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Max Q
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Re-engine The KC10

Sun May 22, 2016 3:23 am

Assuming these aircraft have a decent amount of life left and if they don't so what, the USAF just keeps rebuilding
the KC135 why not look at re-engining this tanker ?


Three RR Trent powerplants are right in the same thrust class with considerably better efficiency, perhaps even a derated
GenX.



It would preserve and improve a uniquely useful platform that would be incredibly expensive to directly replace.
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ThePointblank
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RE: Re-engine The KC10

Sun May 22, 2016 4:42 am

There is no money for a major upgrade of the KC-10. There is a program to do limited avionics upgrades to make the KC-10 fully compliant with new ATC systems, but that's the limit.

With only 59 in active service in the USAF, and about the same number of commercial DC-10's in commercial service, you can't justify the costs to engineer and develop a re-engining program like with the KC-135 (which also leveraged work done by Boeing on the stillborn 707-700 project). I doubt that Fedex would ever perform a re-engining of their DC-10's, especially considering they are slowly retiring the type.
 
Max Q
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RE: Re-engine The KC10

Sun May 22, 2016 4:54 am

Quoting ThePointblank (Reply 1):
There is no money for a major upgrade of the KC-10.

At present.

Quoting ThePointblank (Reply 1):
With only 59 in active service in the USAF, and about the same number of commercial DC-10's in commercial service, you can't justify the costs to engineer and develop a re-engining program like with the KC-135 (which also leveraged work done by Boeing on the stillborn 707-700 project). I doubt that Fedex would ever perform a re-engining of their DC-10's, especially considering they are slowly retiring the type.

That's more than the number of re-engined C5's.


The cost of the engineering work would be far less than a new replacement.



Not discussing FedEx, an irrelevant comparison to a commercial airlifter that is obsolete in that world, far from the case for the KC10.
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ThePointblank
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RE: Re-engine The KC10

Sun May 22, 2016 6:00 am

Quoting Max Q (Reply 2):
At present.

And into the future. The USAF has many more recapitalization programs ongoing to replace large sections of the USAF's fleet.

Quoting Max Q (Reply 2):
That's more than the number of re-engined C5's.

Which was a easier program; the CF6 is actually a related engine design to the TF39. All of the engines also hang off pylons on the wings, which would entail new pylons for the C-5's, which is a easier engineering proposition compared to designing new pylons for the KC-10, AND redesigning the tail-mounted engine mounts. The tail mount is specifically designed for the engines that were available at the time, and the sections involved are load bearing in both supporting the engine, and the vertical fin and rudder. Lots of forces in that section. It is likely that major redesign would be required for the installation of any new engine design, which would probably entail a new tail design.

If you search this site regarding the DC-10's tail engine mount, it reveals that in order to fit a new engine, you are looking at major structural changes in the design of the tail and aft fuselage. The DC-10 and MD-11 could not fit engines with a larger fan size in that tail without a major redesign. A much bigger cost and risk proposition than designing a new pylon.
 
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seahawk
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RE: Re-engine The KC10

Sun May 22, 2016 9:52 am

Would be more expensive than buying 777.
 
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RE: Re-engine The KC10

Sun May 22, 2016 10:16 am

Quoting Max Q (Thread starter):
It would preserve and improve a uniquely useful platform that would be incredibly expensive to directly replace.

I am not so sure that a low qty old airframe with a very unique upgrade is more cost efficient in the long run than buying an existing modern tanker. Developing the update would probably cost about as much as directly replacing half of them with A330 tankers from the start.

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RE: Re-engine The KC10

Sun May 22, 2016 10:24 am

Quoting seahawk (Reply 4):
Would be more expensive than buying 777.

Then it must be darn expensive, because we've seen Boeing spend billions more on the KC-46 than they had planned for, even after doing a KC-767 for Japan and Italy already.
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zanl188
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RE: Re-engine The KC10

Sun May 22, 2016 11:17 am

I'll point out that increasing the mass flow, if required for a new engine, thru the #2 inlet would be a major challenge.
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seahawk
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RE: Re-engine The KC10

Sun May 22, 2016 11:24 am

Quoting Revelation (Reply 6):
Then it must be darn expensive, because we've seen Boeing spend billions more on the KC-46 than they had planned for, even after doing a KC-767 for Japan and Italy already.

Sure because a KC-777 would not need any major structural re-design, a new No.2 engine on a KC-10 would.
 
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747classic
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RE: Re-engine The KC10

Sun May 22, 2016 11:48 am

I would prefer KC-10 installation of the latest type of winglets, as installed at the 737max, to obtain increased performance and/or lower fuel consumption against a fraction of re-engine costs.

