SPR773 From India, joined Jun 2008, 164 posts, RR: 0 Posted (5 years 5 months 1 week 11 hours ago) and read 2762 times:
Recently a doubt came to mind. Why do narrowbody aircraft engines sound louder than widebody ones ?
As a matter of comparison I would like to compare a B738 and a B773. In both cases I was travelling economy (cattle class for some). Also I was sitting fairly behind I mean not near the overwing exit but about 8-10 rows behind w.r.t. the engine. Is it technology of the engines ? Or is it just my imagination ?
Also I used to think that the 744 would be noisy due to 4 powerplants but it seemed kinda OK not very loud though.
Fellow A-netters...any inputs ?
Also if I were to compare an A321 with an A333 perhaps or A343 then is it the same experience ?
By the way I have also travelled on an A320 and it is a bit quieter than the B738 (though I maybe wrong here but just a passing thought).
Spacecadet From United States of America, joined Sep 2001, 3833 posts, RR: 11
Reply 4, posted (5 years 5 months 1 week 8 hours ago) and read 2515 times:
I haven't noticed a whole lot of sound difference between narrowbodies and widebodies, only between different planes (regardless of narrow/wide).
Most of what you're actually hearing at cruise is wind noise, not engine noise. Even the difference in decibel level between the front and back of a plane is mostly the wind - the disturbance caused by the wings and the exhaust from the engines means the air is rushing past the fuselage differently than it does in the front of the plane.
Given that, it's going to be mostly the aerodynamics and sound insulation in the fuselage that make one plane louder than another. It doesn't matter narrow or wide.
If you're just talking takeoff and landing, when the engines are spooled up, then I think it's more down to what people have already said about the engines being closer to the fuselage. I also don't have any data on this but I would bet smaller engines are generally louder. That's usually true of any kind of fan - a smaller fan pushing a near-equivalent amount of air as a bigger fan will make more noise doing it.
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