Any idea why there isn´t a KC-24 (DC-8-54AF), KC-11 (MD-11CF) or A300 MRTT? Surely the DC-8, MD-11 and A300 would serve as good tankers but why McDonnell Douglas and Airbus didn´t consider a DC-8, MD-11 and A300 tanker?

UA857 wrote:

Any idea why there isn´t a KC-24 (DC-8-54AF), KC-11 (MD-11CF) or A300 MRTT? Surely the DC-8, MD-11 and A300 would serve as good tankers but why McDonnell Douglas and Airbus didn´t consider a DC-8, MD-11 and A300 tanker?

KC-11 ??? That would have been a tanker version of the Grumman C-11 (Gulfstream II) as used by US Army and Coast Guard.

A tanker version of the MD-11 would have been KC-something in the high 30'es or low 40'es, or it would have been KC-10B.

GalaxyFlyer wrote:

The DC-8 wasn’t considered because Boeing has the market sewn up. The RAAF and RCAF had bought a couple of KC-137s and other buyers until much later when the Dutch under NATO operated a couple of KC-10s. The market is not that big for a speculative design and test program to be funded.

Would KC-137 be the 707-338 and 707-368 that were originally just the civil airliners and then converted - eg, A20-103 for instance?

I agree with your thoughts on it being a small market, and the converted 707 or the DC-10 probably does the job well enough. Potentially the 747 tanker also, but only a tiny number of those were built if I'm not mistaken.

If buyers did appear for them in the mid-80s, would Boeing have been able to do them?

GalaxyFlyer wrote:

I’m not sure how the RAAF and RCAF procured their 707s but they weren’t 135s, aka Boeing 717-100. I’m sure Boring would have, the 707 line stayed in operation until the last AWACS were delivered to NATO.

Most of the RAAF 707 tankers were ex QF, plus a couple of ex SV machines.

For the A300,
(a) it's a short haul aircraft, I doubt that it would've offered much improvement over the KC-135, let alone the KC-10 or L1011.
(b) Airbus at the time was a strictly civilian manufacturer. EADS (now Airbus Group) didn't form until the year 2000. Of course the individual companies, e. g. BAe and CASA, had military products and there was international cooperation, e. g. for the Eurofighter or Tornado, but it was far from today's highly integrated Airbus.

mxaxai wrote:

For the A300,
(a) it's a short haul aircraft, I doubt that it would've offered much improvement over the KC-135, let alone the KC-10 or L1011.
(b) Airbus at the time was a strictly civilian manufacturer. EADS (now Airbus Group) didn't form until the year 2000. Of course the individual companies, e. g. BAe and CASA, had military products and there was international cooperation, e. g. for the Eurofighter or Tornado, but it was far from today's highly integrated Airbus.

Exactly and there are some A310 converted to tankers around: Canada and Germany.

Anyone know why there isn´t a KC-24 (DC-8-54AF)?

LTEN11 wrote:

GalaxyFlyer wrote:

I’m not sure how the RAAF and RCAF procured their 707s but they weren’t 135s, aka Boeing 717-100. I’m sure Boring would have, the 707 line stayed in operation until the last AWACS were delivered to NATO.

Most of the RAAF 707 tankers were ex QF, plus a couple of ex SV machines.

The a.net photo database is always a good place to start!

Two ex Saudia machines that never became tankers; A20-103 & A20-261 (& the strange ghost A20-809, also ex SV)

The IAI installed Flight Refuelling Mk32B AAR system was fitted to four RAAF B707s

All four ex Qantas, and identified here on a.net as "Boeing 707-338C (KC)"
A20-623 & A20-624


A20-627 and A20-629


The curiosity for me is the appearance/ disappearance /re-appearance of the refuelling pods at various times. Were they easily de-mountable? If so, why?
Or was that just the VIP kit for A20-629?

Good links to the photos. I was going to do something but given the mention of "KC-137" and the chance that someone would start jumping up and down, I thought better to post nothing.

Those grey/white/blue painted versions look so timeless. I had almost forgotten Hulksbury - I've seen it in person. I also remember the enormous fuss made when one of these tankers made a flight over Sydney harbour and people in the office buildings thought it was a terror attack about to happen.

I was chatting the next day to one of the people on the plane - who was involved with these planes back in the day, and at that time with another quite famous Boeing 707. His enthusiasm for the 707 was wonderful to see.

