Velocity in rotation using 2D vectors???

I'm rotating a sprite using the following, but when the spaceship, which is circular, is facing towards the left side of the screen and I press the thrust key it slows down? Any help? Velocity, acceleration and positon are all vectors. Can't think of anymore code you may need!

Code:

---

void drawObject() {
...
...

  //Acceletion moves the spaceship across the screen
  velocity += acceleration * pTheGameTimer->mdFrameTime;

  //Adjust bearing angle according to the above key press
  velocity.setBearing((dAngle/360*6.282), velocity.magnitude());

  //Move helicopter based upon velocity
  position += velocity * pTheGameTimer->mdFrameTime;
}


void Vector2D::setBearing(double angle, double magnitude)
{
  XValue = magnitude*sin(angle);
  YValue = magnitude*cos(angle);
}

double Vector2D::magnitude() const
{
  return sqrt(XValue*XValue + YValue*YValue);
}

---

I didn't develop the 2D class, but it also has:

Code:

---

Vector2D Vector2D::rotatedBy(double angle) const
{
  double s = sin(angle);
  double c = cos(angle);
  return Vector2D(this->XValue * c - this->YValue*s, this->XValue * s + this->YValue * c);

}

---

Thanks

Nevermind, I've figured it out...


Swapped this:

Code:

---

      //Adjust bearing angle according to the above key press
      velocity.setBearing((dAngle/360*6.282), velocity.magnitude());

---

for this:

Code:

---

        //Adjust bearing angle according to the above key press
        acceleration.setBearing((dAngle/360*6.282), acceleration.magnitude());

---

Works like a gem now!