What Servo Horn and Hole for 611?

[LJS]

Hi All,

I just have a quick question. Which servo horn and hole are you using for the 611 gyro in your 600E?

On my 600N, I’m using the star servo horn and the second hole from the center. But now that I’m looking at it, I’m afraid that’s too short. I’d rather go with the third hole from the center. What do you think?

Thanks!

Keep ‘em flying.
LJS

[cudaboy_71]

common wisdom is 8-10mm from center. on the 'large cross' horn, that's the 2nd hold from center, as you have.

[LJS]

Hi CudaBoy 71,

Thanks. I'll get that servo hooked up tonight.

Keep 'em flying.
LJS

[cudaboy_71]

if you havent gone through setting up the amp yet, these instructions (courtesy of nigel brown) are by far the simplest. got me set up in less than 20 minutes.

good luck.

[BarracudaHockey]

The answer really is the hole that lets you set the limit a and b to around 110 or so.

[Skiddz]

Lookin' at my 600 right now.. Looks like I used the "X" arm, cut off three of the "legs" and use the 2nd hole out from the center on the remaining arm. A and B limit are both 118.

[LJS]

Hi All.

Thanks for the posts. They have been very helpful.

I have a question regarding Nigel's instructions:

- We are centering the rudder servo. However, if I also center the tail rotor, then I am not compensating the for the normal torque of the motor. And then, my left and right pirouette rates will be uneven. So I'm assuming that I shouldn't set the tail rotor to 0 degrees when the rudder servo is centered.

- Where should I put the tail rotor when the rudder servo is at 0 degrees?

Thanks.

Keep 'em flying.
LJS

[Mercuriell]

Originally Posted by LJS

Hi All.

Thanks for the posts. They have been very helpful.

I have a question regarding Nigel's instructions:

- We are centering the rudder servo. However, if I also center the tail rotor, then I am not compensating the for the normal torque of the motor. And then, my left and right pirouette rates will be uneven. So I'm assuming that I shouldn't set the tail rotor to 0 degrees when the rudder servo is centered.

- Where should I put the tail rotor when the rudder servo is at 0 degrees?

Thanks.

Keep 'em flying.
LJS

There are at least 3 zeros you can set !
1) Slider in dead centre of travel
2) Tail rotor blades at zero pitch
3) Tail rotor blades set at flight neutral (ie slight right turn to compensate torque)

On the TREX 600 if you set the blades at 1) ie mid travel you will find there is a slight amount of right rudder built in and this works well with the 611 - easy way to find dead centre of travel - mark the pushrod just in front of a guide at one extreme of travel - mark it again at the other extreme of travel then put a mark dead centre between these two and set this as you mid stick position.

Have to say this is not a critical setup point on the T600 and 611 and I do it by eye these days - you can adjust piro rates by changing your rudder end points to make them even. I have done a video on tail setup.

[cudaboy_71]

i followed nigel's directions (centering the pitch). but, then to even out the piro rates adjust ACGA and ACGB values (you'll need to hold the rudder stick on your radio one way then the other to access the values on the Amp). i can't remember what the default/preset value is. but it is adjustable up to 250 in each direction.

most people i talk to adjust the rudder ATVs on the radio for piro rate. but, i have to thank dave neves at century for the help with adjusting the ACGA/B values. it gives a lot more resolution for fine adjustments...not that there's anything wrong with adjusting ATVs. whatever works. but, the amp is designed for adjusting piro rates in each direction, albeit a little more work than just adjusting in the radio.

[aucmax]

"I have done a video on tail setup.

What a great pair of LUCID videos. Very good indeed! I watched Bobs' videos and set up my rudder/611 according to his instructions and I have been fine with that until now. He baked the cake, but mate, you put on the frosting! Thanx to both of you for your time. What would helifreaks do without your expertise and enthusiasm?
But one question.. (there's always one of those that seem to pop up sooner or later)
Why is it necessary to tie normal and AVCS mode to a switch (CMT mode will only allow this?), outside of initial mechanical set-up, so it can be changed in relation to flight mode. (for example, as you mentioned, Throttle Hold tied to Gyro normal mode) This is the one thing about my 611 Gyro that still leaves me dumbfounded from the very start of my learning process for a few months now? How necessary is this and how would I do this on a Futaba 9 CHP TX? I have an electric 600.

