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Do Maddogs Really Pollute?  
User currently offlineboeing71234567 From United States of America, joined Apr 2009, 66 posts, RR: 0
Posted (3 years 11 months 3 weeks 5 days 11 hours ago) and read 4109 times:

Hello,
The other day I was at my local airport (KBDL) and I was watching a maddog MD80, and a Boeing 737-800 both takeoff. The Maddog had a lot of exhaust coming out of the engines, while the 737 had little to none.

http://www.youtube.com/watch?v=3-QMPkZWGa4
Maddog: watch in 1080P to really see the exhaust

http://www.youtube.com/watch?v=bSGOIStrqCM
Boeing 737: Watch in 1080P to see better quality.

I noticed that the MD80 seemed to be very pollutant, and reminded my almost of a 707. (pollutant wise) I am wondering if the maddogs really pollute that much? and if so, why do airlines use them as much as they do? With all of this green enerygy and higher quality aviation stuff, it would seem like this problem would already be taken care of.

-thank you

23 replies: All unread, jump to last
 
User currently offlinenetjets21 From United States of America, joined Jul 2010, 81 posts, RR: 0
Reply 1, posted (3 years 11 months 3 weeks 5 days 10 hours ago) and read 4021 times:

Because it would cost a ton of money to replace them considering they are pretty much already paid off.

User currently offlineDLD9S From United States of America, joined Jun 2006, 260 posts, RR: 0
Reply 2, posted (3 years 11 months 3 weeks 5 days 10 hours ago) and read 3947 times:

Quoting boeing71234567 (Thread starter):
and if so, why do airlines use them as much as they do?

For the same reason I don't have a hybrid car. I think they are great, but I can't justify the cost replacing my relatively new car with an even newer one simply for environmental reasons, plus I just don't have the funding at the moment. A hybrid car would do me no good if I am bankrupt.

That said, when it is time to bu a new car, I will definitely consider it.



717 727 737 747 757 767 777 DC9 DC10 M80 M90 M11 L10 AB6 333 340 319 320 321 ARJ CRJ EM2 EMJ SF3 146 100 BE1...
User currently offlinetype-rated From , joined Dec 1969, posts, RR:
Reply 3, posted (3 years 11 months 3 weeks 5 days 10 hours ago) and read 3929 times:

If you think that the MD-80's are smokers, you should have been around in the mid 60's.

DC-9's and 727's would generate such a cloud of smoke when the throttles were advanced to takeoff that you could hardly see the aircraft, then the a/c would come shooting out of the cloud!

And 707's & DC-8's would leave so much smoke behind that it would hang in the air for about 3-5 minutes after they had departed!

And airplane engines were much more noisier than today's aircraft are.


User currently offlineoly720man From United Kingdom, joined May 2004, 6810 posts, RR: 11
Reply 4, posted (3 years 11 months 3 weeks 5 days 7 hours ago) and read 3773 times:

Quoting type-rated (Reply 3):

Or the CV990


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wheat and dairy can screw up your brain
User currently offlinePWM2TXLHopper From United States of America, joined Jan 2004, 1339 posts, RR: 1
Reply 5, posted (3 years 11 months 3 weeks 5 days 6 hours ago) and read 3743 times:

If anything, I'd think as far as emissions and gasses going into the air, the newer high bypass engines would produce more pollution, because the jet fuel is being more completely consumed or burned and put out as gas in those engine. When you see the visible smoke, that's fuel that hasn't been completely combusted and vaporized into gasses. I don't have any real scientific knowlege backing this up, but that's just my opinion because I know that's what black smoke is. Fuel that hasn't been completely combusted. Then again, I don't completely buy into the global warming, carbon footprint hysteria, either Heck, thirty years ago they said we were going into a global cooling stage.

Plus, I love loud, smokey engines. These modern high-bypass one's are boring!


