Hi Folks,

I need a 15% to 20% thick laminar flow airfoil with a four foot chord for an inflated wing that has a rounded trailing edge 1.25 inches in radius. I would hope to be able to get at least a 10 to 1 lift to drag ratio. I would like to know how thick it can go and still maintain this lift to drag ratio. Can anyone help me. If not, do you know anyone who can? I hesitate to buy software for a one time use. But what is out there that is particularly good?

--Thanks,
Wayne

How fast do you plan to fly this wing (what Reynolds number)? Can you make it with a cambered airfoil? You haven't provided enough info . I believe it won't be a problem finding an airfoil that produces L/D of 10 that fits the criteria you stated - 4' chord and 1" TE radius. If the flight speed is very slow it may be more difficult.

First of all if you are thinking of slow speed flight you shouldnt be looking for a laminar flow airfoil.

Guys, I gather this pertains to his tethered kite thread from a couple of weeks ago.

Modern sailplane airfoils are in that size range and certianly offer more than a 10:1 ratio. How critical they are to shape cocerns vs L/D values is something you'll have to do some experimentation on. I believe that the speed range you want to use them in is within the ballpark of the research done on true sailplane flight. If you look into that area you may/should also find a wealth of wind tunnel data on those airfoils for that Reynolds number and the surface roughness and profile tolerance they will withstand. I know the tolerance is not much but I don't know by how far.

You've gone outside the pervue of the modelling area with this one. Good luck.