Planes spinning out at speed upon departure and arrival

[Andersenman]

Again and again and again. Every bloody landing, KSP does this screwup to planes, even stock ones like the Velociteze:

Quote

What is that? You made a perfect 3-point landing? Why let me spin out and powerslide your plane into a roll-over crash and ruin your landing, surely that's what you intended to do, no?

How is this a thing and how do I make it not a thing, please?

Thanks.

Edited August 24, 2018 by Andersenman

[bewing]

It still all comes down to a question of engineering stability. If there is too much drag at the front of the plane, and not enough at the back, the plane will try to swap ends. This is true while flying and it is also true on the ground.

There are numerous detailed causes and cures all listed out in the FAQ, on the parent forum. But it all really comes down to the same thing. Where is your CoM when it spins? What's the aerodynamic drag on all the parts in front of the CoM, and what's the lever arm distance? What's the ground drag (ie. friction) on all the wheels in front of the CoM and what's the lever arm distance?

What's the easiest first thing to change? In the SPH, reduce the friction on your front landing gear to something very low and see if the problem goes away.

 

[Andersenman]

Thank you, I will investigate. I shall point out again that this happens to the stock, SQUAD-provided Velociteze, and does so from about 50 m/s and upwards, and thus very much so upon typical landing speeds.

[bewing]

The stock craft are specifically designed to have faults and failings. They are not supposed to be examples of perfect craft. They exist to give you an incentive to improve them, or to do better for yourself.

 

[Vanamonde]

While I rarely disagree with @bewing and hesitate to do so now, all of my planes have been doing this for the last couple of versions of the game, regardless of their performance in flight. So I'm pretty sure it's entirely due to funky wheel behavior rather than aerodynamics or physics. It even happens when I set front landing gear brake to zero and back landing gear to full brake, which I do on all my planes as well. 

[bewing]

Friction, not brakes.

[steve_v]

4 hours ago, Vanamonde said:

all of my planes have been doing this for the last couple of versions of the game, regardless of their performance in flight.

I absolutely second this. Every major version release seems to change wheel behaviour, and lately this results in unpredictable sliding and fishtailing on landing.
Aircraft that I landed easily in 1.3.1 are deathtraps in 1.4.5, with no changes to design or wheel settings. And then there's the self-amplifying bouncing...

It'd sure be nice if Squad stopped screwing up wheel physics every major release, it's been going on for years now.

I'm not saying that landings should be easy, or that the craft (mine or stock) are perfect. But needing to learn a new set of workarounds for janky wheel physics and rebuild all your craft every release is infuriating.

3 hours ago, bewing said:

Friction, not brakes.

Friction should be dependent on the materials in question and the forces between them, not some setting added as a workaround for the lousy wheel-collider. Nobody had to muck with friction settings in 0.90, why do we need to now? Can't we at least have a workaround that works the same in each new release?

Edited August 26, 2018 by steve_v

[bewing]

2 hours ago, steve_v said:

I absolutely second this. Every major version release seems to change wheel behaviour, and lately this results in unpredictable sliding and fishtailing on landing.
Aircraft that I landed easily in 1.3.1 are deathtraps in 1.4.5, with no changes to design or wheel settings. And then there's the self-amplifying bouncing...

It'd sure be nice if Squad stopped screwing up wheel physics every major release, it's been going on for years now.

It would be even nicer if people would realize that Squad doesn't change wheel physics at all between most releases. Squad just upgrades Unity game engine versions. Yes, it would be nice if we lived in a perfect world where Squad was in full control of the entire game's code, rather than having to rely on a game engine created by someone else. However, that's not the world we actually live in. Yes, the game changes a bit between versions, and we all have to adapt just a little bit each time.

 

2 hours ago, steve_v said:

I'm not saying that landings should be easy, or that the craft (mine or stock) are perfect. But needing to learn a new set of workarounds for janky wheel physics and rebuild all your craft every release is infuriating.

