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Landing Gears On L1011 And DC10...  
User currently offlineAircanada014 From Canada, joined Oct 2005, 1513 posts, RR: 0
Posted (4 years 9 months 23 hours ago) and read 8593 times:

Hello all I've done a search but can't seem to find it. I was just wondering after browsing through pictures of Air Canada L1011s and CP DC10s, why did McDonnell Douglas decided to add 3rd undercarriage landing gear and Lockheed didn't with their L1011s? Whats the purpose of having a 3rd one on DC10 and not on L1011? You figure they are very identical in size and shapes although DC10 slightly bigger and maybe heavier, they both have 3rd engine mount at the rear.


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30 replies: All unread, showing first 25:
 
User currently offlineArmitageShanks From UK - England, joined Dec 2003, 3609 posts, RR: 15
Reply 1, posted (4 years 9 months 23 hours ago) and read 8583 times:

From what I've heard its all about weight. I think they could have MEL'd the center gear on some missions.

Correct my if I'm wrong.


User currently offlineTdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 2, posted (4 years 9 months 23 hours ago) and read 8574 times:



Quoting Aircanada014 (Thread starter):
why did McDonnell Douglas decided to add 3rd undercarriage landing gear and Lockheed didn't with their L1011s?

The DC-10 packs an extra ~60,000 lbs at MTOW. I assume they needed the third gear to keep the pavement loading at an acceptable level.

Tom.


User currently offlineMSPNWA From United States of America, joined Apr 2009, 1908 posts, RR: 2
Reply 3, posted (4 years 9 months 22 hours ago) and read 8565 times:

The third main leg was added on DC-10-30/40 and subsequent MD-11 aircraft. The longer-ranged DC-10-30/40 was heavier than the DC-10-10/15, so it need that extra weight distribution.

All models of the L-1011 fall short of the DC-10-30/40's MTOW, so it must not have needed the third gear leg.


User currently offlineCanadianNorth From Canada, joined Aug 2002, 3389 posts, RR: 9
Reply 4, posted (4 years 9 months 22 hours ago) and read 8558 times:

Basically at the start both the L1011 and DC-10 were designed to be more as large medium range jets. The weights necessary to carry out these missions only required the standard 8 main wheels. However, as time went on airlines wanted to use their smaller wide-bodies (compared to the 747) on long-haul routes as well. The added range was accomplished in two ways.

Douglas decided to basically leave the aircraft in its original form, but up the weights and increase fuel capacity, which thus required their new -30s and -40s to have an extra pair of wheels installed to support said weight. Lockheed on the other hand, decided instead of adding fuel they'd shrink the airplane into the L1011 series 500. Because any added fuel/structure/etc was compensated for via having a smaller fuselage instead of significantly higher weights, the original 8 main wheels remained sufficient.

Quoting ArmitageShanks (Reply 1):
I think they could have MEL'd the center gear on some missions.

Can't say for sure, but I also remember reading somewhere that if you limited the max weights to below certain numbers, you could send a DC-10 on its way without use of the centre main wheels.


CanadianNorth



What could possibly go wrong?
User currently offlineCosmicCruiser From United States of America, joined Feb 2005, 2255 posts, RR: 15
Reply 5, posted (4 years 9 months 19 hours ago) and read 8519 times:

Yes the center gear can be deferred. You do take a huge weight penalty. I flew one MD-11 flight with the center gr. up.

User currently offlineTristarSteve From Sweden, joined Nov 2005, 3979 posts, RR: 34
Reply 6, posted (4 years 9 months 18 hours ago) and read 8500 times:



Quoting CanadianNorth (Reply 4):
Can't say for sure, but I also remember reading somewhere that if you limited the max weights to below certain numbers, you could send a DC-10 on its way without use of the centre main wheels.

Yes, friend of mine was in Sanaa (Yemen) with a BA DC10 with a wheel change required.
He had to take a wheel from the centre gear to use on a wing gear, then retracted the centre gear with the u/s wheel fitted to get home to LGW.


User currently offline747classic From Netherlands, joined Aug 2009, 2084 posts, RR: 14
Reply 7, posted (4 years 9 months 16 hours ago) and read 8464 times:

The DC10-10 (Domestic) was designed from the start to add a center gear for further range (TOW) increase. In the later DC10-30/40 International this range increase was effectuated. The DC10-15 was a hybrid hot/high variant (Mexicana, Air Mexico) with the CF6-50 engines of the -30 and the fuselage of the -10, with no center gear.

