Overly sensitive controls on high altitude plane

[Keezdoodles]

Hi there. I am building a high altitude plane for the first time.

This plane takes of magnificently, the problem is that the second I touch the pitch the plane will flip and go into a full stall.

Toggling caps lock for more precision doesn't help a bit. Neither does more reaction wheels.

Does anybody have any ideas what could be wrong here? Might be a simple thing I am not getting since I am not very good at aircrafts (which is why I am building this).

Pictures: http://imgur.com/a/SsOzT

I can also upload the craft file if anybody wants to test it themselves.

 

[Gojira1000]

Move your CoL back behind your CoM about half a ball or a little more

[bewing]

First, the little blue ball should always be a little behind the yellow CoM ball -- this is the source of your problems.

Second, your gas tank is way out at the very very front end of your plane. This means that as you use up your gas, your center of mass will shift backwards strongly -- and your little blue ball will be even further in front of your CoM ball at that time.

You should rearrange your plane to put the gas tank just in front of the engine. I would also strongly suggest using the MK1 liquid fuel tank instead of a rocket fuel tank. I would also suggest a small pair of canard wings at the front end. They do a very good job of helping you control pitch.

[fourfa]

The mod RCS Build Aid can show you how your CoM will move as fuel burns off. It's a valuable learning tool that makes it much easier to visualize how different placement of parts can affect flight dynamics. Highly recommended. 

Edited June 29, 2016 by fourfa
added hyperlink