Yaw oscillation - a possible explanation?

[DD_bongodriver]

 

 

So it does not keep going straight when you centre the stick and it does indeed "bounce back"! Anyway, I know you always like to have the last world so I am off for a night out.

 

Then I can't help feeling we are talking about completely different aspects here, yaw does indeed 'spring back' to centre on release of the rudder and yes some aircraft give a tiny wobble on return, yaw is in fact the only control axis that self centres itself returning the aircraft to an undisturbed state as opposed to roll and pitch which will leave the aircraft in the pitched or rolled state without counter input, this has nothing to do with your boat analogy.

 

1. you do not 'steer' an aircraft with rudder in the air

 

2. the test condition you describe is an application of rudder with no other control inputs, the oscillation described there is a very brief period of dutch roll (oscillation in roll and yaw) which in a straight wing aircraft disappears pretty quickly, this is not the 'rubber banding' I or many others were reporting.

 

3. rudder is controlled by the pedals.......not the stick......I'm sure this is something you really understand but is in error in your post.

 

4. your test report explains a half deflection of the rudder only gives a 5 degree bank, having just tested in game I get a very aggressive roll still with half deflection though now it is manageable unlike before and I can actually fly level with fully crossed controls.

 

5. refreshingly since the testing I did today I noticed much of my issues with pitch oscillation have been dealt with.......did I miss an update explaining this being fixed? it's like a different game amazingly.

 

6. I don't like the last word, I mostly prefer it when the last word is a grovelling apology to me

 

7. give her one from me.....or both of them.

[SharpeXB]

The endless flight model discussions are rather pointless at this stage unless there's actual data to be submitted to the developers. I'd rather they spent their time working on actual content than chasing flight model ghosts.

 

Myself I don't experience undue "rubber banding" so it's probably an issue of; practice, controllers and settings.

 

Practice, because the last generation of WWII flight sims was made for PCs that are now outclassed by smartphones. Welcome to reality. BoS has a quite sophisticated flight model. Is it perfect? None are. But it feels very believable.

 

Controllers. Check that they're calibrated and functioning. Also rudder pedals are a big help.

 

Settings. Most devices need a curve of some degree to make them "realistic". Sticks are smaller and even pedals are set a bit closer than the real thing and have no force feedback.

[sturmkraehe]

109's poor stability came from the undersized tail fin, and that actually means a small rudder with less effectiveness.

 

Rubbish. Poor lateral stability means higher rudder effectiveness.

[DD_bongodriver]

Rubbish. Poor lateral stability means higher rudder effectiveness.

 

Rubbish, poor lateral stability means the small vertical fin does not provide enough weathercocking effect, high rudder effectiveness simply means you get stronger yaw control, you do not get high rudder effectiveness from a small rudder.

Edited November 1, 2014 by DD_bongodriver

[DD_bongodriver]

bongo, you're completely wrong here, I am sorry :-/

 

Are you for real?

 

You know full well the immediate effect of pitching and centering the controls is the aircraft will remain piched until the speed changes, the aircraft does not immediately weathercock itself back to a straight and level position as it would with a deflection in yaw, the same applies for roll, bank the aircraft and center the controls the aircraft will remain banked and not immediately return itself to wings level.

Edited November 1, 2014 by DD_bongodriver

[DD_bongodriver]

but, it doesn't require counter control input.....

 

it does if you want to deliberately return to the original state immediately.......how are you not picking up on this?

 

You know exactly what I mean, come on, push the rudder and let go the aircraft returns by itself immediately, not so with roll or pitch.

Edited November 1, 2014 by DD_bongodriver

[DD_bongodriver]

Thank you!

[GP*]

Unreasonable,

 

You do not overturn to capture a heading in an aircraft. On the contrary -- typically, you lead turn your heading by a few degrees.

 

Bongo clarified the rest.

 

And I think its clear what Bongo meant WRT axes returning to their original position, ie rudder versus elevators/ailerons...

 

No disrespect meant to anyone btw.

[unreasonable]

Wrong time of the month And too much coffee so here I am again.

 

Since you do not actually want the last word I shall have another go, but rather than a grovelling apology how about a detailed rebuttal?

