I see the life of a BD-5 evolving again in the jet-Sonex. Especially in this economy. +1 with gunrad, APU power is scary. I have intentions on building another full-scale BD-5, but with the market of 150+lb thrust turbines for UAV's now, it makes sense to use one of those, more than the APU turbines.

The amount of modification's necessary to make an APU produce thrust and be able to have a throttle, would be outrageous. This has already been done/tried and been a failure on the BD-5. They had to run at 100% power all the time, and had thrust attenuator clamshell's to vary the rearward thrust