However the L-1011 was designed as a pure domestic wide body aircraft. Only after a very costly redesign it would have been possible to add a center gear. This inability to increase the TOW to become a real long range wide body aircraft, plus the limited engine choice (only RR, no American engine was certified) led to loosing the competition with the DC10, despite the fact that it was IMO technical more advanced than the DC10.

The range increase was at last produced via a fuselage shrink and a somewhat larger wingspan, in the L-1011-500 series. After only 50 dash 500 aircraft were produced the production was halted, after heavy financial losses and finally resulting in the total stop of civil airliner production by Lockheed.



Operating a twin over the ocean, you're always one engine failure from a total emergency.
User currently offlineWestern727 From United States of America, joined Jan 2007, 743 posts, RR: 4
Reply 8, posted (4 years 9 months 15 hours ago) and read 8434 times:



Quoting CosmicCruiser (Reply 5):
Yes the center gear can be deferred. You do take a huge weight penalty. I flew one MD-11 flight with the center gr. up.

Figures. Out of curiosity can you recall what the penalty is, assuming one starts out at MTOW?

And while some of us are aware of AA's action years ago to remove the center gear from some of its DC-10-30s, this was a "permanent" thing so I'm curious to know why the center main bogey was up on that MD-11 flight you flew...was it MELed or otherwise? Thanks in advance.



Jack @ AUS
User currently offlineWestern727 From United States of America, joined Jan 2007, 743 posts, RR: 4
Reply 9, posted (4 years 9 months 15 hours ago) and read 8430 times:



Quoting TristarSteve (Reply 6):
then retracted the centre gear with the u/s wheel fitted to get home to LGW.

Fascinating. I presume it's relatively easy to do this while on the ground? After all, the center main bogey's "main stem/shaft" (forgive me for I cannot recall the proper label) is angled somewhat forward, like the forward bogey, IIRC.

Further, if the DC-10/MD-11 is, in theory, at MTOW (with the no-center-bogey weight penalty applied) is any special action required to safely retract the center bogey while on the ground?



Jack @ AUS
User currently offlineCosmicCruiser From United States of America, joined Feb 2005, 2255 posts, RR: 15
Reply 10, posted (4 years 9 months 13 hours ago) and read 8390 times:



Quoting Western727 (Reply 8):
Out of curiosity can you recall what the penalty is, assuming one starts out at MTOW?

With ctr gr up MTOGW is 445,000lbs vs. 630,500lbs

Quoting Western727 (Reply 8):
why the center main bogey was up on that MD-11 flight you flew...was it MELed or otherwise? Thanks in advance.

there was a hydraulic leak that couldn't be repaired at that station


User currently offline747classic From Netherlands, joined Aug 2009, 2084 posts, RR: 14
Reply 11, posted (4 years 9 months 12 hours ago) and read 8374 times:

Quoting Western727 (Reply 8):
Figures. Out of curiosity can you recall what the penalty is, assuming one starts out at MTOW?

All relevant info about TOW,ZFW and LW penalties, with center gear retracted, for all variants of the DC10 and MD 11 aircraft are found in the following PDF file :

http://www.airweb.faa.gov/REGULATORY...AB80A862575D1006F7449?OpenDocument

[Edited 2009-10-31 09:27:33]

[Edited 2009-10-31 09:32:32]


Operating a twin over the ocean, you're always one engine failure from a total emergency.
User currently offline474218 From United States of America, joined Oct 2005, 6340 posts, RR: 9
Reply 12, posted (4 years 9 months 12 hours ago) and read 8355 times:



Quoting CosmicCruiser (Reply 10):
With ctr gr up MTOGW is 445,000lbs vs. 630,500lbs

L-1011-250 and 500's have a MTOW of 515,000 lbs and the RAF L-1011-500's are certified to 540,000 lbs. with the same basic landing gear installed on the domestic L-1011-1's.

Quoting 747classic (Reply 7):
However the L-1011 was designed as a pure domestic wide body aircraft. Only after a very costly redesign it would have been possible to add a center gear.

Lockheed never considered a "center gear" their high gross weight designs used a six (6) wheel truck.


