N8911E
Topic Author
Posts: 48
Joined: Fri May 04, 2012 3:20 am

BR715 Start-up Noises

Sun May 13, 2012 4:44 am

Hello,

I am oblivious as to what the noises are when a BR715 FIRST Starts. It sounds like card spokes in a bicycle as it slowly starts up. I never notice this on any other engine.

Can ANYBODY please help me figure out what that sound is, and why it is so noisy at first?

It starts at around 0:30. Do any other High-Bypass Turbofans make that noise, or is it specific to the BR700 series?
http://www.youtube.com/watch?v=QAJMRyJem-M
 
PapaChuck
Posts: 111
Joined: Mon Aug 16, 2010 2:51 pm

RE: BR715 Start-up Noises

Sun May 13, 2012 10:56 am

If you are referring to the loud buzzing sound as the engine starts, that's more than likely coming from inside the cabin. Could be almost anything, perhaps a loose tray table latch or some other plastic fitting vibrating in harmony with the engine. Hard to tell, but it sounds like it's coming from inside, not out.

PC
In-trail spacing is a team effort.
 
njxc500
Posts: 194
Joined: Mon Dec 24, 2007 6:47 pm

RE: BR715 Start-up Noises

Sun May 13, 2012 1:23 pm

It may just be an artifact in the recording caused by the vibration....just a thought.
 
N243NW
Posts: 1597
Joined: Thu Jul 24, 2003 4:29 am

RE: BR715 Start-up Noises

Sun May 13, 2012 8:13 pm

To me, it definitely appears to be some cabin fixture rattling. It's a plasticky sound, so it would strike me as a cabin ceiling or sidewall panel, overhead bin, tray table, seat, etc.
B-52s don't take off. They scare the ground away.
 
SPREE34
Posts: 1560
Joined: Tue Jun 29, 2004 6:09 am

RE: BR715 Start-up Noises

Mon May 14, 2012 1:03 am

Sounds like the inner plasic window.
I don't understand everything I don't know about this.
 
N8911E
Topic Author
Posts: 48
Joined: Fri May 04, 2012 3:20 am

RE: BR715 Start-up Noises

Mon May 14, 2012 4:55 am

Thanks guys. May I ask, and possibly get some answers as to why it does this on the 717 only? DC9s or MD80s don't do it, and I can't recall if the MD-90 did it.
 
SPREE34
Posts: 1560
Joined: Tue Jun 29, 2004 6:09 am

RE: BR715 Start-up Noises

Mon May 14, 2012 11:37 pm

I've never heard it on the 717. Heard it on the L1011 a couple of times. I've heard the 1011 do it windows in a building.
I don't understand everything I don't know about this.
 
kcrwflyer
Posts: 2534
Joined: Tue May 18, 2004 11:57 am

RE: BR715 Start-up Noises

Tue May 15, 2012 12:46 am

Quoting N8911E (Reply 5):
Thanks guys. May I ask, and possibly get some answers as to why it does this on the 717 only? DC9s or MD80s don't do it, and I can't recall if the MD-90 did it.

The 717 engine and the D9/MD engines are drastically different.


The 715 can have a very deep growl when getting started.. sometimes more noticeable than others. The rattling sounded like a vibration in the cabin.
 
AA737-823
Posts: 4888
Joined: Wed Mar 01, 2000 11:10 am

RE: BR715 Start-up Noises

Mon Jun 04, 2012 9:41 am

Yup, it's interior stuff.
The BR715 does have some very distinctive startup noises, though... I always thought the thing sounded like someone filled the oil reservoir with bee-bees.

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