A lot of studies have already been performed about winglet installations in the 2005-2010 time frame.
See : http://www.google.nl/url?sa=t&rct=j&...AFQjCNGjTvIUnUxqClWRfbGOZ-oGme4pQA
However it's more sexy for the high ranking people in all airforces in the world to buy new planes than modify excisting aircraft against a fraction of the costs.

Note : Douglas designed aircraft have an excellent trackrecord regarding WFD (Widespread Fatigue Damage) and the KC10 can be operated for many years, without a major increase in " aging aircraft " related costs.
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zanl188
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RE: Re-engine The KC10

Sun May 22, 2016 12:26 pm

Quoting Max Q (Reply 2):

IMHO C-5B should have had the CF6 from day one in the mid 80s... Would have saved a bunch of money and added a lot of capability vs waiting until 30 years later...

Wait... you want to reengine the KC-10 away from the CF6? The very engine the C-5 is reengining to? I jest.... I jest...
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Stitch
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RE: Re-engine The KC10

Sun May 22, 2016 3:20 pm

Quoting ThePointblank (Reply 1):
With only 59 in active service in the USAF...you can't justify the costs to engineer and develop a re-engining program like with the KC-135.
Quoting Max Q (Reply 2):
That's more than the number of re-engined C5's.

True, but the C-5 has no current replacement. The KC-10 does (the KC-46A).


Quoting Max Q (Reply 2):
The cost of the engineering work would be far less than a new replacement.

If the USAF had to create an all-new replacement airframe, this would be correct. But the KC-10 mission can be handled by the KC-46A and I am positive that is how the USAF will handle KC-10 retirements (via another KC-46A buy).
 
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Francoflier
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RE: Re-engine The KC10

Sun May 22, 2016 4:32 pm

Why are we here on A.net so obsessed with re-engining, re-winging, Maxifying and NEO-ifying everything?

Can't they just buy KC-45s and call it a day?

  
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kc135topboom
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RE: Re-engine The KC10

Sun May 22, 2016 4:36 pm

As Stitch has said, the KC-46 will, most likely be the KC-10A replacement, but I am not sure it will be the KC-46A model, it may be a KC-46B (different engines, higher MTOW, etc.), or something else.

If the USAF decides it needs a (new build) mega-tanker to replace the KC-10, there is the B-777-200LRF, a B-787-8F (if ever built), and B-747-8F from Boeing. Airbus would need a much heavier tanker than the A-330MRTT, perhaps revisiting a freighter version of the A-340-500.

I would say right now the B-767 tanker and B-747-8 would be the leading contenders for a replacement for the KC-10. The USAF is already buying both of these Boeing airplanes.

The used airplane market is full of possibilities for conversion to tankers, A-340s, B-747-400s, B-767-200ER/-300ER, A-330, B-777s, MD-11s, etc.
 
Max Q
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RE: Re-engine The KC10

Sun May 22, 2016 5:12 pm

Good points, I had not considered the complexity of redesigning the #2 engine inlet and surrounding structure.



Winglets seem like a good idea for the KC10 but I wonder if they're compatible structurally with the existing drogue
pods that already add weight outboard on the wing, Boeing left them off the KC46 for a good reason i'm sure.



I'd like to see a bigger tanker to replace the KC10, I don't think the KC46 really does that, the tri-jet carries a very large fuel
load and has a massive amount of cargo space.


I think a triple 7 freighter would be ideal, it could carry an enormous fuel and cargo load.
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bennett123
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RE: Re-engine The KC10

Sun May 22, 2016 5:14 pm

Assuming you would need at least 60 of the same type, and without them being due for the desert, then types like the A340, and B747-400 are becoming non starters.
 
KC135Hydraulics
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RE: Re-engine The KC10

Mon May 23, 2016 3:07 pm

Quoting Max Q (Reply 14):
Winglets seem like a good idea for the KC10 but I wonder if they're compatible structurally with the existing drogue
pods that already add weight outboard on the wing, Boeing left them off the KC46 for a good reason i'm sure.

I was about to mention that very thing. As it stands now, adding MPRS pods to the KC-135 severely reduces their useful airframe life due to the added stress on the wing structure.

Quote:
I'd like to see a bigger tanker to replace the KC10, I don't think the KC46 really does that, the tri-jet carries a very large fuel
load and has a massive amount of cargo space.

