Plane pulling to the side after steering

[splashboom]

I have this plane I like to land over and over(with an amazing low accident rate under ?%!!!)

At landing I hit the brakes and occasionally need to steer to stay on runway. I find there is a big lag between joystick command and steer, which then continues without touching the stick - so I need to correct the other way, and the same happens in the other direction, etc. It seems to be worse when braking, and I take brakes off to steer, but it is not a science(art neither)

Is this how a craft acts in real life? Is it a simulation artifact? Is it because I killed Jeb??

Thanks!

edit: According to the FAQ I might have misaligned landing gear

Edited November 7, 2021 by splashboom
update

[18Watt]

Hard to tell what’s going on, a screenshot might help.

I generally either disable brakes on the nose-wheel, or use greatly reduced braking power.  I set the main gear brakes to 100% or more.

Otherwise, there are a lot of things which could be causing you trouble.

• Landing gear not mounted straight.  Check with the rotate tool- when mounted to a nose section the gear sometimes is angled forward slightly.  This can cause major problems.  KSP wheels aren’t really wheels...
• Check your landing gear settings.  If the suspension is too soft it will wallow around.  If the friction control is too low you’ll see delayed response from steering input.
• Make sure your landing gear is big enough. To support the weight of your plane.  If it looks too small, it probably is.

[Vanamonde]

Sounds like a design problem but it's hard to say without seeing the craft. 

[AHHans]

On 11/7/2021 at 3:39 AM, splashboom said:

I find there is a big lag between joystick command and steer, which then continues without touching the stick

How do rovers behave? Do they show the same behavior? If that's the case then there might be a problem in how the control via joystick is set up.

Edited November 9, 2021 by AHHans

[splashboom]

Thanks all these are good suggestions .. I use the keyboard for rovers but I will check the joystick settings. Also did not fiddle with the gear settings - they are and look big enough though, and can take some punishment at landing. The single gear is on the tail, and two big gears are in front by the engines(no nose wheel, but that should not cause the issue).

Finally, I tries realigning the wheels and seemed to make it worse - which means it has an influence. The issue is that the gears are attached to engines and wings, and the wings are slightly tilted backwards. I wish the angles were displayed somehow during tuning.

[OHara]

 You can, if you like, pitch your plane in the SPH as it would sit on the runway, and use 'absolute' mode, with the hexagon 'snap rotation' indicator on, to rotate the wheels  square to the runway. 

But maybe those details are already good.

The steering you describe sounds like the reaction wheels might be active, because the steering inputs to reaction wheels cause torque, which accelerates the rotation of the craft, and then when you release the input the momentum of the craft keeps it turning.   The same is true to some extent with the rudder and tailwheel steering.

Front-wheel (main wheels) steering is generally not done with tail-wheel aircraft, but if you used steerable wheels there the steering would be enabled by default.

Taildraggers really do tend to "ground loop" because your main contact points with the ground are in front of your centre of mass.  You need to keep pulling back on the stick as you brake, to get some weight on the tail so the tailwheel drags on the ground if you start to loop, and you cannot brake very strongly.

[splashboom]

On 11/9/2021 at 11:12 AM, OHara said:

The steering you describe sounds like the reaction wheels might be active, because the steering inputs to reaction wheels cause torque, which accelerates the rotation of the craft

I switched reaction wheels from 'normal' to 'pilot only', and the steering does stop after a second - still overshoots. Seems like it was a combination of two factors, since I still suspect the alignment can be improved. That and being tail-dragger.

[Goddess Bhavani]

I've had similar issues with a starting aeroplane, I found the following to be the cause

- Landing gear not perfectly aligned, even with snap angles. Made the main gear 'toe out' slightly for stability by doing minute adjustments with the rotation tool. This is a throwback to car tuning - the default positioning seems like there's a slight 'toe in' making the craft too sensitive to yaw, making it toe out is less efficient but allows the plane to stabilize itself in a straight line.
- Rudder is not perfectly aligned, offset the rudder to one side to counter yaw on takeoff (you actually find this done on old piston engine warbirds, like Bf-109!)
- Suspension was either too stiff (causing bounce) or wallowing around too soft, I set it to 0.9 or 1.0. 
- Level 1 Runway is bumpy, ensure your gear can soak up the bumps during the takeoff and landing roll. Realizing unwanted roll was the problem causing the wallowing, I set the roll control to the all-moving tailplanes instead.

And finally: 
I had Kerbal Weather installed and the basic landing gear absolutely cannot take 20 m/s crosswind without tipping over the plane and destroying the craft, so I disabled wind on takeoff/landing. 

Edited November 12, 2021 by Goddess Bhavani

[splashboom]

On 11/11/2021 at 7:35 PM, Goddess Bhavani said:

I had Kerbal Weather installed and the basic landing gear absolutely cannot take 20 m/s crosswind

I think 20m/s crosswind would prevent a lot of planes from landing, and make it significantly harder even for large ones(with higher stall speeds). That is why they design airports with more than one direction for airfields.

For alignment, hopefully KSP2 will provide easier tools. I will try to make it 'toe out' a bit(its not like im paying for worn landing gears ) . However the alignment tool allows angle increments of 5(?)

degrees, which seems too much .

One thing about my craft, the main wheels are not only in front, but quite far apart(got tired of having it tip over). With this geometry it should be that the tendency to ground loop is even higher.

[Goddess Bhavani]

Ah yes, and the fact not all of us have fancy joysticks, and the in-game flight controls and SAS interaction feels like two systems fighting each other. But its fun when it works

For the landing gear angle - for minute adjustments disable the angle snap.
From your description of main wheels far apart it should be like a FW-190 in terms of configuration, this wide landing gear is much easier to handle on the ground without tipping over but I might recommend to reduce the harshness of the shocks and springs so it doesnt bounce left and right while rolling down the un-smooth Lvl 1 runway. This is something I experienced on WW2 flightsims like the Sturmovik one too, so we are not too far off from realism



I would also be happy to look at the craft files and do the necessary tuning as a mechanic would to a classic car, as it is often quite difficult to explain, what are all the small adjustments and settings tweaks done to make a plane lovable to revisit.

 

Edited November 13, 2021 by Goddess Bhavani

[AHHans]

On 11/12/2021 at 1:35 AM, Goddess Bhavani said:

Landing gear not perfectly aligned, even with snap angles.

I align the landing gear on my planes with angle snap, but I make sure that the angle snap is set to absolute (i.e. snap relative to the SPH coordinate system) and not relative (== relative to the parent part). I also make sure that the gear is attached to a part that don't flex around much when the weight of the plane rests on them.

[splashboom]

3 hours ago, AHHans said:

the angle snap is set to absolute

Huh, and here I thought nobody thought of that(plus I owe an apology to the rotation tool too)

 

Here is a pair of engines with plane attached(they should totally build this irl)

https://drive.google.com/file/d/1NgQyYVGcbSAOsKzhzMso-p0U_wRtGyl4/view?usp=sharing

 

Edited November 13, 2021 by splashboom
add pic