F-18 Jet Engines Quietened With New Nozzle Design

Jet aircraft are all loud, but few are as loud as the F-18 fighter jet. Researchers from the University of Cincinnati have created a new engine nozzle designed for F-18 fighter planes. According to the team, the new nozzle reduces the sound created by the jet engine without impacting its performance. Researchers tested their new designs on 1/28th scale jet engines inside the UC aeroacoustics laboratory.

The interior of the newly designed nozzle has triangular fins inside that are similar to rows of teeth inside the mouth of a shark. In the laboratory, the interior design is shown to reduce the sound produced by the engines significantly. This fall, the U.S. Navy plans to test the new nozzle designs and performance they deliver on F-18 Super Hornets.

The new nozzle is described as a "simple attachment" that changes the flow of jet exhaust coming out of the engine while having minimal effect on performance. Researchers discovered in laboratory experiments that their design reduced engine noise between five and eight decibels. The team notes that is a significant amount of noise reduction.

One researcher from the project points out that engine makers are happy to achieve a half-decibel noise reduction. The new nozzle design does have the potential to find use in the civilian aviation world, possibly making noise from commercial aircraft quieter.

The military is keen to reduce the noise produced by aircraft as hearing damage is one of the biggest disability claims the military deals with. The noise produced by jet aircraft is one of the most significant noise threats the military has to deal with. So far, the new nozzle designs have been tested in the laboratory with exhaust as hot as 1100 degrees Fahrenheit. The scale model jet engine used in testing is a scale version of the F-18 F404 engine.