The KC-46 in its current form is a direct KC-135 replacement. It does not/cannot perform the same missions as the KC-10 in its current configuration. There's a reason why KC-10s do coronets and drag fighter unit across oceans and the KC-135 does tactical refueling- capacity.
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seahawk
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RE: Re-engine The KC10

Mon May 23, 2016 4:00 pm

Quoting Max Q (Reply 14):
Winglets seem like a good idea for the KC10 but I wonder if they're compatible structurally with the existing drogue
pods that already add weight outboard on the wing, Boeing left them off the KC46 for a good reason i'm sure.

First winglets change the airflow behind the plane which might be problem for receivers using the wing mounted pods. Secondly those pods already add stress to a wing structure that was not designed for the additional weight of the winglets and this weight would combine with the weight of the refuelling pods.
 
lapa_saab340
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RE: Re-engine The KC10

Mon May 23, 2016 11:55 pm

Quoting Max Q (Reply 14):
Good points, I had not considered the complexity of redesigning the #2 engine inlet and surrounding structure.

They could always leave the center engine alone and replace only the wing engines, similar to the Super 27 program.
 
andydtwnwa7
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RE: Re-engine The KC10

Tue May 24, 2016 1:11 am

Quoting seahawk (Reply 17):
Quoting Max Q (Reply 14):
Winglets seem like a good idea for the KC10 but I wonder if they're compatible structurally with the existing drogue
pods that already add weight outboard on the wing, Boeing left them off the KC46 for a good reason i'm sure.

First winglets change the airflow behind the plane which might be problem for receivers using the wing mounted pods. Secondly those pods already add stress to a wing structure that was not designed for the additional weight of the winglets and this weight would combine with the weight of the refuelling pods.

The 330 MRTT has winglets with wing pods, so I'd be curious to hear if receivers have encountered any issues with them. Also, does anyone know how much reengineering Airbus had to do to the wing so that it could support the weight of both the pod and the winglet?
 
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RE: Re-engine The KC10

Tue May 24, 2016 2:37 am

Quoting andydtwnwa7 (Reply 19):

I don't think any airframe without winglets had had both WARPs and ringlets retrofitted. You're straying into unknown territory, and there be dragons.

Kc-10 winglets are a complete non starter. Even Boeing hasn't gone the winglet route with the KC-46, perhaps they learned something with the issues they had with the wing pods on the KC-767 program.
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Ozair
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RE: Re-engine The KC10

Tue May 24, 2016 2:40 am

Quoting andydtwnwa7 (Reply 19):
Also, does anyone know how much reengineering Airbus had to do to the wing so that it could support the weight of both the pod and the winglet?

Pretty sure the pods sit in the same locations as the outboard engines for the A340, hence there is structural support already there.

Quoting andydtwnwa7 (Reply 19):
The 330 MRTT has winglets with wing pods, so I'd be curious to hear if receivers have encountered any issues with them.

No idea but there are enough flying and operational now that if it was an issue we probably would have heard something.
 
andydtwnwa7
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RE: Re-engine The KC10

Tue May 24, 2016 2:55 am

Quoting Ozair (Reply 21):
No idea but there are enough flying and operational now that if it was an issue we probably would have heard something.

That's what I figured, I just posed the question since others before me were speculating on winglets causing problems with receivers. It doesn't seem like the winglets are causing issues. Wasn't trying to discount the capabilities of the MRTT.

Great point with respect to the pod position on the wing, that pretty much answers it.
 
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seahawk
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RE: Re-engine The KC10

Tue May 24, 2016 6:47 am

Quoting andydtwnwa7 (Reply 19):
The 330 MRTT has winglets with wing pods, so I'd be curious to hear if receivers have encountered any issues with them. Also, does anyone know how much reengineering Airbus had to do to the wing so that it could support the weight of both the pod and the winglet?

The A330 had the lock of sharing the a wing with the A340, which means the structural support for a fourth engine is in place, which greatly benefits the installation of the pods. The wing has also been designed with winglets, although they are not large.

A KC-10 has a wing that was not designed for winglets and also carries the pods. The winglets might not be a problem, but you would not know before simulating the airflow and testing it in real life. Worst case you would need a longer hose. The question is if it is worth the effort of designing, testing and installing the winglets and then re-certifying the plane and the various receivers. I think looking at a KC-777 is a better idea, especially as running the DC-10 will become more and more expensive as the DC-10 and MD-11s are retired from airline service.
 
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747classic
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RE: Re-engine The KC10

Tue May 24, 2016 8:53 am

Quoting 747classic (Reply 9):
I would prefer KC-10 installation of the latest type of winglets, as installed at the 737max, to obtain increased performance and/or lower fuel consumption against a fraction of re-engine costs.

