respectfully-- no
let's take a wing -- say - 12" chord 60"span - trainer
now the airfoil -- let's make it 12% thick-- one a Clark Y type/ 2412/ maybe give it a raised entry -make it what you like
make an identical wing - SAME le radius but symmetrical foil- both airfoils same thickness
same weight same size engine etc
The difference being one is cambered -one is not
pretend these otherwise identical models start down the same runway to take off and they both weigh- say 5 lbs
When either setup reaches 5 lbs lift - the model is flying .
My premise is that the speed for take off (min flying speed) will be the same - tho the physical angle (apparant AOA)may be different.
There is a possible difference in efficiency - but I don't believe -in a model of this size --you will ever find it
I see the two wings as really the same - one with the aft section even. the other with it drooped
Dick,
Hi, first of all, I have to tell you that I really respect your work on models and I think the model airplane community owes you a debt of gratitude for making this hobby/obsession what it is today. I still have one of your Zlins that I'm currently molding because I didn't know who made one of the truest planes I've flown. But I would like to add to your post as to what you're theoretically going to see when you compare the wings.
The first one is the 2412 at that wing size. To lift 5lbs, you will be going about 39 MPH at 0deg AOA.
You said that we will only change the AOA for the symmetrical wing, in this case, a 0012. In order for the foil to lift 5lbs at 38MPH, it would have to reach an AOA of around 2.2 degrees, which is basically very near the start of turbulent flow. Whereas you still have about 1.5 degrees to play with until the 2412 begins to get turbulent. BTW, the drag at this configuration is about the same as the 2412.
Now, to put in another foil in the mix, a 63-A012, a laminar flow, 12% foil. To get 5lbs at 38MPH, the foil would have to be at 2.6 AOA. Because it is a laminar flow airfoil, the oncoming air tends to stick to the surface further than the 0012 and thus giving it a bigger AOA margin than the 0012. As an added benefit, it actually has less drag than both previous airfoils.
Here's the thing. We're talking about small foils that have small consequences on flying...really. I have hooked up wings on trainers backwards and the plane still flew well. When we get to full scale planes, that's when drag becomes a major factor and fuel consumption is critical.
All in all, the airfoil, though important, is not as important to us when selecting for our projects. Here's the caveat before anyone flames me. The airfoils should have the same dimension and, incidence, dihedral, maximum thickness as well as LE roundnes and that the TE comes to a point. Then the shape of the sirfoil should not bother the plane much. No cheating with a flat airfoil that happens to have a 12% thickness ratio...that doesn't count.
B