aircanada014
Posts: 1224
Joined: Sun Oct 09, 2005 2:24 pm

Landing Gears On L1011 And DC10...

Sat Oct 31, 2009 5:12 am

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.


View Large View Medium
Click here for bigger photo!

Photo © Andy Pope



View Large View Medium
Click here for bigger photo!

Photo © Udo K. Haafke

 
ArmitageShanks
Posts: 3754
Joined: Tue Dec 30, 2003 5:30 am

RE: Landing Gears On L1011 And DC10...

Sat Oct 31, 2009 5:21 am

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.
 
tdscanuck
Posts: 8572
Joined: Wed Jan 11, 2006 7:25 am

RE: Landing Gears On L1011 And DC10...

Sat Oct 31, 2009 5:24 am



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.
 
MSPNWA
Posts: 1790
Joined: Thu Apr 23, 2009 2:48 am

RE: Landing Gears On L1011 And DC10...

Sat Oct 31, 2009 6:05 am

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.
 
CanadianNorth
Posts: 3133
Joined: Sat Aug 24, 2002 11:41 am

RE: Landing Gears On L1011 And DC10...

Sat Oct 31, 2009 6:40 am

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?
 
CosmicCruiser
Posts: 2049
Joined: Tue Feb 22, 2005 3:01 am

RE: Landing Gears On L1011 And DC10...

Sat Oct 31, 2009 9:48 am

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.
 
Tristarsteve
Posts: 3362
Joined: Tue Nov 22, 2005 11:04 pm

RE: Landing Gears On L1011 And DC10...

Sat Oct 31, 2009 10:43 am



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 avatar
747classic
Posts: 1970
Joined: Sat Aug 15, 2009 9:13 am

RE: Landing Gears On L1011 And DC10...

Sat Oct 31, 2009 12:23 pm

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.
 
Western727
Posts: 1426
Joined: Wed Jan 03, 2007 12:38 pm

RE: Landing Gears On L1011 And DC10...

Sat Oct 31, 2009 1:51 pm



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
 
Western727
Posts: 1426
Joined: Wed Jan 03, 2007 12:38 pm

RE: Landing Gears On L1011 And DC10...

Sat Oct 31, 2009 1:57 pm



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
 
CosmicCruiser
Posts: 2049
Joined: Tue Feb 22, 2005 3:01 am

RE: Landing Gears On L1011 And DC10...

Sat Oct 31, 2009 3:41 pm



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 avatar
747classic
Posts: 1970
Joined: Sat Aug 15, 2009 9:13 am

RE: Landing Gears On L1011 And DC10...

Sat Oct 31, 2009 4:25 pm

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.
 
474218
Posts: 4510
Joined: Mon Oct 10, 2005 12:27 pm

RE: Landing Gears On L1011 And DC10...

Sat Oct 31, 2009 4:45 pm



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.
 
Western727
Posts: 1426
Joined: Wed Jan 03, 2007 12:38 pm

RE: Landing Gears On L1011 And DC10...

Sat Oct 31, 2009 5:44 pm



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 avatar
747classic
Posts: 1970
Joined: Sat Aug 15, 2009 9:13 am

RE: Landing Gears On L1011 And DC10...

Sat Oct 31, 2009 6:01 pm

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.
 
474218
Posts: 4510
Joined: Mon Oct 10, 2005 12:27 pm

RE: Landing Gears On L1011 And DC10...

Sat Oct 31, 2009 6:26 pm



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.
 
Spacepope
Posts: 3151
Joined: Tue Dec 28, 1999 11:10 am

RE: Landing Gears On L1011 And DC10...

Sun Nov 01, 2009 12:06 am


View Large View Medium
Click here for bigger photo!

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
 
ex52tech
Posts: 553
Joined: Wed Dec 06, 2006 2:28 pm

RE: Landing Gears On L1011 And DC10...

Sun Nov 01, 2009 2:58 am



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"
 
Viscount724
Posts: 18971
Joined: Thu Oct 12, 2006 7:32 pm

RE: Landing Gears On L1011 And DC10...

Sun Nov 01, 2009 3:51 am



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).


View Large View Medium
Click here for bigger photo!

Photo © Satoshi Yamagishi
View Large View Medium
Click here for bigger photo!

Photo © Takashi



View Large View Medium
Click here for bigger photo!

Photo © Eric Phan
View Large View Medium
Click here for bigger photo!

Photo © Takuji Sohmura

 
User avatar
747classic
Posts: 1970
Joined: Sat Aug 15, 2009 9:13 am

RE: Landing Gears On L1011 And DC10...

Sun Nov 01, 2009 3:42 pm



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).

