L1329II From , joined Dec 1969, posts, RR: Posted (7 years 1 month 3 weeks 3 days 17 hours ago) and read 4562 times:
I remember reading here that AA and maybe DL is looking to retrofit thier MD-80 series with different engines. Has there been any more research and or has any STC's been issues for any retrofit for the 80 series? Also, I am under the impression that the MD-90 was a flop. Any reason for that as well?
Pardon my ignorance, I know this topic has been discussed plenty.
1337Delta764 From United States of America, joined Oct 2005, 5752 posts, RR: 2 Reply 1, posted (7 years 1 month 3 weeks 3 days 16 hours ago) and read 4510 times:
Quoting L1329II (Thread starter): I remember reading here that AA and maybe DL is looking to retrofit thier MD-80 series with different engines. Has there been any more research and or has any STC's been issues for any retrofit for the 80 series? Also, I am under the impression that the MD-90 was a flop. Any reason for that as well?
I think that AA might look for new engines for the MD-80s, but not DL. In 10 years, Delta will probably have the MD-80 fleet retired, while AA could be operating them 15-20 more years.
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FlyDreamliner From United States of America, joined Jan 2006, 2759 posts, RR: 15 Reply 2, posted (7 years 1 month 3 weeks 3 days 15 hours ago) and read 4458 times:
Quoting 1337Delta764 (Reply 1): I think that AA might look for new engines for the MD-80s, but not DL. In 10 years, Delta will probably have the MD-80 fleet retired, while AA could be operating them 15-20 more years.
I agree, Delta won't be keeping the MD-80s/MD-90s too much longer. They'll consolidate 4 models into one - the 737-800.
I don't think AA will have the MD-80s 20 years from now. 10 years, probably. The issue they have is this. They sunk a good deal of money into a good sized 737-800 fleet. They want to get as few models in the fleet as possible. I'm not sure they'll wait till Y1 to replace the MD-80s.
"Let the world change you, and you can change the world"
Spartanmjf From United States of America, joined Nov 2005, 463 posts, RR: 0 Reply 3, posted (7 years 1 month 3 weeks 3 days 14 hours ago) and read 4431 times:
Maybe NW will do the retrofits - they can make a great DC9 replacement!
September11 From United States of America, joined exactly 9 years ago today! , 3623 posts, RR: 23 Reply 4, posted (7 years 1 month 3 weeks 3 days 14 hours ago) and read 4412 times:
AA is flying most recent MD-80s off production line, specifically MD-83s acquired from TWA. They will be in service for years to come. Engine retrofits are not suggested on MD-83s at this point?
Lightsaber From United States of America, joined Jan 2005, 10657 posts, RR: 100 Reply 5, posted (7 years 1 month 3 weeks 3 days 12 hours ago) and read 4356 times:
Quoting September11 (Reply 4): AA is flying most recent MD-80s off production line, specifically MD-83s acquired from TWA. They will be in service for years to come. Engine retrofits are not suggested on MD-83s at this point?
The younger the airframe, the more sense an engine upgrade makes.
The reality is, as the years go by and the MD-80 airframes age, the present value of an engine retrofit drops. There are basically only two candidates: The RR 715 and Pratt PW6000. Its all going to come down to AA taking the initiative or not. I'm biased toward the pw6000! It will all come down to purchase price of the engine/nacelle and weight/balance engineering issues will determine if this goes forward. Since the JT8D has a TSFC of (IIRC) .737, there is a ton of room for improvement, over a 20% drop in fuel burn would dramatically change the MD-80's mission profile.
Sllevin From United States of America, joined Jan 2002, 3376 posts, RR: 6 Reply 6, posted (7 years 1 month 3 weeks 3 days 12 hours ago) and read 4337 times:
Quoting Lightsaber (Reply 5): ince the JT8D has a TSFC of (IIRC) .737, there is a ton of room for improvement, over a 20% drop in fuel burn would dramatically change the MD-80's mission profile.
Are yu sure that isn't a figure for the JT8-7/9/15 (low bypass) versions, and not for the -2XX series high bypass? I thought I had seen estimates closer to 10% for fuel savings, which likely pencils out to a near-wash given the age of most of the airframes.
Lightsaber From United States of America, joined Jan 2005, 10657 posts, RR: 100 Reply 7, posted (7 years 1 month 3 weeks 3 days 3 hours ago) and read 4225 times:
Quoting Sllevin (Reply 6): Are yu sure that isn't a figure for the JT8-7/9/15 (low bypass) versions, and not for the -2XX series high bypass? I thought I had seen estimates closer to 10% for fuel savings, which likely pencils out to a near-wash given the age of most of the airframes.