User currently offlineWestern727 From United States of America, joined Jan 2007, 743 posts, RR: 4
Reply 13, posted (4 years 9 months 11 hours ago) and read 8329 times:



Quoting CosmicCruiser (Reply 10):
With ctr gr up MTOGW is 445,000lbs vs. 630,500lbs



Quoting 747classic (Reply 11):
PDF file :

Thank you both. That's a larger penalty that I had surmised and interestingly the other center-gear variants (DC-10-30/40) have significantly lesser penalties.



Jack @ AUS
User currently offline747classic From Netherlands, joined Aug 2009, 2084 posts, RR: 14
Reply 14, posted (4 years 9 months 11 hours ago) and read 8325 times:

Quoting 474218 (Reply 12):
Lockheed never considered a "center gear" their high gross weight designs used a six (6) wheel truck

That's correct.
I stated only that adding a center gear would have needed a very costly redesign.
Lockheed proposed the L-1011-8 in which six-wheel main undercarriage bogies (trucks) were to replace the four wheel units of the original Tristar, and the wing was to be redesigned to house the larger undercarriage and improve performance at higher weights.
The price of the L-1011-8, however, exceeded that of the more straightforward long range versions of the DC10 (the series 30 and 40) and Lockheed could not find a launching customer for this version.

The whole technical and commercial story of the L-1011 is perfectly described in the book :

Lockheed Aircraft since 1913, by René J. Francillon ISBN 0-87021-897-2
Naval Institute Press, Annapolis, Maryland 21402.

[Edited 2009-10-31 11:18:48]


Operating a twin over the ocean, you're always one engine failure from a total emergency.
User currently offline474218 From United States of America, joined Oct 2005, 6340 posts, RR: 9
Reply 15, posted (4 years 9 months 10 hours ago) and read 8303 times:



Quoting 747classic (Reply 14):
Lockheed proposed the L-1011-8 in which six-wheel main undercarriage bogies were to replace the four wheel units of the original Tristar, and the wing was to be redesigned to house the larger undercarriage and improve performance at higher weights.

There was no need to re-design the wing for the 8 wheel truck as only the landing gear strut retracts into the L-1011 wing. The truck retracts into the fuselage.


User currently offlineSpacepope From Vatican City, joined Dec 1999, 2898 posts, RR: 1
Reply 16, posted (4 years 9 months 4 hours ago) and read 8193 times:


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Photo © Mark Abbott



DC-10-40 without extended center gear. Photo says no passengers aboard at the time.



The last of the famous international playboys
User currently offlineEx52tech From United States of America, joined Dec 2006, 559 posts, RR: 1
Reply 17, posted (4 years 9 months 2 hours ago) and read 8143 times:



Quoting 474218 (Reply 12):
RAF L-1011-500's are certified to 540,000 lbs. with the same basic landing gear installed on the domestic L-1011-1's.

Which is a higher MTOW than the DC10-40's had at 535,000 lbs. Thing to remember is that 10 brakes are better than 8. Not sure what JAL -40's MTOW was though.


Quoting Western727 (Reply 9):
is any special action required to safely retract the center bogey while on the ground?

It had it's own guarded retract switch, so it was a simple operation. One would want to ensure that the parking brake was not set when attempting this operation.  Big grin The center gear was the reason that the parking brake had to be off while refueling the -30/-40.



"Saddest thing I ever witnessed....an airplane being scrapped"
User currently offlineViscount724 From Switzerland, joined Oct 2006, 24837 posts, RR: 22
Reply 18, posted (4 years 9 months 1 hour ago) and read 8133 times:



Quoting Spacepope (Reply 16):
DC-10-40 without extended center gear. Photo says no passengers aboard at the time.

It was my understanding that when JL used their DC-10-40s on shorthaul domestic and regional routes they sometimes kept the center gear retracted. Note following photos (coincidentally, all of the same aircraft).


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Photo © Satoshi Yamagishi
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Photo © Takashi



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Photo © Eric Phan
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Photo © Takuji Sohmura



User currently offline747classic From Netherlands, joined Aug 2009, 2084 posts, RR: 14
Reply 19, posted (4 years 8 months 4 weeks 1 day 13 hours ago) and read 8035 times:



Quoting Ex52tech (Reply 17):
It had it's own guarded retract switch, so it was a simple operation. One would want to ensure that the parking brake was not set when attempting this operation.

