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Adverse yaw moment during taxi with high NWS sideslip angles


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Not to be pedantic, but this isn't Adverse Yaw at all. AY is a purely aerodynamic phenomenon, manifesting only in flight.

 

While the aircraft's movement in the horizontal plane is similar in OP's scenario, adverse yaw it is not.

 

Well... kinda.

 

Adverse means “acting against or in a contrary direction” and since the pilot is say requesting a nose right movement with the right rudder pedal but actually getting nose left it does actually work as a description of what’s going on... if we are being pedantic ;)

 

When I was being taught aerodynamics what you are referring to was always discussed as Adverse Aileron Yaw for clarity’s sake.

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A bug ? great ..to be fixed at some point I hope.

 

Not a bug but a math/science thing ? Great, now we know what happens, if you treat the jet wrongly...ok don't treat it wrongly. :)

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Condor_USAF is correct, adverse yaw is a term for the phenomenon that occurs in flight with an aircraft's natural tendency to yaw in the opposite direction of a roll. (Which you correct by keeping the ball centered.) Its just called Adverse yaw. It has nothing to do with anything that happens on the ground during taxing, and is one of the first things you learn and experience in flight instruction. (I remember it was the question my check ride instructor hit me with during my check ride.)

 

Los

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Well... kinda.

 

Adverse means “acting against or in a contrary direction” and since the pilot is say requesting a nose right movement with the right rudder pedal but actually getting nose left it does actually work as a description of what’s going on... if we are being pedantic ;)

 

When I was being taught aerodynamics what you are referring to was always discussed as Adverse Aileron Yaw for clarity’s sake.

 

Except that 'yaw' is also an aerodynamic term. Whilst on the ground during taxi, it's just a 'turn' (I've never heard any pilot refer to a taxiing turn as yawing).

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Except that 'yaw' is also an aerodynamic term. Whilst on the ground during taxi, it's just a 'turn' (I've never heard any pilot refer to a taxiing turn as yawing).

 

Nope its not an aerodynamic term. Yaw is the name for any rigid body movement around the vertical (z) axis. Boats and cars Yaw as well, just as they also Pitch and Roll. My point was not about what pilots call it, it was more that the language being used was technically valid... again, if we are being pedantic ;).

 

While it might not be natural for a pilot to refer to turning the aircraft on the ground as yawing, as the aircraft is turning it is rotating around the Z axis compared to a reference point (IE the ground) and so it is actually yawing, that is the technical term for what that object is doing.


Edited by Deano87

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For clarity's sake many of us in this forum are non native speakers!

Please try to understand others! And stay on topic!

Now normal taxiing turn inputs lead to sea-bathing. (The margin of the carrier deck is only visual.)

sea_bathing.thumb.jpg.fe05a1ecd95af45a4297a9b9fdf58d4a.jpg

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  • 6 months later...
Nope its not an aerodynamic term. Yaw is the name for any rigid body movement around the vertical (z) axis.

 

Exactly! :-)

 

Adverse = Against the direction of the control input (as opposed to proverse).

Yaw = Rotation around the vertical axis (for DCS this is the y-axis)

 

Btw, I actually work in the field, and I wouldn’t know what better term to use to describe this behaviour.

 

But whether you like this expression or not really isn't the topic. What is, is the fact that in this scenario the simulated vehicles in DCS experience an angular acceleration around the vertical axis that is in a direction that is opposite to the control input.

I did my best to bring this to the developers attention and have unfortunately not gotten an answer from anyone who actually worked with vehicle motion dynamics in a professional way.

 

I found this behaviour on other models, so I guess it is not type-specific. Furthermore, I found taildraggers topple over forward (not sideways!) easily with high sideslip angles as well.

 

That observation too supports my thesis: The reason for the strange behaviour at high wheel sideslip angles is that DCS calculates a drag-term that is opposite to the vehicle direction of motion, when it should instead be opposite to the relative direction of the sliding surfaces.

 

For a free spinning wheel that direction is always along the wheel axis.

 

 

And again: Yes, you can still enjoy DCS World. I do too! Not a big thing! It’s just that I would’ve expected to at least hear from a developer briefly.

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For those of you claiming this to be game breaking because you keep taxiing off the carrier.

 

The issue at hand isn't to do with the loss of friction when applying overly aggressive NWS HI inputs, the issue is to do with the yawing behaviour shown when such a slide occurs.

 

If you find yourself sliding when taxiing, instead of blaming the game. LEARN, learn what mistake you are making and rectify your actions accordingly. If you want to do a tight turn keep slow and keep soft. Don't go slamming the NWS HI around; Start gentle and then once you start to turn, then you can go full deflection.

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For those of you claiming this to be game breaking because you keep taxiing off the carrier.

 

The issue at hand isn't to do with the loss of friction when applying overly aggressive NWS HI inputs, the issue is to do with the yawing behaviour shown when such a slide occurs.

 

If you find yourself sliding when taxiing, instead of blaming the game. LEARN, learn what mistake you are making and rectify your actions accordingly. If you want to do a tight turn keep slow and keep soft. Don't go slamming the NWS HI around; Start gentle and then once you start to turn, then you can go full deflection.

 

Yes, we learn... just like we learn to deal with few other quirks...:smartass:

I actually thought this issue was fixed a while back and I praised ED but... on my next virtual deployment I almost ran into another jet on deck. The first time I encountered this wrong way skid I thought I was in Harrier's "caster" mode with freewheeling nose going past 90* but that wasn't it.:huh:

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Gripes323, I have never had an issue with hornet running off the deck. This is because I use the NWS HI gently, its not a bug (Unless you count the side to side sliding of a pitching deck) its just what happens when you try and stop several tons of aluminium with only a few inches of rubber.

 

 

I never have either. I'm referring to what OP was talking about … the direction of slip.

 

 

Oh, as far as the deck environment... absolutely, the deck can be slippery for other reasons too.

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