R&D firm wants to build hypersonic wind tunnel downtown

Comparative noise levels

150 decibels: Jet take off from 25 meters.

120 decibels: Thunderclap, chain saw.

110 decibels: Riveting machine.

88 decibels: Propeller plane flyover at 1,000 feet.

76 decibels: Living room music.

50 decibels: Conversation at home.

Source: Industrial Noise Control Inc.

An aviation research company wants to build a hypersonic wind tunnel in downtown Dayton that could generate the noise equivalent to a propeller plane flying over at 1,000 feet.

GoHypersonic Inc., which has offices at the Entrepreneurs Center business incubator, is the variance for 848 E. Monument Ave., according to an agenda for today’s Dayton Board of Zoning Appeals meeting.

The company is considering buying the building for construction of a wind tunnel lab that could “exceed maximum permissible noise levels,” papers filed with the city show. City staff recommends that a variance be approved.

Sounds are typically measured in decibels.The documents note that 848 E. Monument Ave. is located next to a railroad track. The company says its tunnel would be no louder than the nearby trains, which generate about 80 to 90 decibels at 100 feet or more than 110 decibels when they sound their horns.

If GoHypersonic cannot secure the variance, “We will have to look for a building elsewhere,” the company said in its filing with the city.

According to the website of Industrial Noise Control Inc., 97 decibels equal the noise generated by Boeing 737 or DC-9 airplanes from one nautical mile, or about 6,080 feet. A propeller plane flyover at 1,000 feet equals 88 decibels, the site said.

Ninety decibels is four times as loud as 70 decibels and hearing damage may result from exposure to that noise level for eight hours, the site said.

Go Hypersonic’s website says its president, Lance Jacobsen, formed Go Hypersonic in 2006 “to further contribute to the dream of hypersonic airbreathing flight and affordable space access.” The site said much of the company’s work “revolves around the development of engine and vehicle designs from a flowline perspective.”

Hypersonic flight is faster than Mach 5, or five times the speed of sound, about 3,800 miles per hour.

“We just want to make use of a building,” Jacobsen said Monday. He declined further comment.

The 4:30 p.m. board meeting is at Dayton city hall, 101 W. Third St.