Science Buddies: "Ask an Expert"

I am asking three things.
Is their anything new to wind tunnel test in the area of fanwing improvement?
Does my idea (stated below) have any original merit and are their any problems with it that I have overlooked?
Do you have any suggestions, information, or helpful tips? Any and all are welcome.

If you do not know what a fanwing is please see this site for info http://www.fanwing.com/
I have a wind tunnel that I built and was going to use it for this project. I would build a fully functioning section of fanwing with a modular fan section. Using an anemometer I would find the wind speed of the air blown out and calibrate my wind tunnel accordingly. Then hooking it up with drag and lift meters I would test its aerodynamic efficiency in the wind tunnel. My independent variable would be the different fan sections (like amount of blades, curvature of blades, diameter of rotor compared to depth of wing, ducting, and monoplane vs biplane vs triplane configurations). Dependent variables would be weight, drag, and lift. Data would be collected and compared in ratios (like lift:weight, drag:lift ...)

Thank you for your help. It is very appreciated

Forgot to mention that I would test glide without power. Also I would test reversing a rotor as a means to control the roll of bank a turn instead of using ailerons. I might test ailerons too.

Sounds like you found an interesting area to experiment with. I think you are a bit ambitious in the number of variables you are starting out to experiment with. You might not have thought enough about the variables associated with the fan. For example, I'm not sure how one would approach taking torque and rotational direction and speed measurements on a fan section in wind tunnel flight; however, without some knowledge of what the fan is doing, you have a significant number of unknown variations/variables that will plague your test results.

I suspect the wing areodymanics change considerably between a locked fan, an auto rotating fan blade, and a powered fan blade. If you reverse the fan direction, you will dramatically change the thrust vector and the effective wing shape in a very uncontrolled way. I suspect that you can get considerable yaw control in a multi-section wing by simply changing the rotational speed of one end fan section without coming close to locking it let alone reversing it.

Wind tunnel measurements on wings with variable dynamic shape present a significant challenge because the wind tunnel air speed changes the dynamic shape of the wing and a change in the wing fan rotational speed will affect the speed of the wind tunnel. This means that you will have different performance curves that follow two different controlled variables to produce a family of performance curves. This is definitely a challenging multi-variable problem. To compound it by adding more experimental variations like mono, bi, and tri wing designs would be way beyond what I would recommend tackling.

Even tackling a bi-wing fan-wing design means you introduce a considerable number of variables like wing stagger and under wing turbulence that will probably complicate the problem to the extent that you can't draw valid conclusions.

Even the articles associated with the site that you referenced indicate that there appear to be considerable changes in properties that occur with scaling. This is a good indication that bi-wing fan designs would present even more diverse issues in understanding (e.g. figuring out what experiments are required to draw valid conclusions).

Great interesting area to pursue, just a word of caution to start simple and do some good science and then if you have time, tackle some more if you are so inclined. Just don't start out trying to do too much and end up with something that is a real drag to try and complete enough so you can draw some valid conclusions other than "I tackled too much".

Thanks for your help

Thanks for all your help. I was able to complete my project on fan wing with a narrower set of variables last year (school year). I entered in the LA county and California state Science Fairs and did pretty well. Thanks again for your much appreciated help.

I have not touched my old project for quite some time but am thinking of picking it up again. I am thinking of working with computer simulations. I thought of this when I originally started this project but could not find software that would work. Because of the integrated propulsion system in the wing most airfoil simulation software will not work. I was recently told that matlab would be able to handle the problem. Does anyone know if this is true? Also can anyone think of other programs that would let me model and simulate fanwing designs?

Thanks for the help.

I originally put this post in Physical Science since I thought that you guys would understand how a fanwing works and therefore be able to point me in the right direction in regards to simulation programs. However since I have not heard anything should I move this question to the Computer Science Forums?

Thanks for the help.

I have no experience with MATLAB. Simulating a fan wing design will be a difficult project. The biggest difficulty with any simulation effort is proving that the simulation matches reality. If you want to attempt to do something like that, I recommend that you find a mentor who has applicable experience in the area to assist you. Professors and grauduate students in University programs in aeronautical engineering and people working at Nasa would be were I would go looking for a mentor. You can try posting a new question in the Computer Science forum and see if any of the experts there have any experience with MATLAB or any simulation software that might model a fan wing design.

Thanks for the advice and help.