Question Regarding Control

[FeistyLemur]

I would still call myself a novice with the Black Shark but am getting more confident with it.

 

What I wonder about and I haven't been able to find mention of is something to do with turn behavior. I notice when I'm turning I can be doing a nice slow coordinated turn, but when I reach the 180 degree mark in the turn the aircraft tends to suddenly lurch hard in the direction I'm turning, requiring opposite stick and rudder to correct.

 

I notice this a lot because one of my practice routines is to do the cold start Mozdok mission, fly a circle or two around the airfield, and then land. So it's common to do a complete 180 to come in to the airfield.

 

Is this something to do with the trimmer and the way it functions as I'm reaching the complete opposite heading I'm trimmed on?

[QuiGon]

When you're flying turns you keep the trimmer pressed, do you? If not, then you're fighting against the autopilot which is dangerous and might cause such behaviour.

[FeistyLemur]

No I hadn't been, I didn't know you were supposed to.

[QuiGon]

That's the essence of flying the Shark! The Trimmer button in this aircraft has two functions:

- It sets the Trimmer like in other helicopters.

- It sets the autopilot to a new flight path.

They're both executed on release of the trimmer button. That means you have to keep it pressed during maneuvering and release it once you're back in a stable flight regime.

If you maneuver without keeping the trimmer pressed you will fight against the autopilot which tries to bring you back on course.

 

You can bypass the autopilot by activating the Flight Director mode (the fifth of the blue autopilot buttons). It will disengage the autopilot but will keep the stability systems activated. In this mode you can fly the Shark like other helos without keeping the trimmer button pressed all the time. Useful in situations were much maneuvering is neccessary, like low level flying in hilly terrain.

Edited February 23, 2016 by QuiGon

[FeistyLemur]

I thought I understood how the trimmer worked but I didn't realize it was standard practice to hold it down while maneuvering, I thought you just pressed it to trim once you were oriented.

 

I guess I need to practice more. And pick a new trimmer button assignment, I have it set to the big red thumb button on the warthog to make it mirror the in game stick as much as possible, and that thing is hard to hold down. The tutorials made me think flight director mode was only for use when in route following mode.

[QuiGon]

Oh yeah, holding down that button is pretty uncomfortable :D

I assigned it to the paddle switch behind the stick.

[dburne]

I use the red pinky button on the Warthog joystick for the trimmer button, seems to work well for me. I have my paddle set as a modifier button.

But yes, I hold the trimmer in during the complete turn and do not release until I am stable at my new heading.

[BFBunny]

I just use the rudder and the collective.

 

The rudder helps and then lower the collective going into a turn to stop it rising and power out of the turn. You can scoot around the airfield with some pretty fun maneuvers.

 

I find I often need to counter the rudder in the opposite direction once it's going around to stop it being too violent.

 

A bit like sliding a car around a corner.

 

It went from being my most hated module to just a whole bunch of fun flying and then turn on all the auto hover, etc when you want to get serious with the weapons.

 

You can fly it a bit like the huey if you get used to it and that's how I fly the huey. It's a bit easier in the shark because you can watch your height, etc on the digital display.

[AlphaOneSix]

I'm pretty sure that "lurch" you get at 180 degrees is a bug. It happens in either direction at 180 degrees from the heading where you last released the trimmer button.

[FeistyLemur]

I played tonight flying frequently with flight director off or holding the trimmer while maneuvering like it was suggested and I had way more fun. It's 200% easier to fly in that way.

 

Had a lot of fun in multiplayer and even flew in formation with 2 other KA-50s for a while.

[Martillo1]

The downside of using FD is that you lose Barometric/Radar Altitude Hold if you engaged it.

[QuiGon]

You loose all holds (altitude, pitch, roll) with FD which is it's very purpose.

[Martillo1]

You loose all holds (altitude, pitch, roll) with FD which is it's very purpose.

 

And Attitude (Yaw). I said Altitude (height).

[Necroscope]

FD is for active flying, and Autopilot is to hold your attitude.

I.E.:

If you going to maneuver a lot - turn FD on (except altitude). It will keep stabilization (shake compensation, other 4 buttons) but allow you fly whatever you want. In this case trim will work as "click" - set you attitude and click trimmer - this will _trim_ chopa.

Is you just flying strait - Disable FD. Trim will work as "press-set-release". Press trim, set desired attitude, release trim - autopilot will hold this attitude. 'd like to change course, pitch or bank - press-set-release.

Please note - in Route mode autopilot will fly according route only if FD disabled. If FD enabled - it will just indicate desired way in HUD.

 

In short: No FD - for flying, FD for fight. :)

 

P.S. With FD disabled you can even use auto to fly choppa to attack point. It's in manual.

[Necroscope]

And Attitude (Yaw). I said Altitude (height).

 

Not really. Attitude is the position of your plane in all axis at given moment.

[Martillo1]

Not really. Attitude is the position of your plane in all axis at given moment.

 

Change "attitude" by "heading" and you have it.

 

Mi original post was about Altitude.

[BitMaster]

Actually I think what you were asking is why helicopters behave this way when you do a turn with modest speed and bleed out most speed when you reach the 180° marker.

