After 24 hours fighting with FT, i've finished it. Instead of aiming your canon into the sky and hoping it will hit something after thousands of shots, this will help you to aim your artillery precisionly

THE INDICATOR:

DEMONSTRATION:

HOW TO SET IT UP?

• Save the labels as subassembly and place it on your craft
• Make sure that the cockpit part, the hinge rotator, the canon are at the same X and Y positions
  
• The current velocity of the canon is 850m/s, you could change as you will. Remember to change the velocity value in the "Calculated elevation" code too
  

Note:
- Tested on high physic, not sure about the accuracy on low physic, you may have to adjust the code a little bit
- The codes are meant to be used on plain grounds, so its useless on uneven grounds
- The height where you put your canon also effect the accuracy of the code, if the projectile is too high or too low, you have to adjust the code like below:

Be patience and it'll be accurate

FREE TO USE

a credit will make me happy but not required