Rate of Yaw

[Tango]

Hi,

 

I had to check my config to ensure I was getting maximum control deflection, which I am. So....

 

Anyone find this thing is a bit slow on the yaw?? I saw a video of a real Ka-50 doing yawing motion and even flying backwards at the same speed, but I'll be damnned if I can do this in the sim. :joystick:

 

I'll see if I can find the footage.

 

EDIT:

 

Best regards,

Tango.

Edited December 23, 2008 by Tango

[Harlock]

I "feel" the same lack of yaw, what I could do was to use the max yaw to the side, trim it, centre joystick, return it to centre position, and yaw again. Hope that makes sense.

[RvETito]

It does. Ka-50 is a big helicopter with big inertial momentum around it's vertical axis. It takes time till it accelerates to the maximum yaw angular velocity which is more than 90 deg/sec. Try deflecting full pedal at hover and trim- in 3-4 sec it will spin like mad. Note that it will also reduce the yaw angular velocity with the same delay, even if you apply full opposite pedal. It's all about inertia.

 

Check the Airshow Min Vody track in the demo folder, it is me who flies there ;) About at the end of the demo I bring it to hover in front of the apron, then full right pedal and collective up to the EEG limit. The yaw angular velocity increased smoothly on the climb till it reaches constant >90 deg/sec.

Edited December 23, 2008 by =RvE=Tito

[Tango]

Hi AirTito,

 

Thanks for that, but if you watch the video posted above, it yaws (for real) quicker than it does in the sim. I'll post the track.

 

I'll go check out your flying! I definitely need rudder pedals - will make a lot of difference to the precision of my flying.

 

Try deflecting full pedal at hover and trim

I shouldn't need to trim. All trim does is release the loads on the controls, that's all. Full deflection should be full deflection regardless of trim.

 

Still not convinced...

 

Best regards,

Tango.

[Guest AdamJB]

Notice that he was not carrying a full load of external stores. Also, flight demonstrations are often performed with only partial internal fuel to increase performance. A Blackshark carrying a combat load is not going to have the same level of performance as one flying a demonstartion that has no payload and only partial internal fuel.

 

Now I have not tested this, mind you, but here is what I would do to try and replicate the yaw performance seen in the video:

 

Take off with half fuel quantity and no payload.

Make sure that Yaw stabilization and Flight Director mode are both disabled. (Blue buttons on the right console.)

[Frazer]

AdamJB is right, without full fuel and weapons load the Ka-50 is more maneuverable.

 

And you can do the exact thing like the example movie.

 

Here is a demonstration with a standard startup and 20% of fuel in DCS:

Link: Movie

Link: Track

 

Note: make sure you don't fly too fast if you make the 90 degree nose turn. 100km/h is about the max the Ka-50 can fly sideways.

Edited December 23, 2008 by Frazer

[MiG-77]

 

Check the Airshow Min Vody track in the demo folder, it is me who flies there ;) About at the end of the demo I bring it to hover in front of the apron, then full right pedal and collective up to the EEG limit. The yaw angular velocity increased smoothly on the climb till it reaches constant >90 deg/sec.

 

Watched it... and that musicflight aswell. Who ever flew that know how to fly ;)

[RvETito]

I shouldn't need to trim.

 

Correct. I only gave example of how you can judge for the yaw velocity with released controls after trimming. I don't have pedals neither, I use the X52 twist instead that's why I always need to trim in yaw because my hand get tired.

 

Take off with half fuel quantity and no payload.

Make sure that Yaw stabilization and Flight Director mode are both disabled. (Blue buttons on the right console.)

 

Yes, this is how I flew it- no payload and 50% fuel. I never use FD including in this track but without Yaw damping and stabilization you'll find yourself in a little adventure ;) Pitch, bank and yaw channel must always be on.

[Tango]

that's why I always need to trim in yaw because my hand get tired.

Is it possible to trim without trimming yaw? I'd prefer it if it didn't trim yaw.

 

I never use FD including in this track but without Yaw damping and stabilization you'll find yourself in a little adventure

My kind of flying. ;)

 

Pitch, bank and yaw channel must always be on.

