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Helicopter
e-
Mikado
Logo 400 › Argg, LOGO 400 TAIL OSCILLATIONS!!!!! HELP!!! ***FIXED***
09-01-2009 05:52 PM  8 years agoPost 21
ivor-bigen

rrApprentice

Harlow. UK

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It sounds daft but i have done this myself before.
In your TX when trying to enter program mode, do you have a default throttle curve on your TX?
The curve needs to be default 0,,25,,50,,75,,100
If it is default allready then i dont know.
I would just ask your local hobby shop to get the USB device, its not expensive and makes programing very easy.

Mikado

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09-01-2009 06:30 PM  8 years agoPost 22
Jag72

rrProfessor

South of Boston

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My Guess...

here are the 2 things I think it could be

Governor on the ESCis unloading too fast and creating a wag..

OR

you just need to drop the gain a few points on the vbar..

Piro opt has nothing to do with a wag really...it is only for piro moves that include sustained cyclic input as well..if the machine was wobbly during piro flip or funnels then you would want to tinker with the piro opt values..

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09-01-2009 07:37 PM  8 years agoPost 23
mmc205

rrElite Veteran

PA - USA

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Hmm, given that info maybe i'll try to drop the gain first. The tail is still holding really well so it can't hurt i guess to drop a few points at a time.

***Logo 600 vbar***Henseleit TDR vbar***

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09-09-2009 07:51 PM  8 years agoPost 24
mmc205

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PA - USA

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just thought i'd update this in case anyone else was having the same problem. I switched to kbdd tail blades the kind made for 500 size/ 425mm blade helis and the problem went away. Its like the old tail blades were just too big. I didn't adjust the gain at all. I have a feeling adjusting the gain would have fixed the problem too but i liked the orange kbdd blades for visibility anyway.

Anyone know what the tail "I" method is i keep hearing about, i'd like to try it.

***Logo 600 vbar***Henseleit TDR vbar***

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09-09-2009 08:13 PM  8 years agoPost 25
THX1138

rrElite Veteran

Camp Bondsteel, Kosovo

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What tail servo are you using?

Lou

Just give me five dudes and two flashbangs...

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09-09-2009 09:27 PM  8 years agoPost 26
mmc205

rrElite Veteran

PA - USA

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9257

***Logo 600 vbar***Henseleit TDR vbar***

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09-10-2009 03:05 AM  8 years agoPost 27
THX1138

rrElite Veteran

Camp Bondsteel, Kosovo

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Can you post your PI and D settings?

Lou

Just give me five dudes and two flashbangs...

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09-10-2009 06:01 PM  8 years agoPost 28
MrMel

rrProfessor

Gotland

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Cracked tailcase?

Happened to me when tighten them too hard, hairline fracture, created havoc on the system

That said, the Logo 400 _really_ benefit from a fullsize real tailservo.

Gone fishing..or hunting..or something
My site: http://heli.dacsa.net - VBar videos and more

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09-11-2009 04:22 AM  8 years agoPost 29
THX1138

rrElite Veteran

Camp Bondsteel, Kosovo

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Well, I had a NIB DS8900 sitting on the coffee table staring at me so I decided to throw it at my L400. I will test it this weekend and see what happens.

Lou

Just give me five dudes and two flashbangs...

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09-16-2009 08:09 PM  8 years agoPost 30
mmc205

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PA - USA

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okay, update. Still have the shakes. so i checked the tailcase as MrMel suggested, seems to be fine. I then took a trip to the field an dropped by gain in steps from 65 down to 55 (until the tail started blowing out a bit) still had the shakes. Then from 65 up to 70, tail oscillatioin was a bit worse but not terribly different from when i was a t 65. so here's my latest theory. I run the hacker motor set, 6S 30C lipo and a 19T pinion (came with it when got it) and the hacker in goveornor mode governed at 67% to yield 2500 rpm. i'm thinking th pinion is too large causing the governor to overershoot/undershoot much like an unbalanced dynamic system such as a servo system with unbalanced inertia matching. the tail oscillates a little under hard collective moves but moresoe during a reduction in collective back towards zero pitch. So for example it may be fine on a hard climbout but oscillates when i reduce the rate of climb rapidly and the motor is less loaded.
I'm going to get a 18T pinion and test my theory. i think i may have finally nailed it as all the data is matching up..

***Logo 600 vbar***Henseleit TDR vbar***

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09-16-2009 08:12 PM  8 years agoPost 31
mmc205

rrElite Veteran

PA - USA

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My Guess...
here are the 2 things I think it could be

Governor on the ESCis unloading too fast and creating a wag..

Jag called it if this is the problem

Although Ron also suggested disabling the gov early on though i still cannnot get it into programming mode

***Logo 600 vbar***Henseleit TDR vbar***

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09-16-2009 08:13 PM  8 years agoPost 32
Ronald Thomas

rrMaster

Gainesville, Fl, USA

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Like I said earlier

Did you try to turn off the gov anyways just to eliminate it as a possible suspect?

