1.1 wheels:

[Beryllium Dragon]

Steam is awesome!

Screenshots in Steam is F12, which is also the Aerodynamic Forces overlay key.

http://imgur.com/a/Lvakq

The base craft which is just wheels, Mk1 inline cockpit, and a top mounted Juno assembly.

While under acceleration the arrow directions usually point north, which means the force is being applied to push it north (which is left). With the steerable wheel there is no indicator (if this means anything I have no idea). The four wheel assembly can generally move up and the down the runway fine (except when turning and the whole thing flips over).

Now when you add the steerable and watch the aerodynamic indicator you can generally get a feel for what the craft will do. Without SAS it should drift in the direction the force is pushing it, and with SAS it will overreact violently.

[Knaapie]

@Beryllium Dragon I tend to agree with the phantom force to the left and the overreaction from whatever forces (sas/steering).

There is a force disrupting stability for whatever reason (can be seen in flight as well, your craft keeps on wobbling never finding its balance). On the ground this wobble is overcompensated creating dynamic instability.

This is very likely to be caused by what JJE64 sais, yet I do believe it is possible to program around it.. for KSP at least.. I dont see the harm in creating overly stable landing gears to drive on.

[Beryllium Dragon]

9 minutes ago, Knaapie said:

@Beryllium Dragon I tend to agree with the phantom force to the left and the overreaction from whatever forces (sas/steering).

There is a force disrupting stability for whatever reason (can be seen in flight as well, your craft keeps on wobbling never finding its balance). On the ground this wobble is overcompensated creating dynamic instability.

This is very likely to be caused by what JJE64 sais, yet I do believe it is possible to program around it.. for KSP at least.. I dont see the harm in creating overly stable landing gears to drive on.

Yeah, the one I linked had landing gears slightly inverted to keep them level with front gear, when I re-ran the craft with the gears at 90/270 point on fuselage it had better stability, but still did the whole "flip in the air" thing at 70m/s (which is about 40km/h, and you'll never get any real craft off the ground at that velocity).

I think what is happening is the force is small, but large enough that it has a significant impact on lighter (smaller) craft.

[Knaapie]

1 hour ago, Angelus2141 said:

lane. I was able to overcome it with friction controls I made a video for it here. Hope it helps

 

 

 

Phantom force changes direction after the "fix" ^^ (check the rudder force during takeoff).. this seems to be 1.1 though ^^  ahh i'll still leave this post here

Edited April 30, 2016 by Knaapie

[Violent Jeb]

I set the front wheel friction to 0 to avoid phantom forces.. In testing, the craft begins to drift around 1 (default) and above. When cruising at the threshold of spinning out, the instant the front wheel is set to 0 the control went back a la 1.0.5, just straight. That was the single biggest factor on my configuration above. I'm going to do some more testing over the weekend using the starting runway, and some new wheel configurations.

It almost seems like these wheels are just massively customizable for different bodies/circumstances. I'm willing to bet when i get wheels on the mun i'll be using different settings, which is probably the logic behind it. Though i don't think that's necessarily a good thing for the average player who just wants to throw on a set of wheels and go.

Yousa Gonnaneed to make a few new pages on the KSPedia!

[Beryllium Dragon]

On the last attempt I was able to get the basic craft to 85m/s before instability hit.

Take aways are:

1. Phantom force
2. When placing LY-01's they must be perfectly perpendicular with the ground (so try to place them at 90 and 270 on Mk1 fuselages)
3. Small craft must be able to lift off at < 85 m/s or will tumble wildly in the sky
4. Due 1. small craft must be perfectly stable, see 2. and 3.

 

[Knaapie]

34 minutes ago, Violent Jeb said:

I set the front wheel friction to 0 to avoid phantom forces.. In testing, the craft begins to drift around 1 (default) and above. When cruising at the threshold of spinning out, the instant the front wheel is set to 0 the control went back a la 1.0.5, just straight. That was the single biggest factor on my configuration above. I'm going to do some more testing over the weekend using the starting runway, and some new wheel configurations.