"Must" as in "mandatory", or "must" as in "best practice"? If it is permissible to fly without stabilization, I might actually get on better with it.

 

Best regards,

Tango.

[Tango]

Hi,

 

It's definitely imporved without Yaw stability, even with combat load!! :joystick::thumbup: I don't mind working the controls to keep the thing level! ;)

 

Who wants to donate some rudder pedals? :D

 

Best regards,

Tango.

[slug88]

"Must" as in "mandatory", or "must" as in "best practice"? If it is permissible to fly without stabilization, I might actually get on better with it.

 

In real life, it's "must" as in "mandatory".

[815TooCooL]

Hi,

 

It's definitely imporved without Yaw stability, even with combat load!! :joystick::thumbup: I don't mind working the controls to keep the thing level! ;)

 

Who wants to donate some rudder pedals? :D

 

Best regards,

Tango.

 

You'll never regret. Buy a rudder pedals asap. It's a must in helo sim.

I recommend Saitek Pro Flight Rudder.

I already donated a CH rudder last christmas so no for you. :D

[RvETito]

Is it possible to trim without trimming yaw? I'd prefer it if it didn't trim yaw.

 

Negative, by pressing the trim button you release the brakes holding the srpings in cyclic (pitch&bank) and pedals (yaw). Either all or nothing, by design.

[AlphaOneSix]

All trim does is release the loads on the controls, that's all. Full deflection should be full deflection regardless of trim.

 

In normal autopilot mode (that is, AP on with Flight Director mode off), trimming also zeroes the AP input to the servos, which can take away up to 20% of your control if it's maxed out in an opposite direction.

[nemises]

Hi AirTito,

 

Thanks for that, but if you watch the video posted above, it yaws (for real) quicker than it does in the sim. I'll post the track.

 

I'll go check out your flying! I definitely need rudder pedals - will make a lot of difference to the precision of my flying.

 

I shouldn't need to trim. All trim does is release the loads on the controls, that's all. Full deflection should be full deflection regardless of trim.

 

Still not convinced...

 

Best regards,

Tango.

 

Heya Tango,

Allmost but not quite true!(I think)..if you have the Heading assitant on, then your Yaw control will attempt to correct onto your last set heading, which will potencially take 20% of your yaw deflection away (20% or 10%..not sure).

Holding trim will stop this from hapenning (and reset your preferred heading on release) though be sure to re-center your pedals BEFORE relasing the trim button!.

Also, you need to have positive tourque on the rotors to be able to yaw, so in a hover or low tourque situtation, your yaw control will be less than in a high tourque situation I believe.

 

You can get the shark to turn on a dime in the right situtuation..just whatch Frazers vfat display for proof!

[Tango]

I'm loading that as I type! :thumbup:

 

I think yaw stabililty was my biggest issue. How does this work in the real thing then? Surely if I applied full left or right yaw, that I'd get maximum deflection of the controls?

 

Best regards,

Tango.

[nemises]

*all of this its theoretical, and needs to be confirmed by someone who actually knows instead of my extrapolations*

 

The Assistant chanel can take up to 20% total play (+ / - 10%) from your set autopilot center position of the Yaw (or any cyclic control ), so in theory if you were pointed at 180 deg, and your Yaw AP was also set to 180 deg, then if you input less than 10% of your Yaw control, the Autopilot would be able to counter that with up to -10% input, and you would not Yaw.

If you exceeded the 10% physical input, then you will Yaw the aircraft against the Autopliot, however with %10 less authority in total from your physical input than if the Autopilot was off (ie Director mode, trim held in, or Yaw channel turned off).

 

So, if you are deviating from your Autopilot preferred Heading with Yaw control on, and with out trimming or using Flight Director mode, you could achieve 90% (?) of your input in Yaw by inputting 100% of the physical rudder movement.

 

*gasp-for-air*

 

So, it is better to change your preferred heading by re-trimming (or holding down trim) so that your control inputs are not fighting against the Autopilot!

