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LX015
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I've heard the "barking dog" explanation, but...

Fri Mar 22, 2019 11:16 pm

What's the deal with the CS100/A220 "humpback whale" noise?
 
JFK31R
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Re: I've heard the "barking dog" explanation, but...

Sat Mar 23, 2019 1:05 am

It's the geared turbo fan- you'll hear it on many A320N series planes as well.
 
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yeogeo
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Re: I've heard the "barking dog" explanation, but...

Sat Mar 23, 2019 1:41 am

I thought it was a mating seal
 
Zeke2517
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Re: I've heard the "barking dog" explanation, but...

Sat Mar 23, 2019 2:30 am

Just one mating seal? That’s a little sad.
 
Apprentice
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Re: I've heard the "barking dog" explanation, but...

Mon Mar 25, 2019 4:03 am

JFK31R wrote:
It's the geared turbo fan- you'll hear it on many A320 series planes as well.


Hi: In A320, noise come from RMP or Reversible Motor Pump, an Emergency devices that were designed as an Emergency Hydraulic Pumps. They have mainly two identical parts, a motor and a pump. Noise come from hydraulic operated motor. For instance, should in sys I (out of 3 Hyd system) power drops and cause is not caused by leak, the RMP will convert Hydraulic Pressure from available system, that action the “noise hydraulic motor” in to hydraulic pressure ( in the low pressure system) created by the Pump part of RMP.
They are R for reversible, because they are able to work both way.

There were not first used by Airbus, I remenber at least DC-10, to have them

Rgds
“An4; IL18; IL6; Tu5; D10; MD11; MD83; B32; B34: B37; B744; B748; B752; B763; B772; B773; B77W; A320; A332; A333; A342; A343.
"A NO" is a positive answer., "DON'T KNOW" is not. My Tutor (a wise man)
“CUBANA” 90 years Flying”
 
masi1157
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Re: I've heard the "barking dog" explanation, but...

Mon Mar 25, 2019 8:34 am

LX015 wrote:
What's the deal with the CS100/A220 "humpback whale" noise?

I never heard an A220 from close, so I don't know what noise you are talking about. Does it occur during climb and is it rather continuous? Then I would assume it is the so called buzzsaw noise.But that is not exclusive to A220, you have it on virtually any turbofan. Or is it intermittent like whales sing? Then I really can't say without hearing it. Might be combustor howl if it occurs during spool-up.

JFK31R wrote:
It's the geared turbo fan- you'll hear it on many A320 series planes as well.

I am not aware that the geared turbofan (I assume you mean the gear itself?) makes any special noise.

Apprentice wrote:
Hi: In A320, noise come from RMP or Reversible Motor Pump...

What you are trying to explain is called PTU (Power Transfer Unit), but that is explicitly not what was meant here (see the "barking dog" in the thread title).


Gruß, masi1157
517 different segments on 101 airlines to 212 airports in 55 countries
 
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LX015
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Re: I've heard the "barking dog" explanation, but...

Wed Mar 27, 2019 11:20 pm

masi1157 wrote:
LX015 wrote:
What's the deal with the CS100/A220 "humpback whale" noise?

I never heard an A220 from close, so I don't know what noise you are talking about. Does it occur during climb and is it rather continuous? be combustor howl if it occurs during spool-up.

JFK31R wrote:
It's the geared turbo fan- you'll hear it on many A320 series planes as well.

I am not aware that the geared turbofan (I assume you mean the gear itself?) makes any special noise.

Apprentice wrote:
Hi: In A320, noise come from RMP or Reversible Motor Pump...

What you are trying to explain is called PTU (Power Transfer Unit), but that is explicitly not what was meant here (see the "barking dog" in the thread title).


Gruß, masi1157



The noise I'm speaking of is after engines have started and aircraft is already taxiing.
 
Apprentice
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Re: I've heard the "barking dog" explanation, but...

Thu Mar 28, 2019 6:21 am

Gruß, masi1157[/quote]


The noise I'm speaking of is after engines have started and aircraft is already taxing.

