I cut down the prop nacelle mount for the Polaris and added a 70mm EDF. She runs on a 4S 1850 battery. Lots of power but I'm only getting about 3-1/2 minutes of run time. To be expected I guess.... I may look into a larger battery but that may add too much weight. I also put the rudder in the jet-stream blast to allow for turning while taxiing! She flies great though! Love it!

Polaris EDF Jet RC (3 min 4 sec)