Sponsor Message:
Aviation Technical / Operations Forum
My Starred Topics | Profile | New Topic | Forum Index | Help | Search 
DC10 / MD11 Using Only Two Engines?  
User currently offlineB6A322 From United States of America, joined Jan 2010, 291 posts, RR: 0
Posted (3 years 11 months 2 weeks 3 days 14 hours ago) and read 8853 times:

Hi all,

I've noticed over the past few years that most of the DC10s or MD11s I see appear to only have two engines. Although the housing for the third engine remains, It does appears to be vacant. Is this due to re-engining? Or is it just an optical illusion? Is this something, say, DHL could do to their 727s if they wanted to?

Thanks.


The content I post is solely my own opinion. It is not an official statement by/of/for nor representative of any company
32 replies: All unread, showing first 25:
 
User currently offlineEMBQA From United States of America, joined Oct 2003, 9364 posts, RR: 11
Reply 1, posted (3 years 11 months 2 weeks 3 days 14 hours ago) and read 8847 times:

Ah.. no ALL DC-10's and MD-11's are still flying with 3 engines.


"It's not the size of the dog in the fight, but the size of the fight in the dog"
User currently offlineStarlionblue From Greenland, joined Feb 2004, 17000 posts, RR: 67
Reply 2, posted (3 years 11 months 2 weeks 3 days 14 hours ago) and read 8836 times:

Optical illusion. They all have three engines.

Do you have any pics that illustrate this phenomenon?



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlineFX772LRF From United States of America, joined Apr 2009, 675 posts, RR: 12
Reply 3, posted (3 years 11 months 2 weeks 3 days 13 hours ago) and read 8786 times:


View Large View Medium
Click here for bigger photo!

Photo © Vishal Jolapara - Indian Aviation Photographers



Here's a good example of what B6A322 is talking about.

It's just an optical illusion due to the fact that the engine is really far recessed in the nacelle. If you can compare the size of engines #1 and #3 to the length of the nacelle of #2, you can figure about how much "empty" space there is at the front of the nacelle. In the photo above, you can see the shape change of the nacelle where the engine starts which makes a slight bulge.

-Noah   

Not sure if I'm using the term "nacelle" correctly - I'm referring to the outside engine "cover" that protects the internal parts.



Cleared to IAH via CLL 076 radial/BAZBL/RIICE3, up to 3k, 7k in 10, departure on 134.3, squawk 4676, Colgan 9581.
User currently offline474218 From United States of America, joined Oct 2005, 6340 posts, RR: 9
Reply 4, posted (3 years 11 months 2 weeks 3 days 12 hours ago) and read 8699 times:

The picture below illustrates where the engine is (was) located on a DC-10.


View Large View Medium
Click here for bigger photo!

Photo © Felix Bahamonde - PR Planespotters



User currently offlinetravelavnut From Netherlands, joined May 2010, 1586 posts, RR: 7
Reply 5, posted (3 years 11 months 2 weeks 3 days 12 hours ago) and read 8695 times:

Which leads me to the following question;

If you remove engine No. 2 you would save quite a lot of weight. Although it´s impossible that something like that would offer better economics then 3 engines. I still wonder what kind of economics removing eninge 2 would give. Any experts wanna give this a go? 



Live From Amsterdam!
User currently offlinebonusonus From United States of America, joined Nov 2009, 403 posts, RR: 0
Reply 6, posted (3 years 11 months 2 weeks 3 days 11 hours ago) and read 8666 times:

I don't think weight is as much as an issue as drag here. I doubt there would be significant improvements in economics having a hole in the tail instead of a feathering engine, for example. Either way, as you can see in the picture, actually removing that engine likely changes the aerodynamics of the tail quite a bit, and would make the airplane inoperable.

User currently offlinelonghauler From Canada, joined Mar 2004, 4913 posts, RR: 43
Reply 7, posted (3 years 11 months 2 weeks 3 days 10 hours ago) and read 8608 times:

Recall though, that McDonnell Douglas did offer a 2 engine version of the DC-10, named the "DC-10 Twin".

Smaller than the DC-10, it was about the size/weight of a domestic B767-200. No airlines however were interested.



Never gonna grow up, never gonna slow down .... Barefoot Blue Jean Night
User currently offline474218 From United States of America, joined Oct 2005, 6340 posts, RR: 9
Reply 8, posted (3 years 11 months 2 weeks 3 days 9 hours ago) and read 8542 times:

Quoting longhauler (Reply 7):
Recall though, that McDonnell Douglas did offer a 2 engine version of the DC-10, named the "DC-10 Twin".


