Constantly tipping over on vertical takeoff and landing

[Art-J]

^ Double check if the "control helper" is turned on in special options, messing up your inputs, 'cause they should not be that extreme. Keep it off and don't forget to use roll&pitch autopilot channel.

[Nealius]

Control helper is off, roll/pitch autopilot channel on. I noticed this only happens when wheel brakes are engaged.

[javelina1]

the new English manual covers this. (thank you belsimtek!!)

 

it is dynamic roll-over caused by to much right rudder to early.

 

the lateral thrust from the tail rotor pushes you over. it wants to turn you to the right but as the wheels form a triangle. it tips you left and forward and unbalances the triangle and you roll over. especially if you have the wheel brakes on.

 

the square profile of the skids must prevent this being an issue in the huey.

and its lower profile.

 

so use less rudder until the collective takes effect. if this happens to you.

only use right pedal to counter left yaw. don't put it in early.

 

in the huey i was setting the rudder before raising the collective.

and that kills you in the MI -8

 

and i thought it was a cyclic issue...

 

but no,reading the glorious new manual and testing it, it is all rudder..

 

(I have just swapped racing wheel pedals for MFG crosswinds.. why my pedal and collective inputs are now more in tune.. no more needing to get the pedal right before raising the collective.)

 

so its a quirk of the mi-8 , its height, its triangle wheel profile, and the strong positive tail rotor trim built in for ease of cruise. (why you need lots of left pedal to taxi straight)

meaning right rudder on the ground can cause dynamic roll over.

 

its also a bad habit you may have brought over from the huey... rudder in to early.. like me.

 

That's exactly what I was doing... Putting rudder in right away, like I was flying the Huey. Needing to learn this bird. :thumbup:

[Quadg]

That's exactly what I was doing... Putting rudder in right away, like I was flying the Huey. Needing to learn this bird. :thumbup:

 

Start on 0 degrees collective, the wheel brake off and a little left pedal to hold it straight.

between 0-1 degrees collective the engines actually provides more thrust to the tail than lift. so you may need a little more left pedal.

as you increase collective through 1-2 degrees bring the pedals neutral and then between 2-3 degrees start putting in right pedal.

 

mileage may vary (will vary depending on load :) ) but something like that will allow you to take the 5 seconds to raise the collective 3 degrees (as recommended in the manual) without rolling it.

 

the other way to overcome it is to smoothly yank the collective :)

then the thrust from the main disk quickly overcomes the lateral thrust..

 

edit: i have just noticed on the sling loading thread cibit has a video of him taking off using the rudder autopilot.

you can clearly see it putting in the left pedal at first and holding it after the collective begins to rise (the H on the autopilot display)

it really kicks in when he takes the brake off.

https://forums.eagle.ru/showthread.php?t=177638

Edited December 11, 2016 by Quadg

[javelina1]

Start on 0 degrees collective, the wheel brake off and a little left pedal to hold it straight.

between 0-1 degrees collective the engines actually provides more thrust to the tail than lift. so you may need a little more left pedal.

as you increase collective through 1-2 degrees bring the pedals neutral and then between 2-3 degrees start putting in right pedal.

 

mileage may vary (will vary depending on load :) ) but something like that will allow you to take the 5 seconds to raise the collective 3 degrees (as recommended in the manual) without rolling it.

 

the other way to overcome it is to smoothly yank the collective :)

then the thrust from the main disk quickly overcomes the lateral thrust..

 

edit: i have just noticed on the sling loading thread cibit has a video of him taking off using the rudder autopilot.

you can clearly see it putting in the left pedal at first and holding it after the collective begins to rise (the H on the autopilot display)

it really kicks in when he takes the brake off.

https://forums.eagle.ru/showthread.php?t=177638

 

Thanks for the info. I am getting a bit better with the ground control and hover. working on the landings. :thumbup:

[Weta43]

"edit: i have just noticed on the sling loading thread cibit has a video of him taking off using the rudder autopilot."

There's one on the previous page of this thread too