I'm sceptical that that's true. We can put mufflers on gas engines to make them quieter. The prop, though, is moving a lot of air, and there's no way to get around that and have it still work.
It's a muffler for a jet engine. Mufflers are great things for humanity, there's nothing wrong with that. They are not even included in drawings if you asked the average person to draw an engine.
What a silly idea for a study. Of course sounds closer are going to be louder.
Where I live there’s an airport near an island with very expensive houses. They certainly care much more about the very loud jet engine than they do about a guy with a cut off exhaust and a v8
I'm seriously not trying to be confrontational and say you're wrong, you're not.
I'm perfectly familiar with typical ICE and the design of jet engines. Exhaust is no less important in ICE. If you block it, the engine doesn't run.
Jet engines use exhaust as propulsion, so it just moves the mechanism from inside to out, in a way.
A muffler is a device that baffles air to quiet it. That's -exactly- what this device does. You can argue, rightly, that more is at stake and more considerations must be made here. But it's still, by definition, a muffler.
And the problem is that they put loud mufflers on purpose. The stock mufflers aren't very noisy, or at least they're as silent as a 16k RPM engine can be.
A muffler restricts the exhaust and will lead to decreased power from the engine, even for properly tuned engines. Removing the muffler will remove the restriction in the exhaust and undo the power decrease, and also increase the noise.
I will skip the ignorant ageat drivel, but why would there be exhaust spewing any more than any car, electric or otherwise? The noise point is fair, as passing airliners are already quite loud, and I am quite far from any airport.
If you live anywhere where people love Harleys and Dodge Ram trucks with aftermarket exhausts, then 65 is luxury levels of quietness.
Also, whether in my small village or in a fancy suburb, there seems to always be someone with a 2 cycle, muffler-free piece of lawn equipment running. Leaf blowers are the worst, but weed trimmers and now even leaf vaccuums are common.
Or, if you live in an urban area, especially in NYC, there's rarely a moment that you don't hear an emergency vehicle siren echoing throughout the neighborhood.
Unfortunately, it's just a noisy world. At least this aircraft is electric and has some goal of keeping noise as low as possible.
This does not seem reasonable. Internal combustion engines with mufflers are not very loud. If the goal is to reduce noise, why not simply set a maximum noise level, such as n dB at 1m from the tailpipe?
It's not just you. It's also other people who don't have much experience with engine performance. Quieter mufflers restrict more airflow, something you don't want to do when you're trying to pass more fuel through a small engine.
Most road noise generated from a vehicle is from tires on the ground once you get above 18 mph. Modern mufflers are remarkably effective at silencing the engine.
IIRC at highway speeds the overall shape of the car moving through the air is also a significant noise generator, but I don't remember where I read that right now.
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