Need help at Echo Gorge

I need help at Echo Gorge.I'm supposed to kill all the angels while riding on this beast,but I keep getting killed when they shoot rockets at me!!!

This is really frustrating,I've killed a couple of angels but these ones keep shooting rockets and I try to avoid them but always take damage.And shooting them doesn't seem to be working as well as I want it to.

Does anybody know how to get past this part of the game and get to Twilight Cathedral?

I should have known those alien maggots booby trapped this sub