SheikhDjibouti wrote:

The curiosity for me is the appearance/ disappearance /re-appearance of the refuelling pods at various times. Were they easily de-mountable? If so, why?

Most likely to facilitate maintenance / replacement of the pods, just like the various weapons and fuel tanks attached to pylons at the "hard points" under the wings of various military fighter aircraft. These pylons are easily removed/replaced by trained military aircraft maintenance personnel or just left off to provide a "clean wing" .

UA857 wrote:

Anyone know why there isn´t a KC-24 (DC-8-54AF)?

GalaxyFlyer provided the answer in the first post.

Anyone know why the KC-10B (MD-11CF) failed?

Did the US Navy ever consider a KC-24 (DC-8-54F)?

UA857 wrote:

Anyone know why the KC-10B (MD-11CF) failed?

There was no requirement, plus it would have been invariably worse as a tanker; the smaller stabilizer and relative instability vs. the DC-10 made it an inferior platform for the mission in almost every respect (CG, ballast, etc). The USAF didn’t (and doesn’t) care one iota about the latest engine/fuel efficiency for the tanker fleet, and new build MD-11’s wouldn’t have offered any significant additional capabilities they wanted.

Now, had they known getting a real KC-135 replacement in sizable numbers would take until the mid-2020’s, maybe the procurement folks woulda....hahaha.

More here;

https://www.avgeekery.com/why-wasnt-the ... ed-tanker/

GalaxyFlyer wrote:

No, under DoD regulations they wouldn’t have been allowed to operate them.

So a US Navy KC-24 would not been allowed to operate?

UA857 wrote:

Did the US Navy ever consider a KC-24 (DC-8-54F)?

No tankers, but they did have this one:


They also had a Convair 880 based tanker/testbed known as the UC-880:

Was the KC-10B (MD-11CF) meant to replace the KC-135?

SheikhDjibouti wrote:

The curiosity for me is the appearance/ disappearance /re-appearance of the refuelling pods at various times. Were they easily de-mountable? If so, why?
Or was that just the VIP kit for A20-629?

As others said, they could've been removed for maintenance. Or perhaps for fuel savings/takeoff performance when not needed.

There are many missions in the KC-10 where the TACC flight planner will specify a non-WARP (pods) for mission requirements such as takeoff performance.

Going back to the question posed in the opening post, I think the answer is in advances in aircraft design. Older frames could be pax transport OR tankers, whereas the A330 can be pax AND tanker. The A330MRTT has no additional tankage beyond the routine pax version as far as I know, so can be configured for a full pax load AND normal max fuel load for its tanker role at the same time.

Obviously not operated in both roles concurrently, but provides for alternate roles in a highly flexible package.

JerseyFlyer wrote:

Going back to the question posed in the opening post, I think the answer is in advances in aircraft design. Older frames could be pax transport OR tankers, whereas the A330 can be pax AND tanker. The A330MRTT has no additional tankage beyond the routine pax version as far as I know, so can be configured for a full pax load AND normal max fuel load for its tanker role at the same time.

Obviously not operated in both roles concurrently, but provides for alternate roles in a highly flexible package.

I don't know about other air forces, but I do know the RAAF has operated their KC-30s as tankers and pax transport concurrently whilst dragging their F-18s overseas. KC-10s do it, too, but the KC-30 is certainly more modern and more comfortable. It's an excellent airframe and, as you said, is fitted with standard A330 tanks; no additional tankage in the belly.

https://www.facebook.com/AusAirForce/posts/dyk-that-no-77-squadron-77sqn-travelled-more-than-8500-km-to-get-to-chitose-air-/10157074128962639/

Did the RNAF consider a KMD-11 tanker?

Was the KC-10B ever a proposal?

UA857 wrote:

Was the KC-10B ever a proposal?

Yes.

The KC-10B / KC-11 would not have offered any appreciable MTOW boost over the KC-10A and since the KC-10A was almost fuel-volume limited, anyway, additional MTOW would not have allowed much additional fuel to be carried. And KC-10A's rarely left at MTOW because missions did not call for maximum available fuel load, so again, the minimal extra MTOW offered would not have been used often, if at all.

McD did pitch them to the Dutch, anyway, but they were not interested.

https://www.avgeekery.com/why-wasnt-the ... ed-tanker/

Can the KC-10 land on short runways?

UA857 wrote:

Can the KC-10 land on short runways?

It's OWE is around 122,000kg so looking at the DC-10 ACAPs, that is around 4500 feet at ASL.

