Tattoo,

I have read a few posts here about sharp-edged wings being unstable in pitch and 'hunting'. There could be something going on that I don't know about, but currently, I don't think those are genuine characteristics of sharp-edged wings. A sharp leading edge causes a few things:

1) It 'fixes' stagnation line ( the line at the leading edge where the air divides between the upper an lower surfaces ) so that it doesn't move up and down as the angle of attack changes.
2) At moderate angles of attack, it does result in a small, localized separation bubble just behind the leading edge. This separation bubble is sometimes called a 'rolled vortex', and is what Johng called the 'bound vortex'. In actuality, this is not what the term 'bound vortex' refers to. This separation bubble does have really strong vorticity, but the term 'bound vortex' refers to the 'circulation' which always exists around a wing which is generating lift. This separation bubble can indeed cause the flow to become turbulent, and hence prevent a larger, laminar, separation bubble from forming further back on the upper surface, under some circumstances.
3) It causes massive separation ( stall ) at a lower angle of attack than a rounded leading edge would.

None of these effects results in pitch instability, or hunting, as far as I know, so it is not surprising to me that your wing works just fine. My impression is that these characteristics of sharp leading edges are aerodynamic urban legends, but I would be happy to learn otherwise.

I would guess you get such good results because you have a perfectly reasonble wing shape, and low wing loading. If you needed really high lift out of your wing, which is very rare for our models, then the sharp leading edge might cause some problems.

banktoturn