ELIPPSE propeller, Contact! magaine article

The 3-blade ELIPPSE prop on the Lancair 235 doesn't use a symmetrical
airfoil; it's a highly-cambered NACA 63 series laminar flow airfoil,
with 13% thickness. It would probably be best defined as a 63 3 513.
Thin and symmetrical prop airfoils have very low L/D ratios, making
them unsuitable for high-efficiency props. The 3-blade ELIPPSE prop
designed for the "Phantom" biplane racer at Reno 2004 allowed it to
smoke the field. The plane went 20 mph faster (241 mph vs. 221mph) on
245 less rpm. See the write-up in the Fall 2004 "Sporstman Pilot",
www.sportsmanpilot.com .