Hi: Agree. An A-320 have only 2 engines and 3 Hydraulic system. There are 2 options to pressurize system Green and Yellow on ground
a) both engine started and moving EMP
b) On eng started, his EMP is on a supply pressure
C) RMP convert Kinectic energy from pressurized system and convert it kinetic as energy, who will be transformed on rotary energy, converting it late on Hidraulics, (for instance) for yellow system

Rgds
“An4; IL18; IL6; Tu5; D10; MD11; MD83; B32; B34: B37; B744; B748; B752; B763; B772; B773; B77W; A320; A332; A333; A342; A343.
"A NO" is a positive answer., "DON'T KNOW" is not. My Tutor (a wise man)
“CUBANA” 90 years Flying”
 
masi1157
Posts: 462
Joined: Sun Feb 06, 2011 11:56 am

Re: I've heard the "barking dog" explanation, but...

Thu Mar 28, 2019 7:14 am

Apprentice wrote:
RMP convert Kinectic energy from pressurized system and convert it kinetic as energy, who will be transformed on rotary energy, converting it late on Hidraulics, (for instance) for yellow system

Again: That system is called PTU. It has been discussed in hundreds of threads in this forum. But this time we are talking about something else.

LX015 wrote:
The noise I'm speaking of is after engines have started and aircraft is already taxiing.


Would you have a link to a video where it can be heard? I listened to a few and in this one there is something during engine spool-up. One might want to call it "humpback whale singing". I would assume it is combustor howl. Is that what you meant? It is, I have to admit, not "after engines have started and aircraft is already taxiing", but rather during the start of the engines.


Gruß, masi1157
517 different segments on 101 airlines to 212 airports in 55 countries
 
KUZAWU08
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Re: I've heard the "barking dog" explanation, but...

Thu Apr 04, 2019 4:01 am

Specifically, in what area of the aircaft did you observe the noise? Perhaps it actually was a "barking dog..." either cabin pet or a live animal travelling in cargo. I'm convinced that if some of the Dogs travelling in the cargo area were barking, could be heard in the passenger area. There are some rather large (and sometimes multiple) dogs that fly. Sometimes what you observe literally is what you think it is!
 
masi1157
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Re: I've heard the "barking dog" explanation, but...

Thu Apr 04, 2019 6:56 am

KUZAWU08 wrote:
Sometimes what you observe literally is what you think it is!

So you think this might really have been a humpback whale in the cargo hold?

Gruß, masi 1157
517 different segments on 101 airlines to 212 airports in 55 countries
 
bgm
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Re: I've heard the "barking dog" explanation, but...

Thu Apr 04, 2019 10:56 am

Is this what the OP is talking about?

https://www.youtube.com/watch?v=4W_rOVwhXEE&t=74
 
KUZAWU08
Posts: 25
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Re: I've heard the "barking dog" explanation, but...

Fri Apr 05, 2019 8:27 pm

masi1157 wrote:
KUZAWU08 wrote:
Sometimes what you observe literally is what you think it is!

So you think this might really have been a humpback whale in the cargo hold?

Gruß, masi 1157

maybe when pigs fly... or uh, humpback whales fly... just saying though, sometimes in the air it is, in fact, worth "noting what you notice"
 
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T18
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Re: I've heard the "barking dog" explanation, but...

Sat Apr 06, 2019 8:24 pm

masi1157 wrote:
KUZAWU08 wrote:
Sometimes what you observe literally is what you think it is!

So you think this might really have been a humpback whale in the cargo hold?

Gruß, masi 1157


He was on an A220 not a Bird of Prey.
“Racing's important to men who do it well. When you're racing, it's life. Anything that happens before or after is just waiting.” ― Steve McQueen (Le Mans) 1971
 
KUZAWU08
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Re: I've heard the "barking dog" explanation, but...

Sat Apr 13, 2019 12:12 am

T18 wrote:
masi1157 wrote:
KUZAWU08 wrote:
Sometimes what you observe literally is what you think it is!

So you think this might really have been a humpback whale in the cargo hold?

Gruß, masi 1157


He was on an A220 not a Bird of Prey.


best. response. all. year... never know when one had a crazy mission... "cap'n... thar be whales here..."
 
ryanov
Posts: 247
Joined: Sat Nov 03, 2012 4:38 am

Re: I've heard the "barking dog" explanation, but...

Sat Sep 21, 2019 6:37 am

bgm wrote:
Is this what the OP is talking about?

https://www.youtube.com/watch?v=4W_rOVwhXEE&t=74


I've been on a couple A220 flights as well -- that's definitely it. You'll hear it several times during taxi and spooling up for takeoff. Something related to applying power on the engines.

Also, people: READ. He says he knows the explanation for the barking dog, but how about this other completely different sound that is definitely not an Airbus PTU.

Also, "LOLZ": https://airlinerwatch.com/airbus-a220-s ... nts-claim/

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