It was a "paper airplane" just like the L-1011-600 Twin-Star. Neither were ever offered to the airlines just sketches on paper.


User currently offlineKELPkid From United States of America, joined Nov 2005, 6346 posts, RR: 3
Reply 9, posted (3 years 11 months 2 weeks 3 days 8 hours ago) and read 8466 times:

Quoting travelavnut (Reply 5):
If you remove engine No. 2 you would save quite a lot of weight. Although it´s impossible that something like that would offer better economics then 3 engines. I still wonder what kind of economics removing eninge 2 would give. Any experts wanna give this a go?

Probably not economically feasible. The aircraft has many redundant systems that assume there will be three engines in place at all times, and redesigning the systems for a twin engined role would probably cost about half of what engineering a new aircraft would. Not to mention that the DC-10/MD-11 are designed to be tail heavy (due to not only the engine, but the massive stucture that is needed to support an engine pylon in the tail). Re-engineering the airframe to put the CG/Center of pressure in the proper place, and leaving a substantial payload envelope, without moving the position of the wing on the airframe would be quite the engineering miracle  



Celebrating the birth of KELPkidJR on August 5, 2009 :-)
User currently offlineStarlionblue From Greenland, joined Feb 2004, 17000 posts, RR: 67
Reply 10, posted (3 years 11 months 2 weeks 3 days 5 hours ago) and read 8353 times:

Here's an MD-11 with an afterburner fitted to #2.


View Large View Medium
Click here for bigger photo!

Photo © M.Oertle




"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlinelonghauler From Canada, joined Mar 2004, 4913 posts, RR: 43
Reply 11, posted (3 years 11 months 2 weeks 3 days 4 hours ago) and read 8306 times:

Quoting 474218 (Reply 8):
It was a "paper airplane" just like the L-1011-600 Twin-Star. Neither were ever offered to the airlines just sketches on paper.



I was under the impression that everything starts as a "paper airplane" and when airline interest is garnered, further development is taken.

The McDD internal designation of D-969C was given to the project, although it was always known as the DC-10 Twin. McDD worked on project from before the first DC-10 flight, and continued to refine it until the project was canceled in 1976. It was offered to all airlines, the most interest came from Allegheny, Delta, Swissair, Iberia and Eastern.

However, no airlines were willing to commit, citing the fear the aircraft would still be too large. The DC-X-200 resulted, smaller than the D-969C ... again no interest was shown from airlines and that project was canceled in 1978. That was considered the end of the "DC-10 Twin".



Never gonna grow up, never gonna slow down .... Barefoot Blue Jean Night
User currently offlinespacecadet From United States of America, joined Sep 2001, 3609 posts, RR: 12
Reply 12, posted (3 years 11 months 2 weeks 3 days 1 hour ago) and read 8223 times:

Does having that long cowling with all that empty space in front of the engine change anything about the characteristics of the #2 engine vs. the other two? I would think the air rushing in there would get "concentrated" or compressed a bit more than the other two engines before it reaches the engine itself.


I'm tired of being a wanna-be league bowler. I wanna be a league bowler!
User currently offlineKELPkid From United States of America, joined Nov 2005, 6346 posts, RR: 3
Reply 13, posted (3 years 11 months 2 weeks 3 days 1 hour ago) and read 8213 times:

Quoting spacecadet (Reply 12):
Does having that long cowling with all that empty space in front of the engine change anything about the characteristics of the #2 engine vs. the other two? I would think the air rushing in there would get "concentrated" or compressed a bit more than the other two engines before it reaches the engine itself.

Center engines on jetliners are notorious for having various assorted air flow problems, mostly in the takeoff or landing regimes. Even with all the aerodynamic tweaks and tricks, overzealous use of the elevator can disturb the smooth airflow into the intake. Look at Starlionblue's picture in post #10 above. If that wasn't a bird strike, the other distinct probable cause of the flame coming out of the back of #2 is most likely a compressor stall   I have been on a 727 when the pilot flying caused a compressor stall in #2 on takeoff...scares the bejezzus out of everyone on board.



Celebrating the birth of KELPkidJR on August 5, 2009 :-)
User currently offlineStarlionblue From Greenland, joined Feb 2004, 17000 posts, RR: 67
Reply 14, posted (3 years 11 months 2 weeks 2 days 21 hours ago) and read 8146 times:

727 was/is notorious for compressor stalls on rotation. It happened on the maiden flight. The subsequent optimization of the s-duct cost Boeing quite a bit of money.

As for the VASP pic, I think that may have been an oil leak, but not sure.