User currently offlineN685FE From United States of America, joined Dec 2003, 451 posts, RR: 11
Reply 6, posted (3 years 11 months 3 weeks 5 days 4 hours ago) and read 3679 times:

Quoting oly720man (Reply 4):



Oh but the speed of the 990. Even though it fell short on range that Convair promised it cruised at mach 0.92 or better. Thus the need for the shock body mod. I would like to learn more about this a/c, if anyone has any old manuals or photos that wouldn't mind sharing I would appreciate it.


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psp. lead by example
User currently offlinetdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 7, posted (3 years 11 months 3 weeks 5 days 4 hours ago) and read 3658 times:

Quoting PWM2TXLHopper (Reply 5):
I'd think as far as emissions and gasses going into the air, the newer high bypass engines would produce more pollution, because the jet fuel is being more completely consumed or burned and put out as gas in those engine.

Complete combustion is a good thing. All engine are taking in air + jet fuel (essentially CxHy with some S floating around).

The output, in the case of complete combustion, is CO2 and H20...they're both greenhouse gases but not really pollutants in the traditional sense.

Incomplete combustions means you get a bunch of other stuff out the back...CO, C, assorted lower-order hydrocarbons, etc...those are generally worse for your than CO2 and H20. What you can see as smoke is mostly C, unburned hydrocarbons, and possibly some oil.

There's not much you can do about the sulpher...SOx reduction is a goal of most combustors, but whatever comes in with the fuel has to go out the back as something. NOx comes from high temperatures around the "inert" nitrogen in the air...good combustor design can help mitigate this but the higher temperatures in today's engines make that more difficult.

Overall, modern engines produce a lot less traditional pollutants than their older brethern.

Quoting PWM2TXLHopper (Reply 5):
Heck, thirty years ago they said we were going into a global cooling stage.

Sort of off topic, but thirty years ago they were probably right. Nobody saw India and China coming back in the 70's.

Tom.


User currently offlineDocLightning From United States of America, joined Nov 2005, 19927 posts, RR: 59
Reply 8, posted (3 years 11 months 3 weeks 5 days 3 hours ago) and read 3627 times:

Quoting PWM2TXLHopper (Reply 5):
If anything, I'd think as far as emissions and gasses going into the air, the newer high bypass engines would produce more pollution, because the jet fuel is being more completely consumed or burned and put out as gas in those engine. When you see the visible smoke, that's fuel that hasn't been completely combusted and vaporized into gasses. I don't have any real scientific knowlege backing this up, but that's just my opinion because I know that's what black smoke is. Fuel that hasn't been completely combusted. Then again, I don't completely buy into the global warming, carbon footprint hysteria, either Heck, thirty years ago they said we were going into a global cooling stage.

Black smoke is soot, which is partially consumed fuel that is turned into graphite particles (and some fullerines, probaly, too).

The newer HBPR engines use the heat from combustion more efficiently, which decreases their CO2 output. But you are correct in saying that the CO2 output doesn't decrease quite as much as the fuel burn does. They also burn the fuel more completely, which decreases NOx and soot output.

Soot is a pollutant and a very annoying one at that. Soot is why so many historic buildings need to be power-washed and wind up looking a completely different color once that's done.


User currently offlinePWM2TXLHopper From United States of America, joined Jan 2004, 1339 posts, RR: 1
Reply 9, posted (3 years 11 months 3 weeks 5 days 2 hours ago) and read 3576 times:

Quoting DocLightning (Reply 8):

The newer HBPR engines use the heat from combustion more efficiently, which decreases their CO2 output. But you are correct in saying that the CO2 output doesn't decrease quite as much as the fuel burn does. They also burn the fuel more completely, which decreases NOx and soot output.

Soot is a pollutant and a very annoying one at that. Soot is why so many historic buildings need to be power-washed and wind up looking a completely different color once that's done.


Yeah, but whining, thunderously loud, and smokey engines are so much cooler. I miss them, and it takes half the fun out of plane spotting. Before hushkits came around, I could here the 727's and 737-200's taking off ten miles away.

[Edited 2010-10-31 18:21:17]

User currently offlineDocLightning From United States of America, joined Nov 2005, 19927 posts, RR: 59
Reply 10, posted (3 years 11 months 3 weeks 4 days 20 hours ago) and read 3471 times:

Quoting PWM2TXLHopper (Reply 9):


Yeah, but whining, thunderously loud, and smokey engines are so much cooler.

Yes and no. When you live under an approach and t/o path to a major airport, you are grateful to modern, quiet engines. Living in my part of SF would have sucked when there were 727's and DC-9's flying out here.


User currently offlineImperialEagle From United States of America, joined Jan 2006, 2630 posts, RR: 23
Reply 11, posted (3 years 11 months 3 weeks 4 days 16 hours ago) and read 3389 times:

Just because you can't see it doesn't mean the pollutants aren't there. Once that air and fuel mixture takes place you are going to get something back.

Quoting N685FE (Reply 6):
cruised at mach 0.92 or better

Yeah, but nobody wanted to do it because of extensive fuel burn and extra engine wear.
Those GE CJ's were the essentially the same engines as on the 880, they just snapped a fan section on the rear and re-designed the nacelle. They did improve the combustion process a bit later in the game but were not able to make that much of a difference.
Were it not for fear of AA switching to the (brand new) JT-8's, GE (and CV) wouldn't have bothered.

In the end the 720B could do it better anyway.



"If everything seems under control, you're just not going fast enough!"
User currently offlinecobra27 From Slovenia, joined May 2001, 1017 posts, RR: 0
Reply 12, posted (3 years 11 months 3 weeks 2 days 4 hours ago) and read 2891 times:

Airplanes are polluters, all of them, the only way to reduce emissions is to stay on ground
The black smoke looks bad, it is unburnt fuel, soot and other particulate matter, like in diesel engines. The things you can't see is CO2, NOx and a little or none SOx (cause fuel is almost sulfur free), these thing are worst
There are worst things like coal powerplants, even with scrubber there is around 150 kgs of SOx per Megawatt hour produced, a little. Marine bunker fuel for ships is has around 5 % sulpfur, it is really cheap to buy and is one of the things that makes things from China really cheap. So planes are somewhat dirty, ships even more, but the badddddest things here are coalpowerplants


User currently offlinebri2k1 From United States of America, joined Dec 2004, 988 posts, RR: 4
Reply 13, posted (3 years 11 months 3 weeks 1 day 11 hours ago) and read 2733 times:

Pollution is a byproduct of combustion. Even though city buses spew out thick black smoke, they reduce overall pollution emissions by taking cars off the road (in theory). Airliners can play a similar role. For example, the 777 was touted as being the most specific fuel efficient conveyance in existence when it came out. Specific fuel consumption is the amount of fuel consumed per seat mile. We can infer that by consuming less fuel, we are also producing less pollution on a somewhat proportional scale. Also, as engine technology advances, the combustion become more efficient and the pollution produced by burning the same amount of fuel decreases.


Position and hold
User currently offlineMDShady From United States of America, joined Jan 2010, 74 posts, RR: 0
Reply 14, posted (3 years 11 months 3 weeks 1 day ago) and read 2611 times:

What about noise pollution?   

All kidding aside most have mentioned CO/NOx/SOx/VOC's etc but yeah they'll never be 100% pollution free, it's just not in the nature of hydrocarbon combustion.

Here's a nice smoky Spanair T/O

http://www.youtube.com/watch?v=Lh95MH74V2A


User currently offlinecpd From Australia, joined Jun 2008, 4879 posts, RR: 37
Reply 15, posted (3 years 11 months 3 weeks 23 hours ago) and read 2609 times:

Quoting DocLightning (Reply 10):
Yes and no. When you live under an approach and t/o path to a major airport, you are grateful to modern, quiet engines. Living in my part of SF would have sucked when there were 727's and DC-9's flying out here.

