Right pedal input limited - cannot counter left-turn spin movement

[jetsimace]

Hi all,
sometimes the Hind enters an uncontrollable spin to the left which I am not able to counter with right pedal. Right pedal input (although fully deflected to the right) is somehow limited (see attached picture). I have set instant trim and pedal micro switch logic to off.
Does autopilot yaw channel interfere with my pedal inputs?

What is the meaning of the marker/chevron that appears at pedal input bottom rightmost?

Many thanks!

Edited August 28, 2023 by jetsimace

[admiki]

6 hours ago, jetsimace said:

Hi all,
sometimes the Hind enters an uncontrollable spin to the left which I am not able to counter with right pedal. Right pedal input (although fully deflected to the right) is somehow limited (see attached picture). I have set instant trim and pedal micro switch logic to off.
Does autopilot yaw channel interfere with my pedal inputs?

What is the meaning of the marker/chevron that appears at pedal input bottom rightmost?

Many thanks!

 

Mark in yellow square is an indicator of how much you can move pedal to the right to avoid damaging tailboom. It's an automatic system. 

Was this a hot start helicopter? And did you turn off yaw channel autopilot?

 

[AeriaGloria]

7 hours ago, jetsimace said:

Hi all,
sometimes the Hind enters an uncontrollable spin to the left which I am not able to counter with right pedal. Right pedal input (although fully deflected to the right) is somehow limited (see attached picture). I have set instant trim and pedal micro switch logic to off.
Does autopilot yaw channel interfere with my pedal inputs?

What is the meaning of the marker/chevron that appears at pedal input bottom rightmost?

Many thanks!

 

Hello, setting microswitch to off doesn’t stop your problem, becuase it defaults to heading hold. So since you have yaw channel of autopilot on, it is trying to hold heading and trimming your pedals to maintain heading when the difference between current heading and heading it’s trying to hold is more then 9 degrees 

Basically if this happens press trim reset to undo pedal trim. And to prevent either never turn yaw AP on unless you explicitly want heading hold, or have the specific microswitch bind activated while AP is on so it enters a “coordination” mode that stabilizes you but won’t fight turns or trim you or hold heading 

For micro switch there is both a hold button and a toggle, I just use the toggle and make sure I hit that toggle Atleast once at startup before takeoff. This way I am sure when I turn on yaw autopilot it won’t trim me or hold heading 

There is also a special options setting you will find in Mi-24P section that is called “Pedals auto move,” making sure it is not checked will stop the yaw autopilot from trimming you. However it will still hold heading in heading hold mode, just with less authority. I find it has plenty of authority anyways, so I think it’s always a good idea to make sure it’s off 

 

Here are my settings, I do use force feedback stick so that’s why my trim settings are the way they are 

[admiki]

1 hour ago, AeriaGloria said:

Hello, setting microswitch to off doesn’t stop your problem, becuase it defaults to heading hold. So since you have yaw channel of autopilot on, it is trying to hold heading and trimming your pedals to maintain heading when the difference between current heading and heading it’s trying to hold is more then 9 degrees 

Basically if this happens press trim reset to undo pedal trim. And to prevent either never turn yaw AP on unless you explicitly want heading hold, or have the specific microswitch bind activated while AP is on so it enters a “coordination” mode that stabilizes you but won’t fight turns or trim you or hold heading 

For micro switch there is both a hold button and a toggle, I just use the toggle and make sure I hit that toggle Atleast once at startup before takeoff. This way I am sure when I turn on yaw autopilot it won’t trim me or hold heading 

There is also a special options setting you will find in Mi-24P section that is called “Pedals auto move,” making sure it is not checked will stop the yaw autopilot from trimming you. However it will still hold heading in heading hold mode, just with less authority. I find it has plenty of authority anyways, so I think it’s always a good idea to make sure it’s off 

 

Here are my settings, I do use force feedback stick so that’s why my trim settings are the way they are 

Wouldn't autopilot trim in more right pedal in OP case? And his collective wasn't high in the first place.

My guess is that AP trimmed pedals to the left (comon situation at ground hot start) and then got disconnected somehow, leaving him with limited right pedal.

 

Edited August 28, 2023 by admiki

[AeriaGloria]

4 minutes ago, admiki said:

Wouldn't autopilot trim in more right pedal in OP case? And his collective wasn't high in the first place.

My guess is that AP trimmed pedals to the left (comon situation at ground hot start) and then got disconnected somehow, leaving him with limited right pedal.

 

 

Yes, I agree with that guess

[Genberi]

@jetsimace are you sure you are not over loaded your heli, and you are not flying with a strong side wind? Uncontrollable left spin with a full right pedal usually says that you are doing something totally wrong as a pilot in Mi-24.

[AeriaGloria]

1 hour ago, Genberi said:

@jetsimace are you sure you are not over loaded your heli, and you are not flying with a strong side wind? Uncontrollable left spin with a full right pedal usually says that you are doing something totally wrong as a pilot in Mi-24.

It would be, but the posted screenshot shows that they can’t even reach the limit on right pedal travel set by SPUU-52, which could only happen on its own if settings where such that heading hold was on at one point and trimmed the pedals left to stop a right turn at some point. 
 

 Usually I suggest never going below 90% rotor rpm and staying as close to 95%, the governor commands max power below 95% so you don’t get more power really below that, just a little more torque that requires a lot more tail rotor. But I don’t think that’s OPs problem 

[Schlomo1933]

If you try to climb high mountains in Caucasus with an overloaded hind, with collective almost maxed out, then you have a really hard time to hold the 24 in a straight flight.

It starts to turn left more and more as your speed degreases. Wih the pedal full right, the only thing what you can do is decreasing the collective carefully or push the nose down to increase the speed. 
(this behavior start at 11 degree of collective and i believe is correct) 
 

Edited September 7, 2023 by Schlomo1933