changing velocity through scroll wheel

[cidmodder]

I have a flying script that works well but I need to be able to adjust the speed to some maximum value when you scroll up and be able to go backwards if you scroll down past zero. Right now I have it where it reads the input of the scroll wheel but it only moves as I roll the scroll wheel and doesn't move when I am not scrolling. How do I get it to change its velocity and not just move it with the scroll wheel? here's the script:

      var rotateAmount = -5.0;
 function FixedUpdate() {
   // Turn
   var h = Input.GetAxis("Mouse X");
   var v = Input.GetAxis("Mouse Y");

   rigidbody.AddRelativeTorque(0, h * 20, v * 20);
   // Other way you may like
   //transform.Rotate(0, h * 20, v * 20);
engine=Input.GetAxis("Mouse ScrollWheel");

rigidbody.velocity = transform.right * engine*5;

//Also if transform.forward doesn't work try transform.right

       if (Input.GetAxis("Horizontal") < 0) 
       { transform.Rotate(rotateAmount, 0, 0); 

       }
       else if (Input.GetAxis("Horizontal") > 0) transform.Rotate(-rotateAmount, 0, 0); 

       }

ignore any odd negatives. My model had some of the axis backwards so I had to switch some signs. Hope someone can help! Thanks:)

[system]

Alright...

var speed = 1;
function Update () {
    if(Input.GetAxis("Mouse ScrollWheel") > 0){
        speed++;
    }
    else if(Input.GetAxis("Mouse ScrollWheel") < 0){
        speed--;
    }
    print(speed);
}

That shows a very raw and basic form of it... But, you can then implement it however you think's best.

Good luck!

[system]

Assuming you know how you're going to make him go forward (Can't see it in your code... I'm a little bad at reading code haha)...

http://answers.unity3d.com/questions/6106/implementing-the-scrollwheel

That'll help with the scroll wheel... Did you need more help? Like, do you know how to make him go forward? Or no? Sorry. Hope this helps though. Comment if you need more.