adjusted for later update F-16 Rolling Left during High G turns and Normal Loops

[Teej]

11 hours ago, NineLine said:

This effect is from the modelling of the gyroscopic effect of the engine. We believe it is correct as is. Thanks all. 

For that explanation....the effect is backwards. 

The F-16's engines (regardless of block) spin "clockwise" when viewed from the rear - as does every turbine GE and PW make (Rolls is the opposite. Wouldn't be surprised if Russian derived are as well).  If you apply a nose-up force (positive pitch) to something spinning like that, the gyroscopic precession that results is a yaw to the right.

The engine also spins the wrong way graphically in the sim, so at least that's a consistent error. 

Tailwheel pilots experience the reverse of this - when you push the nose down to raise the tail, that adds to the prop plane's left turning tendency.

When you compare an F-16 to a P-51, for example, the resultant effects on the plane from gyroscopic precession should be much much smaller. The rotational inertia of the engine is about 10x as large (smaller diameter of heavy rotating parts, but at a higher velocity). On the other hand the plane has about 100x the rotational inertia...so the net force on the airframe should be on the order of 1/10 what it was on a WW2 fighter.  

 

 

 

 

Edited April 16 by Teej

[PanicMan15]

In light of the new evidence that has been found, I urge ED to please look into this more instead of labeling "correct-as-is". The engine outside is spinning counterclockwise (from the back) when it should be spinning clockwise. This is a massive oversight and very well could be the cause of the rolling issue.

[Mapi]

"gyroscopic effect of the engine"
But probably a bit exaggerated. It's not a propeller plane and it's not from WWII.
I found this:  https://aviation.stackexchange.com/questions/49499/why-dont-single-engine-jets-suffer-severe-gyroscopic-effects
The effect is described as vanishingly small. 1% ?

AH64: Propeller plane (code) turned by 90°? And it tips over ...

[PanicMan15]

40 minutes ago, Mapi said:

"gyroscopic effect of the engine"
But probably a bit exaggerated. It's not a propeller plane and it's not from WWII.
I found this:  https://aviation.stackexchange.com/questions/49499/why-dont-single-engine-jets-suffer-severe-gyroscopic-effects
The effect is described as vanishingly small. 1% ?

AH64: Propeller plane (code) turned by 90°? And it tips over ...

The fact of it is, the engine (at least the model and most likely the code) on the outside, is backwards. The F-16 is affected by gyroscopic effects but it's minimal and effects it by yawing right (confirmed by real F-16 pilots). So either in the code the engine is translated wrong (which seems more likely) or there is a deeper underlying issue.

[Raven (Elysian Angel)]

20 hours ago, Teej said:

So...yeah.  Let's see what you've got!

Sure, here you go (track included).
Looking back at the replay, can you see some movement to the right of centre? Sure but that's only when specifically looking for it, as I never noticed it (it took me a few moments to figure out how to use the control indicator even as I have never used it). To put it in perspective: it's about half the movement generated if I tap the top of the stick with the tip of my index finger. I don't see that as a problem... Again, I only saw that when replaying the track as I never noticed it while actually flying.

Also, look at any flight instructor video where the instructor asks the student to pull the nose up and he repeatedly comments "to keep the wings level".

Now you please show me where in the Thrustmaster/Virpil software there is the option for RCA (roll control assistance). I don't use a Thrustmaster stick, but I do use Virpil and I haven't seen it.
This is from the ReamSimulator software:
null

F16 track.trk

[oldcrusty]

Couple of posters in this thread stated they don't see any yaw at all.  So...  something specific to strain gauge sticks?

EDIT:  One of them just responded so never mind.

Edited April 16 by oldcrusty

[Teej]

5 hours ago, Raven (Elysian Angel) said:

Sure, here you go (track included).
Looking back at the replay, can you see some movement to the right of centre? Sure but that's only when specifically looking for it, as I never noticed it (it took me a few moments to figure out how to use the control indicator even as I have never used it). To put it in perspective: it's about half the movement generated if I tap the top of the stick with the tip of my index finger. I don't see that as a problem... Again, I only saw that when replaying the track as I never noticed it while actually flying.

Also, look at any flight instructor video where the instructor asks the student to pull the nose up and he repeatedly comments "to keep the wings level".

Now you please show me where in the Thrustmaster/Virpil software there is the option for RCA (roll control assistance). I don't use a Thrustmaster stick, but I do use Virpil and I haven't seen it.
This is from the ReamSimulator software:
null

F16 track.trk 1.26 MB · 0 downloads

Thanks, I will take a look. However before I do let me make some things 100% clear.

1:  It is not in any way dependent on input method. I can reproduce it with keyboard, moving stick or FSSB R3L. There is nothing special in DCS for FSSB. Yes, it “feels right” because the (real) viper was designed to be flown with a force input and there may be FLCS code within DCS that mimics the function of the real bird. Regardless, that is definitely not the problem here. 
 

2: Your roll control setting is quite simple - it reduces how much roll the pilot can input with THAT device while pitch is input.  As in if you’re pulling more than a small amount on the stick, your roll input is capped at ~25%.  That cannot help here as the problem is not due to pilot inputting roll. This is coming from an intentional act by ED developers. If RCA were the answer I would happily create and release some custom code to do this with _any_ stick and release it for everyone. Wouldn’t take but an hour or two. But it won’t help. 
 

3: The reason it’s a big deal to Panic and not to you is he is flying formation aerobatics - holding a sight picture with a lead jet while close enough to overlap several feet of wing with the jet he’s following  - the leader’s wingtip is closer to Panic’s canopy than Panic’s own wingtip. Having your jet make uncommanded and unrealistic movement is the problem.  
 

4: The other reason RCA won’t help is Panic, like the Thunderbirds, is flying with full “nose down” trim. That means even flying flat and level, the stick is pulled back far enough that RCA would cause him to have to use much larger roll inputs to hold paint, and full roll authority isn’t even an option (with RCA). 

The key things here are that this is resulting from a deliberate FM configuration by ED that cannot be mitigated by choice of input method. 
 

If as Nineline said this is coming from modeling the gyroscopic precession of the engine, then it’s in the wrong direction, as if they modeled an engine spinning the other way. Regardless, the magnitude is suspiciously high. If it’s going to be modeled, it should be modeling a very slight right yaw moment. 

 

 

Edited April 16 by Teej

[NineLine]

Hey all, this has been fixed internally, we lowered the gyroscopic moment effect from the engine. Thanks!

[Teej]

2 hours ago, NineLine said:

Hey all, this has been fixed internally, we lowered the gyroscopic moment effect from the engine. Thanks!

Excellent news, NineLine.  Can't wait to see it! 

 

 

[Teej]

2 hours ago, NineLine said:

Hey all, this has been fixed internally, we lowered the gyroscopic moment effect from the engine. Thanks!

Asking strictly out of curiosity, did you/they check the engine rotation as I had been commenting on? 

[Actual FM engine simulation feeding that gyro - I'm well aware the animation could've been different)

Again - curiosity since the direction of the yaw suggests anticlockwise engine spin.  

Edited April 24 by Teej