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlinedaviation From United States of America, joined Sep 2008, 593 posts, RR: 2
Reply 15, posted (3 years 11 months 2 weeks 2 days 12 hours ago) and read 7901 times:

Yes, I was a passenger in an Eastern 727-200 when we had a compressor stall on takeoff from LGA. It was quite a bang. But we continued the climbout, and the cockpit crew made up for it with the smoothest landing (in RIC) that I have ever experienced.


PlaneFlown:717,727,737,747,757,767,777,DC8,DC9,DC10,L1011,F100,A300,319,320,321,330,340,CRJ,ERJ,E190,Av85,DH8,Beaver,ATR
User currently offlineCitationJet From United States of America, joined Mar 2003, 2425 posts, RR: 3
Reply 16, posted (3 years 11 months 2 weeks 2 days 11 hours ago) and read 7858 times:

I am surprised that no one has mentioned the two engine 727 or the three engine 747.


View Large View Medium
Click here for bigger photo!

Photo © Brian Harrison
View Large View Medium
Click here for bigger photo!

Photo © Norman Gage




Boeing Flown: 701,702,703;717;720;721,722;731,732,733,734,735,737,738,739;741,742,743,744,747SP;752,753;762,763;772,773.
User currently offlinetb727 From United States of America, joined Jun 2005, 1576 posts, RR: 9
Reply 17, posted (3 years 11 months 2 weeks 2 days 8 hours ago) and read 7790 times:

Quoting CitationJet (Reply 16):
I am surprised that no one has mentioned the two engine 727

Check Essential!!! (Just seeing who the real 727 guys are )



Too lazy to work, too scared to steal!
User currently offlineStarlionblue From Greenland, joined Feb 2004, 17000 posts, RR: 67
Reply 18, posted (3 years 11 months 2 weeks 1 day 18 hours ago) and read 7599 times:

Quoting daviation (Reply 15):
the cockpit crew made up for it with the smoothest landing (in RIC) that I have ever experienced.

Going to nitpick here and say that very smooth is not a requirement for a good landing. It is just a bonus, and really only for the pax.



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlineFlyHossD From United States of America, joined Nov 2009, 849 posts, RR: 2
Reply 19, posted (3 years 11 months 2 weeks 1 day 1 hour ago) and read 7355 times:

Yes. I'll never forget that one, though I usually said it as "Check Essential, cover the bus."

The 727 was (is) a fine, fine machine.



My statements do not represent my former employer or my current employer and are my opinions only.
User currently offlineKELPkid From United States of America, joined Nov 2005, 6346 posts, RR: 3
Reply 20, posted (3 years 11 months 2 weeks 23 hours ago) and read 7319 times:

Quoting Starlionblue (Reply 18):
Going to nitpick here and say that very smooth is not a requirement for a good landing. It is just a bonus, and really only for the pax.

In the 727, it is a double bonus, as a smooth arrival in a 727 is something of a miracle (one more thing the 727 was notorious at-making an aircraft carrier arrival rather than a smooth landing)  



Celebrating the birth of KELPkidJR on August 5, 2009 :-)
User currently offlinetb727 From United States of America, joined Jun 2005, 1576 posts, RR: 9
Reply 21, posted (3 years 11 months 2 weeks 14 hours ago) and read 7209 times:

Quoting FlyHossD (Reply 19):
Yes. I'll never forget that one, though I usually said it as "Check Essential, cover the bus."

The 727 was (is) a fine, fine machine.

Sure is! Thankfully the only times so far that I have called Check Essential, outside of the sim of course, is when the FE forgets to switch Essential to APU when we shut down! Of course when the APU shut itself down and we were sitting in there in the pitch black it got a good chuckle from the crew. Never heard anyone say the "cover the bus" part but it makes sense.



Too lazy to work, too scared to steal!
User currently offlinebri2k1 From United States of America, joined Dec 2004, 988 posts, RR: 4
Reply 22, posted (3 years 11 months 2 weeks 12 hours ago) and read 7179 times:

Quoting Starlionblue (Reply 18):
only for the pax

Operationally speaking and for safety, smoothness is a secondary factor, I agree. But to the pilot's ego (which fuels the pilot, who flies the plane) it's rather important.



Position and hold
User currently offlinekimberlyrj From United Kingdom, joined Mar 2008, 385 posts, RR: 1
Reply 23, posted (3 years 11 months 2 weeks 7 hours ago) and read 7087 times:

Hey hey

While the MD11 is taxing on the ground am I correct in saying that the number 2 engines is started at the same time as 1 and 3?

