>>12114725yes you are right they are more efficient and belive it or not a traditional propeler+piston engine (with turbo-compund and intercooler) is even more efficient
the problem is mainly too much noise and lower speeds and also higher maintenance requiere in the case of a piston engine
GE I think has developed a geared turbo-fan this would be the next step for a turbo-fan, this allows the fan to work at its best speed while the turbine works at its best speed(much higher speed that the fan)
