Tail won't hold.

[akabud]

Now that my flying skills are improving I need my Spirit to work better.
I'm flying backwards pretty good on the sim bit in real life I can't get the tail to hold.
I can fly slow figure 8's backwards and it holds pretty good but when I try hurricanes or funnels it keeps blowing out.

I have two T-Rex 550's with similar set ups. One has 550 blades and one has 520 blades. It seem to hold better with 520 blades. 90 mm tail blades on a 600 tail boom. BK DS7005hv tail servo. Mechanically it's very smooth.

Spirit setup: Rudder end points 160 and 115. Gain 75 X 1.25. Rudder rotation speed 8. Rudder delay 4. Rudder Dynamic 6. Pirouette Consistency 195. I have the 1.3.1 firmware.

What can I try to make it better?

[ZeXx86]

Hello,

what is your headspeed and collective pitch angles?
Is the rudder limit at the end (especially side closer to the boom).
What is angle of the rudder blades when you enable Subtrim (tuning) parameter? Is rudder servo arm at 90°?
It should be configured according to the manual of your helicopter.

At certain point, when your RPM is too low and collective pitch too high, your rudder can't hold, since it is not possible mechanically.
So the easiest solution is to increase RPM.

[akabud]

Head speed is 2300, 12° pitch. Rudder limits are maxed out.
Rudder pitch is 0° with arm at 90° per Spirit manual.
I had some positive pitch per the Align manual. Made no difference.

I'll try increasing RPM how much would you suggest?

[ZeXx86]

I recommend to set 3-4° pitch for the rudder as per manual.
It should work better - you can also increase tail gain.
This pitch must be configured mechanically, not by servo arm.

For your helicopter 2400 RPM should be really enough.
Do you use stock main blades or Pitch Pump Booster?

[akabud]

I recommend to set 3-4° pitch for the rudder as per manual.
It should work better - you can also increase tail gain.
This pitch must be configured mechanically, not by servo arm.

For your helicopter 2400 RPM should be really enough.
Do you use stock main blades or Pitch Pump Booster?

I'll try your recommendations this weekend and report back.
I have Align 520 blades on one and Edge 550 on the other.
I do not use pitch pump booster. Would that make it better or worse?

[ZeXx86]

It will make it worse.

Bigger blades are more demanding for the tail, so higher RPM may be necessary there.
Alternatively longer rudder blades will work good as well.

[akabud]

I recommend to set 3-4° pitch for the rudder as per manual.
It should work better - you can also increase tail gain.
This pitch must be configured mechanically, not by servo arm.

For your helicopter 2400 RPM should be really enough.
Do you use stock main blades or Pitch Pump Booster?

On both 550's I increased the head speed to 2400 and put about 4° pitch in the rudder.
First flight on the one with 550 blades it stripped the TT gears. Not the first time this has happened.
The one with 520 blades I flew 5 flights and the tail held well even doing funnels.
The Spirit works but I think it's time to invest in a better heli.
Thinking Logo 550 SX.