No Errors But ship wont move

programming flash
1

Hi all, im trying to capture keyboard events to steer my ship. I’m getting no errors but my ship wont go. the key trace and the burn trace works.

var lForce:Number;
stage.addEventListener(KeyboardEvent.KEY_DOWN,moveShip);

ship_mc.EnterFrame = function()
{
this._x +=Number(rForce)-Number(lForce);
this._y +=gravityConstant -Number(uForce);
}

function moveShip(evt:KeyboardEvent):void
{
switch (evt.keyCode)
{
case Keyboard.UP:
uForce ++;
burn();
break;

            case Keyboard.LEFT:
                lForce ++;
                burn();
                break;

            case Keyboard.RIGHT:
                rForce++;
                burn();
                break;
            default:
                trace("keyCode:",evt.keyCode);
        }
    

}

function burn():void
{
trace(“burn”)
}