Heading AP not working with FFB

[Dr_Arrow]

The heading autopilot is not working with FFB trim (G940 stick), because with FFB trim enabled, there is no rudder trim and the heading AP will try to maintain only the position when it was switched on and ignores heading input by trimming. This means that when I press trim the AP still wants to return to previous heading. So basically pressing the trim doesn't somehow assign a new heading.

[Cibit]

You can assign the trim adjustments to spare hat switchesif you have any. This allows you to steer left or right of your auto assisted heading .

[Dr_Arrow]

You can assign the trim adjustments to spare hat switchesif you have any. This allows you to steer left or right of your auto assisted heading .

 

This works - I have mapped this to a rotary, but it is practical only for small heading adjustments. Assigning a new heading by pressing the trim does not work when I want to reverse heading and keep it there. Heading AP with my setup works well with KA-50, so I suppose it has something to do with the rudder not being trimmable with FFB on Mi-8.

[Laro]

The heading AP will allways ignore trim, but if you move the pedals it will be disengaged until you center the pedals (the AP will then try to hold the new heading)

 

http://forums.eagle.ru/showpost.php?p=1874429&postcount=4

[Dr_Arrow]

The heading AP will allways ignore trim, but if you move the pedals it will be disengaged until you center the pedals (the AP will then try to hold the new heading)

 

http://forums.eagle.ru/showpost.php?p=1874429&postcount=4

 

I understand all that, but it doesn't work, I center the pedals but the AP wants to go to the previous heading (when it was engaged). Maybe it is waiting until I recenter all controls to complete the TRIM script and assign a new heading, however I cannot do it as I have FFB stick.

[Flagrum]

I understand all that, but it doesn't work, I center the pedals but the AP wants to go to the previous heading (when it was engaged). Maybe it is waiting until I recenter all controls to complete the TRIM script and assign a new heading, however I cannot do it as I have FFB stick.

Your rudder pedals do not have those switches mentioned in that posting. So how does the helo know that you have your feet on the pedals? Only if you actually do give input with the pedals.

 

Therefore, if you give rudder input with the pedals while performing a turn, DCS knows that your feet are on the pedals and thus disables the AP heading channel. When you are done with the turn and center the pedals by putting your feet off, the AP channel is engaged automatically again and the helo tries to maintain that new heading.

If you don't use your pedals during a turn, you will fight the heading channel AP which tries to maintain the original heading. The helo starts to "crab", to fly sideways, instead of a coordinated turn.

Edited September 23, 2013 by Flagrum

[Dr_Arrow]

Your rudder pedals do not have those switches mentioned in that posting. So how does the helo know that you have your feet on the pedals? Only if you actually do give input with the pedals.

 

Therefore, if you give rudder input with the pedals while performing a turn, DCS knows that your feet are on the pedals and thus disables the AP heading channel. When you are done with the turn and center the pedals by putting your feet off, the AP channel is engaged automatically again and the helo tries to maintain that new heading.

If you don't use your pedals during a turn, you will fight the heading channel AP which tries to maintain the original heading. The helo starts to "crab", to fly sideways, instead of a coordinated turn.

 

Thanks that's it! I thought that holding down the trimmer button would have the same effect - disconnecting AP, but apparently it doesn't. So the only way to disconnect the heading AP is to always use the pedals during heading changes - I wonder if that is how the real thing works.

Edited September 23, 2013 by Dr_Arrow

[Flagrum]

Thanks that's it! I thought that holding down the trimmer button would have the same effect - disconnecting AP, but apparently it doesn't. So the only way to disconnect the heading AP is to always use the pedals during heading changes - I wonder if that is how the real thing works.

I think, this is the best way to emulate those switches in the pedals. In the real thing, you would not really need to actually give rudder input - it would suffice to just put your feet on the pedals.

But as helos usually always need rudder input when performing a (coordinated) turn maneuvre, that tiny difference is quite acceptable, I think. :o)

[AlphaOneSix]

Thanks that's it! I thought that holding down the trimmer button would have the same effect - disconnecting AP, but apparently it doesn't. So the only way to disconnect the heading AP is to always use the pedals during heading changes - I wonder if that is how the real thing works.

 

Correct. The TRIMMER button in the real aircraft does not have anything whatsoever to do with the autopilot. It's only purpose is to "recenter" the controls (remove and introduce cyclic and pedal spring tension).

 

Unless you're going to be flying on the same heading for a prolonged period, it's probably best to just leave the heading mode off.

[Dr_Arrow]

Correct. The TRIMMER button in the real aircraft does not have anything whatsoever to do with the autopilot. It's only purpose is to "recenter" the controls (remove and introduce cyclic and pedal spring tension).

 

Unless you're going to be flying on the same heading for a prolonged period, it's probably best to just leave the heading mode off.

 

I've found that landing with the heading channel engaged is trickier, as the AP is quite slow to compensate and gives you more work especially when changing collective when entering hover or going into ground effect.

 

Anyway it is even written in the manual (I should have read it better):

 

In execution of turns be sure to place feet onto the pedals and depress

the tiptoe pedals.

Warning: Never remove feet from the pedals during turn since this

causes severe skidding of the helicopter due to an autopilot

tendency to hold the heading occurring at the moment of releasing

the pedals.