Where I live, I'm under a flight path, where planes are going at it full power and climbing/accelerating. You really are thankful for no more B742s or B743s and no more B727s. Those were very loud.

Concorde was a relatively rare site by comparison. The A380 these days is so quite you hardly hear it - especially in comparison with other planes. Compare QF31 (A380-842) with QF63 (B747-438 RR) and you hear the difference.


User currently offlineAccess-Air From United States of America, joined Sep 2000, 1939 posts, RR: 13
Reply 16, posted (3 years 11 months 2 weeks 6 days 11 hours ago) and read 2385 times:

Quoting PWM2TXLHopper (Reply 9):
Before hushkits came around, I could here the 727's and 737-200's taking off ten miles away.

Thats why NIMBYs complained....
Me I would have loved to have lived near and airport where there were loud jets all the time.....To me its music to my ears...
I regard today's cookie cutter airliners/engines to rap or hip hop music.....Sound all the same and as boring and annoying as hell...

Gimme some DC9s, 727s, 737-100/200s BAC One Elevens, etc.....

Access-Air



Remember, Wherever you go, there you are!!!!
User currently offlineNorthwest727 From United States of America, joined Jul 2005, 491 posts, RR: 0
Reply 17, posted (3 years 11 months 2 weeks 5 days 12 hours ago) and read 2218 times:

I recall reading about jet engines, and how the reason they were so smokey back in the day was that the combustion chamber(s) was very short, thereby not allowing fuel to burn completely, and with partially-burned fuel, you get soot, NOx, VOCs, and everything else. Today's engines have much longer combustion chambers to facilitate more complete combustion of the fuel, and even newer technologies such as GE's dual-dome combustion chamber which further help to reduce emissions.

Whether or not you believe in global warming, CO2 is always going to be a byproduct of burning hydrocarbons, regardless. By using less fuel, not only do you decrease the amount of other emissions, but you reduce the CO2 output.

Quoting oly720man (Reply 4):
Quoting N685FE (Reply 6):

How about a nice CV880 takeoff in color video:

http://www.youtube.com/watch?v=isP1LVVZ6nU&feature=fvw

Skip to about 5:47 for the actual takeoff and flyby

Quoting Access-Air (Reply 16):
I regard today's cookie cutter airliners/engines to rap or hip hop music.....Sound all the same and as boring and annoying as hell...

I couldn't agree any more.

[edit: YouTube time]

[Edited 2010-11-07 07:12:37]

User currently offlineImperialEagle From United States of America, joined Jan 2006, 2630 posts, RR: 23
Reply 18, posted (3 years 11 months 2 weeks 5 days 9 hours ago) and read 2182 times:

Quoting Northwest727 (Reply 17):
How about a nice CV880 takeoff

Thankyou so much for sharing this!
The sights and sounds bring back wonderful memories! The only thing missing is the smell!

It is hard to believe the 880's have been gone for so long now. They were such a big part of our life at ATL back in the day.
They were such fun.

Quoting Access-Air (Reply 16):
Sound all the same and as boring

Agreed!
I can remember when I could identify an aircraft type by the sound of the engines, piston, propeller-turbine, or jet.
I haven't been able to do that for a long time. Excepting maybe an L10 or T-7 and certainly a C-5.



"If everything seems under control, you're just not going fast enough!"
User currently offlineDocLightning From United States of America, joined Nov 2005, 19927 posts, RR: 59
Reply 19, posted (3 years 11 months 2 weeks 5 days 4 hours ago) and read 2129 times:

Quoting Access-Air (Reply 16):

Thats why NIMBYs complained....

You can call them that, but when every three minutes your entire life goes on hold as a roaring noise fills your entire home, even though you live miles from the airport, that's a problem.

Today, you can stand right at the end of RWY 28 at SFO and, while you can hear the departing A/C, they aren't deafening.


