In order to get my tail to hold, no yaw, I need the pitch slider when the servo has centered halfway between center and the tail box (3/4 from the grips). I believe this is due to the decreased thrust of the rotors at my altitude, 8,000FASL.

With this setup I've been able to get the stock gyro to hold really well with no drift.
But my main concern is that I am over driving the tail servo with right rudder input since it is already way over to that side.

Is the correct way to limit the servo throw to lower Trav. Adj. in that direction?
I know that lowering the Dual Rate would limit throw in both directions but I'm not sure if Trav. Adj. is the right thing to try.

What say you?

Thanks.

Wolfpackin,

If you have to give it right rudder control to keep the the heli straight and forward. Move the tail servo up closer to the main frame.
Move it up about 2 mm test fly. Keep doing this until you have the trim lever on the TX center and don't have to input any right rudder with the stick.

Dave / Choppersrule

Dave,

On the B400 the servo is stationary and the adjustment is to the tail push rod.
I have done that but what I mean is the slider is now way over to one side.
I'm afraid that when I input right rudder commands to turn, I will over throw it into the tail box.
I'd like to eliminate that possibility by reducing the throw in that direction.

Thanks.

My mistake there, I'll dig a little. I'm soooo confused, all these helis with different STUFF. Man, I saw the Subject line with B400, but had Belt-CP on my mind.

Dave / Choppersrule

No worries, Dave

I was just informed that Trav. Adj. on the rudder channel does effect tail servo throw, just piro rate.
I don't really understand that.

Wolfpackin,
The Trav. Adj. doesn't do anything for the servo at all. It controls the gyro Trav. Adj. How the gyro responds, not a whiz on the gyro but that's how it works. Go figure.

Anyway, back to your problem.. Just a question here, I don't have a B400, but can you move the boom in or out of the main frame or is stationary too? If you can, there's your answer.

Dave / Choppersrule

You're not controlling the servo with the radio, the gyro is controlling the servo and you're controlling the gyro. So the servo travel limit depends on the gyro.

With an HH gyro, the gyro will move the servo as much as it has to in order to get the rate you command. If the heli is sitting on the bench and you give it just a little stick, the servo will move all the way to the limit because the heli isn't turning. Better HH gyros like the GY401 have a limit adjustment in the gyro itself, cheap ones leave it out.

In rate mode I think the travel adjust on the TX will actually limit the travel on the servo to some degree, but the gyro is still in charge and will add or subtract based on what the gyro senses.

So is there no way to limit the servo arm travel?

Again, my setup is good.
But my slider has to be way over towards the tail box in order to get the pitch/thrust I need to hold the tail.
And it holds well in this configuration.
I'm just worried what happens when I give it full right rudder input, with the stick, to rotate/piro the heli.

I don't know that the slider is rubbing the tail box in flight but it doesn't have far to go before it would.
On the bench, full right collective stick pins the slider against the tail box.
Maybe this isn't a problem, maybe I'm not explaining myself...maybe I just don't know.

I do understand now that Trav. Adj. will not help.

Like I said, if your gyro doesn't have a limit adjustment, there's no way to adjust it directly (actually, a programmable digital servo might let you adjust it also). But the travel adjust on the radio may limit it in flight to some extent. If you aren't telling the gyro to piro as fast, it's generally not going to have to move the servo as far unless there's a gust or something that it tries to correct.

BTW, if you can increase you head speed it might help your tail problems.

gnd2,

Good points above.

A programmable servo would do the trick.
I have already increased head speed and it did improve tail authority.

Thanks.

Wolfpackin,

Just for an ease of mine for a bench test.. To observe the tail box. Take the main blades AND tail blades off, that way you don't have to worry about the heli going anywhere. This way you can test to your hearts content and not have to be concerned.
I do this all the time when bench testing for different problems. Kinda cool to watch too.

Dave / Choppersrule

I use travel adjustment for the rudder channel on my Belt CP and have no problems. I just hold the rudder all the way to one direction then lower the travel until the servo stops making bad noises by going to far.

I see from another thread you have a DSP75 on the tail. You can use the Spektrum servo programmer to set the end points for the servo. You set the end points separately so in your case you could set up a shorter throw to the right.

Thanks guys.