LMP737 From , joined Dec 1969, posts, RR: Reply 8, posted (7 years 1 month 3 weeks 3 days 3 hours ago) and read 4222 times:
Quoting L1329II (Thread starter): I remember reading here that AA and maybe DL is looking to retrofit thier MD-80 series with different engines. Has there been any more research and or has any STC's been issues for any retrofit for the 80 series? Also, I am under the impression that the MD-90 was a flop. Any reason for that as well?
I'm not really sure about any STC's being issued. But I have heard AA has at least studied it. If it were to happen my money would be on the BR715. It's light, it's been fitted to a DC-9 airframe and it's an RR product.
As for the MD-90 being a flop that was due mainly to it's unrelaiablity when it first entered service. Mainly attributed to it's electrial syste,.
FlyDreamliner From United States of America, joined Jan 2006, 2759 posts, RR: 15 Reply 9, posted (7 years 1 month 3 weeks 3 days 3 hours ago) and read 4208 times:
Quoting Spartanmjf (Reply 3): Maybe NW will do the retrofits - they can make a great DC9 replacement!
Hahaha, nope. NW has never been interested in MD-80s. They're replacing DC-9 with A319 and EMB-170/175/190 in the future.
Quoting Lightsaber (Reply 5): The younger the airframe, the more sense an engine upgrade makes.
The reality is, as the years go by and the MD-80 airframes age, the present value of an engine retrofit drops. There are basically only two candidates: The RR 715 and Pratt PW6000. Its all going to come down to AA taking the initiative or not. I'm biased toward the pw6000! bigthumbsup It will all come down to purchase price of the engine/nacelle and weight/balance engineering issues will determine if this goes forward. Since the JT8D has a TSFC of (IIRC) .737, there is a ton of room for improvement, over a 20% drop in fuel burn would dramatically change the MD-80's mission profile.
Even if AA's frames are new, fleet commonality counts for a lot. They've started to phase in 737-800s to start taking up MD-80 routes. Putting new engines on MD-80 would require a lot of engineering. Even the 200 series JT8D's are not terribly high bypass, nowhere near like the CFM56-5 or CFM56-7's. PW6000 might work, but the only modern high bypass turbofan that the engineering has already been done for is the IAE V2500 - that was used on MD-90. MD-80 isn't that much smaller, IAE V2500 could work. The question is if anyone really cares enough to do it.
"Let the world change you, and you can change the world"
AA737-823 From United States of America, joined Mar 2000, 5336 posts, RR: 11 Reply 10, posted (7 years 1 month 3 weeks 3 days 3 hours ago) and read 4208 times:
Quoting Sllevin (Reply 6): Are yu sure that isn't a figure for the JT8-7/9/15 (low bypass) versions, and not for the -2XX series high bypass?
There ARE no high bypass JT8D's.
2:1 is NOT high bypass.
And that's the reason a retrofit would make such sense- put something on there that blows some air!!!
Starlionblue From Hong Kong, joined Feb 2004, 15870 posts, RR: 66 Reply 11, posted (7 years 1 month 3 weeks 3 days 2 hours ago) and read 4168 times:
If someone has too much time on their hands and is so inclined, I'd love to see a side by side comparison of JT8D, RR 715 and Pratt PW6000. Thrust, weight, fuel consumption, bypass ratio, size and all that good stuff.
Also what is TSFC?
"There are no stupid questions, but there are a lot of inquisitive idiots." - from Citadel by John Ringo
AeroWeanie From United States of America, joined Dec 2004, 1600 posts, RR: 52 Reply 12, posted (7 years 1 month 3 weeks 3 days 2 hours ago) and read 4158 times:
Why reengine an elderly airframe? The mod would probably cost more than the airframe hull value. To meet noise regulation, there are two hush kits available - Jet Engineering/Goodrich's and Aviation Fleet Solutions' (they got their STC last week).
Prebennorholm From Denmark, joined Mar 2000, 6016 posts, RR: 55 Reply 13, posted (7 years 1 month 3 weeks 3 days ago) and read 4127 times:
Both CFM56 and V2500 are too large and heavy. They would create a serious balance problem. Having to fly around with a thousand lbs concrete block in the nose would not only take away much of the gain, but combined with the heavier engines it would seriously increase empty weight and that way reduce the airframe's useful load for fuel and payload.
That leaves us with high powered versions of BR-715 and the PW6000.
But whatever way we go, maybe one major obstacle will be that it will be a change from mechanical to FADEC controlled engines. That will mean a lot more changes to the plane than just putting on new engines. A new certification procedure may be long and costly.
So I doubt that it will happen.
Quoting L1329II (Thread starter): Also, I am under the impression that the MD-90 was a flop. Any reason for that as well?
No, not so. MD-90 is arguably the finest plane ever made.
It had its teething problems in the beginning. It showed all the signs of a product which was too hastily introduced by a company without economic resources. The problems have been corrected now.
