How to rotate Object In Air Like Hill Climb Racing

Hi. I have a question about rotating an object and controlling it with Race n Brake Button. I have been trying to do it by following method. That I think should have been done by now. But it is not working.

 if (touch.phase == TouchPhase.Stationary && accelerator.HitTest (touch.position)) 
    accelerator.texture = btn_accelerator [1];
    accel = 1;
    PlayerCar.Rotate(Time.deltaTime * 500, 0 , 0);		

Does Anyone know any better approach?

“Not working” is a hard problem to help solve. But if you want to rotate in the air, you need isGrounded to be false, not true: