CoronadoConrad
Topic Author
Posts: 5
Joined: Sat Jul 06, 2019 9:25 am

Delta 747 Question

Sun Jul 07, 2019 2:35 am

Hello guys.

I have a question regarding Delta/Northwest 747s. I was wondering why their engines seem to have consistently run a bit richer than other operators? They seemed to be almost like B-52's taking off. I found a few videos to highlight what I am talking about.

https://youtu.be/tQqqmSBr2XA?t=131
https://youtu.be/NXLsb4mTkfY?t=76
https://youtu.be/htaRlDlrZv8
https://youtu.be/grDtyOnh31k
https://youtu.be/NphHfmP9RKg
https://youtu.be/eQ0Rvvfjvr8
https://youtu.be/GtAYfgoD21M

Now I know that a few of their aircraft were some of the earliest -400's built, but I have noticed other early operators such as United didn't seem to have aircraft that were this smokey. Here is a couple of 1989/1990 build models operating long haul flights out of Narita as well, so I can't imagine that a derate is the excuse either.

https://youtu.be/qK1WbjQDzJk (SFO)
https://youtu.be/ALuJeQH4ecI (SFO)
https://youtu.be/7x265O7bg_8
https://youtu.be/JljQxTYi6lM

What I am wondering is, was there some sort of combustor upgrade that occured in the PW4000 development cycle that Delta/Northwest never bothered to add to their aircraft? Any information would be appreciated.

CoronadoConrad
 
unimproved
Posts: 90
Joined: Sun Jun 22, 2014 7:14 pm

Re: Delta 747 Question

Sun Jul 07, 2019 9:04 am

I have not heard of any real upgrades that should make a difference in smoke. It's probably a case of operator procedure as they only get real smokey when pushed to full power.

It's not just the DL 747's either, PW4000 is smokey in general:
 
GalaxyFlyer
Posts: 3147
Joined: Fri Jan 01, 2016 4:44 am

Re: Delta 747 Question

Sun Jul 07, 2019 5:43 pm

Jets don’t have carburetors, so they don’t “run rich”.
 
CoronadoConrad
Topic Author
Posts: 5
Joined: Sat Jul 06, 2019 9:25 am

Re: Delta 747 Question

Sun Jul 07, 2019 11:46 pm

GalaxyFlyer wrote:
Jets don’t have carburetors, so they don’t “run rich”.

OK I should have said "for lack of a better technical term". Visible particulate matter from inefficient combustion.

And the poster above yes I understand that its probably somewhat related to the design of the PW4000 just the Delta ones seemed noticeably more visible than others so was wondering if something happened in the development cycle of the PW4000. Probably correct that it's just airline maintenance procedure/technique.
 
strfyr51
Posts: 3775
Joined: Tue Apr 10, 2012 5:04 pm

Re: Delta 747 Question

Wed Jul 10, 2019 10:26 pm

CoronadoConrad wrote:
Hello guys.

I have a question regarding Delta/Northwest 747s. I was wondering why their engines seem to have consistently run a bit richer than other operators? They seemed to be almost like B-52's taking off. I found a few videos to highlight what I am talking about.

https://youtu.be/tQqqmSBr2XA?t=131
https://youtu.be/NXLsb4mTkfY?t=76
https://youtu.be/htaRlDlrZv8
https://youtu.be/grDtyOnh31k
https://youtu.be/NphHfmP9RKg
https://youtu.be/eQ0Rvvfjvr8
https://youtu.be/GtAYfgoD21M

Now I know that a few of their aircraft were some of the earliest -400's built, but I have noticed other early operators such as United didn't seem to have aircraft that were this smokey. Here is a couple of 1989/1990 build models operating long haul flights out of Narita as well, so I can't imagine that a derate is the excuse either.

https://youtu.be/qK1WbjQDzJk (SFO)
https://youtu.be/ALuJeQH4ecI (SFO)
https://youtu.be/7x265O7bg_8
https://youtu.be/JljQxTYi6lM

What I am wondering is, was there some sort of combustor upgrade that occured in the PW4000 development cycle that Delta/Northwest never bothered to add to their aircraft? Any information would be appreciated.

CoronadoConrad

yes there were fuel nozzle upgrades that eliminated the smoke trail. And United did the upgrades in our shops
 
CoronadoConrad
Topic Author
Posts: 5
Joined: Sat Jul 06, 2019 9:25 am

Re: Delta 747 Question

Sat Jul 13, 2019 10:47 am

strfyr51 wrote:
yes there were fuel nozzle upgrades that eliminated the smoke trail. And United did the upgrades in our shops

Thanks for that. Do you know more about what specifically was improved in the newer fuel nozzles? Did they further atomise the mixture?

CoronadoConrad
 
strfyr51
Posts: 3775
Joined: Tue Apr 10, 2012 5:04 pm

Re: Delta 747 Question

Mon Jul 15, 2019 5:18 am

CoronadoConrad wrote:
strfyr51 wrote:
yes there were fuel nozzle upgrades that eliminated the smoke trail. And United did the upgrades in our shops

Thanks for that. Do you know more about what specifically was improved in the newer fuel nozzles? Did they further atomise the mixture?

CoronadoConrad

No, I don't we have our own nozzle shop but I never got a chance to go up there very often. The turbine shop. is Huge and I worked the line. So Only on specific occasions when I had a problem would I go up there to get a part or a fitting fix an out of service Airplane.
 
User avatar
747classic
Posts: 2550
Joined: Sat Aug 15, 2009 9:13 am

Re: Delta 747 Question

Mon Jul 15, 2019 5:55 am

P&W has certified in 1993 a Phase 3 reduced pressure combuster on the PW4056, as installed at the 747-400 series.
The smoke number was original 18,4 (100,2% of the Original limit)
After this modification the smoke number was reduced to 10,9% (59,4% of the limit.)
See : https://www.easa.europa.eu/easa-and-you ... s-databank
- Select and download : current data sheets
- Select P&W and P&WC
- Select 1PW041 for the original PW4056 emission data (1986)
- Select 1PW055 for the modified PW4056 emission data (1993)

Compare the PW4056 with the engines of other manufacturers installed at the 747-400 :

GE CF6-80C2B1F : Original certified smoke number 8.3%
RR RB-211-524G : Original certified smoke number 5.0%
Operating a twin over the ocean, you're always one engine failure from a total emergency.
 
CoronadoConrad
Topic Author
Posts: 5
Joined: Sat Jul 06, 2019 9:25 am

Re: Delta 747 Question

Mon Jul 15, 2019 8:45 am

747classic wrote:
P&W has certified in 1993 a Phase 3 reduced pressure combuster on the PW4056, as installed at the 747-400 series.
The smoke number was original 18,4 (100,2% of the Original limit)
After this modification the smoke number was reduced to 10,9% (59,4% of the limit.)
See : https://www.easa.europa.eu/easa-and-you ... s-databank
- Select and download : current data sheets
- Select P&W and P&WC
- Select 1PW041 for the original PW4056 emission data (1986)
- Select 1PW055 for the modified PW4056 emission data (1993)

Compare the PW4056 with the engines of other manufacturers installed at the 747-400 :

GE CF6-80C2B1F : Original certified smoke number 8.3%
RR RB-211-524G : Original certified smoke number 5.0%

Thanks for that 747classic, great information and confirms what I suspected. So I guess Delta never bothered to install the reduced emissions combustor and must have kept it consistent across their fleet of engines. I wonder if someone like lightsaber can explain what was involved in the modification and whether it invoked any penalties in performance to dissuade some operators from installing it. Interesting stuff.
 
johns624
Posts: 2105
Joined: Mon Jul 07, 2008 11:09 pm

Re: Delta 747 Question

Mon Jul 15, 2019 11:25 am

Sure it doesn't have to do with the chemtrail nozzles???
 
CoronadoConrad
Topic Author
Posts: 5
Joined: Sat Jul 06, 2019 9:25 am

Re: Delta 747 Question

Mon Jul 15, 2019 11:30 am

johns624 wrote:
Sure it doesn't have to do with the chemtrail nozzles???

Thanks for the contribution.

CoronadoConrad

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