I'm looking for some free or cheap software to help me design a standard wing for a small, motor powered, traditionally shaped airplane. I'm familar with solid wing design but not ribs and spars.

My project is to build a very tought plane with a span of 32 - 36 inches and a RTF weight of 310 grams. It will be electrically powered and radio controlled. It should look something like a block of wood impersonating a P51.

I need something pretty simple. I majored in business and can't deal with coefficient of friction and so forth.

Thanks for your help!

Mike

Piece of paper, pencil and ruler. If you add a rubber (eraser) you can delete unwanted pencil lines too! Cheap as chips, no sofware (or computer) required, works every time, and the learning is stored in your personal memory.
Evan, WB #12.

Not free.... but reasonably priced and excellent software. Pay only for the modules you need, periodic updates are free. Google "Compufoil"

ChiefK

This is kind of ironic.  My ex brother-in-law completed his PhD thesis by writing a program to design the optimal glider wing for a given set of variables.  Wish he was still my brother-in-law but he was very difficult to communicate with.

Thanks for the tip on Compufoil.  I've tried a couple of others but had some technical problems.  I wish I could do it as PIMMNZ suggested.  Just haven't got the skill.

There is a good program called Profili that will do very simple but helpful 2-D airfoil comparisons (In terms of lift and drag polars). It has a very large library and will output rib templates if you get the full version. There is a free version that will do most things, but if you want to output complex data or templates, you have to get the full version. I think it's like $10 or something. It's an Italian program I think but it carries over to English just fine. If you need to do 3-D simulations (if you want to include tip loss, wake rollup, tail effects, etc.) then XFLR5 is a good free program. Kinda tough to get the hang of, but there are good tutorials for it out there. Really slick once you understand how to input your constraints.

I had a problem with Profili.  Big download and kept getting a violation when trying to run.  I also got a security warning saying it was a "seldom downloaded" - i.e. little know program.

I did get a demo copy of Compufoil.  It's much more than I can truly understand but I guess there's a lot of variables when you designing software for many different apps.

I've got Compufoil for 15 days.  I should be able to figure it out by then.  I'm definetly learning some stuff.

The reason I'm doing this is that I built a fragile scale plane and converted it from wind-up to electric / rc.  Problem is, it kept wingtip-stalling and I got tired of repairing it.  It had a gull-wing with a decreasing camber on the ends.  

 I'm trying to build something very tough and very easy to repair.  No gear.  No frills.  Just a real tough plane.  Then I can experiment on the affects of wing design with small rc planes.

No skill needed for the pencil/paper thing, otherwise I couldn't do it...at the size of model you are considering the shape of the foil will make b...all difference. You will notice a small difference in gross shape changes, ie symmetric to curved plate, but nothing much between. Most differences will come from wing plan shape, but then only towards the stall angle. Take up thy pencil, and draw...
Evan, WB #12.

310 gram model-
thats about 11 ounces
OK-
the best setup is a simple flat piece of EPPfoam or Depron - 1/4" thick- brace it all using small carbon rods
really
You could make one look like aP51 - and as long as you kept the weight at 300grams and the size about whre you mentioned - it will fly fine
The airfoil?
knock yourself out but the flat foam at that size and weight works as well as anything.
Theories are fine but at thissize- weight means everything - airfoil is of no real concern
I have built hundres -well at least a hundred - of modelsin this size range and flown and evaluated all of em .
the glide is nothing to brag about but as a powered setup the airfoil simply does not matter -
lowest weight with enough rigidity is the criteria for success. The litle models here ar profile but a light,l shaped fuselage will also work