View Large View Medium
Click here for bigger photo!

Photo © Paul Barbee
View Large View Medium
Click here for bigger photo!

Photo © Bruno David



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

View Large View Medium
Click here for bigger photo!

Photo © Kalle Kostia

Operating a twin over the ocean, you're always one engine failure from a total emergency.
 
Western727
Posts: 1426
Joined: Wed Jan 03, 2007 12:38 pm

RE: Landing Gears On L1011 And DC10...

Sun Nov 01, 2009 8:22 pm



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
 
kimberlyRJ
Posts: 249
Joined: Thu Mar 06, 2008 7:35 am

RE: Landing Gears On L1011 And DC10...

Sun Nov 01, 2009 10:54 pm



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
 
Western727
Posts: 1426
Joined: Wed Jan 03, 2007 12:38 pm

RE: Landing Gears On L1011 And DC10...

Mon Nov 02, 2009 3:57 am



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 avatar
747classic
Posts: 1970
Joined: Sat Aug 15, 2009 9:13 am

RE: Landing Gears On L1011 And DC10...

Mon Nov 02, 2009 10:07 am

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

View Large View Medium
Click here for bigger photo!

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.
 
kimberlyRJ
Posts: 249
Joined: Thu Mar 06, 2008 7:35 am

RE: Landing Gears On L1011 And DC10...

Mon Nov 02, 2009 1:03 pm



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
 
Western727
Posts: 1426
Joined: Wed Jan 03, 2007 12:38 pm

RE: Landing Gears On L1011 And DC10...

Mon Nov 02, 2009 8:28 pm



Quoting 747classic (Reply 23):
Here is another way to remove the (MD11) CTR landing gear.

OUCH! The photo comments do not say anything about what happened. Does anyone know?

Quoting Kimberlyrj (Reply 24):
D versions had this removed

Intriguing; thanks for sharing. IIRC, AA had the center gear removed from some of its -30s in their final years because they still had some cycles left on them after many years of high-time cycles. From what I understand AA wanted to wring what cycles they could out of those airframes for its high-density, non-long-range routes.
Jack @ AUS
 
User avatar
747classic
Posts: 1970
Joined: Sat Aug 15, 2009 9:13 am

RE: Landing Gears On L1011 And DC10...

Mon Nov 02, 2009 9:57 pm



Quoting Western727 (Reply 25):
OUCH! The photo comments do not say anything about what happened. Does anyone know?

See following thread : Varig MD11 Incident At BSB (by JJMNGR Jun 17 2006 in Civil Aviation)
Operating a twin over the ocean, you're always one engine failure from a total emergency.
 
jarheadk5
Posts: 216
Joined: Thu Nov 03, 2005 2:45 pm

RE: Landing Gears On L1011 And DC10...

Tue Nov 03, 2009 10:12 pm



Quoting CosmicCruiser (Reply 5):
Yes the center gear can be deferred. You do take a huge weight penalty.

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 has ever done it for any other reason. We take a big weight penalty, and there's also a big takeoff-distance penalty, due to the loss of 20% of the aircraft's braking capacity.
Cleared to Contact
 
User avatar
n901wa
Posts: 409
Joined: Thu Oct 15, 2009 5:38 pm

RE: Landing Gears On L1011 And DC10...

Thu Nov 05, 2009 1:53 am

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 overcenter lock the pressure in the strut would force the strut foward and bend the retract actuator. You dont want to know how I know  Smile Then you had to walk the Gear fwd as it went up to get it to fit in the Center Wheel well. Then service the strut so it would stay in the extend postion in the well. It took some time and was same on the 10-30 and MD-11. HTH Darren
 
Western727
Posts: 1426
Joined: Wed Jan 03, 2007 12:38 pm

RE: Landing Gears On L1011 And DC10...

Thu Nov 05, 2009 4:22 pm



Quoting N901WA (Reply 28):
When Retracting the Center Gear on the Ground.

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-retracted MTOW.

I would've liked to think the center bogey's strut would be somewhat compressed even at "only" 400-some thousand pounds of weight which is the neighborhood of MTOW for all DC-10/MD-11 family models with no center gear in use.

Quoting N901WA (Reply 28):
It took some time

With the correct number of seasoned A&Ps working the task with all necessary tools on hand, how long would that be? Thanks in advnce.
Jack @ AUS
 
User avatar
n901wa
Posts: 409
Joined: Thu Oct 15, 2009 5:38 pm

RE: Landing Gears On L1011 And DC10...

Thu Nov 05, 2009 7:11 pm

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 guys 1 hour to stow and defer the Center strut. HTH Darren

Who is online

Users browsing this forum: AT and 11 guests