 

First off you can indeed steer aircraft in the air using the rudder, cross controlled with airlerons. Of course I know this is not at all efficient when you have a wing to turn for you, but even so, you can do it. Obviously you would not normally want to, but it is an interesting case because it simplifies the physics. Airships and submarines all work on this principle and the physics are the same.

 

I understand why you say that only the rudder self centres (after oscillating), but I think that pitch must self centre a little as well since any condition where you pull back the elevator will result in some inertial movement in the original vector creating a weathercock effect on the horizontal stabilizer which will be manifested when you release the back pressure. Not normally to the original position, just enough to offset the inertia, although if you are going really fast, make a huge elevator movement, and therefore create a huge inertia, you might get a correction that has enough inertia of its own to take you back to the original position or even past it. Which is what I think was happening in those silly videos we all watched months ago.

 

Or put it another way: if you take an Me109 and drop it from a stationary balloon, level, engine off, controls centred, what would happen? I suspect it would end up dropping nose first. This can only be because the horizontal stabilizers exert a weather cocking effect.

 

Alternatively, I expect your preferred solution, is that I do not have a clue what I am talking about.

 

Whether the BoS FM models this correctly I freely admit I have no idea, but I am glad you have tried it again and found it improved. I find it quite easy to control my 109's yaw with the 50/4% solution, but my nose is still bobbing up and down so I might try something like that on pitch as well.

Unreasonable,

 

You do not overturn to capture a heading in an aircraft. On the contrary -- typically, you lead turn your heading by a few degrees.

 

Bongo clarified the rest.

 

And I think its clear what Bongo meant WRT axes returning to their original position, ie rudder versus elevators/ailerons...

 

No disrespect meant to anyone btw.

We are talking about the specific case where you yaw a plane with ailerons held cross controlled to see how much weather cocking or oscillation you get. Nothing to do with how you would normally operate an aeroplane, which I do understand. No offense take!

Edited November 1, 2014 by unreasonable

[Hoots]

Man, I'm glad I've got some beer in, I can really sit back and enjoy this one

[DD_bongodriver]

 

 

First off you can indeed steer aircraft in the air using the rudder

 

'Can' does not mean you 'do'

 

 

 

Airships and submarines all work on this principle and the physics are the same.

 

in some principle yes, the inertias of these different vehicles call for very different methods.

 

 

 

Or put it another way: if you take an Me109 and drop it from a stationary balloon, level, engine off, controls centred, what would happen? I suspect it would end up dropping nose first. This can only be because the horizontal stabilizers exert a weather cocking effect.

 

great, I cannot argue with this theory, the inherent stability of the airframe would indeed result in the main mass (engine) to pull the aircraft into a nose down position due to the drag of the rest of the aircraft trailing it (how a parachute works) and indeed the elevator does form part of that airframe and will have the greatest effect.......but we aren't talking about dropping planes from balloons........are we?

 

 

but rather than a grovelling apology how about a detailed rebuttal?

 

I await eagerly

[unreasonable]

Ahah, but the point of my balloon example was to show what happens when the direction of travel of the aeroplane is not exactly aligned looking straight ahead.

 

So if you are flying level and then pull up sharply, your plane is moving forwards along its original vector due to inertia until air resistance cancels this out, as well as being pulled along the new vector by engine power and change in the lift vector. That inertial vector is going to create a moment on the tail surfaces. If you release the controls before that inertia has dissipated you must get some turning movement.

 

Hard to see what is so hard to see....  

[DD_bongodriver]

 

 

Hard to see what is so hard to see....

 

it's not hard to see, I know what you mean.....it's just somewhat tenuous, the effect is so minimal, but I concede it's validity.

[unreasonable]

Hooray! I have no idea what the magnitude of the effect must be ... certainly seems to be less in the newest releases.

 

At least arguing with you I know you not one of the creepy, hidden lobbyists!

 

Edited November 1, 2014 by unreasonable

[DD_bongodriver]

 

 

hidden lobbyists!

 

OOHH! juicy!!.....tell me more.

[kiershar]

The wobble on the bf109 is for balance purpose, if it wasn't present german planes would have too good accuracy.

[TG-55Panthercules]

The wobble on the bf109 is for balance purpose, if it wasn't present german planes would have too good accuracy.