 

Ever been on roller coasters ? remember how you slowed down with both feet outward ending in a fast circling that bleeds off all ypour speed ?? well, that is somehow what is happeneing I guess if speed & turn rate are within certain limits. The faster you fly through the circle the less to non existent this will be. Start real slow and you wont even get to 180 if u bank too far while turning, causing an inward spiral DOWNWARD :)

 

Does that somehow match your scenario ?

 

Try FD mode and see if that eliminates it, then it was AP and not what I assumed.

[FeistyLemur]

FD is for active flying, and Autopilot is to hold your attitude.

I.E.:

If you going to maneuver a lot - turn FD on (except altitude). It will keep stabilization (shake compensation, other 4 buttons) but allow you fly whatever you want. In this case trim will work as "click" - set you attitude and click trimmer - this will _trim_ chopa.

Is you just flying strait - Disable FD. Trim will work as "press-set-release". Press trim, set desired attitude, release trim - autopilot will hold this attitude. 'd like to change course, pitch or bank - press-set-release.

Please note - in Route mode autopilot will fly according route only if FD disabled. If FD enabled - it will just indicate desired way in HUD.

 

In short: No FD - for flying, FD for fight. :)

 

P.S. With FD disabled you can even use auto to fly choppa to attack point. It's in manual.

 

So you're saying Russian choppa gets to you...? I'll just show myself out now.

[AlphaOneSix]

Actually I think what you were asking is why helicopters behave this way when you do a turn with modest speed and bleed out most speed when you reach the 180° marker.

 

Ever been on roller coasters ? remember how you slowed down with both feet outward ending in a fast circling that bleeds off all ypour speed ?? well, that is somehow what is happeneing I guess if speed & turn rate are within certain limits. The faster you fly through the circle the less to non existent this will be. Start real slow and you wont even get to 180 if u bank too far while turning, causing an inward spiral DOWNWARD :)

 

Does that somehow match your scenario ?

 

Try FD mode and see if that eliminates it, then it was AP and not what I assumed.

 

Not to derail you, but I think the best way to see exactly what he is talking about is to do this:

 

1. Get into straight and level flight somewhere.

2. Start a nice level turn in one direction or the other (you can hold the trimmer in for this for best results.)

3. Release the trimmer in such a way that the aircraft will maintain a level turn all on its own (preferably without altitude hold, as that is how I tested it).

4. Every time the aircraft goes through 180 degrees from where you released the trimmer, the heading will "bump" or "lurch" or "slip"...etc. If I remember correctly, if you did the turn one way it would sort of stop the turn then bump back into it, but if you did it the other way, the aircraft would slip ahead of itself at the 180 degree point, then resume the level turn, but I can't be sure if that's right.

 

I did a lot of research on that a while back with tracks and everything showing the issue and nothing was ever done with it. Low priority, I guess.

[FeistyLemur]

Not to derail you, but I think the best way to see exactly what he is talking about is to do this:

 

1. Get into straight and level flight somewhere.

2. Start a nice level turn in one direction or the other (you can hold the trimmer in for this for best results.)

3. Release the trimmer in such a way that the aircraft will maintain a level turn all on its own (preferably without altitude hold, as that is how I tested it).

4. Every time the aircraft goes through 180 degrees from where you released the trimmer, the heading will "bump" or "lurch" or "slip"...etc. If I remember correctly, if you did the turn one way it would sort of stop the turn then bump back into it, but if you did it the other way, the aircraft would slip ahead of itself at the 180 degree point, then resume the level turn, but I can't be sure if that's right.

 

I did a lot of research on that a while back with tracks and everything showing the issue and nothing was ever done with it. Low priority, I guess.

 

Yeah that's pretty much exactly what I was asking about in the original question. It's rock stable in flight director mode or with the trimmer held through the turn. I didn't know if it was a bug or if it's really supposed to behave that way.

[AlphaOneSix]

My belief is that it is a bug, although it's not currently in the bug reporting system. I've mentioned it before and got no traction. When I get some time I can collect the data again and submit it as a bug report but I wouldn't get any hopes up, as it would likely be quite low priority. Right now it's really just a slight annoyance, as far as I can tell.

[Frederf]

The explanation is that when the autopilot is attempting to hold a heading it uses up to 20% control authority to steer the helicopter to align with the stored value. If the heading is departed by the pilot steering strongly enough the helicopter rotates despite the AP input to return. For a right turn the AP will apply left steering.

 

However when the helicopter has turned enough (180° away) the AP will stop attempting to turn against the pilot's input and start turning in the same direction since this is the smaller angle to return to the stored heading. This sudden change of AP input bias is felt as an upset in controls in the direction of turn.

 

How realistic compared to the real helicopter's behavior I do not know.

 

This can be countered easily by either holding down the trim button throughout the turn or by trimming once a suitable heading rate has developed. If the trim button is released when the helicopter is turning beyond a certain rate the rate itself is captured instead of a particular heading.*

 

*Assuming the AP is not in route mode

 

Once the helicopter is trimmed for a constant rate turn then the turn can be continued indefinitely without any upset at any point as there is no heading at which the AP will sharply switch direction of its input of turn.