Sitting in the forward half of the cabin of an MD-90 you enjoy the quietest and most comfortable ride of any airliner in the world.
Its only problem was that it competed head on with the B737-800, and when the MDD money tank ran dry, then there was nobody but Boeing to take over the program. Of course they could not continue two competing programs. And of course they could not scrap their all new entire family of 737NGs.
My theory: Douglas and MDD made too good airliners. They were more expensive to produce than the competitors, but they were unable to obtain a substantially higher price. Ends didn't meet. Any proofs?
Why can NW still fly fuel guzzling, hushkitted DC-9s these days? They must be immensely cheap and efficient to maintain.
Why is the DC-8 practically the only successfully re-engined civil airliner? And why do they seem to last for ever as freighters? They are 40 years old and nobody talks about retirement.
DC-10s are practically all (at least the -30 model) being converted at considerable cost to MD-10 freighters, while similarly aged products from the competitors are being scrapped.
There is a constant and high demand for pax MD-11s being released for freighter conversion.
There must be a reason.
Further proofs? SAS planned on exchanging their large DC-9 fleet with loads of MD-90. They got only 8 before production was ended. Then they bought 50+ 737NGs, got disappointed, and continued buying A320 family planes.
But they have been very reluctant to shed those 8 MD-90 even if they carry their own type rating and must be a terrible headache in crew planning.
I have heard that they try the best they can to let all MD-90 crews carry double type rating - being rated for MD-80 in addition to MD-90. That adds some flexibility, but at some not insignificant cost.
Always keep your number of landings equal to your number of take-offs, Preben Norholm
Starlionblue From Hong Kong, joined Feb 2004, 15870 posts, RR: 66 Reply 15, posted (7 years 1 month 3 weeks 2 days 22 hours ago) and read 4105 times:
Quoting FLY2HMO (Reply 14): Also, since MDD is dead, who would do the engineering part, Boeing?
The customer of course If you have 350+ planes in your fleet, the cost of certification can be pretty nicely amortized.
If re-engineing can give those MD-80s another 20 years at a cost lower than buying a new product (with costs adjusted for lifetime of new airliner) it's worth looking at.
"There are no stupid questions, but there are a lot of inquisitive idiots." - from Citadel by John Ringo
AeroWeanie From United States of America, joined Dec 2004, 1600 posts, RR: 52 Reply 16, posted (7 years 1 month 3 weeks 2 days 21 hours ago) and read 4092 times:
Quoting FLY2HMO (Reply 14): Quoting LMP737 (Reply 8):
it's been fitted to a DC-9 airframe
Avioniker From United States of America, joined Dec 2001, 1109 posts, RR: 11 Reply 18, posted (7 years 1 month 3 weeks 2 days 4 hours ago) and read 3988 times:
Just to add my 2 (or so) cents
The 717 is not much more than a 30 series 9 with pretty avionics so AeroWeanie's point is valid. In fact DAC went back to the DC9 wing because of the ice fod problem with the MD80 wings.
The 715 engine has serious reliability issues which is the principal reason for the 717's demise.
The V2500 engine is the only current realistic candidate. Looking at the mounting and CG on the MD90 it doesn't seem that big a mod compared to some others. Just putting a heavyweight hushkit on a 727F requires almost a complete empenage rebuild.
Just one man's opinion mind you...
One may educate the ignorance from the unknowing but stupid is forever. Boswell; ca: 1533
LMP737 From , joined Dec 1969, posts, RR: Reply 19, posted (7 years 1 month 3 weeks 2 days 3 hours ago) and read 3976 times:
Quoting Prebennorholm (Reply 13): No, not so. MD-90 is arguably the finest plane ever made.
It had its teething problems in the beginning. It showed all the signs of a product which was too hastily introduced by a company without economic resources. The problems have been corrected now.
Sitting in the forward half of the cabin of an MD-90 you enjoy the quietest and most comfortable ride of any airliner in the world.
The first airliner I ever worked on was an MD-90. So I guess you can say I have a soft spot for the aircraft. However I have to admit it's one of the more temperamental aircraft I have worked on. Even with a lot of the bugs that troubled it in it's early years having been worked out. With that said it's a good looking airplane that's gives you the quietest and smoothest ride of any airliner.
2H4 From United States of America, joined Oct 2004, 8950 posts, RR: 62 Reply 20, posted (7 years 1 month 3 weeks 2 days 3 hours ago) and read 3969 times:
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Quoting LMP737 (Reply 19): With that said it's a good looking airplane that's gives you the quietest and smoothest ride of any airliner.
That's a pretty strong statement...is it really that much nicer? I've never been in one.
