Prop Shredder question



I have been practicing the Acid Raid loop and from what I have understood is that the Prop Shredder at the very top and launch up. Sometimes when I hit it, they just flip out rather then launch up, sometimes they just launch like usual. Is there something I am missing?


If they flip out you did it too early and the hit that knocks them up will not hit.


Okay, that makes sense. So in that case is thier a visual reference I should be looking for so I can press S after the shots?