It almost seems like these wheels are just massively customizable for different bodies/circumstances. I'm willing to bet when i get wheels on the mun i'll be using different settings, which is probably the logic behind it. Though i don't think that's necessarily a good thing for the average player who just wants to throw on a set of wheels and go.

Yousa Gonnaneed to make a few new pages on the KSPedia!

Imo engeneering in KSP should be slightly easier than irl, making this update proof of the inability to properly adres the problem at the time. I've been skitting on Eve, with its intense gravity on almost flat surfaces in 1.1 on the LY-10. Only lowering the gear could make you stop. Ofc you can now adjust your brakes, but imo it should automatically be compensated for due the higher wheel friction and braking friction at higher gravities (Nforce). This would also automatically lower the wheel friction of your front wheel when taking off..  win win

Edited April 30, 2016 by Knaapie

[Beryllium Dragon]

1 hour ago, Violent Jeb said:

I set the front wheel friction to 0 to avoid phantom forces.. In testing, the craft begins to drift around 1 (default) and above. When cruising at the threshold of spinning out, the instant the front wheel is set to 0 the control went back a la 1.0.5, just straight. That was the single biggest factor on my configuration above. I'm going to do some more testing over the weekend using the starting runway, and some new wheel configurations.

It almost seems like these wheels are just massively customizable for different bodies/circumstances. I'm willing to bet when i get wheels on the mun i'll be using different settings, which is probably the logic behind it. Though i don't think that's necessarily a good thing for the average player who just wants to throw on a set of wheels and go.

Yousa Gonnaneed to make a few new pages on the KSPedia!

Didn't work, at 30 m/s the LY-05 failed with the front wheel friction at 0.

Following that I made an attempt and got to 134 m/s on the runway when an LY-01 failed.

Putting the LY-01's at 90-270 seems to resolve 95% of the instability issue.

[GoSlash27]

From my experience thus far, the problem stems from

1) gear not being placed perfectly in the VAB due to a discrepancy in the programming,

2) Unity 5's wheel collider sucking out loud

and

3) less- than- ideal settings in the stock .cfg files (blame me for that part)...

The yaw moment attendant with multiple engines isn't a major factor in the problem, though it may aggravate it.

The fix so far is to

1) try the .cfg rebalance I posted upstream (only for the entry level gear at the moment)

2) be sure to snap your gear to global zero instead of local,

and

3) Design your aircraft to take off and land at lower speeds.

If you do all 3, you shouldn't have any problems with the landing gear in 1.1.2. And if you do, *please* let me know so I can try to chase down a better fix!

Best,
-Slashy

Edited April 30, 2016 by GoSlash27

[pincushionman]

7 hours ago, JJE64 said:

...This isn't a KSP problem.  It's not a Unity problem or a PhysX problem.  It's an integration problem...[stuff about PhysX wheels and Unity]...  This is also going to be a problem with landing - if you don't make a perfect 3-point landing with the wheel lines perpendicular to the runway, Unity is going to see those offset collisions and apply forces to compensate, probable upward and forward, which explains the bouncy landings people are posting all over youtube...

Surely the wheel "stick" can be pointed in an arbitrary direction. Including "whatever direction the nearest surface/edge/point to/within the wheel locus is this frame," rather than a pre-defined direction. Could that kind of catch eliminate the misalignment corrections and force all responses to be as if the wheel alignment is in the correct direction? The only problem I see there is the wheel physics routines are themselves what you count on to determine whether an interaction has happened. And that your suspension might actually be in a different direction. Okay, maybe not such a clean solution.

7 hours ago, JJE64 said:

...There is a petition on the Unity forums to get the Unity developers to enable a legacy compatibility mode so that U5 can use older versions of PhysX... seems to me that's probably the best solution at this point.  So if you want to see this work, that's probably where the community needs to focus its energy right now - getting Unity to make their product work.  In the meantime, KSP devs, thank you for all you've done, and I really hope it works out.

Uh...we don't want to use older PhysX. We already had it, and it's part of the limitations the old KSP had. Which, besides wheels, appears to be working out pretty well for us.

[NikkyD]

I tried some mini plane stuff on the weekend and i'm thinking that the game has a huge problem that most don't even see, the whole physics calculations are too "simplified" or "dirty tricks" to simulate something that the engine was never written for.

