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OlDirtyTriple t1_irp9mj9 wrote

Reply to comment by InevitableRip8968 in TIL that passenger jet engines produce most of their thrust from fan at the front, not from the jet exhaust, and that this is called a high-bypass engine. by Rilot

They're also incredibly noisy. Passengers would need hearing protection.

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8bitslime t1_irpcb1t wrote

The Q400 exists and passengers certainly don't wear any hearing protection. It does have a lot of features in the realm of noise reduction inside the cabin though, much more than a turbofan airliner.

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camwhat t1_irqklnp wrote

I tend to fall asleep quickly in Q400s. Ironically most of my family does so

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Zebidee t1_irpmmkf wrote

>They're also incredibly noisy. Passengers would need hearing protection.

What are you even talking about??

There's thousands of turboprop passenger planes operating every day without passengers wearing hearing protection.

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barath_s t1_iryxkfd wrote

Probably talking about turboprops where the prop tips are supersonic. These tend to be noisy.

Such as the Tu-95 and XF-84 Thunderscreech

> the outer 24–30 inches (61–76 cm) of the blades on the XF-84H's propeller traveled faster than the speed of sound even at idle thrust, producing a continuous visible sonic boom that radiated laterally from the propellers for hundreds of yards. The shock wave was actually powerful enough to knock a man down; an unfortunate crew chief who was inside a nearby C-47 was severely incapacitated during a 30-minute ground run. Coupled with the already considerable noise from the subsonic aspect of the propeller and the T40's dual turbine sections, the aircraft was notorious for inducing severe nausea and headaches among ground crews. In one report, a Republic engineer suffered a seizure after close range exposure to the shock waves emanating from a powered-up XF-84H

also wiki for Tu-95

> The Tu-95 is one of the loudest military aircraft, particularly because the tips of the propeller blades move faster than the speed of sound.

Note that turbofan tips for modern engines may also be supersonic

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Reascr t1_irpbxeq wrote

Turbofans are plenty loud too, you still need hearing protection for them. But commercial aircraft go heavy on sound deadening for passenger comfort, so even turboprop civilian aircraft aren't too bad.

Military ones though? Yeah you'll get hearing damage if you don't use something.

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FriendlyDespot t1_irplecs wrote

There are plenty of turboprop commercial passenger aircraft flying around, and while you can notice the difference, it's not really much louder inside the cabin.

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