Update: The way I see it, when in an auto, the main rotor blade will spin counter-clockwise. In this situation, it would be necessary to sever the gyro control as there is no longer a torque issue (motor is off). This will allow full rudder control from the TX without AVCS interference? Am I on the right track here?

[Mercuriell]

Good question ! - I'm sure there's more than one answer but my take is this - in normal mode a gyro responds to movement - when the tail moves the gyro acts to cease the movement - if your heli is controlled in this mode the wind blows the tail round until it is pointing away from the direction of the wind when there is no more movement - the so-called 'weathervane effect'. By way of contrast in heading hold mode (or Angular Vector Control System in Futaba speke) the gyro responds to stop movement and then over correct to restore position hence hold the heading.

If you carry the helicopter out in HH mode the gyro will have lost its centre reference and attempt to restore the heading present when the gyro initialised in HH mode which can either lead to excess servo movement or an unexpected tail shift on lift off. These latter can be prevented by switching into HH mode just before spool up or else resetting centre by flicking into HH/normal mode 3 times rapidly.

The switch between normal mode and HH mode can be set to the throttle hold / idle up or a separate switch and all have their pros and cons!

Hope that helps !

[cudaboy_71]

Update: The way I see it, when in an auto, the main rotor blade will spin counter-clockwise. In this situation, it would be necessary to sever the gyro control as there is no longer a torque issue (motor is off). This will allow full rudder control from the TX without AVCS interference? Am I on the right track here?

no, the mains never reverse directions in an auto, the stored energy in the blades plus momentum gained while applying negative pitch during descent is used to flare on approach. on a clockwise spinning head, the mains will continue to spin clockwise.

also, some tails are not driven at all--that is when the motor is not driving the mains, nothing is driving the tail. therefore there is no tail control at all. but, (as you correctly stated there is no torque) the heli will still fly in a predictable direction weathervaning with the wind. in cases where there is a driven tail, it can still be flown with yaw control. in HH mode, the gyro would still try to hold its vector by applying pitch to the tail blades. the only spot i'm hazy on is whether or not the gyro would correct yaw in normal mode since there is no torque to offset....i've never really tried. seems like it would have no effect.

[LJS]

Hi All,

Installation went very well. As Mercuriel recommended, I found the center point of travel on the tail rotor rod. This corresponded to a slight right yaw command which is what I wanted. Then I locked the servo down and set my A and B limits each to 115. I’m hoping this setting compensates for motor torque and gives me equal piro rates. But no big deal if it doesn’t, because I can just adjust the rudder end point adjustments in the transmitter to get the desired left and right piro rates. Should be a sweet setup.

While I don’t like the separate amp found on the 611, I have to say that I really like the amount of control one has over the tail rotor. Stop delays for smoother stops, right and left limits, easily adjusted piro rates, a display that indicates when your servo is centered. This truly is a much better gyro than my JR 770 3D.

Thanks again for all the posts.

Keep ‘em flying.
LJS

[BarracudaHockey]

For autos without a driven tail, having throttle hold activate rate mode with an offset to flat pitch does two things.
1. It reduces parasitic drag
2. (and the important one) If the gyro stays in heading hold and the tail turns even slightly the gyro will drive the tail rotor to full pitch trying to compensate. If you come out of throttle hold on the way down the heli will do a piro or three or four before it regains control of the tail.

On a driven tail rotor just leave it in heading hold and let it do its thing.

[cudaboy_71]

I’m hoping this setting compensates for motor torque and gives me equal piro rates.

no, that has no bearing on piro rate. it just defines the endpoints of travel for the gyro so it doesnt 'peg out'.

as i stated above, if you want to alter piro rate you adjust ACGA and ACGB, or as is popular, just adjust rudder ATVs on the radio.