Interestingly, the surface area of a lightbulb (~100-120 cm^2 if my google-fu is working) is pretty similar to the surface area of the blade, which would be 4 cm (length of filament) * 4 (number of filaments in a lightbulb) * 1.185 (blade diamater in cm) * PI = 94.245. However, the gas in the lightbulb is probably a decent thermal conductor, while the diffuser in the blade, is decidedly not. Using a standard diffuser will lead to a lot of thermal compression... Either way, I'm just going to have to do some experimentation to figure out how hot it really gets.