Rotation of complex object

[P_Kras]

I'm creating space ship.

ship1.png

Ship consisting of modules. Each of them have btRigidBody. Contacting modules connected with constraints.
Four small spheres at sides are maneuvering thrusters.
I want to control my ship by applying forces to them.
When I tries to apply force like this:

ship3.png

everything is ok, ship is moving forward.
But when I tries to rotate ship (yaw in this case) ship isn't rotating.

ship3.png

I also noticed that when I apply side force to only one thruster (can't attach fourth image, look at second) ship is moving sideway but not rotating.

I'm sure there is something wrong with constraints here. I tried to use fixed, hinge and dof6 constraints but it didn't help.

[P_Kras]

I've found problem. I didn't call m_shape.calculateLocalInertia() and didn't specify inertia in rigid body constructor.