User currently offlinePWM2TXLHopper From United States of America, joined Jan 2004, 1339 posts, RR: 1
Reply 20, posted (3 years 11 months 2 weeks 4 days 23 hours ago) and read 2071 times:

Quoting DocLightning (Reply 19):

You can call them that, but when every three minutes your entire life goes on hold as a roaring noise fills your entire home, even though you live miles from the airport, that's a problem.
Quoting Access-Air (Reply 16):
Me I would have loved to have lived near and airport where there were loud jets all the time.....To me its music to my ears...



I'm with AccessAir, wouldn't bother me a bit! I use to spend the summers at my uncle's, near DTW in the early 1990's. He lived about three miles from the airport, directly under the final approach and departure paths of one of the main runways. The jet noise started at about 6am, and went until midnight. He had no air conditioning, so at night the windows were always open, and I went to sleep listening to the DC-9's, 727's, and and 737-200's among others. Never bothered me at all! It was music to my ears. Later on, he moved out to Orchard Lake, near Bloomfield Hills. Out there, he was still under the approach, but it was a good 25-30 miles away and the planes we still several thousand feet up. However, they still came over all day and I got good at identifying aircraft without even looking up, just by the sound they produced.

I've always thought someday when I buy a house, I should find a nice, new, modern house on some property near a major airport that few other people would want to live in. I figure you could get a great deal if the property value was depreciated enough because of airport noise?



[Edited 2010-11-07 20:19:06]

User currently offlineB737-112 From United States of America, joined Nov 1999, 891 posts, RR: 5
Reply 21, posted (3 years 11 months 2 weeks 4 days 22 hours ago) and read 2059 times:

I actually put up an HD video on YouTube taken from the end of the runway just to look at the effects of an MD-80 takeoff. I didn't follow the plane with the camera, I just kept recording the runway and you can see a faint brownish cloud coating it.

Make sure to play it in HD

http://www.youtube.com/watch?v=zbKKCCxccuo

Northwest727, I'm glad you enjoyed the CV-880 video, thanks for posting it here! There's a lot of good stuff coming up on my channel in the following months like a taxi and engine run-up on-board a Boeing 707, an Alaska MD-80 tailscrape at night, an SR-71 flyby at Burbank Airport and a ton of other classic stuff.

Ryan


User currently offlinejwenting From Netherlands, joined Apr 2001, 10213 posts, RR: 19
Reply 22, posted (3 years 11 months 2 weeks 4 days 20 hours ago) and read 2038 times:

Just because you don't see what's coming out the back of an engine doesn't mean there's nothing coming out of it...

Yes, those old engines burn more fuel per passenger/mile than more modern ones on average, and that's all you can say about it.

Older engines will emit more soot and partially combusted carbohydrates, newer ones larger amounts of NOx.
Which one people think is worse depends on the current hype in the environmental movement (and currently it's CO2, which is a complete laugh as it's not a pollutant at all, in the 1980s it was NOx which caused engines to be designed to burn at different temperatures to reduce NOx emissions which increased CO2 emissions so now engines are being designed to reduce CO2 emissions which increases NOx emissions. go figure).



I wish I were flying
User currently offlinePWM2TXLHopper From United States of America, joined Jan 2004, 1339 posts, RR: 1
Reply 23, posted (3 years 11 months 2 weeks 4 days 17 hours ago) and read 2015 times:

Quoting B737-112 (Reply 21):
I actually put up an HD video on YouTube taken from the end of the runway just to look at the effects of an MD-80 takeoff. I didn't follow the plane with the camera, I just kept recording the runway and you can see a faint brownish cloud coating it.

Make sure to play it in HD

I like your channel! I've just subscribed! I'm working on adding to my own. The MD-80 is about the best thing going right now for smokey take-offs, aside from the Fedex 727's and charter 737-200's.

I've got an MD-80 takeoff on my own channel as well. Easy to compare the exhaust cloud compared to the newer planes taking off and shot from the same location

Delta MD-88 at about 6:00 min. mark

http://www.youtube.com/watch?v=mWlFaVeP_Is


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