Is the number 2 engine used as the others on the ground? I mean the same amount of thrust? Or is it used less or more? I was just thinking that the height of the number 2 engine could cause problems at certain airports to terminals and buildings?

Also, after landing is the number 2 engine kept running or is it shut down before the other engines? Thinking logically I guess the number 2 engine would be kept running when the MD11 aircraft arrives at the stand? I mean there is less risk of ingestion due to its position?

Thanks

Kimberly


User currently offlineCosmicCruiser From United States of America, joined Feb 2005, 2255 posts, RR: 15
Reply 24, posted (3 years 11 months 2 weeks 3 hours ago) and read 7014 times:

Actually, you're thinking right but don't have the facts.

Quoting kimberlyrj (Reply 23):
Is the number 2 engine used as the others on the ground? I mean the same amount of thrust? Or is it used less or more? I was just thinking that the height of the number 2 engine could cause problems at certain airports to terminals and buildings?

Not really to buildings because the engine points downward therefore creating a hazard for ground things far behind the jet. In tight ramps we use 1 & 3 first then bring up #2. We limit all engs to 40% N1 in tight ramps.

Quoting kimberlyrj (Reply 23):
Also, after landing is the number 2 engine kept running or is it shut down before the other engines? Thinking logically I guess the number 2 engine would be kept running when the MD11 aircraft arrives at the stand? I mean there is less risk of ingestion due to its position?

We usually shutdown #2 on the taxi in because 1 & 3 have the hydraulics on them for brakes.


25 Post contains images KELPkid : Any sort of cool down period that has to be observed before shutting it down? Seems like the MD-11 carries a bit of thrust on a typical stabilized ap
26 Post contains images Fly2HMO : Ahh so that was the long forgotten MD-11 Sport version that MD offered for hot and high airports wasn't it (This would have been the perfect troll th
27 KELPkid : Close to this topic: Didn't McDD create a special DC-10 version for either AeroMexico or Mexicana that had Pratt & Whitney JT9D's so that they co
28 Post contains links and images MrFord : The DC-10-15, with CF6-50C2Fs tho, derated Series 30 engines. View Large View MediumPhoto © Fergal Goodman Series 40 were equipped with JT9D, main c
29 CosmicCruiser : It's not the thrust used for the approach which isn't really that high but the temp achieved during reverse thrust. The GE has a different cooldown t
30 Viscount724 : Seven DC-10-15s were built -- 5 for MX and 2 for AM.
31 Post contains images Fly2HMO : Indeed. I've heard more than a few older captains call them the "sport", that's what I based my lame joke on
32 Post contains links and images DocLightning : In fact, your idea was considered by McDD and Lockheed (for the Tristar...er "Bistar"). But it was Boeing who actually pulled it off. See, the proble
Top Of Page
Forum Index

Reply To This Topic DC10 / MD11 Using Only Two Engines?
Username:
No username? Sign up now!
Password: 


Forgot Password? Be reminded.
Remember me on this computer (uses cookies)
  • Tech/Ops related posts only!
  • Not Tech/Ops related? Use the other forums
  • No adverts of any kind. This includes web pages.
  • No hostile language or criticizing of others.
  • Do not post copyright protected material.
  • Use relevant and describing topics.
  • Check if your post already been discussed.
  • Check your spelling!
  • DETAILED RULES
Add Images Add SmiliesPosting Help

Please check your spelling (press "Check Spelling" above)


Similar topics:More similar topics...
Could A C-17 Be Stretched Using The Same Engines? posted Mon Apr 26 2010 19:40:24 by 747400sp
Is It Possible To "land Using Only The Knobs"? posted Fri Feb 5 2010 21:18:05 by MrSkyGuy
Why The Airbus A380 Has Only Two Thrust Reverser? posted Sun Jul 2 2006 14:26:20 by 747400sp
Can A Quad Fly On Two Engines? posted Sat Sep 10 2005 18:35:55 by TaromA380
Is The A380 Having Only Two Mains? posted Mon May 31 2004 05:08:24 by Bio15
Cargo Containers On 767, DC10, MD11, Etc... posted Fri Aug 15 2003 09:53:23 by QANTAS747-438
DC10/MD11/Tristar Tail Fin Extension posted Thu Jul 10 2003 18:48:13 by Nfield
Airbus A380 Only Has Two Thrust Reversers? posted Sat Jun 26 2010 16:36:00 by Reggaebird
MD11-DC10 posted Sun Nov 12 2006 17:11:04 by Kearney
Can An Airliner Stop By Only Using Reverse Thrust? posted Thu Dec 15 2005 18:13:39 by Tarantine

Sponsor Message:
Printer friendly format