New Engine Design Dampens Fighter Jets’ Noise

Oct, 2021 - By SMI

Engineers developed a new nozzle design for F-18 fighter planes that would reduce the loud noise of the engine without affecting its performance.

Fighter jets are military aircrafts that are built for air to air combat. These aircrafts are somehow very loud. To make this deafening engine noise of such fighter jets smoother, a team of aerospace engineers at University of Cincinnati developed a new nozzle on 1/28^th –scale engines that softens the loud noise of the engines and does not affect performance of the engines of the fighter aircrafts. When tested in the lab, the nozzle having triangular fins inside decreased jet engine noise considerably.

The University of Cincinnati teamed with the U.S. Naval Research Laboratory and Naval Air Station Patuxent River for this project. The team began the testing by starting the 1/28^th-scale engine of the F404 jet engine that is used in the F-18 fighter jet. The engineers assessed the noise created by exhaust plumes of the jet, they tried using different exhaust nozzles. After testing some nozzles it was found that, a nozzle having triangular fins on its inner surface reduced the noise of the engine by 5 to 8 decibels. As the decibels are measured in a logarithmic scale, 20 decibels is a very loud noise, therefore reduction of the noise to 5 to 8 decibels was significant. Moreover, it was established that the use of nozzle wouldn’t cause any hindrance in the performing capabilities of the fighter jet, it would only help smoothen the vibrations caused by loud noises that could shake apart the aircrafts.

Jet noises can cause severe health risk in military and commercial aviation. These noise reduction technologies such as nozzles developed by the engineers at UC, are beneficial to the communities living around air bases and personnel working on aircrafts. The full-scale test of the these finned nozzles are planned to be conducted on F-18 Super Hornets, later this fall by the US Naval Air Systems Command (NAVAIR).