Regarding the fairings shown in the pics of Steve Nelson's lakester, these were fabricated by the guys at New Metal Customs in Santa Rosa, CA. They are very well made and the fit is outstanding, the only thing that I did not care for was the leading edge as it is a combination of a sharp edge, that you can see and then a straight angle down that allows the lower skin to go below the radius rod that helps to locate the rear end. The leading edge of an aero foil shape is very important. The "original" fairings, which were on the car when it set the record in 2014 were ones that I fabricated, not nearly as pretty as the New Metal Custom fairings but their general shape was based upon the NACA 66018 air foil section with an extended nose to cover the radius rods. The radius rods are a 1 inch rod that are angled to the center line of the car at approx 30 degrees. This makes the actual shape of the radius rod normal to the direction of motion (hopefully straight ahead!) a 30 degree elliptical shape which is fairly close to the nose radius of a 66018 section of the size required to cover the axle housing. The actual shape that went over the axle housing was a 66018 section, which means that the top of the fairing and the bottom from where it increases in thickness is the 66018 section and I assume that the New Metal Custom fairing is some what the same. As you can see from the oil tracks on both the top and bottom of the fairing it certainly appears that the air is attached and flowing as we would hope that it would. My thinking is that if the axle fairings were needed to provide some aero down force I would attach some small 1/4 to 3/8 inch Gurney strips to the top of the trailing edge to increase their angle of incidence and make some down force or at least cancel any lift with minimum drag increase. I tried to get Steve to completely remove the radius rods but he was not in agreement so we integrated their shape into the fairing. I would personally not run a radius rod on the rear end as there are other ways to make it stiff enough to carry the acceleration and braking loads and this would allow the fabrication of a true air foil to cover the axle which then should be the optimal aero shape and also possibly be used to generate some down force as per what the Rob Freyvogle is doing on his streamliner.
Rex