Too bad watson's flying Cuisineart just doesn't accelerate enough air fast enough for their to be enough thrust to allow for climb performance. Any climb performance. I know for a fact that if he geared these same two motors down to drive a 48" to 50" diameter prop, he would get some usable thrust. A medium sized pilot requires at bare minimum of 8 kW of power to see a usable climb in an aircraft with very high aeroelasticity such as a flex wing Hg. But, that power has to be put into the air in the most efficient manner possible. The larger and slower rotating the propeller is, the more efficient the energy transfer. At least at the airspeeds we are talking about (zero compressability). The propeller tips must not approach mach for any efficiency to be had. Even if one was to enshroud a large enough prop, the form drag of the shroud would negate any benefit, especially while soaring. The only conditions in which a shrouded prop or fan makes sense is when approaching mach airspeeds (compressible flow).
Watson most likely spent way too much for those larger fans, and now has discovered that fans are terribly inefficient at low airspeeds. Next time, please do more research, and run the numbers. Derive your information from believable sources (NASA, NACA, research papers, etc.) rather than manufacturers that want to make a buck off of gullible people and modellers. Read research papers and engineering texts to find the algorithms to calculate thrust. It ain't rocket science. If you have to, brush up on your calculus, physics, and trig. It ain't rocket science. That's why you saved all your texts from college, right?!