UA857 wrote:

Can the KC-10 land on short runways?

It's technically capable of shorter runways, but restricted by the AF to 7,000 ft or greater. 'Back in the day', Templehof was waived as their runway was ~ 6900 feet, but the crews had to have specific training to land there.

There was a KC-10B proposal in the early 80s that would've focused on increased cargo capabilities, but it went nowhere.

https://apps.dtic.mil/dtic/tr/fulltext/u2/a194398.pdf

Stitch wrote:

Yes.

The KC-10B / KC-11 would not have offered any appreciable MTOW boost over the KC-10A and since the KC-10A was almost fuel-volume limited, anyway, additional MTOW would not have allowed much additional fuel to be carried. And KC-10A's rarely left at MTOW because missions did not call for maximum available fuel load, so again, the minimal extra MTOW offered would not have been used often, if at all.

McD did pitch them to the Dutch, anyway, but they were not interested.

https://www.avgeekery.com/why-wasnt-the ... ed-tanker/

Interesting article, but I think the author should clarify that takeoffs at MTOW are much more common in the pacific than the Atlantic; while he may count on one hand, in the last few years I would use all my hands and feet and still need a few more. Hickam, Guam, Eielson, and Kadena often mean MTOW for fighter drags.

Speaking of KC-10. How come the military didn’t go for the MD-10 conversion or do it now. The price on that technology has to be cheaper by now. Fed ex has dozens parked in the desert could you refurbish the main hardware. And use them in the KC-10. That conversion was not done so long ago. It would also eliminate the flight engineer I don’t see any near retirement plans for the KC-10 and as far as Tankers go they are relatively young compared to the KC-135

DL757NYC wrote:

Speaking of KC-10. How come the military didn’t go for the MD-10 conversion or do it now. The price on that technology has to be cheaper by now. Fed ex has dozens parked in the desert could you refurbish the main hardware. And use them in the KC-10. That conversion was not done so long ago. It would also eliminate the flight engineer I don’t see any near retirement plans for the KC-10 and as far as Tankers go they are relatively young compared to the KC-135

I'm afraid your newsfeed is a trifle behind, as 3 KC-10s are already in the boneyard, with more to come in the next few years. They're certainly younger than the KC-135 in years, but just as old (or older) in flight hours. The KC-135 was essentially a nun whilst on alert, keeping her flight hour age low, whereas the KC-10 went everywhere there was a party and after 40 years of happy living and making it happen, with no major updates, the train has sailed for the MD-10 mod.

At the time (late 90s - early 2000s) there was scuttlebutt of the AF buying into the MD-10 mod for the KC-10 but there were 3 main stumbling blocks: money, money, and money! Before 9/11 there was no money and after 9/11 all the new money went into buying new uniforms and buying out our new, trustworthy friends (read: warlords) in garden spots around the world but mainly centered in the middle east and a bit more east. The AF was also skeptical of crew workload without an FE. They did studies of the no-FE workload during different phases of flight and found some phases exceeding their targets. There were also some practical considerations in the day-to-day: how would an automated fuel panel designed for a DC-10 handle the additional body tanks and CG constraints of the KC-10? How would the fuel transfer work? Would the PM (pilot monitoring) simply input the amount of fuel to be offloaded to each receiver via the FMS? Ok, what if the receiver wants more fuel than programmed? The KC-46 and KC-30 get around this annoying problem by equipping the boom operator with a 'squirt switch' on the stick which overrides the computer and keeps the fuel flowing; however, this wasn't a practical solution on the KC-10 and the entire mod would entail many, many changes (read: money), both up front as well as in the boom pod in the back. I vaguely remember a seed being planted about the FAA certification for an aircraft carrying passengers, but I'm not certain. Don't get me started on the poor soul who would draw the short straw and have to do TOLD while the boom operators mock and pretend to be busy!

Detailed effort for the FE, yes. A true labor of love involving scrambling between hundreds of pages of identical looking charts and graphs, cursing the idiot at Current Ops who sent a WARP podded-jet to Nellis in July for a dual role with boom equipped fighters, and wishing he'd signed up for the lazy channel run to Yokota instead. Delicious coco curry...

Not so detailed for the copilot, who peruses the sheet for 2 minutes comparing the numbers to his checklist inserts, then goes back to the demanding task of figuring out how to stuff his Darth Vader lunchbox into the fridge without tipping his juice box over, and then kicking the fridge door a hundred times because the latch is too difficult to master.