Only the original blended winglet as installed at the 737,757, 767 by Boeing aviation partners have been assessed up to now for the KC-10 (and also the KC46). These winglets produce a wing twisting moment, requiring an structural wing re-enforcement on earlier built aircraft and are producing a disturbed airflow at the wing tip, that may interact with the installed refuelling pods.

The latest generation of AT winglets as installed at the 737MAX however have laminar flow over the winglet, reducing the drag and also smooting out the airflow produced by the winglet, reducing the disturbed tip airflow. Also the twisting moment at the wing structure has been reduced by the lower winglet fin., requiring less wing re-enforcement.
See : http://www.boeing.com/commercial/737max/737-max-winglets/

Quoting seahawk (Reply 23):
A KC-10 has a wing that was not designed for winglets and also carries the pods.

The KC-10 airframe is based on the commercial DC-10 airframe, and early commercial DC-10 flight tests validated a 2-3 percent improvement in fuel efficiency at cruise conditions with winglets as compared with the original wing design.4 Not only was the DC-10 modified and tested with winglets, but its successor, the MD-11, was designed and certified with winglets. With the computational fluid dynamics (CFD) tools of today, moreover, a winglet or other wingtip modification designed for the KC-10 aircraft might well achieve greater fuel savings than were demonstrated on the DC-10 fitted with winglets some 25 years ago. In addition, recent winglet design experience using high Reynolds number (RN) wind tunnels could have applicability for winglet designs that may be more effective on the KC-10

Are all KC10 capable of wing pod refuelling ?
AFAIK only 20 are fitted with provisions for pods.
How often are the wing pods actually installed and used ?
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bikerthai
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RE: Re-engine The KC10

Tue May 24, 2016 1:48 pm

Quoting kc135topboom (Reply 13):
there is the B-777-200LRF,
Quoting Max Q (Reply 14):
I think a triple 7 freighter would be ideal,

Specially if you get the end of the line discount as you did with the 767. As far as the model is concern, a 777F with 777-X wing may do the trick.

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INFINITI329
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RE: Re-engine The KC10

Tue May 24, 2016 5:27 pm

Quoting 747classic (Reply 24):
How often are the wing pods actually installed and used ?

The majority of USN & USMC can only refuel using the hose and drogue method. So in theater this capability is essential.
 
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Spacepope
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RE: Re-engine The KC10

Tue May 24, 2016 11:04 pm

Quoting INFINITI329 (Reply 26):
The majority of USN & USMC can only refuel using the hose and drogue method. So in theater this capability is essential.

True, but both the KC-10 and KC-46 have full time centerline drogues standard. The KC-135 without wing pods needs a drogue to be attached to the boom before becoming compatable.

http://www.defensemedianetwork.com/s...-deploys-aerial-refueling-systems/


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RE: Re-engine The KC10

Tue May 24, 2016 11:06 pm

Quoting KC135Hydraulics (Reply 16):
The KC-46 in its current form is a direct KC-135 replacement. It does not/cannot perform the same missions as the KC-10 in its current configuration.

Absolutely true. The real question in my mind is will it be imperative to build a larger 'KC-Y' tanker, or is it feasible and also cost effective to try to use a larger number of KC-46 to do the mission.

From what I've read the requirement for KC-10 came when US was denied access to bases in Europe for KC-135s for certain US to Middle East missions. Is that still a significant concern?
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ThePointblank
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RE: Re-engine The KC10

Wed May 25, 2016 2:07 am

Quoting Revelation (Reply 28):

From what I've read the requirement for KC-10 came when US was denied access to bases in Europe for KC-135s for certain US to Middle East missions. Is that still a significant concern?

Probably not as much anymore, the KC-135E's and R's are nothing like the KC-135A's in terms of offload capabilities as a result of their re-engining programs, with the R's even more so.
 
Ozair
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RE: Re-engine The KC10

Wed May 25, 2016 3:07 am

Quoting Revelation (Reply 28):
Absolutely true. The real question in my mind is will it be imperative to build a larger 'KC-Y' tanker, or is it feasible and also cost effective to try to use a larger number of KC-46 to do the mission.

I'm not sure even a larger number of KC-46s would be required. If we consider the aircraft in service, and what will be in service throughout the next two to three decades, none of them are getting bigger than the current and most are more fuel efficient than the previous generation. The big gas guzzlers like the B-52 will eventually go and the whole bomber fleet is transitioning to a B-2 and B-21 fleet, even the C-5 is getting a engine upgrade.

What I can see 15 years from now are the KC-46s being used as hubs with smaller stealthy drone refuellers taking on the tanking role near and beyond the FEBA, suppling F-35s, F-22s and B-21s.
 
