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: