Anyone got a tail wag with the Kosmik installed??

[NTM]

Originally Posted by 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 have 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,

They'd all wag if it were just the tail push rod.
Likely just the slider being tight is the issue.

So cold your hands were numb in san fransisco ?

[recurry]

Originally Posted by NTM

They'd all wag if it were just the tail push rod.
Likely just the slider being tight is the issue.

So cold your hands were numb in san fransisco ?

Don't know if it's not all of them? Even so, there seems to be more than the ordinary number based on all the posts here and on RR and while that long spindly little push-rod with only one guide may have nothing to do with it it doesn't mean that combined with the slightly higher friction of the beefier tail mechanism it doesn't contribute. We'll see.

RE:Cold. Heh, heh, first, if you like the weather up there in the Great White North good on you friend! There's a good reason why some of us don't live in places that turn all icy and white this time of year and windchill temps below 45 degrees F are one of them - along with not owning a set of gloves or other Eskimo like clothing! :-) Of course that's probably like summer weather to you but I'll take the warmth of being a bit closer to the Equator any time! Oh, and BTW, it says "SF Bay AREA" I don't live in San Francisco and have no plans to - fun place to visit for a day but can't stomach the politics there!

Cheers!

[Jdarc1]

I too am having a tail wag. I am systematically going through piece by piece to find the problem. Yesterday, I started eliminating things. I glued the plated that the sensor sits on..
Result...still had a wag......took tail slider apart... Polished output shaft, opened blade grip links and glued the tail control rod holder....result still have wag.

Right now the tail is extremely smooth and the control rod is extremely smooth. Next I will take apart the blade grips and check and rebuild. Ill keep you posted.

What I'm upset about is, I've built and flown at least 30 of my own helis, with mechanical gyros to VBars and everything in between. I've built very expensive and dirt cheap helis.
I consider Mikado an expensive set up. I use good products as far as radio gear is concerned. For an expensive top of the line heli is shouldn't have this kind of problem out of the box. It's not like this is an isolated problem. I've seen on threads where a lot of people have this problem with Mikados in general. Now I have had this problem before with gyro gain on my 600 se, which was easy to repair but this is B.S.. No one should have to go through this kind of problem with a product of this quality.

Don't get me wrong, I own 4 Mikado helis with VBars and I love the way they fly but this is a problem that they should address and repair for future kits.

[robbarnes1098]

I have covered about 20+ flights on mine now and all the parts have worn in so to speak. I think the tolerances are a little to tight on first assembly and just need time to bed in a little.
I too have other Mikado helicopters with no problems at all and they all flew perfectly first time out the box with no issues at all. The Logo 700 is an awesome heli and once you cure the tail wag it flies really really well.I just love mine !

My findings once again are:
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

[OICU812]

Main disc gain over 80? Wow not sure how you're able to fly it aggressive at all?

[robbarnes1098]

Not agressive but here we go !

[ame]http://www.youtube.com/watch?v=C7fatBuZyFc&feature=share&list=UUPiXe-PNGTN6ZWkt5eX4StQ[/ame]

[hareedy]

Originally Posted by robbarnes1098

Not agressive but here we go !

http://www.youtube.com/watch?v=C7fat...TN6ZWkt5eX4StQ

well thats not aggressive but thats just great
you have some real skills
i would love to have a tail like that
may be its about time i change my good old bls 251
cheers

[astrocyte]

RCmarty and myself helped someone with wag, in the vbar forum on this site ,which may be of some help.It was titled " tail wag on Logo 700" or something like that.The problem was in the pitch link balls.

[rcmarty]

Both my 700 and 800 had a 'tight spot' in the shaft when the slider ran over it.

I fiddled and fiddled for hours trying to figure it out ( I have more time than money for heli's )

In the end I ended up using a very thin washer between the ball end and the grip where the bolt goes in , smooth as glass the whole way thru.

Only 1 washer on 1 side. As much as I hated to have it uneven 2 was too much.

Pop the link off and test out the slider with grips , it should be super smooth with no bumps.

Mikado quality


Martin

[robbarnes1098]

Hi if you look on midland helicopters uk website under the tab team I have some vbar parameters for the tail written down ! I was using a outrage 9188 tail servo on mine but you really need to make the tail super smooth without the servo attached ! Rob

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