On following pics are the guarded CTR GEAR switch of the DC10-30 (with chain) and the push button of the MD11 clearly visible at the RH side of the gear lever. Both are marked CTR GEAR NORMAL/UP. Above the gear lever are the four (4) gear down lights (green).

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Photo © Bruno David



Or better visible on this pic of the Finnair MD11 simulator :

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Photo © Kalle Kostia




Operating a twin over the ocean, you're always one engine failure from a total emergency.
User currently offlineWestern727 From United States of America, joined Jan 2007, 743 posts, RR: 4
Reply 20, posted (4 years 8 months 4 weeks 1 day 8 hours ago) and read 7967 times:



Quoting Spacepope (Reply 16):
DC-10-40 without extended center gear.



Quoting Viscount724 (Reply 18):
Note following photos

Lovely! These "impossible DC-10-10s" look awesome. Thanks.

Quoting Ex52tech (Reply 17):
It had it's own guarded retract switch, so it was a simple operation.

Thanks. I'd love to see a video of this happening. Any of you know of such a video?



Jack @ AUS
User currently offlineKimberlyrj From United Kingdom, joined Mar 2008, 385 posts, RR: 1
Reply 21, posted (4 years 8 months 4 weeks 1 day 6 hours ago) and read 7928 times:



Quoting Viscount724 (Reply 18):
It was my understanding that when JL used their DC-10-40s on shorthaul domestic and regional routes they sometimes kept the center gear retracted. Note following photos (coincidentally, all of the same aircraft).

I can’t recall where I saw it (which magazine or book) but I remember reading that JL removed the centre gear to reduce weight as the aircraft as the aircraft in question would never reach the weight limit which would require the use of the centre gear – as the aircraft was used on short haul ops and carried no were near as much fuel as it was designed for (being the long range 40 series).

Did anyone ever hear/read about this?

KimberlyRJ


User currently offlineWestern727 From United States of America, joined Jan 2007, 743 posts, RR: 4
Reply 22, posted (4 years 8 months 4 weeks 1 day 1 hour ago) and read 7879 times:



Quoting Kimberlyrj (Reply 21):
JL removed the centre gear

I don't know about JL; that's news to me. AA as I understand it did this with some of its -30s.



Jack @ AUS
User currently offline747classic From Netherlands, joined Aug 2009, 2084 posts, RR: 14
Reply 23, posted (4 years 8 months 4 weeks 18 hours ago) and read 7840 times:

Here is another way to remove the (MD11) CTR landing gear.

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Photo © Allan K. B. Ramos



[Edited 2009-11-02 02:10:53]


Operating a twin over the ocean, you're always one engine failure from a total emergency.
User currently offlineKimberlyrj From United Kingdom, joined Mar 2008, 385 posts, RR: 1
Reply 24, posted (4 years 8 months 4 weeks 16 hours ago) and read 7794 times:



Quoting Western727 (Reply 22):
I don't know about JL; that's news to me. AA as I understand it did this with some of its -30s.

Hi

Been looking at the photo database and seen that JL used two sub versions of the DC10-40, I for international and D for domestic.

The I versions had the centre rear landing gear and the D versions had this removed – this is shown when you search the Airlines.net database for JL DC10-40 photos...

Domestic versions:
http://www.airliners.net/photo/Japan...nnell-Douglas-DC-10-40D/0134527/L/

International versions:
http://www.airliners.net/photo/Japan...nnell-Douglas-DC-10-40I/0447096/L/

KimberlyRJ


25 Western727 : OUCH! The photo comments do not say anything about what happened. Does anyone know? Intriguing; thanks for sharing. IIRC, AA had the center gear remo
26 Post contains links 747classic : See following thread : Varig MD11 Incident At BSB (by JJMNGR Jun 17 2006 in Civil Aviation)
27 JarheadK5 : The KC-10 can operate with the center gear retracted as well. It's pretty much only done when sending the aircraft to C-check; no one I've spoken to
28 N901WA : Hi, For Western727. When Retracting the Center Gear on the Ground. First you had to deflate the Center Strut, otherwise after the hyd broke the overce
29 Western727 : Thanks, Darren. I had a hard time believing one could just retract the center gear "in a snap" while on the ground, let alone at center-gear-retracte
30 N901WA : Hi Western727, sorry for the late reply. I work the Night shift and just got home. The first time it took about 2 hours and 2 guys, but after that 2 g
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