Smooth KineticJS animation, controlled speed

Question

I am creating a simple plane animation in KineticJS for the fun of it.

Currently the animation runs a little jerky I would love to have some easing or tweening although I don't know how to begin.

Can anyone lend me a hand with the math?

<div id="container"></div>

<script src="http://www.html5canvastutorials.com/libraries/kinetic-v4.5.0-beta.js"></script>

<script defer="defer">
  var stage = new Kinetic.Stage({
    container: 'container',
    width: 870,
    height: 392
  });

  var layer = new Kinetic.Layer();

  var xPos = 0;
  var yPos = 126;
  var growthFactorX = 6;
  var growthFactorY = 2.6; 
  var growthFactorP = 3; 
  var planeRotation = 30;     

  // dashed line
  var trail = new Kinetic.Line({
    points: [{x: xPos,y: yPos}],
    stroke: 'white',
    strokeWidth: 2,
    lineJoin: 'round',
    dashArray: [6, 5]
  });

  var imageObj = new Image();
  imageObj.src = '/assets/img/plane.png'; 
  var plane = new Kinetic.Image({
    x: xPos,
    y: yPos - 15,
    width: 54,
    height: 30
  }); 
  imageObj.onload = function() {

    plane.setImage(imageObj);
    layer.add(plane);
    stage.add(layer);
  };
  plane.rotateDeg( planeRotation );


  layer.add(trail);
  stage.add(layer);

  var anim = new Kinetic.Animation(function(frame) {


        if( xPos < 500 ) {

            xPos = growthFactorX + xPos; // adds 3 to xPos on each loop

            if( xPos > 400 ) {

                yPos = yPos - growthFactorY;

                if( plane.getRotationDeg() > 0 )
                    plane.rotateDeg( (-growthFactorP) ) ;
            }

            var curPoints = trail.getPoints();
            var newPoints = [{x: xPos, y: yPos}];

            trail.setPoints(curPoints.concat(newPoints));
            plane.setX(xPos + 10);
            plane.setY(yPos - 35);
        }
        else {

            anim.stop();
        }
  }, layer);

  anim.start();      
</script>

Answer 1

I have created a fiddle for you,

and have changed this factors, al thought it looks smooth to me, please let me know if any specification

  var xPos = 0;
  var yPos = 126;
  var growthFactorX = 5;
  var growthFactorY = 2; 
  var growthFactorP = 1; 
  var planeRotation = 30;    

The fiddle link

I hope this will do :)