Guest

DC10 Buzzing

Sat Jul 22, 2000 5:49 am

When I've flown on DC10's I notice that when the engines accellerate on take off they make a loud buzzing sound. No other planes seem to do this. What is that buzzing?
 
Guest

RE: DC10 Buzzing

Sat Jul 22, 2000 6:05 am

There was an article in AIRLINERS magazine (in the ask airliners? section.)

"When jet fan blades rotate, they generate a supersonic flow at their tips, which creates and audible shock wave. Because each blade is slightly different (there is a small variation from tip to tip), several different frequencies are created, resulting in the distinct "combination noise." This is the "buzz saw" sound that we hear, especially in the foreward cabin, when the engines are at high power settings such as takeoff roll and initial climb. Some high-bypass engines do not exibit this effect. According to the acoustic engineers at Pratt & Whitney, a possible reason for this is differences in engine inlet and fan blade sizes."

It also says that this happens on alot of aircraft, 747, L-1011, DC-10, 757, 767, etc.

Hope this helps

BOBO2196
 
UNDpilot
Posts: 65
Joined: Tue Dec 21, 1999 3:31 pm

RE: DC10 Buzzing

Sat Jul 22, 2000 6:38 am

You took this topic write out of my mouth! I just got back from Hawaii on a Hawaiian DC-10 to Seattle, and I was wondering what that buzzing was as well. I never really noticed the sound before, but this really got my attention. I was sitting right next to the right engine and I first heard it while we were taxing at HNL, then we taxiied on to the runway and accelerated. During the long takeoff role and accent my friend and I really heard the buzz and then it died down once we got to cruising altitude. Really interesting though...it sounds sort of like a chainsaw. Ive also heard it on a US Airways 757.
 
D L X
Posts: 11628
Joined: Thu May 27, 1999 3:30 am

757s Too

Sat Jul 22, 2000 7:40 am

I know for fact that you'll hear it on RR powered 757s like American and US Airways use. I haven't heard this on Pratt powered 757s like UA uses though.
 
Guest

RE: 757s Too

Sat Jul 22, 2000 7:57 am

When i use to live in PHX, the 57's that AWA flies would make that sound too, very distinct. You could always tell when a 57 was taking off.
 
ILUV767
Posts: 3035
Joined: Mon May 29, 2000 2:21 pm

DC10 Buzzing

Sat Jul 22, 2000 8:04 am

With the DC10's GE engines, they have always made that buzzing. Even if your outside (by an airport) and a DC10 takes off, you will hear that buzzing. It's the signiture sound of a DC10

Hope that helps
 
airman99o
Posts: 871
Joined: Sat Aug 21, 1999 4:15 am

Also A-320 Series

Sat Jul 22, 2000 8:13 am

I know that Air Canada's A-320's and Canadian's 320's do this as well. I have flown numours times on Air Canada's and the first time that I flew on them it was a totally different sound for me. I was used to flying on the older jets and just hearing that roar!! then I get on this and look out to see if it actually a Jet engine. only joking!!

Airman99o
Safety is Everyones Responsibility.
 
AA777
Posts: 2358
Joined: Thu May 20, 1999 7:07 am

RE: DC10 Buzzing

Sat Jul 22, 2000 11:42 am

I have noticed it on MEA's A320's. It was quite loud, and at first I was quite alarmed by this noise... I havent Heard it on the 757, On the 757 All I hear is the loud sound of the engines at high trust levels on take-off. In the 757, when sitting in the last row, you feel it too...woa.
-AA777
 
Adam84
Posts: 1368
Joined: Sat Jul 24, 1999 6:10 pm

RE: DC10 Buzzing

Sat Jul 22, 2000 9:19 pm

I think it depends on how much power they use. I was on a CO 757 which has the RB211, I was right next to the engine and it didnt buzz, but also I was on a CO 737-300 that did buzz but its not as pronounced as DC-10s. Also I noticed that the JT9D's on NW DC-10-40's have a more pronounced buzz than the GE's. (my personal observation)
 
AerLingus
Posts: 2280
Joined: Wed Mar 08, 2000 9:22 am

RE: DC10 Buzzing

Sun Jul 23, 2000 12:43 am

You know, I've heard that particular buzzing on numerous occasions myself but never really thought anything of it.
Get your patchouli stink outta my store!
 
Ex NWA
Posts: 116
Joined: Sat Apr 01, 2000 4:12 pm

RE: DC10 Buzzing

Sun Jul 23, 2000 1:34 am

I totally forgot about that "buzzing" noise I've heard on USAirways 757's until now. I was flying with a companion on a US 757 flight from PIT-DCA a few years ago and she heard that noise and got really nervous and asked me what is was, because she knew I fly all the time. I had absolutely NO idea what it was, but I played it off and said it was just the engines on this this type of plane.

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