1) That's not a "jet engine". It's a turboshaft. A turboshaft is a gas turbine producing its power mechanically at the shaft. A turbojet is a gas turbine produc

1) That's not a "jet engine". It's a turboshaft. A turboshaft is a gas turbine producing its power mechanically at the shaft. A turbojet is a gas turbine producing its power in the form of reaction thrust out the tailpipe. 2) Gas turbines scaled down to small size (let alone "micro" size) generally have dismal thermal efficiency. All the most efficient gas turbines are gigantic (tens of thousands of hp).