How improve wheels grip and torque.

[Angorek]

Hi

Recently I`ve build a rover using stock parts, but 5 times smaller than original ones. The problem is that it can barely move. I just changed rescale factor and mass, now it weights 0.95t, and it can`t drive up the launch pad using 6 Rovemax M1 ... Any idea how to fix it ?

Daniel

Edited August 6, 2014 by Angorek

[LaytheAerospace]

Friction is pretty weird in KSP, I'm not sure you're going to have a lot of luck at the fringes like this. I've done some experiments with a 48-7S facing upward and throttle limited to some very low value to provide increased traction, but decided it wasn't really worth it on the types of rovers I was building. Maybe it will be more beneficial to your ultralight design. Could angle it backward as well to provide a little forward thrust if you still can't top the hills. Also, maybe the different wheels will give you better results.

[Laie]

No real solution, but a general idea: in my experience, the "TR2L Ruggedized Vehicular Wheels" have vastly superior grip. They still suffer badly when in low-g, but there is a notable difference in performance. My Minmus rover could accelerate twice as fast with TR2Ls compared to M1s; given the abysmal performance of M1s, twice as much still ain't good, of course. And when trying to make a turn, there was a visible effect; again not much, but far superior to M1s.

Looking in the part files, I see this

//M1
	torqueCurve
	{
	  key = 0 250 0 0
	  key = 20  100 0
          key = 30 14 0 0
	  key = 34 0 0 0
	}

//TR2L
	torqueCurve
	{
	  key = 0 100 0 0 
	  key = 2.5 70 0 0
	  key = 30 0 0 0
	}

...and can't make much sense of it. Looks as if the first number might be surface speed, the second figure would give the relative traction at said speed. Which would imply that M1 should have really aggressive traction at low speeds, which they don't. So I don't really know what it means.

Still, I suggest you change the first line from "0 250 0 0" to "0 800 0 0" and see what happens. And please let us know the outcome.

Edited August 5, 2014 by Laie

[DrMonte]

I have no idea what a rescale factor is but it doesn't sound good if you still got 1t. Mine "undestroyable" weighted just a bit above 1t and carried 4 kerbonauts.

Try using "TR-2L" for better grip.

[Angorek]

So basically the rescale factor is the size of the model, if You have 1 meter tank with rescale factor set to 1, then it will have 2 meters with rescale factor set to 2 and so on

torqueCurve
	{
	  key = 0 250 0 0
	  key = 20  100 0
          key = 30 14 0 0
	  key = 34 0 0 0

The first number is the surface speed, and the second one is torque. I don`t know what are these 0 for.

I`ve made it like this :

torqueCurve
	{
	  key = 0 800 0 0
	  key = 3 160 0
          key = 20 80 0 0
	  key = 130 0 0 0
	}

And it rides fine, maximum speed on Kerbin is around 4m/s, but it still does not have grip. If hill has more than 20 degrees or so it behaves like a car on ice...

( Sorry for any mistakes, English is my second language )

[Laie]

Well, I don't see anything that could describe grip. You might toy around with that steering curve: steering 0 means going straight ahead, doesn't it? If that won't help, rescale the TR2L --as has been said twice, it has much better grip out of the box.

[Angorek]

I found it ! I`ve changed maximum_drag and minimum_drag to 1.5 and 1.3 and it rides awesome. No more slipping and speed while going up the launch pad increased from 0.9m/s to 3.2