Unsolvable tail wag

[thepiper92]

Originally Posted by Ah Clem

"This is similar to the 250 and I had an issue with this which wouldn't allow for proper movement of the pitch slider and when moving the control rod by hand, it was nearly impossible under power. The result was wagging in no proper tail control."

The issues with the 250 tail were not from the same cause. I had a very long bout with tail wag on the original version of the 250. There were several sets of tail grips issued (I think we are on the third or fourth version now)-initially there was a bearing change, then increasing sizes of Chinese weights. There were also tolerance issues and, the small brass sleeves in the tail spider links were not symmetrical (they were tapered, as someone else pointed out to me)-insert any one of them backwards, and the tail would bind. The problem was compounded if you inserted more than one backwards. The tail bellcrank length on the first versions was too short (also plastic and flexible). Align went to a longer, metal arm later on. I went through the tail on my 250 carefully three times to get it right. Hand fitting all the parts, installing the later tail grips, a metal arm, a JR 3500G tail servo, and KBDD Tail Blades corrected mine. The 250 was the most difficult tail to get right in almost 40 years (it was worth the effort, by the way).

The pivot point on the 250, IMHO, was never the issue:


https://youtu.be/fz4MpowFO7E?list=FL...CRKXw7b1Ftkr3A

I had this issue on the 250, however, where the plastic developed some issues, and moving to a pro tail assembly result in proper tail control. This was after everyone said it couldn't be the problem, but the smooth functioning metal assembly completely removed all issues apart from finicky gain settings.

[Ah Clem]

thepiper92,

A smooth functioning tail system is everything. I hand fit every tail part to get the best performance.

[thepiper92]

Originally Posted by Ah Clem

thepiper92,

A smooth functioning tail system is everything. I hand fit every tail part to get the best performance.

As do I, just was trying to suggest a potential issue after hearing that it was difficult to change tail pitch by hand. It was an issue worsened by the Chinese weights and it took time to pinpoint the problem. I don't doubt anyone not assembling the Heli incorrectly, one of which I don't have.

[Ah Clem]

"As do I, just was trying to suggest a potential issue after hearing that it was difficult to change tail pitch by hand. It was an issue worsened by the Chinese weights and it took time to pinpoint the problem. I don't doubt anyone not assembling the Heli incorrectly, one of which I don't have."

I thought about this a lot last night and figure that I owe you an apology. Just because the pivot point was not the issue with my 250, does not mean that it was not with yours. Interesting that the Chinese weights made yours worse, but mine better.

Many people seem to have very different experiences with the same equipment.

Either way, I was too heavy handed in my response and definitely and not open-minded enough.

My apologies, sir.

[thepiper92]

Originally Posted by Ah Clem

"As do I, just was trying to suggest a potential issue after hearing that it was difficult to change tail pitch by hand. It was an issue worsened by the Chinese weights and it took time to pinpoint the problem. I don't doubt anyone not assembling the Heli incorrectly, one of which I don't have."

I thought about this a lot last night and figure that I owe you an apology. Just because the pivot point was not the issue with my 250, does not mean that it was not with yours. Interesting that the Chinese weights made yours worse, but mine better.

Many people seem to have very different experiences with the same equipment.

Either way, I was too heavy handed in my response and definitely and not open-minded enough.

My apologies, sir.

It's all good. Like I said, I don't have the Atom, so I am not one to provide input on it. I was browsing around and came across that issue that sounded like my 250. It took weeks to figure out and I has ordered Chinese weights and spacers before the problem came up and I gather it happened during a light crash that tweaked the part, but I didn't know it was damaged. I asked around, some said I had the spacers too tight and it was binding, some said the Chinese weights on the weighted grips are worse. The one part didnt look right, so I asked about it. Was told it was not possible. Took the weights off and idled up with just the tail blades. Moving the control rod was difficult. With the weights it was worse. I actually snapped the control arm because of it. This resulted to getting the metal assembly, instant tail perfection, and the pivoting felt different.

[SamCassidy]

Originally Posted by Ah Clem

"Im trying to figure out if that is 'normal' for the Atom's poor tail design or if that is a sign of an underlying mechanical issue that could be causing my problems."

