Every Spaceplane falls over accelerating

[Rashim]

Hi there, spacepilots,

I have a curios problem i can't solve.

Ervery spaceplane i build starts to shake an falls over after a few meters down the runway. regardles if i use 3 or 4 wheels.

Its completly symetrical and the lift is right behind and above the center of weight.

the only model i got up was realy wide and heavy at he wingtips where the wheels where.

Anyone got an idea on this?

Edited October 11, 2014 by Rashim
Edit: Answerd

[*Aqua*]

Can you upload a screenshot of your plane?

What mods do you use?

[Rashim]

Occurs with and without mods. at around 70m/s.

Must be a designerror, but i can't figure it out.

Right now, after i asked for helped it worked just fine.. like all the month before.

screenshot follows next failure.

[Epthelyn]

Why don't you post a screenshot before the next failure - that way there may not be a next failure.

[Rashim]

Ok so this is it.. its shaking and falling over by about 70m/s

this is with carbonite engines but its the same with stock parts.

Why don't you post a screenshot before the next failure - that way there may not be a next failure.

I like to mess around

[Rashim]

Maybe the Cow (centerof weight) is to far in the back and should be more in the center of the craft?

[Master Tao]

Two potential problems:

1. Wheels need to be straight up and down. KSP's physics are broken that way, so putting the wheels at an angle like you have will usually cause problems. You can attach them to the sides of the jet fuselages, but they still need to be vertical. Padishar's Part Angle Display could help.
   
2. The radially-attached jet fuselages are only attached to the main fuselage at one point, so they'll wobble around that point. With the current design, the only fix is struts between the fuselages.
   

[Rashim]

Struts did help i figured that out.

The wheels .. uhm.. worked great with 2.2 i'll try that later.

[nine_iron]

The wheels under the wings are reversed, make them all fold like the front one (correctly) and it should fix the issue.

For me this and ENSURING all wheels are not angled in ANY way other than level, straight and facing forward.

Lastly strutting up can ensure bending does not occur, which also helps a lot.

See you in a bit when we can help you solve planes flipping over backwards

[problemecium]

^ That. The landing gear are most likely not parallel. It's okay if they "camber" a little, but if they're misaligned even a tiny bit the plane will flip. I suggest putting an I-beam or some other straight part where you plan to put the wheels to check that the surface is straight before attaching the real wheels.

[Mesons]

Cow (centerof weight)

*Cringe*

Try turning off the torque from your command pod. Sometimes I have issues with that on the runway. You might also bind the steering to separate keys than your reaction wheel torque keys (which are WASD by default). That way, if you turn off SAS, you can control only the wheels to keep you straight and not wobble all over from just trying to keep on the runway.

[Rashim]

It was the wheels. I thank you all.

i used to attach them 45° sideways for safer takeoff, but that was some patches ago.

putting thm straight down solved the issue.

And yeah.. Cow is cooler then Com. Allways watch your Cow