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RE: Re-engine The KC10

Wed May 25, 2016 5:49 am

Quoting ThePointblank (Reply 1):
With only 59 in active service in the USAF

Yep they manufactured 60 with one loss at Barksdale AFB back in the late 80's

Quoting Revelation (Reply 28):
From what I've read the requirement for KC-10 came when US was denied access to bases in Europe for KC-135s for certain US to Middle East missions.

The KC-10 came from the Advanced Tanker Cargo Aircraft requirement. Two companies responded to the ATCA program. Boeing based its proposal on its 747, while McDonnell Douglas based its proposal on the KC-10. The proposal was based on airlift and tanker requirements not on European bases.
 
ThePointblank
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RE: Re-engine The KC10

Wed May 25, 2016 8:04 am

Also, a re-engining may not bring a significant benefit to the KC-10. The KC-135 benefited significantly because the original engines were designed in the early 1950's. The TF33's were already significant advancement compared to the Pratt J57's, while the CFM56's was like going from slide rulers to a digital calculator.

The CF6's as found in the KC-10's are already very competitive engines, even today. A newer engine would bring very marginal benefits for a lot of expenditure to achieve a operationally significant level of improvement. And it's not like parts for the CF6's are in short supply; the engine is still being made and supported today.
 
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747classic
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RE: Re-engine The KC10

Wed May 25, 2016 9:23 am

Quoting ThePointblank (Reply 32):
The CF6's as found in the KC-10's are already very competitive engines, even today. A newer engine would bring very marginal benefits for a lot of expenditure to achieve a operationally significant level of improvement. And it's not like parts for the CF6's are in short supply; the engine is still being made and supported today.

The General Electric CF6 engines installed at the KC10 are CF6-50C2 engines. These CF6-50 engines are not produced anymore since 1991, the last (CF6-50E2 variant) are installed at the last 747-200F, delivered to NCA in 1991.



This type of engine is the first CF6 version (CF6-6/50 type certificate E23EA) that has been produced for the A300B2/B4/C4, B747-100SR/200B/300, E4B and DC10-10/30 series and competing with the PW JT9 series and the RR RB-211-524B/C/D series.

A totally new CF6 version, the CF6-80 series (CF6-80A/C type certificate E13NE) was developed, for A310, A300B4-600, late built 747-300, 767, 744, MD11, C-5M and VC25 aircraft, and competing with the PW4000 series engines and RR RB211-524 G/H series.

The GE CF6 -6/50 series and the CF6-80A/C series have practically no common spare parts.

CF6-50 = USAF F103 engine
CF6-80 = USAF F138 engine

Difference of TSFC between the two CF6 versions is around 8-9%

However, re-engine/certification costs of the KC10 would be excessive and only possible with the F138, due engine # 2 duct constraints.(fan size). GEnx installation. would require a total redesign of the KC10.

A latest generation winglet design could produce almost the same SFC gain, but against a fraction of the re-engine costs.

The only constraint could be winglet/refuelling pod issues, but these pods could be deleted , only 20 KC10 have provisions for these pods and all new KC46A aircraft have pods installed.

[Edited 2016-05-25 03:22:28]
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RE: Re-engine The KC10

Wed May 25, 2016 10:31 am

Quoting windy95 (Reply 31):
Quoting Revelation (Reply 28):
From what I've read the requirement for KC-10 came when US was denied access to bases in Europe for KC-135s for certain US to Middle East missions.

The KC-10 came from the Advanced Tanker Cargo Aircraft requirement.

It seems both statements are true. ATCA started as a concept in the 60s but did not move forward till the missions I mentioned highlighted the need.

http://www.amc.af.mil/news/story_print.asp?id=123149523 says:

Quote:
Additionally, in June 1967, SAC published a requirement for an advanced capability tanker to supplement the KC-135 force. While ideal for supporting the bomber mission, planners judged the KC-135 force as inadequate to support a general force deployment of attack, rescue, air defense, and airlift aircraft.

Although Headquarters Air Force endorsed the concept, little was done while the Vietnam War continued.

A tanker support study in 1970 called for adapting a current wide-body transport aircraft as the most cost-effective solution. A limited number of feasibility tests followed in 1971 and 1972. United States material support during the October 1973 Yom Kippur War (a coalition of Arab states against Israel) highlighted the need for air refueling of airlift forces.

In December 1973, SAC reissued its tanker requirement, now entitled the Advanced Tanker Cargo Aircraft. Both Military Airlift Command and Tactical Air Command agreed that the new aircraft should be primarily a tanker with an airlift augmentation capability. As such, they agreed SAC should be the single manager for planned new tanker/cargo aircraft.