Sam,

There is nothing wrong with the Atom's tail design-I have had one for almost 7 years and the other for about a year-the tail design is excellent (solid, sharp, precise). If you look at threads overall on HF regarding problems, one of the most frequently occurring is tail wag-regardless of helicopter brand.

Keep the faith and between all of us we will figure it out, sir.

Do you have a tail servo from another ship that you can borrow for test purposes?

You are right, I should have worded that differently. I just wish the atom had been done like the 6hvu / 7hv / chronos / warp. Its not poorly designed, just not exactly what I want.

Its driving me real crazy! I think I'm going to try and get somebody local to lay an eye on it and see if they notice anything or have any ideas. Im just at a total loss. It sucks nobody local flies Compass, except for me. Id drive er down to Joe Nall but I'm not going to be able to go

Im going to see if somebody around has a servo too, I don't have an extra laying around unfortunately. Thats one of the problems with only having one heli I guess.

Originally Posted by aburkhardt

Sam, have you done the "grip-flip" mod? Both my machines have leading edge control on the tail.

I have

[skunkworx]

Originally Posted by SamCassidy

I just wish the atom had been done like the 6hvu / 7hv / chronos / warp. Its not poorly designed, just not exactly what I want.

Its driving me real crazy! I think I'm going to try and get somebody local to lay an eye on it and see if they notice anything or have any ideas.

The Atom was actually the precursor to all of the current Compass models. I kind of agree that I wish it could get a bit of an update but it flies incredibly well considering the age of the design.

I don't know exactly how far away you are from me, but I have friends out in Richmond if you ever wanted to meet me half-way and I could have a look at your machine? There's the HOT event in July I think if you're going to that as well?

[SamCassidy]

Originally Posted by skunkworx

The Atom was actually the precursor to all of the current Compass models. I kind of agree that I wish it could get a bit of an update but it flies incredibly well considering the age of the design.

I don't know exactly how far away you are from me, but I have friends out in Richmond if you ever wanted to meet me half-way and I could have a look at your machine? There's the HOT event in July I think if you're going to that as well?

Yep, I call it the prototype tail. Haha. It does fly well, usually. Not mine, right now.

Ahh man, I really appreciate the offer but I'm pretty far down, I think its right around 6 hours to Richmond from here. I really wish I could. I have seen that event, it looks sweet! I will actually be out in Montana June-August.

[skunkworx]

I kind of skimmed through most of this thread but I wanted to ask if you've tried a different tail servo yet?

I have an 8900G in my Atom right now that I can loan to you if you don't have any other options? I was going to swap in my MP80G anyway so the 8900 will just be a backup. I already have it set up with good spacing for my machine so it should just be a straight drop in for yours if the center pulse and the hertz rate match (1520usec, 333Hz).

I've used a 520 for a long time in a 450 but I would think you want something with a little more oomph in the Atom. I've flown quite a few of them and the full size servos have traditionally done the best (although I've seen an Airtronics mini that could put the whoopin' on the Atom tail! )

There are a lot of incredible, modern servos that would likely do even better than the old 8900g, But it's still a great servo for what it is.

[aburkhardt]

+1 on the full size servo. Do it!

[SamCassidy]

Hey all. Working on procuring a servo to try. Will report back with my findings.

[gilligansc]

Is it possible it is the gov on your esc? If you are running gov. , try turning it off and run flat th curve.

[quinn]

I'm in bigfork Montana (near kalispel). I've deal with headaches on my compass tails but I feel like I have a pretty good grasp on them now. I've built the old 6hv, atom, 7hv (originally v1 tail, now upgraded) 6hvu, and 550u

[SamCassidy]

Originally Posted by gilligansc

Is it possible it is the gov on your esc? If you are running gov. , try turning it off and run flat th curve.

I'm not running a gov

Originally Posted by quinn

I'm in bigfork Montana (near kalispel). I've deal with headaches on my compass tails but I feel like I have a pretty good grasp on them now. I've built the old 6hv, atom, 7hv (originally v1 tail, now upgraded) 6hvu, and 550u

Oh man, gah! Know of any work around out that way?

[hrefab]

Don't know if I missed it somewhere but did you ever get the tail wag issue solved?