So I just built my first spaceplane

[Zutha]

Perfectly symmetrical, so why does it veer left every time and crash in a hair of a second?

[cesarcurado]

Your landing gear must be exactly vertical

if you put then in a diagonal position they will roll on the sides of the runway

[Zutha]

Thanks. Still rolls unfortunately

[kerbomatic]

Thanks that's very useful information - I had the exact same problem but didn't think much of it.

[cesarcurado]

a picture would help, you know

Oh, and I'm glad to help kerbomatic

[Zutha]

doh, game crashed

Will rebuild again to see if I can get it running.

[Cal'Mihe]

It can also be due to the balance of the craft on the landing gear. If too much weight is on a single wheel (the front one usually) it will buckle and veer.

The reason it happens during the takeoff roll and not while resting idle on the runway is because of changing lift. If the wings are to the back, as the plane gains speed, the back end will start to lift before the front, thus putting more strain on the front wheel than while the plane was idle.