Engine question for a lifter design.?

i need a vertical engine with the shaft on top so i can mount a prop on the crank shaft going vertical. this is a project i am in designing phase. or would a 2stroke be the idea to use? only problem is i dont want the vibrations to get out of hand. lol. i need four of these engines to go on a lifter i am designing. thanks. p.s. i am going to build a flying electric model version then replace the electric motors with rc type 2strokes. wish me the best!