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Tail wag issue...suggestions please

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Tail wag issue...suggestions please

Old 06-09-2008, 04:53 PM
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Elgreco3
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Default Tail wag issue...suggestions please

I got a new Freya (bought from someone that never finished it) and I am having a tail wag issue.
Some background first...
Heli came partially built, ie: main frame and engine was built, I put the tail and head (partially assembled) together, and installed my electronics.

All linkages are fine, gyro is the 601 with it's dedicated 9251 i think servo,(which I also got slightly used) and I have setup the rest fine. My other helis fly fine with no issues, I am not a newbie in this.

I hovered it and it feels great, the only thing is that there is a constant tail wag which will not go away no matter where I set the gain. In the beginning I thought I had the gyro setup wrong as I only have experience with the 401 so far. I checked however my settings with someone on the field with the same heli and a 611 (similar) and we have it at almost the same.

The wag increases with increasing rpms also. I think I might be getting some kind of vibration maybe but can't really notice anything. My blades are tracking perfect, sensor seems mounted good, tail and main shaft look fine, I just don't know what else to look for. I am just looking for some hints before I decide to start taking things apart.

There is a metal plate 1x1 inch that came with the gyro and have the sensor mounted on the heli using it, by putting sensor-foam-plate-foam and finally attaching it to the heli frame. I don't know if that metal plate causes any interference but wouldn't think so...
I am planning to check the balance of the tail blades(didn't check before, I used carbon) and possibly the tail shaft, although it really looks straight.

Linkage is smooth, sensor mounted properly, tracking is fine, and from what I see, the engine runs smooth, no obvious vibration.

Also to add, there is really no indication of vibration other than the left to right tail wag which is proportional to the rpms. So I can't say for sure it is from vibration. Maybe a bad gyro, who knows. I will attempt to mount a 401 just for the heck of it just to eliminate that possibility.

So please, any thoughts on the matter would be appreciated.
Old 06-11-2008, 05:10 PM
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Elgreco3
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Default RE: Tail wag issue...suggestions please

Anyone .....?[&o]
Old 06-11-2008, 06:33 PM
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brice_arnold
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Default RE: Tail wag issue...suggestions please

Is your rudder servo also Oscillating? Two things off the top of my head.

1. your rudder servo is too slow or you have too much flex in yout control linkage

2. Try turning the gain down on your gyro. If this work I think this proves my point about the servo. I know in the past that when I get tail wag I usually just turn the gain down and it goes away.
Old 06-11-2008, 07:04 PM
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Default RE: Tail wag issue...suggestions please

Thanks for the reply but these two points are not the issue. The servo is the one dedicated for the specific gyro (9251) but I will have to check for the flex.

As far as the gain goes, it fixes nothing. Not a gain issue.

Also to add, that I changed the gyros around in my helis, putting the 401 on the Freya, and it flies fine. My Sceadu now was, so it has to be the gyro.

Either I am missing something on the setup (although I am using defaults except limits and gain ) or the gyro is defected. I will try to figure this thing out.

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