How can I apply BodyVelocity to an object based on it's local orientation?

I need to apply Velocity to a ship based on it's local rotation. My only issue is that the methods that I have tried so far fail in one area: When more then one rotational axis has force applied to it she ship rotates on another axis,

Eg if the X and Y rotational axis both have force applied to them, the Z axis starts rotating as well. Is there any way to fix this?

(if it helps at all I am trying to make a space craft move based on it's rotation applied from a BodyAngularVelocity bodymover)

BodyGyro objects are great for maintaining orientation. Give their CFrame property this constructor:

BodyGyro.CFrame = CFrame.new( [Vector3]Origin, [Vector3]Focus )

As for figuring the direction to apply force, use this formula:

local p = workspace.Part;
local power = 100;

p.BodyVelocity.Velocity = p.CFrame.lookVector * power;