Why do planes tend to move to the left or right during liftoff

[Supergamervictor]

I make my planes perfectly balanced and still they always tend to move to the left or right during liftoff.This gets me annoyed because most of my crafts never even reach to the sky So does anyone know the solution to this?

[RSwordsman]

It appears to me that Kerbin has a slight wind effect which occasionally makes planes tip over at certain speeds on the runway. If not, then no clue. It's happened to me a few times, giving me no choice but to revert and try again.

[leax256]

post a few pics of the plane from the front, back, left, right, top, and under

it'll help find the problem faster

[twilite20K]

my 4 gear planes with twin angled tails and stabilizers do pretty well at high speed, but I still have to edge left or right. My tripods have a tendency to tip is symmetry is off at higher speeds. With these I try to use rocket assist and high lift a soon as I can, or experiment with the wheel placement.

I even cheat a bit sometimes with two SRS pods because they kind of bump the entire plane left or right with that strong torque effect.

[Rarity]

I believe it has to do with the placement of your wheels. While you're trying to take off, the plane will lift up ever so slightly (not enough that you can see) but it's enough that one side of the plane will be up higher than the other, and thus the plane will veer off in whatever direction until you force it to switch. Of course, this fails to explain why all my rovers like going to the right no matter what. Really annoying.

Edit: I've found that having wheels closer to the center of the craft makes it worse. If you can add wheels farther out along the wings, it makes it a lot easier to manage and in general makes the moving left/right not as bad.

[Geschosskopf]

Well, 1st thing is to turn on SAS before you start moving. That really helps keep the plane heading straight ahead.

I've also heard that if at all possible, do not attach landing gear directly to the control pod that's actually controlling the plane (if you have more than 1). This also seems to be good advice in my experience but I have no idea why it works.

[antbin]

With three-wheel (tricycle) gear, 9 times out of 10 side-to-side veers happen because of "wheelbarrowing".

Your plane's back wheels are lifting off first, putting all the weight on the lone front wheel. Even the tiniest wiggle will set it swerving off to the side.

Solutions: Make sure your center of mass is a little forward of the center of lift. Make sure your back wheels are only a little behind the center of mass. Possibly jack up the back gear if you must, so that your plane has a slight nose-down angle on the runway.