 

 

 

Unfortunately, I'm sure there are some folks out there who will believe this.

 

Too bad the devs aren't Swiss - probably the only way they might be perceived as "neutral" in this regard by some folks     

[6./ZG26_5tuka]

I actually think kiershar is right!  This wobble was indeed built on purpose, on German ww2 fighters, to compensate the wobbling of the pilot's heads while singing laudly in the cockpit those German war songs.

 

There are many sources and flight tests proving this.

Yea an I think to inicrease it's effect german pilots are modeled drunk ingame all together. You thought those Opel Blitz at the airfield were fuel trucks? No, it's Bier!

[unreasonable]

The German zombies shuffling around the airfields are also clearly more hung-over than the Russian zombies, but this is historically accurate since the Ivans were better habituated to locally made vodka.

[senseispcc]

The stability of a fighter is normally as poor as possible otherwise it is not a fighter but a bomber!  

 

[GP*]

The stability of a fighter is normally as poor as possible otherwise it is not a fighter but a bomber!

Not at the expense of its abilities as a gun platform and overall flying machine.

 

I.e. too much instability is counter-productive.

[jacsJERSEY]

Without everybody getting at each other. what can one do to make the aircraft more stable when trying to lock onto a target?

[=LD=Penshoon]

Without everybody getting at each other. what can one do to make the aircraft more stable when trying to lock onto a target?

For me tiny movements on the stick and same for ruder. Also the Yak seems most stable for me. I'm not good at gunnery. Here's a video of three fights against AI. Share tips if you have em 

Shooting at 1:40-2:30 4:30-7:15 and 10:20-10:30

[FuriousMeow]

Not at the expense of its abilities as a gun platform and overall flying machine.

 

I.e. too much instability is counter-productive.

 

Well, that's arguable. Some aircraft were great gun platforms, but that was all they were. Others are extremely maneuverable but are not great gun platforms. These days the fighter aircraft are extremely unstable - so unstable a human can't control them and they have computers between the stick and the control surfaces. Not just due to the speeds the aircraft fly at, but also due to their aerodynamic instability that is always going to be present due to their design and the speeds they need to reach. There were several aircraft produced that were unstable platforms and required being in close to reliably put rounds on target. The best shots of WWII got in to 50 meters of their targets. The best shots of WWI got within 20 meters.

 

And some times "overall flying machine" matters little compared to getting something out that will just be faster than the enemy and hopefully turn the tide - Me163, He 162, Ta-154, and more. Or early variants of aircraft that clearly needed more time to mature - early Hawker Typhoon that would lose its tail due to high speed oscillation, early P-38s in Europe (and all P38s up until the L that introduced the dive flap to prevent the elevator from being rooted in cement in high speed dives), and several more early aircraft versions that were sent to the front lines just to be found they still had several problems and needed to be fixed. Some due to additional filets, or a metal tray in the wing ammo trays, or just pulling the damn thing out of service because it was killing more of their side than the side it was supposed to be fighting against.

 

Lots were forgiven in those days of pushing the boundaries of aviation in the name of war, and fighters back then had to be inherently unstable - that's where their maneuverability came from then. WWII was still new aviation, lots of stuff still wasn't known. So, "overall flying machine" to that era was - does it take off? Does it meet the requirements? Does it land? Is the pilot still alive? Is it better than the other aircraft? Put it into production!

Edited December 23, 2014 by FuriousMeow

[LizLemon]

"Additional tuning was done to stability and controllability of planes in the yaw axis so wobbling on gliding angle was significantly reduced"

 

Looks like the devs finally realized that there was a problem with yaw oscillations.

[LizLemon]

Lots were forgiven in those days of pushing the boundaries of aviation in the name of war, and fighters back then had to be inherently unstable - that's where their maneuverability came from then

I don't know of any ww2 aircraft that was deaignes to be inherently unstable. Sure the Wright brothera believed that an aircraft had to be unstable in order to turn. But by ww2 thus was known to be false.

 

And inherently unstable ww2 fighter would cause all sorts of problems, with high pilot load being one of the more pressing issues.

[jacsJERSEY]

Thanks a lot for all the info, but is there a way of reducing the sensitivity of flying controls? Nothing in Controls set up!!