While looking at the articles on the flitetest website I stumbled across a very interesting wing build with a rather strange airfoil. After further research I decided to build one for myself and I was pleasantly surprised with the flight characteristics. The airfoil has a rounded front and then a series of steps in the back. The steps are what make it unique, as there are alos many different combinations available for different performance characteristics. The one of most interest to me is the KFm4, which has a single symmetrical step halfway back on the wing. I drew up a pretty basic wing in cad, and just copies the dimensions down on to foamboard.

On the first flight it is very apparent how stable the airfoil is. Even on a rather heavy build the wing goes exactly where you point it. Low speed performance isn't great, but cruising speed and above is amazing. Control stays almost too responsive in the higher speed range, and "slop" in the controls just doesn't feel like it is there at all. A bit of up elevator trim is required, but that is to be expected. Even hauling aroud a 1500mah 3s this thinug does not seem to care. I have also created a smaller LOS version running a 450mah 4s that absolutally rips.

Electronics are basically identical to the ones useing in my Wing Thing build

Here is a folder with all of the plans and basic instructions