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NASA moves a step closer to supersonic passenger flights (www.cnn.com)

submitted 1 year ago by deconstruct@lemm.ee to c/technology@lemmy.ml

127 comments fedilink hide all child comments

In July, Lockheed Martin completed the build of NASA’s X-59 test aircraft, which is designed to turn sonic booms into mere thumps, in the hope of making overland supersonic flight a possibility. Ground tests and a first test flight are planned for later in the year. NASA aims to have enough data to hand over to US regulators in 2027.

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[–] Ryumast3r@lemmy.world 6 points 1 year ago (2 children)

They're promising a perceived 75 dB level, equivalent to the volume of a dishwasher. Sonic booms are normally about 110 dB or about a jackhammer or a rock concert

And it's not like you'd hear it all the time, just once in a while and only if you're in the flight path.

[–] keeb420@kbin.social 3 points 1 year ago (1 children)

will it reduce the air pressure difference on the ground? i was in a building and it moved. i felt it. sound is only one problem.

Overpressure
Sonic booms are measured in pounds per square foot
of overpressure. This is the amount of the increase
over the normal atmospheric pressure which surrounds
us (2,116 psf/14.7 psi).
At one pound overpressure, no damage to structures
would be expected.
Overpressures of 1 to 2 pounds are produced by
supersonic aircraft flying at normal operating altitudes. Some public reaction could be expected between 1.5 and 2 pounds.
Rare minor damage may occur with 2 to 5 pounds
overpressure.
As overpressure increases, the likelihood of structural
damage and stronger public reaction also increases.
Tests, however, have shown that structures in good
condition have been undamaged by overpressures of
up to 11 pounds.
Sonic booms produced by aircraft flying supersonic at
altitudes of less than 100 feet, creating between 20 and
144 pounds overpressure, have been experienced by
humans without injury.
Damage to eardrums can be expected when overpressures reach 720 pounds. Overpressures of 2160
pounds would have to be generated to produce lung
damage.

https://www.nasa.gov/centers/dryden/pdf/120274main_FS-016-DFRC.pdf

[–] Ryumast3r@lemmy.world 3 points 1 year ago

Yes, they would reduce the overpressure. By how much I'm not sure, but that's part of the research.

[–] KevonLooney@lemm.ee 0 points 1 year ago (1 children)

They're promising

I guarantee it will be louder than that. Unless the flight path is directly over a senator's house or an historic golf club (where donors play), it will be too loud.

Literally make the flight path over the richest part of town or I won't believe it.

[–] Ryumast3r@lemmy.world 2 points 1 year ago

NASA has no control of flight paths. The FAA also doesn't specify sonic-boom allowed flight paths. They just outright ban it (with a few exceptions) for any boom that could reach anywhere in the US.

FAA also doesn't want to deal with people complaining about sonic booms like they did back in the 50s when this all started (they received tens of thousands of complaints) so they have an interest in making sure NASA lives up to their promises.