Do turbo prop airliners generate thrust using the propeller and compressed air or just the propeller?
Turboprop engines transfer almost all of the turbine's rotational energy to the propeller, though there is some waste in heat and exhaust gas as in all engines. The exhaust does not form any major amount of thrust unlike in other turbine engines ("jet engines", like a turbofan or turbojet). Turboprops are more efficient than other "jet engines" at lower altitudes due to the thickness of the air at lower altitudes whereas jets are more efficient at higher altitudes, though turboprop pilots will tell you they fly a jet, being that a turboprop is still a turbine engine, aka a jet. :-)