Friction should be dependent on the materials in question and the forces between them, not some setting added as a workaround for the lousy wheel-collider. Nobody had to muck with friction settings in 0.90, why do we need to now? Can't we at least have a workaround that works the same in each new release?

You don't need to rebuild all your craft. You just have to tweak a couple little settings on each one. And why do you have to muck with a couple settings? To make your planes work. No you can't have a workaround that's identical with each release, because the Unity engine changes with each release, and that changes the entire physics that the game runs on.

 

[steve_v]

13 minutes ago, bewing said:

It would be even nicer if people would realize that Squad doesn't change wheel physics at all between most releases. Squad just upgrades Unity game engine versions.

Squad decided to use and to keep using Unity. Squad decides which Unity versions to target, when to ship releases, and which bugs are acceptable for release. Of course they get a share of the blame for the recurring wheel problems.
As the old saying goes: A poor workman blames his tools.

[Andersenman]

On 8/25/2018 at 10:28 PM, bewing said:

The stock craft are specifically designed to have faults and failings. They are not supposed to be examples of perfect craft. They exist to give you an incentive to improve them, or to do better for yourself.

 

I bet you say that to all the girls bugs/quirks/shortcomings/design decisions./s

Respectfully, that's nonsense and I don't believe you. I highly doubt that SQUAD (no matter whether before or since you joined) deliberately provisioned the game and/or the stock vehicles in such a way that they malfunction during regular gameplay just to teach players some passive-aggressive lesson. Coding costs money, and coded nonsense is still code.

 

That said, why is changing tyre friction something that should be invoked in the first place? Let's ignore the fact that for some reason it must be hidden by a switch in the Settings that governs its accessibility in the first place for now. In reality, reducing friction is not an option, let alone desired. If, as a vehicle engineer I have to rely on the behaviour of my tyres to specifically lose traction at a certain moment to keep my vehicle stable, then there is something seriously wrong in my design. So, recommending just this method, to slap a baby buggy's rubber wheel on an airplane instead of the regular landing gear so that it starts slipping when it exceeds a certain amount of cornering force just to prevent it from performing the litho dance, does not sound sane, practical, or realistic, let alone self-evident or intuitive.

Edited October 21, 2018 by Andersenman

[natsirt721]

My advice here is: don't land with the brakes on.  Wait until your aft gear are solidly down, then active the brakes.  If one wheel touches down first, with brakes that is going to apply a good amount of torque to the airframe before the other wheel touches down.  Aircraft aren't nearly as stable in the yaw direction, especially at low speed, so it doesn't take much of a disturbance to induce a spin.

Edit: did not check the timestamps, hope this thread isn't too necrotic.

Edited October 24, 2018 by natsirt721

[Scarecrow]

Unwanted sliding all over the place has pretty much been a feature in KSP ever since Squad introduced the ability to adjust spring/damper/friction rates for wheels.  I spend almost as much time trying to tweak the settings to get my craft to behave as I do in designing and building the craft in the first place.  It's a pain in the proverbial.

[swjr-swis]

4 hours ago, Scarecrow said:

Unwanted sliding all over the place has pretty much been a feature in KSP ever since Squad introduced the ability to adjust spring/damper/friction rates for wheels.  I spend almost as much time trying to tweak the settings to get my craft to behave as I do in designing and building the craft in the first place.  It's a pain in the proverbial.

The adjustment sliders are not the cause. They were added as a workaround due to the wholly unacceptable default behaviour of wheels when the game's wheel system got 'upgraded'. Without those sliders we'd still be completely helpless to wheels acting in whatever random way they feel like.

I have no issue with the sliders at all. More control is always better in my book, and it's almost a must-have when building complex, large, or 'weird' craft. I do wish however that they'd figure out how to make wheels and suspension work more or less as expected in the basic vanilla use cases, without having to tweak the sliders all the time.