Help! Tail Dropping in Consecutive Rolls

[LJS]

Hi All,

I'm in desparate need of some help. I've got 40 flights on my new 8S 600E and I'm having trouble with consecutive rolls and rolling circles. The problem is that the tail is dropping considerably in consecutive rolls.

Here's what I've done:

- Moved the CG significantly forward (this provided a slight improvement, but also made backwards rolls erratic. I have since moved the CG back to level)

- Put on the Align Ultralight Extreme 3D Swash Plate (this helped tracking in loops considerably, but did not solve the tail dropping issue)

- Mixed in 10% up elevator into my negative pitch (this helped slightly and did not adversely affect inverted hovering characteristics)

My 600N flies perfectly in all respects without any of the above changes. Because they have the same head, I can't figure out why my 600N flies so much better than my 600E.

Any help would be appreciated. (Someone else must have experienced and corrected this!)

Thanks!
LJS

PS It is a CF 600E with 8S FP Evolite 4270 batteries and a Neu 1910/1Y motor.

[blueviewlaguna]

Originally Posted by LJS

Hi All,

I'm in desparate need of some help. I've got 40 flights on my new 8S 600E and I'm having trouble with consecutive rolls and rolling circles. The problem is that the tail is dropping considerably in consecutive rolls.

Here's what I've done:

- Moved the CG significantly forward (this provided a slight improvement, but also made backwards rolls erratic. I have since moved the CG back to level)

- Put on the Align Ultralight Extreme 3D Swash Plate (this helped tracking in loops considerably, but did not solve the tail dropping issue)

- Mixed in 10% up elevator into my negative pitch (this helped slightly and did not adversely affect inverted hovering characteristics)

My 600N flies perfectly in all respects without any of the above changes. Because they have the same head, I can't figure out why my 600N flies so much better than my 600E.

Any help would be appreciated. (Someone else must have experienced and corrected this!)

Thanks!
LJS

PS It is a CF 600E with 8S FP Evolite 4270 batteries and a Neu 1910/1Y motor.

How about switching the head/blade assemblies between the N and the E as a test?, a slow servo could also do what you describe - I had a slow 65MG in my 450SE that caused the swash to behave strangely.

[LJS]

Hi BVL,

Now that's a creative solution! I cringe to think that I could mess up my 600N dream machine. But it should drop right on, right? At the very least, I could give it a try without adjusting any links to see if it would drop right on.

Man, I wouldn't think it would be the servos. They were $100 each! They all seem unbelievably fast. But it would be easy to switch them to see if anything would change. And a slow servo could definitely throw things off.

Those are great ideas. I might try switching out the heads this week.

Thanks for helping me track this thing down.
LJS

[sparky]

Why not just mix it out? A heli with blades that spin CW, needs a little up elevator trim on full right deflection of ailerons and give down on full left aileron. Just do a Aileron to Elevator mix that will move your ele servo up on right aileron and down on left just a little, Like around 5 to 7%, and problem is solved.

[Billybuck]

Interesting thread. I'm really interested in the mixing soloutions to sport flying. Loops and rolls, piroetts...etc.

I would love to see someone take a crack at posting mixing soloutions for different flying applications. I know when I do bank turns, I tend to rise faster than I want to and can't hold the turn for long without the tail dropping.

How could I use mixing to improve longer and smoother bank turns without balloning like i'm in a 40 mph wind?

If there are threads already dealing with mixing soloutions, please give a link.

[sparky]

that is rudder control. The best thing i can recomend for that is sim and practice! But if you really want to mix it, you will need to tie it to a switch so it is not always on. But that mix would be Aileron to rudder with aileron as the master. But I do not really recomend doing this. You just need more practice.

[LJS]

Hi Sparky,

Holy smokes, I've never heard that one before. Or maybe I have. A guy on another forum was saying that his tail drops in right rolls and his nose drops in left rolls. I guess that's the same thing.

I forgot to check to see if that's what my heli is doing when I was flying before work this morning. I'll give it a try at lunch if it's not too windy.

You may have just solved the problem!

Thanks for the post!
LJS

[LJS]

Hi All,

Well, thanks for your help. The problem appears to be solved thanks to the advice of a couple posters on the forums.

I mixed in 7% up elevator with right aileron. I was able to do three consecutive right rolls this morning without the tail dropping. The rolls appear axial and there is no tendency for the tail to drop.

I also mixed in 4% down elevator with left aileron. 7% felt like too much and the tail dropped slightly in consecutive rolls with 7%. I’m going to have to do more adjustment with left aileron on a calmer day. It was too windy to tell exactly what was happening.

But to get the rolls straightened out, here’s what I have for the time being:

- 10% up elevator mixed in with negative collective pitch
- 7% up elevator mixed in with right aileron
- 4% down elevator mixed in with left aileron

A pleasant surprise is that backwards rolls also appear to have improved. I was worried that the above fixes would adversely affect backwards rolls, but they are fine. In fact, these fixes have not adversely affected any of the other maneuvers in my routine. I don’t do piro flips yet, so that will be something to watch for in the future.

My 600E now flies as well as my 600N. The thing I can’t figure out is why I didn’t have to do any of these things to my 600N. It even still has the original swash plate on it.

Keep ‘em flying.
LJS

[Big Fil]

Cool man, glad you got that sorted out. I'm still leaning towards there being some difference in your servos either being faster and more susceptable to interactions, one is slightly slower than the others, or is not centering well.