Why are they using a 2-stroke ICE instead of a small turbine I wonder? The pack looked quite cool from the front but when the pilot spun around it looked like he had a VW beetle strapped to his back...
I can only guess fuel-consumption-to-thrust efficiencies (longer flight times) or pure cost since a pure gas turbine will always beat out a mechanically linked fan-stroke in specific power (i.e. kW/kg), but will almost always be more costly due to the extremely high manufacturing tolerances required for turbines.