I made a mini plane (tricycle style) and made the suspension maximum stiff. Then i played around with SAS on/off, all steering surfaces off etc

The plane starts in a straight line, ofc, but at some speed, as others have already reported, it starts jumping left/right (rolling). When i looked at the aero-forces with F12 i saw a lot of stuff going on and was wondering where the hell those forces would come from ? Ofc once my plane rolls to the left by 5° within a second, that movement causes lift and so on. But why can the plane roll to the left all of the sudden ? I did put the engines and 60% of the whole weight on the wing tips, now the wings have terrible leverage and it should steady the whole thing but the engine just knows a center of mass aparently. I forgot how the engine deals with it all, someone explained it sometime somewhere but i think the major issue is there. If every plane is basically a sphere with wings then ofc it is very unstable.

The wheels SHOULD have dampening and thus a sudden shock from the wheels should be eaten up completely by the dampeners. The force that makes the plane jump must come from the wings/aero then.

But how can only ONE wing generate force on a symetrically built plane ? The wing itself, not any control surfaces. Real planes ofc are not perfect, so its ok to say that the forces are distributed non evenly, but material flex eats up that difference in reality, it may cause vibration and stuff but here every force is applied down to the smallest amount (it seems) and thus a 0.0001 Newton force on one wing causes a slight roll which in turn causes other "things" to generate forces and so on, it just builds up until the plane flips.

I also notice on some wobbly rocket designs that the trajectory marker /the orbit is very jittery. With no engine working there should be no change but ofc if you think about it. If some heavier part of the rocket is suddenly a bit closer to the source of gravity, it experiences more gravitational force. So if a part wobbles towards the planet and then away from it, gravity applies different forces all the time. That is ofc in the nano-digits, but it might throw a calculation off as it is based on floating point numbers somewhere in the code.

So my fear is that the whole thing is more and more a manifestation of this. In the beginning (maybe) some bugs leveled eachother out, but as the bugs get fixed more and more of the real problem is becoming visible.

 

Just my weekend thoughts

 

[Overland]

Theres much to say but ill compress it into 3 things

 

1. These new wheel physics killed my trains

 

2. I liked the old wheel physics

 

3. See 1 and 2..

 

Performance is better.. Again point 1

 

[Warzouz]

I have a related question :

Do wheels or landing struts can induce phantom force ? (PS : struts aren't clipped, just regular radial mounted)

I have a lander that shows such rotating force even without any toque activated.

[steve_v]

28 minutes ago, Warzouz said:

Do wheels or landing struts can induce phantom force ? (PS : struts aren't clipped, just regular radial mounted)

I have a lander that shows such rotating force even without any toque activated.

An excellent question. I'm pretty sure I have been seeing the same thing, but so far I can't reproduce it accurately enough for a decent bug report... About all I can say is that if it does exist (and it's not mods causing it), it only does so on craft with landing struts or wheels.

I vaguely recall some mention of Squad applying a force to counter a phantom force from the wheels / struts and make them stay still on the surface... but TBH I can't recall where, so I may have imagined it. If this was actually the case it would explain much.

Anyone else seeing this?

[Tr1gg3r]

On 30 April 2016 at 0:00 AM, GoSlash27 said:

2) be sure to snap your gear to global zero instead of local,

How dya tell if ur global/ local? dont  get this bit, anyone? Sure its simple

NVM

Edited May 3, 2016 by Tr1gg3r
Worked it out myself.

[Overland]

It was in the pre release thread about overcoming the new wheel physics issue of drifting parked vehicals.. And that they were struggling to find a fix until they simply applied one in the opposite direction to counter it

 

Someone did wisely say itll come back to bite us..

 

Indeed it has... 

 

Needing unrealistic gear configurations..check

 

Aircraft slowly pulling to one side and showing forces applied left for no good reason...check

 

Even submarines with ungodly amounts of vertical stablisation rolling left with SAS off..and NO controller plugged in

Edited May 3, 2016 by Overland

[eddiew]

Is the phantom forces thing likely to be why one of my plane designs does doughnuts on the runway at ~50m/s? I didn't think about turning on aero overlay...