Two companies responded to the ATCA program. Boeing based its proposal on its 747, while McDonnell Douglas based its proposal on the KC-10. On Dec. 19, 1977, the Air Force selected the KC-10A as the more advantageous aircraft. While the 747 version offered a larger capacity, the KC-10 was cheaper and offered the ability to take off with a maximum load from a shorter runway. From 1981 to 1990, the Air Force received 60 KC-10s.

And http://www.globalsecurity.org/military/systems/aircraft/atca.htm says:

Quote:
The need for a long-range, large-capacity tanker to operate from the United States with reduced reliance on foreign bases for refueling was recognized in a formal Air Force requirement document in April 1976.

----

Quoting ThePointblank (Reply 29):
Probably not as much anymore, the KC-135E's and R's are nothing like the KC-135A's in terms of offload capabilities as a result of their re-engining programs, with the R's even more so.

Interesting point. It should be an interesting staff exercise to see what impact a fleet of KC-135Rs and KC-46As will have on the need for KC-Y.

Quoting Ozair (Reply 30):
I'm not sure even a larger number of KC-46s would be required. If we consider the aircraft in service, and what will be in service throughout the next two to three decades, none of them are getting bigger than the current and most are more fuel efficient than the previous generation. The big gas guzzlers like the B-52 will eventually go and the whole bomber fleet is transitioning to a B-2 and B-21 fleet, even the C-5 is getting a engine upgrade.

The USAF article above says that KC-135s were more or less stationed one for one with B-52s on alert. I'm sure there were many other usage models, but indeed it highlights that the largest airframes have a lot to do with determining the size of the tanker fleet, and with drones taking on more missions and jet engines becoming more efficient we'll have as big a need for tankers as we've had sinze the Cold War.

Quoting 747classic (Reply 33):
The GE CF6 -6/50 series and the CF6-80A/C series have practically no common spare parts.
Difference of TSFC between the two CF6 versions is around 8-9%

And the CF-6 was the "feed stock" for the GE-90, and in turn GE-90 has begotten GEnX / GE9X.

I think you can make a good argument that the CF6-50 is now two generations of engine tech behind.

But that doesn't itself justify a re-engining program.

Interestingly enough, no one felt the fact that the PW4000s on KC-46 are a generation behind the state of the art was a big issue.

In my mind, here during the various KC-X battles it made a lot of sense to me to make the KC-135s last one more generation, and wait for the 787 class technology to age well enough to the point where it could be made in quantities large enough to replace KC-135R. The big reason is the ultimate determinant of lifecycle is metal fatigue, and the 787 generation has a lot less metal to fatigue. A second benefit is what I just said, it has current engines, not ones that are a generation old. So we're now going to buy a few hundred 767s which will again become the last of their generation to fly, and that is another big issue with KC-135R, there is no support base for them.

All in all I think the USAF could and should have waited one more generation to start replacing KC-135Rs, but there seemed to be a need to toss a bone to the defense industry.
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747classic
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RE: Re-engine The KC10

Wed May 25, 2016 11:03 am

Quoting Revelation (Reply 34):
I think you can make a good argument that the CF6-50 is now two generations of engine tech behind.

But that doesn't itself justify a re-engining program.

Interestingly enough, no one felt the fact that the PW4000s on KC-46 are a generation behind the state of the art was a big issue.

I think we our replies partly crossed and you missed my latest addition at reply 33.

I agree that re-engine is no-go, because of the issues and costs to install a present generation engine at the #2 position.

A far better solution would be a minor investment in an aerodynamic wing improvement that is possible with a scaled up version of the latest laminar flow winglets, as installed at the 737 MAX.

Note : a KC-46A with derated GEnx-2B engines plus T/R's would have been the optimum solution for the next 50 years.

[Edited 2016-05-25 04:17:52]
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RE: Re-engine The KC10

Wed May 25, 2016 11:51 am

Quoting 747classic (Reply 35):
I think we our replies partly crossed and you missed my latest addition at reply 33.

Yes, thanks for pointing this out.

If you really want to count the generational transitions, they would be CF6-50 -> CF6-80 -> GE-90 -> GEnX so it could be said the KC-10 is three engine generations behind, but I agree with the conclusion that the KC-10s are too small a fleet and too difficult to upgrade to make it worth the effort.

I still don't have a good sense for the true need to have a KC-10 class tanker. Sure, they're the best tool in the drawer for long distance fighter drags, but that doesn't mean it's worth replacing them. On the other hand you don't want to get to the point the RAF was in the Falklands where they had to use a pyramid of tankers refeulling tankers refuelling tankers that refuel the one or two bombers at the tip of the spear.

