Projectiles won't fire correctly. Help! (C#)

Projectiles will only fire correctly between 42 and 50 degrees, any other angle that i have tried sends them either directly down or backwards. Please take a look at the code:

using UnityEngine; using System.Collections;

public class Cannon : MonoBehaviour { public GameObject projectilePrefab; public int Angle = 10; // Use this for initialization void Start () {

 }
 
 // Update is called once per frame
 void Update () {
 
 }

 void FixedUpdate()
 {
     if (Input.GetButtonDown("Fire1"))
     {
         GameObject projectile = Instantiate(projectilePrefab, transform.position, transform.rotation) as GameObject;
         projectile.rigidbody.AddRelativeForce(new Vector3(0, 0, -1000));
     }
 }

 void LateUpdate()
 {
     transform.rotation = Quaternion.Euler(Angle, 0, 0);
 }

}