Working on flight-sim-like physics. Hit a first bump.

Goal : simulate semi-realistic flight physics and flight control (roll instead of yaw/steer).

At first I tweaked the FlyingVehicle class but I decided there wasn't enough in common with what I wanted to I created a new class called "Plane". This class inherits the "Vehicle" class. It currently only deals with thrust, so it doesn't roll or pitch or yaw ( I thought, one axis at a time :-) ). The thrust behaves as it should for the most part except if I happen to be on a flat terrain AND my velocity reaches perfect 0, then I'll never ever be able to move again, no matter how much "force" I apply. Here's the code for my UpdateMove and UpdateForce methods:

Any tip would be greatly appreciated.

void Plane::updateMove(const Move* move)
{
Parent::updateMove(move);

// this just sets what the pilot wants his speed to be.
wantedSpeed += (move->y)*20;
if (wantedSpeed < 0) wantedSpeed = 0;
if (wantedSpeed > mDataBlock->maxSpeed){
wantedSpeed = mDataBlock->maxSpeed;
}
}

void Plane::updateForces(F32 /*dt*/)
{
bool isGrounded = isOnTheGround();
MatrixF currPosMat;
mRigid.getTransform(&currPosMat);
mRigid.atRest = false;

Point3F massCenter;
currPosMat.mulP(mDataBlock->massCenter,&massCenter);

Point3F xv,yv,zv;
currPosMat.getColumn(0,&xv);
currPosMat.getColumn(1,&yv);
currPosMat.getColumn(2,&zv);
F32 speed = mRigid.linVelocity.len();

sprintf(infoString, ">");

Point3F force;
Point3F torque = Point3F(0, 0, 0);

if (isGrounded && mRigid.linVelocity.len() == 0 && wantedSpeed > 0){
sprintf(infoString, "%s [AG]", infoString);
// Should makes the plane go completely nuts if a grounded plane's linear velocity is null but it's wanted speed isn't. Unfortunately it doesn't help (tried positive and negative values on all vectors) :-(
force = Point3F(-1000, -1000, -1000);
torque = Point3F(125,12,44);
}else{
force = Point3F(0, 0, sPlaneGravity * mRigid.mass * mGravityMod);
}

// Is the linear velocity less than what the pilot wants? If yes then apply thrust
if (speed < wantedSpeed){
sprintf(infoString, "%s [TR]", infoString);
force += yv*mDataBlock->thrust;
}

// Is the linear velocity more than what the pilot wants? If yes then apply brakes (airbrakes if airborne, also wheelbrakes if grounded)
if (speed > wantedSpeed){
sprintf(infoString, "%s
", infoString);

force -= mRigid.linVelocity * (mDataBlock->airBrakes);
if (isGrounded){
force -= mRigid.linVelocity * (mDataBlock->wheelBrakes);
sprintf(infoString, "%s [WB]", infoString);
}
}

// Prints out info line
sprintf(infoString, "%s W : %2.2f V : %2.2f V: [%2.2f,%2.2f,%2.2f] F: [%2.2f,%2.2f,%2.2f]", infoString, wantedSpeed, speed, mRigid.linVelocity.x, mRigid.linVelocity.y, mRigid.linVelocity.z, force.x, force.y, force.z);

// Reduces torque to stabilize aircraft.
torque -= mRigid.angMomentum * 5;

// Applies force and torque
mRigid.force = force;
mRigid.torque = torque;
}