Stitch wrote:

UA857 wrote:

Was the KC-10B ever a proposal?

Yes.

The KC-10B / KC-11 would not have offered any appreciable MTOW boost over the KC-10A and since the KC-10A was almost fuel-volume limited, anyway, additional MTOW would not have allowed much additional fuel to be carried. And KC-10A's rarely left at MTOW because missions did not call for maximum available fuel load, so again, the minimal extra MTOW offered would not have been used often, if at all.

McD did pitch them to the Dutch, anyway, but they were not interested.

https://www.avgeekery.com/why-wasnt-the ... ed-tanker/

Was the KC-10B proposed as a KC-135 replacement?

UA857 wrote:

Was the KC-10B proposed as a KC-135 replacement?

I can't find any record of it in a quick search.

McD called it the KMD-11 and they pitched to the Dutch Air Force and the Royal Australian Air Force looked at second-hand conversions of passenger/freighter MD-11s to KMD-11 as part of their tanker 2000s RFP before choosing the A330MRTT. It was also evidently pitched to the Royal Saudi Air Force in 1997, but looks like the RSAF chose to keep their KC-135s until ordering the A330MRTT in 2008.

Stitch wrote:

UA857 wrote:

Was the KC-10B proposed as a KC-135 replacement?

I can't find any record of it in a quick search.

McD called it the KMD-11 and they pitched to the Dutch Air Force and the Royal Australian Air Force looked at second-hand conversions of passenger/freighter MD-11s to KMD-11 as part of their tanker 2000s RFP before choosing the A330MRTT. It was also evidently pitched to the Royal Saudi Air Force in 1997, but looks like the RSAF chose to keep their KC-135s until ordering the A330MRTT in 2008.

I didn't think the Saudis had their own KC-135s. IIRC they have 8 KE-3 tankers, so basically CFM-engined 707s.

Spacepope wrote:

I didn't think the Saudis had their own KC-135s. IIRC they have 8 KE-3 tankers, so basically CFM-engined 707s.

They are indeed classified as KC-707s per Wikipedia.

Stitch wrote:

UA857 wrote:

Was the KC-10B proposed as a KC-135 replacement?

I can't find any record of it in a quick search.

McD called it the KMD-11 and they pitched to the Dutch Air Force and the Royal Australian Air Force looked at second-hand conversions of passenger/freighter MD-11s to KMD-11 as part of their tanker 2000s RFP before choosing the A330MRTT. It was also evidently pitched to the Royal Saudi Air Force in 1997, but looks like the RSAF chose to keep their KC-135s until ordering the A330MRTT in 2008.

My question is, was the KC-10B/KMD-11 ever offered to the USAF as a potential KC-135 replacement?

UA857 wrote:

My question is, was the KC-10B/KMD-11 ever offered to the USAF as a potential KC-135 replacement?

If only he'd answered your question in the very first sentence of his post...

Or Ask the Experts: https://www.publicaffairs.af.mil/Contact-Us/

mxaxai wrote:

For the A300,
(a) it's a short haul aircraft, I doubt that it would've offered much improvement over the KC-135, let alone the KC-10 or L1011.
(b) Airbus at the time was a strictly civilian manufacturer. EADS (now Airbus Group) didn't form until the year 2000. Of course the individual companies, e. g. BAe and CASA, had military products and there was international cooperation, e. g. for the Eurofighter or Tornado, but it was far from today's highly integrated Airbus.

The A-300 doesn't carry half the fuel load of the KC-135

Airbus will now develop the Airbus 380 into tanker ...

kc135topboom wrote:

The A-300 doesn't carry half the fuel load of the KC-135

there never was an A300 tanker around.
The A310 was the better airframe for that application.

A310MRT(T) 77,500kg of fuel
KC135 90,718kg of fuel
both models got extra tankage.

17% difference

Mortyman wrote:

Airbus will now develop the Airbus 380 into tanker ...

no they task the 251t A330-800 mit Aux tanks ( ~20t capacity ) installed.
intrinsically more fuel offload by way of better sfc.

Mortyman wrote:

Airbus will now develop the Airbus 380 into tanker ...

I'm thinking that would be a great what-if to go next to the KC-33 what-if (747-8 based wraparound Euro 1 camo) I just started building over on Britmodeller. But, hey, I'm a civvy, so these lovely (uneconomic, inefficient, impractical) ideas will always appeal.