Quoting 747classic (Reply 35):
a KC-46A with derated GEnx-2B engines plus T/R's would have been the optimum solution for the next 50 years.

I will disagree. To me it makes little sense to purchase end-of-the-line 767s. Can you imagine how hard it is going to be to replace the computing elements in a 767 in 40/50 years time? That stuff was done in the 70s. I hope the USAF is doing a binge purchase of all such devices right now.

Why buy one of the last mostly-metal frames in production when we see clearly the way forward is CFRP? Why not extend the current metal ships to the end of their projected life (USAF was saying that was 2050 or so before the 9/11 crisis made the KC-767 pop up on their radar) and start buying CFRP frames in a decade or so when there will be production slots available?
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RE: Re-engine The KC10

Wed May 25, 2016 1:25 pm

Quoting Revelation (Reply 36):
I will disagree. To me it makes little sense to purchase end-of-the-line 767s. Can you imagine how hard it is going to be to replace the computing elements in a 767 in 40/50 years time? That stuff was done in the 70s. I hope the USAF is doing a binge purchase of all such devices right now.

Why buy one of the last mostly-metal frames in production when we see clearly the way forward is CFRP? Why not extend the current metal ships to the end of their projected life (USAF was saying that was 2050 or so before the 9/11 crisis made the KC-767 pop up on their radar) and start buying CFRP frames in a decade or so when there will be production slots available?

-Indeed, the computing elements are aging must faster than the engines and airframe.

- However, the relative "straight forward" 767 black boxes can be replaced one by one with new updated boxes, with state of the art electronics against relative minor certification costs at a mid live update.

- A mid-live re-engine of the B767 will be far more expensive, I would have started with the most modern engine available when purchasing the first tanker from Boeing.

- A mid live electronics upgrade of the far more complicated and interconnected systems of a B787 or B777X would be far more demanding. Especially the FBW systems wil require a very expensive re-certification, when replaced by other electronics.
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KC135Hydraulics
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RE: Re-engine The KC10

Wed May 25, 2016 2:54 pm

Quoting Revelation (Reply 36):
I will disagree. To me it makes little sense to purchase end-of-the-line 767s. Can you imagine how hard it is going to be to replace the computing elements in a 767 in 40/50 years time? That stuff was done in the 70s. I hope the USAF is doing a binge purchase of all such devices right now.

This doesn't seem like a valid argument. KC-135s with old-style analogue gauges were easily retrofitted during the Pacer-Crag modification, which gave them digital MFDs and a highly functional FMS system, which by the way makes the KC-135 completely GATM capable. KC-135s actually have quite a decent avionics suite onboard now, despite the age of the aircraft (approaching 60 years for most on my installation!) I find it difficult to believe that an avionics upgrade cannot be done to the KC-46 if and when the need arises in the future.
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RE: Re-engine The KC10

Wed May 25, 2016 5:10 pm

Quoting 747classic (Reply 37):
A mid live electronics upgrade of the far more complicated and interconnected systems of a B787 or B777X would be far more demanding. Especially the FBW systems wil require a very expensive re-certification, when replaced by other electronics.

Interesting observations. It will be interesting to see if in the future we end up throwing out airframes with lots of mechanical life left in them just because the computer hardware/software is obsolete and it's too costly to support them. I would hope this problem is pretty obvious now so it's being dealt with via requirements imposed on new systems, but of course no development program wants to accept a lot of costs now to deal with the fact that the computers will become obsolete decades in the future.

Quoting KC135Hydraulics (Reply 38):
I find it difficult to believe that an avionics upgrade cannot be done to the KC-46 if and when the need arises in the future.

My thoughts were more about how costly it will be to maintain the existing hardware and software 40-50 years from now. If you have the option of tearing it all out and replacing it with new (or in the case of KC135 starting from an analog baseline) you end up resetting the clock, but it takes a great deal of cost and down time to do this. I agree with the point above that it will be even more expensive to deal with obsolete fly by wire implementations as opposed to FMCs or displays.

It seems like from what was made public is that the KC-46 will come with new display tech but the underlying FMC tech is not being modernized at this point in time, but I am not a subject matter expert on this topic.
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Max Q
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RE: Re-engine The KC10

Wed May 25, 2016 5:26 pm

Quoting KC135Hydraulics (Reply 38):
find it difficult to believe that an avionics upgrade cannot be done to the KC-46 if and when the need arises in the future.

