I finally found a way to do this on ios! First, you add a tiny cube made out of a fuselage block to your subassemblies, next, you put one down and put a prop on it, then, you have to have the cursour thing enabled and by that i mean the thing you can disable in the bottom right corner that is enabled by default, after that, you zoom through the prop and when you see the front of the other fuselage, put that one from your subassemblies onto the front of it, now you make the new one about 1 block long, next, put it all into your subassemblies and put a few onto the front of your origonal one, lastly, edit the size of the tiny peice of fuselage you can see between the props that is 1 block long to be 2 taps shorter or .5 length. Now if you understood any of that you probably have some prop blades stacked on top of each other! P.S. If there is still a small stub left on the tip you can remove that.