For example, document U.S. Pat. No. 3,936,017 has already disclosed an aircraft comprising:                a fuselage;        two wings arranged laterally with respect to said fuselage and not carrying any engines;        a rear vertical tail section consisting of at least two fins and forming, with the rear portion of said fuselage, a channel arranged on the back thereof; and        at least one turbine engine arranged on the back of said fuselage such that the gas streams generated by said turbine engine enter said channel.        
Thus, owing to the design of the rear tail sections in the form of a channel and to the arrangement of the turbine engines at the entrance to the channel, it is possible to achieve a considerable reduction in sound emissions since the noise generated by the turbine engines is sucked in by the channel and is evacuated along the latter and upwardly away from the fuselage, that is to say away from the passengers situated at the rear of the aircraft cabin, and a fortiori away from residents living near airports. The noise generated is thus masked by the rear tail sections of the fuselage, which constitute an acoustic shield.
USPTO Backgrounds
USPTO Backgrounds