I know that its not what a UNSC Destroyer would look like, and sorry but its not a frigate, Ive made one of those as well, the Frigate has Vertical "jaws" this ship's are horizontal.
this is a ship from a upcoming Halo Mod for Star Wars Empire at war called Covenant at War.
Not to be a nerd on you but that's a UNSC Frigate not a destroyer. Look at the link to see what I'm talking about. (Warning: due to the fact that this is a wikia site, facts may not be true or accurate.) But the build is great! 4/5! ~Stay green my friends