I played around with various parameters to air foils using Foilsim http://www.grc.nasa.gov/WWW/k-12/airplane/foil3.html What I found was that for a given wing length, a smaller chord gives a better lift/drag ratio. This will make the wing area small, hence the total lift will be small and there will be structural challenges in making a long but small wing. But what about having a lot of such small wings put together in an array? Together they would give larger wing area hence more lift, and they would give structural strength if they were connected together at the far end. There are bi-planes and tri-planes that seems to kind of use this idea. Why don't larger airplanes use this idea? Why aren't there something like "sexagint-planes" (60 pair of wings)? I'm guessing the answer is that wings interfere with each other. So then my question is, how far apart must wings be placed to not interfere with each other? What if their placement is shifted a bit forward?