Doing a Star Fox Style barrel roll? how best to rotate a gameobject over a period of time and have it return it's original rotation?

I been trying to do a star fox style barrel roll but I can seem to get anything working.

I thought I found a solution on a great youtube tutorial (code below) but it's not very smooth, it looks weird when using this to rotate the ship.

does anyone know of a tutorial or asset store asset (doesn't matter if it's paid) that has a way or a example on how to do this.

 public class roll : MonoBehaviour {
 
     public float barrelRollDuration = 1.0f;
 
     public bool inBarrelRoll = false;
 
     private float movementAxis;
 
 
     // Use this for initialization
     void Start () {
     
     }
     
     // Update is called once per frame
     void Update () {
 
         if(!inBarrelRoll)
         {    
             
             (Input.GetKeyUp(KeyCode.F ))
             {
 
                 StartCoroutine("BarrelRoll");
                 
             }
             
           }
     }
        
     IEnumerator BarrelRoll()
     {
         inBarrelRoll = true;
 
         float t = 0.0f;
 
         Vector3 initialRotation = transform.localRotation.eulerAngles;
     
         Vector3 goalRotation = initialRotation;
 
         goalRotation.z += 180.0f;
         
         Vector3 currentRotation = initialRotation;
         
         while(t < barrelRollDuration/2.0f)
         {
             currentRotation.z = Mathf.Lerp(initialRotation.z,goalRotation.z,t/(barrelRollDuration/2.0f));
 
             transform.localRotation = Quaternion.Euler(currentRotation);
 
             t += Time.deltaTime;
 
             yield return null;
         }
         
         t = 0;
 
 
     
 
         initialRotation = transform.localRotation.eulerAngles;
 
         goalRotation = initialRotation;
 
         goalRotation.z += 180.0f ;
 
         while(t < barrelRollDuration/2.0f)
         {
             currentRotation.z = Mathf.Lerp(initialRotation.z,goalRotation.z,t/(barrelRollDuration/2.0f));
 
             transform.localRotation = Quaternion.Euler(currentRotation);
 
             t += Time.deltaTime;
 
             yield return null;
         }
 
 
         inBarrelRoll = false;
 
         ResetRotation();
 
         }
 
     void ResetRotation()
     {
         transform.localRotation = Quaternion.identity;
 
     }