENTS:
The BLS256HV is designed only for gyro rudder control. Dead band is set as narrowly as possible. When the fuselage is static, the servo may jitter. This condition is normal. Very high current drain is normal at startup. Always use a 6V - 7.4V battery.

Martin

[MrMel]

Not sure if Will has enabled .vbr files again as attachments, but please try to add your setup here.

If not I will need some more info, I need to "see" your tail setup's values, Setup step (tail) and Normal + Expert Tail settings

[robbarnes1098]

I'm going out today to do some more test flights and then I will post my vbar set-ups on here as asked MrMel thank you once again for participating in this thread !


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[stocksy27]

Currently building mine and the tail was a little tight some work on the brass pitch slider and the link arms and its now really smooth the plastic links are tight in the holder just removed tiny bit of material to free them up a bit not test flown yet though

[MrMel]

Rename the .vbr file to .txt instead and you can upload.
I will rename it later to check it.

I do fly Torq on my as well so I have done some testing on mine with various settings.

[KONTRONIK]

Originally Posted by robbarnes1098

I will look at all options tonight if I can as this is my problem ! On my 700 Xxtreme


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Hi, if this is an issue with the Kosmik please feel free to contact our English speaking support ben.varley@kontronik.com who will gladly assist you with any issue you may have.

[MrMel]

Sure they are in contact as Ben is the topic starter?

[jamin_00]

Originally Posted by MrMel

Sure they are in contact as Ben is the topic starter?

Yep and it was not the Kosmik, the tail was not perfect. Needed things doing to it but Im sure Rob will let all know what exactly he done to free the tail up.

[robbarnes1098]

Hi all,
After a little head scratching and lots of questions my first reply is that, its not the Kontronik 160 Kosmik that works brilliantly as you would expect on this helicopter. Ben Varley who is a very good friend of mine has offered loads of advice on the subject and we have been in contact through out this process

My findings on this Logo 700 Xxtreme are as follows:

• I found the main aluminum hub didn't fit correctly into the main gear causing the gear to appear warped when assembled in the Heli for the first time. After further investigation the main gear molding measured 0.2mm smaller than the aluminum hub, so it needed some re-work in order for it to sit flat so that the main gear ran true. The gear mesh as you would expect needs to be done carefully to obtain a smooth transition and no binding takes place.

• The tail assembly I found a little tight and almost definitely was the main cause of my tail wag. The tail needs careful assembly and you must watch you don't over tighten the screws and everything aligns well.

• The ball links on the pitch slider are also a little tight and need a small pinch with some flat pliers to loosen them off a little.

• When assembling the pitch slider ensure when screwing in the brass bush is square and true, when done check to see if the arms are level.

• The brass bush is a little tight on the output shaft, its worth putting a little metal polish on the shaft to ensure the movement beds well together and Im sure after a few flights the whole tail assembly will loosen up.

• Just out of the process of elimination I also change the 4 bearings for better quality ones.

• Sensor pad, although my first results on the vbar vibration analysis were fine, I decided to add a metal sandwich plate between the sensor and the main frame. This allows a little less vibration to get too the vbar sensor.

• vbar settings as follows: These were achieved after several flights and we believe they work very well for my style of flying !

• Style 64
Agility 94
Gyro Gain 84
Rc Deadband 2
Elevator precomp 10
Paddle Sim 20
15% Expo
Control loop Ele 47 Ail 47

Tail
Yaw Rate 94
Giro Gain 90
Rc Deadband 5
Acceleration 55
P gain 90
I gain 55
Stop gains A and B 20 20
50% expo
Control loop 38 47
Torque pre-comp
22 collective
9 cyclic
0 Zero Col

[stocksy27]

Same on my main gear trimmed one way slightly now have main gear about 98% true and flat

[recurry]

It seems many have this tail wag issue on first assembly. I flew the maiden flight on mine just yesterday with Jesse's gain recommendation and it showed up as about a 1-2 cycles per second wag in hover. It was dang cold and my hands got numb so I didn't mess around trying to tune it or test it in further flight.

It seems unusual though that the Logo700 is so fussy about the tail assembly. I've never had a wag like that on a new build Logo. None of my other Logo (or Aligns) are that fussy on the tail although on various occasions I have experienced wag in forward flight due to excessive tightness at any of the points between the servo and the tail blade grips. However, I don't detect any of the items - grip bearings, grip pitch arm balls and links, pitch slider, pitch arm, or push-rod guides having excessive friction on this heli.

One area that surprised me as soon as I opened the box was the tail push rod. The push rod size has always felt a little wimpy on all Logos relative to what most other brands use but it was rather shocking to see such a small push rod on such a big ship. I am pleased to see they have the plastic cap to prevent the rod from splintering now but it seems like it probably needs one or two more guides given how spindly it is.

On all my other Logos except one I've changed to a larger diameter rod and used aluminum end caps made by Align to prevent the rod from splitting. It feels MUCH more robust and positive with no appreciable weight gain. I've not noticed any difference in the flying but it made me feel better and I've never had a rod fail as I've seen photos of some of the stock one's that have.

Perhaps it just needs a more robust tail rod? That's my project for this afternoon. First I'll add a second push rod guide and test that. If that doesn't change anything then I'll build a larger diameter push rod and test that.

Cheers,