Wortmann Gear Leg Fairings

    Thanks to Wayne Blackler's CSA article (thanks Wayne!), I had a mod that needed doing, and one that's best done now, rather than on a completed airplane.  This would be a Wortmann airfoil symmetrical gear leg fairing.
    The stock Long-EZ gear leg, stout yet light though it is, has a couple flaws:  it's too thick for its chord, thus causing separated flow (read:  drag), AND it's at a strong positive angle of attack, creating yet more drag.

    The idea, then, was to build a fairing that would add chord without thickness, and at the same time, be at a negative AOA of 3 degrees (since that's the AOA of the fuselage in level cruising flight).  At the same time, I ran channels in the foam on the leg backside to carry brake lines, relief tube, and comm antenna (rolled up in a straw).
    I had no idea how much work this mod would be!  Good thing, too, or I probably would not have attempted it.  It was my first attempt at hot-wiring and laying up relatively large parts, so I didn't do so hot...but fortunately, this is a very non-critical part.  All I need to do is get the final shape right...for that, I needed some filler.

    The basic technique is to hotwire the airfoil and a cutout for the gear leg on a foam section long enough to cover the gear leg; then you take this long section and chop it up into fractional-inch lengths, and stack them on the gear leg.  My problem was that those little bits wouldn't line up perfectly, and some snapped, buckled, or bent in the process, too.  I filled with X-30 a lot, then sanded, which didn't help much because X-30 is a lot harder to sand than is blue styrofoam.
    Eventually, I got an acceptable surface, and with my brother's VERY WELCOME help, glassed the things.
    The trailing edge surface undulated a bit, so I had to sand it straight, compromising some structural strength, then stiffened it back up by laying 2 ply carbon on the trailing edge.

Sure, it LOOKS like a lot of filler, but most of it is pretty shallow.  The 1/4" thick foam airfoils didn't join up perfectly, leaving flat spots.


Once it's painted in primer, though, it looks great!


Wow, it LOOKS 5 or 10 knots faster....

Fairings to the fuselage and wheel pants were simple affairs, once both were in place: