Paul hadn't. He had measured just about everything about his airplane, even the stagnation temperature rise. Self-taught, he had absorbed the principles of aerodynamics to a point that, while short of the professorial, stood well up in the gifted-amateur range. His odd-looking, pointy-tipped Elippse propellers, based on a propeller theory of his own invention, achieved some remarkable speed gains in Reno races. He would cut and try, often recording speed changes down to half a knot, a precision which, as I told him, I found frankly implausible. He didn't mind. He reported gains, losses and lack of any change at all with equal alacrity: He was, to my mind, the quintessential salt-of-the-earth homebuilder, equally adept with brain and hands.