Other planes are fine, just a couple that really cannot go in a straight line on any surface. Usually they're fine once off the ground.

[pandaman]

@Overland   I was just thinking yesterday, and wondering how you were getting on with your amazing trains with the new wheel physics.

It seems that my concerns were valid.

[Overland]

1 hour ago, pandaman said:

@Overland   I was just thinking yesterday, and wondering how you were getting on with your amazing trains with the new wheel physics.

It seems that my concerns were valid.

Thanks... Yeah.. Its been a tough road, waiting for things to settle down bug wise these days.. I miss my trains

 

Sadly loading 4429 into 1.1 invokes explosions so violent due to wheel forces that ive actually had wheels escape kerbins atmosphere

 

The old 1 ton modified M1 wheels simply dont like these wheel physics..

Im slowly trying to modify new ones but I find myself disheartened longing for the old wheels I both trusted and knew how to handle down to an artform

 

Given that I cant takeoff the simplest logical designs from the runway.. I dearly hope this is just a terrible teething phase for KSP

 

If not...I shall make landtrains based off baldwin centipedes (not fake)

 

Looks 1.1 wheel compatable..

Edited May 3, 2016 by Overland

[steve_v]

2 hours ago, Overland said:

It was in the pre release thread about overcoming the new wheel physics issue of drifting parked vehicals.. And that they were struggling to find a fix until they simply applied one in the opposite direction to counter it
Someone did wisely say itll come back to bite us..
Indeed it has...

Yeah, that. If I recall correctly, one of the points I made in my most recent "1.1 is still a freaking beta" rants was... All these bandaid wheel fixes (that don't address the underlying problem) have caused other issues.
I rest my case.

2 hours ago, Overland said:

Even submarines with ungodly amounts of vertical stablisation rolling left with SAS off

And.. left is the direction my landers spin with SAS off too.

 

On a slightly different note, I just had a ~30T aircraft fired ~500m into the air by a gear malf   Apparently taxiing on a slope is kraken bait now.

As is touching any surface that's not dead-level. Or touching landing legs with anything. Or putting landing legs on a craft at all, for that matter.

This is getting ridiculous, the more I play try to play 1.1.<whatever broken patch we're running now>, the more I come to realise just how bung it is, and how half-arsed the Squads last minute "fixes" really are.

---

Ya know what the best bit is? Since you mentioned it, I checked... grounded craft still drift. It's so slow now that you have to be pretty patient to see it, but it's there. "Fixed" indeed.

I keep coming back to this game, thinking "maybe it's mods" - nope "maybe it's my craft" - nope "maybe if I just muck with it a little longer"... Screw it. Bravo Squad. Whatcha got planned for the next "hot fix"? There must be something left to break.

Edited May 3, 2016 by steve_v

[eddiew]

40 minutes ago, steve_v said:

Ya know what the best bit is? Since you mentioned it, I checked... grounded craft still drift. It's so slow now that you have to be pretty patient to see it, but it's there. "Fixed" indeed.

Yeah, I parked a plane next to the crashed UFO at the north pole. It quietly vanished down the (minor) slope while I was getting selfies   Heaven help you if you timewarp, you'll be lucky if it doesn't pirouette and fling itself into the air.

[Kryten 2X4B 523P]

3 hours ago, Tr1gg3r said:

How dya tell if ur global/ local? dont  get this bit, anyone? Sure its simple

NVM

its referring to the rotation tool in the VAB / SPH - select the rotation tool from the toolbar, select the part you want to rotate,  then the F key toggles between the two modes.

[EpicSpaceTroll139]

Last night I walked into the wheel of a car I had flipped over (was too busy doing J-turns and 360s to pay attention where I was going) with a kerbal, and my car got launched ab 150m into the air, flipping end over end... Somehow it landed right-side-up, so I just got back in and went on my merry way lol... These bugs amuse me more than frustrate me actually... Just waiting for Danny2462 to discover this!

Edited May 3, 2016 by EpicSpaceTroll139

[[email protected]]

nice thread!

[squeaky024]

My wheels just cause instantaneous detonation of anything I ever do as soon as it spawns.

I started using I-beams to sled around.