CRJonBeez From United States of America, joined Nov 2004, 317 posts, RR: 4 Reply 21, posted (7 years 1 month 3 weeks 2 days 2 hours ago) and read 3968 times:
Quoting AA737-823 (Reply 10): There ARE no high bypass JT8D's.
2:1 is NOT high bypass.
good call! IIRC, the standard consideration for high bypass is 5.1
the JT9D, though certainly not used on the mad dog, was a high bypass P&W.
quiztime hotshots! what US plane received the first high bypass engines???
LMP737 From , joined Dec 1969, posts, RR: Reply 22, posted (7 years 1 month 3 weeks 2 days 2 hours ago) and read 3966 times:
Quoting 2H4 (Reply 20): That's a pretty strong statement...is it really that much nicer? I've never been in one.
Of course my statement is just an opinion. However my experience so far is that the MD-90 has the smoothest, quietest ride of any airliner I have been on. Even in back where traditionally on th MD-80 things get a bit noisier.
2H4 From United States of America, joined Oct 2004, 8950 posts, RR: 62 Reply 23, posted (7 years 1 month 3 weeks 2 days 2 hours ago) and read 3962 times:
AIRLINERS.NET CREW HEAD DATABASE EDITOR
Quoting LMP737 (Reply 22): However my experience so far is that the MD-90 has the smoothest, quietest ride of any airliner I have been on.
Cool. It would be interesting to see a graphic comparison of cabin noise between all airliners currently in use. Maybe a sampling of the front, center, and the aft portions of each cabin.
Starlionblue From Hong Kong, joined Feb 2004, 15870 posts, RR: 66 Reply 24, posted (7 years 1 month 3 weeks 1 day 22 hours ago) and read 3922 times:
Quoting 2H4 (Reply 23):
Cool. It would be interesting to see a graphic comparison of cabin noise between all airliners currently in use. Maybe a sampling of the front, center, and the aft portions of each cabin.
The real trick would be to get an independent entity to perform it. If you ask the manufacturers their plane is quieter...
"There are no stupid questions, but there are a lot of inquisitive idiots." - from Citadel by John Ringo
25 MD-90: I don't know where to find it, but I've seen an FAA chart with this data. The MD-90 had the quietest cabin of any jetliner in the world until you got
26 Lightsaber: Not really, it doesn't turn down well to the low thrust leveles the MD-80 family would required. We're talking 18k to 22k for the MD-80's. This is RR
27 OyKIE: If American gets 35 new 738 pr year starting this year they could replace all their MD-80 in a 10 year time. That also means there will be 35 MD-80 a
28 LMP737: My guess that maybe a handfull will be picked up by small carriers overseas. The rest will end up as beer cans. Here's what I think is going to happe
29 Lightsaber: Thrust specific fuel consumption in lbm (fuel) per hour per lbf of thrust. Number range from 0.510 (rumored GEnX/Trent 1000), 0.575 for the V2500 (on
30 A342: Once again, I have to point my finger to the MTU website. The PW6000 is actaully HEAVIER than the CFM56 ! The CFM56 is lighter than the JT-8D-200 whi
31 OyKIE: Do you have the TSFC for the PW600 and RR-715? Thank you for your numbers. So if AA and others like DL and SK goes through with this it means that th
32 Starlionblue: With a fleet the size of AA's, existing models such as the 738 are not terribly relevant. You should not base the decision for 300 new aircraft on 80
33 MX757: I call them DC-9NGs. Boeing still handles engineering issues for MDD products. It's called Boeing Douglass Products Division. Boeing was developing a
34 MD-90: It's not good to have a freight door in the front with cargo that has to be pushed to the rear of a T-tail aircraft. Causes loading problems. The 727
35 LTU932: They did have MD-80s at one point but phased them out and kept the fully paid for DC-9s. What about modifications to the flightdeck? If a CFM56 was u
36 A342: No it isn´t. All RR engines assembled in Germany are twin-spool. Recently the Tay assembly line was moved to Germany because Dahlewitz will be the R
37 Lightsaber: Alas, I don't. Well, I'm a little NDA "tongue tied" on the PW6000. When I find a good link, I'll share. But I haven't found one that isn't anything m
38 F14D4ever: Lockheed C-5 Galaxy, with General Electric TF39s. Approx. 8:1 bypass ratio.
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From , joined Dec 1969, posts, 
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It will all come down to purchase price of the engine/nacelle and weight/balance engineering issues will determine if this goes forward. Since the JT8D has a TSFC of (IIRC) .737, there is a ton of room for improvement, over a 20% drop in fuel burn would dramatically change the MD-80's mission profile. 
From Hong Kong, joined Feb 2004, 15870 posts, 
From Denmark, joined Mar 2000, 6016 posts, 
If you have 350+ planes in your fleet, the cost of certification can be pretty nicely amortized.
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