My understanding is the KC46 is fitted with the same avionics and displays as the 787, this will go a long way towards alleviating obsolescence concerns.
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RE: Re-engine The KC10

Wed May 25, 2016 8:30 pm

Quoting Revelation (Reply 36):
I will disagree. To me it makes little sense to purchase end-of-the-line 767s. Can you imagine how hard it is going to be to replace the computing elements in a 767 in 40/50 years time? That stuff was done in the 70s. I hope the USAF is doing a binge purchase of all such devices right now.

The tankers have updated avionics and a 787-like flight deck. Don't worry about that.
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RE: Re-engine The KC10

Wed May 25, 2016 8:56 pm

Quoting Max Q (Reply 40):
My understanding is the KC46 is fitted with the same avionics and displays as the 787,
Quoting hilram (Reply 41):
The tankers have updated avionics and a 787-like flight deck.

Pretty much every reference I've found says that KC-46 has a new display subsystem based on the 787s but no where did I read that there has been a wholesale switchover to the 787s computing infrastructure. That would clearly add a lot of cost and risk to the program so if it was happening we'd have read about it. Feel free to provide a reference that would clarify it, but I can't find evidence of it and I've been following our threads here for a very long time now.

FWIW,

KC-46 Might Be More Advanced? (by OyKIE May 28 2011 in Military Aviation & Space Flight)

has the best list I found from here of what was changed.
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XT6Wagon
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RE: Re-engine The KC10

Wed May 25, 2016 9:10 pm

Quoting seahawk (Reply 8):
Sure because a KC-777 would not need any major structural re-design, a new No.2 engine on a KC-10 would.

Any re-engine would be the wing engines only. Which is 1/2 the reason it will never happen.

More KC-46 would be cheaper and just as good now that we don't have the heavy offloads near the bases like in the SAC days. Lower fuel burn would more than offset the lack of raw capacity for things like dragging fighters across the Atlantic.
 
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RE: Re-engine The KC10

Thu May 26, 2016 3:07 am

Quoting XT6Wagon (Reply 43):
More KC-46 would be cheaper and just as good now that we don't have the heavy offloads near the bases like in the SAC days. Lower fuel burn would more than offset the lack of raw capacity for things like dragging fighters across the Atlantic.

Yeah, I think re-engining these is 15 years too late. At this point the KC-46 is coming online and its cheaper, operations and maintenance wise, to eliminate the KC-10 altogether and fly just 2 tanker types (KC-135 and KC46). You eliminate the entire supply chain that way.

However, I think selling these to someone that needs it, like Israel, Saudi Arabia etc., is a perfectly viable option. South Korean, Japan, Taiwan, Thailand etc. might take a few frames too. It would be a shame to scrap them. Does anyone know how much flying time these frames have left?

I always thought it strange they bought so few. Really, KC-10 should have been a 150 tanker purchase with the KC-135 getting retired 20 years ago. Then the KC-46 could have replaced the KC-10 instead or it might have been a viable fleet for another 10 years. In 2025, maybe you'd have a 787 based tanker then.
 
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RE: Re-engine The KC10

Thu May 26, 2016 4:35 pm

Quoting ThePointblank (Reply 1):
you can't justify the costs to engineer and develop a re-engining program

You wouldn't have to "develop" a program, there is already one out there...Fed Ex uses it on the MD-10 program. The costs wouldn't be "initial" as you seem to think.

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RE: Re-engine The KC10

Thu May 26, 2016 6:02 pm

Quoting 135mech (Reply 45):
you can't justify the costs to engineer and develop a re-engining program
You wouldn't have to "develop" a program, there is already one out there...Fed Ex uses it on the MD-10 program

What kind of re-engining program was performed at the MD10 ????????
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JohnM
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RE: Re-engine The KC10

Thu May 26, 2016 6:45 pm

Quoting 747classic (Reply 46):
What kind of re-engining program was performed at the MD10 ????????

Got rid of the FE. They generate lots of BS write-ups!
 
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RE: Re-engine The KC10

Thu May 26, 2016 7:07 pm

Quoting JohnM (Reply 47):
Got rid of the FE. They generate lots of BS write-ups!

yeah, that's more of a re-engineering program  

We all know Douglas products are bulletproof and can fly for millennia, but how many hours are on the average KC-10 nowadays?
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trex8
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RE: Re-engine The KC10

Sat May 28, 2016 7:39 pm

Quoting Ozair (Reply 21):

Pretty sure the pods sit in the same locations as the outboard engines for the A340, hence there is structural support already there.

A reason the RAAF gave as mitigating risk and why they went with the A330 over the 767

Didnt Air Europe order RR powered DC10s??? How far did MDC go engineering this version?? How much difference is there in the DC10-30 vs Pratt powered -40 in terms of structure except for the different number 2 engine inlet and cowl shape?

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