rudder in one direction makes 400 drop?

[nyc_863]

I'm flying my 400 in a spacious garage (for now), and I can hover for most of a pack but am finding rudder in one direction (to prod the tail to the right, as I look at the back of the heli) makes the heli drop - from about 3 or 4 feet, down to bounce on the skids - then it comes back up to where it was. It isn't even a big move, eg a 15 degree move to adjust the tail.

making the same move the other way doesn't make the heli fall out of the sky like this :( it'll piro without losing power.

what do I need to look at?

the power/pitch curve is factory, the throttle is about 55-60% maybe, this isn't idle-up.

[int2str]

Two things are at work here:

1) Your left thumb... It's very likely that you apply some input on the throttle/pitch as you apply rudder. It happens, you'll just have to learn to get used to it and adjust.

2) When you piro in one direction (can't remember, I think nose-left), you work against the motor and when you piro the other way (nose-right; might be wrong) you work with the inertia of the motor. When you work against the motor you require more power which slows down the head which makes you drop slightly. You need to account for those drops with additional throttle/pitch.

In the garage you also have down-wash turbulence to deal with. But 1) and 2) are the bigger issues, IMHO.

[nyc_863]

makes sense.

Would idle-up, or a throttle curve that offered more head speed and less pitch, also help my thumbs?

What is the correct way to slow down the demands the tail makes on the motor? add expo to rudder (currently INH), decrease D/R percentage on rudder (currently 100%), or reduce HH gain (currently I'm comparing 65% and 77% on the gyro switch)?

[carlo_the_wonder_frog]

increase your throttle curve, the higher the headspeed the more authority your tail will have.

[widower]

First, make sure you aren't accidental changing pitch when applying rudder. Stiffer pitch stick helps prevent accidental input. Even get someone to watch your thumb while you apply rudder. Adding expo to your pitch/throttle curve will also help reduce this tendency. Expo to rudder will only change how fast the piro happens so don't bother.

For the 400, the main rotor is rotating clockwise so if you turn the heli to the right, the effective airspeed of the rotor increases causing lift. Turning heli to the left (nose moves counter clockwise) decreases effective airspeed of rotor causing decrease in lift. You can correct for this by adding mixing between yaw (rudder) input and pitch/throttle. Turning to the right, decrease pitch/throttle and visa versa. I've seen some people mention 15% mix, but I'd start off really small like 5%. Personally, I don't bother mixing. I actually rely on right turns to help reduce loss of altitude.