I looked at the post here but still have some questions Why are push-propellers so rare, yet they are still around?
This is along the same idea but the answers are not too helpful either. Pros and cons of a pull-push propeller configuration
I am sw engineer so maybe this is a dumb question (if you can link resources i can read that would be the tits) but suppose you had an engine prop setup in three possible ways.
- push prop behind the plane
- pull prop in front of the plane
- push and pull prop in the back/front respectively
Now suppose your not trying to fly, but just generate as much thrust as possible in a closed environment (or move as much air as possible like an AC duct system or wind tunnel). Is the third setup superior? If so by how much? Assume the same engine/props in all setups.
Assuming the third setup is superior at moving air, if you keep adding props in a closed environment like a wind tunnel at some point you must hit diminishing returns. If you had 100 pull/push/pull/push/pull etc in a row for example, would that be even better than 1 set of pull/push motors/prop setups? I would imagine at some point the flow would be so disturbed that it would actually lower the airspeed.
I am trying to build a wind tunnel and i want to create the most airspeed possible. I currently have designed 4 pull/push motors/props setup throughout the system but I dont know WHY i did this, it just seemed to make sense. There are 8 DC motors with 5" props in a 6" piping system that loops back on itself.
EDITTED FOR CLARITY
To clarify what i am asking, I want to create a wind tunnel with the highest airspeed i can generate. I have designed 4 sets of push-pull props (placed back to back on electric motors) and each set is placed along this closed system (wind tunnel) in different places where i think the air would slow down. In my head each set will resemble the coaxial rotors from this video:
I am looking for insight as to if this is worth doing, and how they scale. Is a single prop better than having the two back to back forcing air in the same direction? If there are gains by adding more props to the system, is there a limit where the flow just becomes so turbulent that it actually pushes air slower?
I could put 8 props all forward along the way, or i could put 4 sets of push-pull props, or i could use some number less than 8. In this image i plan on placing the 4 pairs of motors/props where the arrows are:
I apologize for the confusing question, im a relative aviation noob compared to the people here. I can try to re-ask this question if things are still confusing, but please help me ask a better question next time (if im using the wrong terminology or missed a tag or whatever)
Thanks in advance.