[Reticuli]

The trim should not be affecting the pedals. That's what Heading Hold is for. Glitch. You should never have to trim the pedals in a coaxial helicopter. It should either rotate freely (Head Hold OFF) or the trim button should be resetting your heading (Head Hold ON). Because of this glitch (either a mistake on ED's part or incredibly stupid Kamov design decision), you are constantly fighting the Heading Hold reset feature and the pedals becoming trimmed. The pedals should ALWAYS be untrimmed in a coaxial helicopter. Either you (Head Hold OFF) or the AFCS (Head Hold ON) do constantly make small, varying corrections to the yaw (actually the rotation difference between the two main rotors), but that's not a trim. DCS:BS does not have yaw dampening. I have no idea if the real helo has it, but the Head Hold function effectively gives you the same end results...or it would if it wasn't conflicting with the trim. Until ED fixes this, my recommendation is to only turn Head Hold on when you actually want to hold a heading. And when you do have that channel on, either tap it off/on to reset new headings as needed, or when trimming make sure you center the pedals/twist before tapping Trim Button since it will reset your heading. If you want to see what Head Hold is currently using as its reference marker, change the heading diamond selector switch to the middle so it's on neither Desired Heading nor Desired Course. It's right next to the Flight Director button. When autopilot flying is not on, it's always there, but unless it's in the middle position you're not seeing it since the PVI-800 is hogging the diamond for itself. Piggy, piggy...give me back my diamond. I always have it in the middle unless I'm actually using the autopilot.

[Yo-Yo]

The trim should not be affecting the pedals. That's what Heading Hold is for. Glitch. You should never have to trim the pedals in a coaxial helicopter. It should either rotate freely (Head Hold OFF) or the trim button should be resetting your heading (Head Hold ON). Because of this glitch (either a mistake on ED's part or incredibly stupid Kamov design decision), you are constantly fighting the Heading Hold reset feature and the pedals becoming trimmed. The pedals should ALWAYS be untrimmed in a coaxial helicopter. Either you (Head Hold OFF) or the AFCS (Head Hold ON) do constantly make small, varying corrections to the yaw (actually the rotation difference between the two main rotors), but that's not a trim. DCS:BS does not have yaw dampening.

Where did you dig this statement? I only could guess that you never take a look at the rudder when BS decelerates in yaw after rudder impulse... Take a look and it will turn your universe...

I have no idea if the real helo has it, but the Head Hold function effectively gives you the same end results...or it would if it wasn't conflicting with the trim. Until ED fixes this, my recommendation is to only turn Head Hold on when you actually want to hold a heading. And when you do have that channel on, either tap it off/on to reset new headings as needed, or when trimming make sure you center the pedals/twist before tapping Trim Button since it will reset your heading. If you want to see what Head Hold is currently using as its reference marker, change the heading diamond selector switch to the middle so it's on neither Desired Heading nor Desired Course. It's right next to the Flight Director button. When autopilot flying is not on, it's always there, but unless it's in the middle position you're not seeing it since the PVI-800 is hogging the diamond for itself. Piggy, piggy...give me back my diamond. I always have it in the middle unless I'm actually using the autopilot.

 

Too many letters... no vital power to understand... :)

 

I can only say that there is only one thing we fixed as we had got new info about AP functionality: yes, yaw channel has a general conflict with bank channel if the helo is turning. To avoid it the heading channel latches the heading only if the yaw angular velocity is less thana certain threshold otherwise it latches current angular velocity value.

It works much better.

[AlphaOneSix]

ALL controls in ALL helicopters have force trim, including the pedals.

[Vortex]

ALL controls in ALL helicopters have force trim, including the pedals.

 

:huh: Can you explain this further?

[RvETito]

The servo acuators are irreversible- they don't feedback any tension from the controls (swashplates and sliders). To simulate aerodynamic forces in the controls the cyclic and pedals use srping mechanisms with electromagnetic brakes. That last forms up the force trim system- springs and brakes. By trim is meant neutral position of the controls (cyclic and pedals only) in terms of force (srpings fully unloaded). The collective is diferent, it's artificial tension is provided by a friction mechanism which you operate with e lever bellow the collective handle- you squeeze the lever, that pushes a spring compressing the disks of the friction and you move the collective lever. When you let go on the small lever on the handle the collective is fixed in the current position. One must be really strong to move it without squeezing that small lever on the handle.