Team MikadoUSA 480XXTreme, 550SX, 600SX, 700XXTreme, 800XXTreme!!

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09-21-2009 03:51 PM  8 years agoPost 33
mmc205

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PA - USA

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Ron,
I paraphrased your comment in my post above. Like i said though can't get into darn govenor mode. I'll try again tonight, maybe the first time i was doing something wrong. I'm a step away from putting an ice 50 in there.

***Logo 600 vbar***Henseleit TDR vbar***

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09-21-2009 03:55 PM  8 years agoPost 34
MrMel

rrProfessor

Gotland

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If you are going for an ice make that 75 at least

Gone fishing..or hunting..or something
My site: http://heli.dacsa.net - VBar videos and more

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09-23-2009 07:09 AM  8 years agoPost 35
Stolla

rrKey Veteran

Port elizabeth South Africa

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You have to get the usb programmer for the hacker esc, for some unknown reason the stick programming is inhibited in the software
I also had a wagging tail which would come and go, just as you thought you had it fixed it would show up in subsequent flights.
Having said that i switched the governer off and it's been perfect ever since.
BTW i'm running a cheapy tail servo align 520, so was almost ready to replace with a bls but am happy with the end result now as the 400 is my son's learning toy!
I also had to drop a tooth on the pinion as the amps were too high on the hyperion 35c's and made the hacker thermal.
But considering we're running vbar the internal bec behaves very well, we haven't had another thermal and it's now an absolute joy to fly.

Common sense may not be common after all

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09-23-2009 07:55 AM  8 years agoPost 36
OICU812

rrMaster

Edson, Alberta, Canada

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Sorry if got mentioned, the "L" pitch lever on back, check for any small hairline cracks or anything, put small force from servo, lightly hold tr blades, if there is any it will show..

...Once upon a time there were Nitros, flybars and frequency pins...

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09-23-2009 12:36 PM  8 years agoPost 37
mmc205

rrElite Veteran

PA - USA

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Okay i went over the tail thoroughly. took the tail apart, polished the mold flash from the balls until they rotated inside teh ball links smoothly (they were a bit tight). but mostly polished the tail pitch slider. after taking off the tail blade holders it was VERY tight on the tail shaft. Funny cause i move the tail via the servo by hand before and it didn't feel too bad. I polished the tail shaft and the tail slider bushing pretty well until they slid nice and smooth. did this by putting the tail shaft in a drill and using 400 grit then 800 grit sandpaper and then running the slider bushing at high speed over the tail shaft to give it a nice running surface. Everything is much smoother now so i'll give it another try hopefully tomorrow and let everyone know what happened. The only thing i'm not crazy about the design i'm not crazy about is the fact that the tail pitch slider bushing basically presses into the plastic slider. Also, when you move both tail blades by hand the whole thing slides very smoothly, but when you turn only one blade it binds up. this seems to be because using only one tail blade to turn everything puts a moment on the slider causing the front or rear to "bite" in and not want to move. A thicker tail slider bushing with radiused edges on the end would probably help.
I'm surprised mikado ships tails like this, it was very tight and now that i've done some research i've even heard of a few people saying that full size servos can have the same oscillations (i'm assuming due to the tightness)

***Logo 600 vbar***Henseleit TDR vbar***

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09-23-2009 12:41 PM  8 years agoPost 38
MrMel

rrProfessor

Gotland

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Final touch is a bit of triflow on the shaft
At least, that works for me.

When you pull ONE blade it's always getting hard to turn, its different inflight.

Do check the Thrust bearings if you havent done so though.

Gone fishing..or hunting..or something
My site: http://heli.dacsa.net - VBar videos and more

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09-23-2009 03:00 PM  8 years agoPost 39
mmc205

rrElite Veteran

PA - USA

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which way is correct mr mel, the thrust bearing that is snug on the shaft going on the shaft first or the other way around? the shaft goes through both, in my mind it didn't make a difference but i may not be thinking about it correctly.

I figured the tail would be receiving near equal force on both blades in flight but it did make me wonder what would happen if there was a force imbalance due to one blade stalling or the pitch not being dead even.

I hate to say it but i kind of like the tail mechanics on my trex 500 a bit better. I little beefier and much smoother out of the box. I think mikado has some room for improvement here. Its not exactly like the logos are inexpensive and fixes out of the box are expected. Otherwise i love it though.

***Logo 600 vbar***Henseleit TDR vbar***

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09-23-2009 03:06 PM  8 years agoPost 40
MrMel

rrProfessor

Gotland

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Smaller inner diameter - Outside, towards the blades.
Bigger inner diameter - Inwards towards the hub.

Gone fishing..or hunting..or something
My site: http://heli.dacsa.net - VBar videos and more

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Helicopter
e-
Mikado
Logo 400 › Argg, LOGO 400 TAIL OSCILLATIONS!!!!! HELP!!! ***FIXED***
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