Well now, this was an unexpected development.

Active winglets are to be fir to the KC-135 fleet, with some possibly in service toll FY 2050...

https://www.thedrive.com/the-war-zone/k ... g-winglets

Sounds like a good and relatively cheap way of life extension for the fleet.

That is interesting, not least because it's happening so late in the life of the aircraft.

On a related note, does anyone know why the airliner style 767-300 winglets weren't fitted to the KC-46?

afterburner33 wrote:

That is interesting, not least because it's happening so late in the life of the aircraft.

On a related note, does anyone know why the airliner style 767-300 winglets weren't fitted to the KC-46?

Boeing started with the winglets, but in the 'trade' studies it didn't make the cost /benefit analysis.

...

I this load alleviation along with a couple added feet of wing is the key for this to work, load alleviation allowed the existing wing structure to not be reinforced.

For a lot of detailed USAF winglet info :
Assessment of Wingtip Modifications to Increase the Fuel Efficiency of Air Force Aircraft (2007)
National Academies of Sciences, Engineering, and Medicine.
See : https://nap.nationalacademies.org/read/11839/chapter/1

Especially interesting are chapters 3 and 4 !!

747classic wrote:

For a lot of detailed USAF winglet info :
Assessment of Wingtip Modifications to Increase the Fuel Efficiency of Air Force Aircraft (2007)
National Academies of Sciences, Engineering, and Medicine.
See : https://nap.nationalacademies.org/read/11839/chapter/1

Especially interesting are chapters 3 and 4 !!

Thanks for this. I'm wondering why it has taken so long between the publication of the study and the projected implementation if the cost savings were clear, e.g., 2 year ROI for Southwest. Perhaps because they fly less than commercial jets?

Avatar2go wrote:

afterburner33 wrote:

That is interesting, not least because it's happening so late in the life of the aircraft.

On a related note, does anyone know why the airliner style 767-300 winglets weren't fitted to the KC-46?

For the KC-46, the radar warning receivers are built into the wingtips.

That's kind of silly, as I'm sure it's not such a huge engineering challenge to have both the RWR and the winglets at the same time. Like for example putting those either in the winglet or at the base of the winglet. To me it's yet another failure of the KC-46 system. The latest and greatest tanker couldn't find a way to incorporate winglets . The USAF logic is stunning - "we don't need them on our new tanker, but we do need them on the old tanker which will be replaced by the new tanker!"

Spacepope wrote:

Well now, this was an unexpected development.

Active winglets are to be fir to the KC-135 fleet, with some possibly in service toll FY 2050...

https://www.thedrive.com/the-war-zone/k ... g-winglets

As with winglets, aircraft engine upgrades are another item that the Air Force and Navy simply refuse to incorporate unless they are forced to. When/if they do, it gets dragged out for decades.
Been the status quo since the mid-70's

744SPX wrote:

Spacepope wrote:

Well now, this was an unexpected development.

Active winglets are to be fir to the KC-135 fleet, with some possibly in service toll FY 2050...

https://www.thedrive.com/the-war-zone/k ... g-winglets

As with winglets, aircraft engine upgrades are another item that the Air Force and Navy simply refuse to incorporate unless they are forced to. When/if they do, it gets dragged out for decades.
Been the status quo since the mid-70's

That’s not true, it’s more a matter of defense procurement rules and Congress. The KC-135 and C-5 re-engine programs were dragged out over decades due to budget priorities from Congress and competition from other programs. The services would like nothing more than speeding up these lines—Congress and budget gets in the way.

GalaxyFlyer wrote:

744SPX wrote:

Spacepope wrote:

Well now, this was an unexpected development.

Active winglets are to be fir to the KC-135 fleet, with some possibly in service toll FY 2050...

https://www.thedrive.com/the-war-zone/k ... g-winglets

As with winglets, aircraft engine upgrades are another item that the Air Force and Navy simply refuse to incorporate unless they are forced to. When/if they do, it gets dragged out for decades.
Been the status quo since the mid-70's

That’s not true, it’s more a matter of defense procurement rules and Congress. The KC-135 and C-5 re-engine programs were dragged out over decades due to budget priorities from Congress and competition from other programs. The services would like nothing more than speeding up these lines—Congress and budget gets in the way.

Might have been a blessing in disguise. These winglets are active so they manage loads throughout. The original first Gen fixed winglets might have ended up causing fatigue issues ending the life of the KC-135 decades ago due to cracking.

Modern winglets will give a better percentage improvement on a 1950's wing than a 1980's wing.

The performance gain on the KC-46 would be small. The E-7 wedgetail AWAC based on the 737 also has no winglets. Boeing have sensors installed on the wingtips of the KC-46 and E-7. Adding sensors to a winglet might result in the winglet not working as good.

This whole idea of adding winglets to an aircraft, with relative low utilisation at the very, very end of its career, is IMHO the result of non-technical skilled politicians and below par skilled decision making bras.

The same is valid for the KC-46A design requirements :
- no winglet from the start for obscure reasons, now winglets may be installed later ?
- no T/R's for weight / maintenance saving, resulting in expensive non standard PW4062 cowlings and less safety for the (expendable) flight crew.
- selecting PW4062 engines , while the GE CF6-80C2B6F/B7F is the engine of choice for all civil 767 operators for the last 5-10 years. Also the KC767's are GE powered, so the combination airframe /engine / warps was already certified. PW seems to have a lot of lobby power inside the DOD. and politicial decision makers..
- The constant change in requirements for the KC-46A or not properly described requirements.

GalaxyFlyer wrote:

744SPX wrote:

Spacepope wrote:

Well now, this was an unexpected development.

Active winglets are to be fir to the KC-135 fleet, with some possibly in service toll FY 2050...

https://www.thedrive.com/the-war-zone/k ... g-winglets

As with winglets, aircraft engine upgrades are another item that the Air Force and Navy simply refuse to incorporate unless they are forced to. When/if they do, it gets dragged out for decades.
Been the status quo since the mid-70's

That’s not true, it’s more a matter of defense procurement rules and Congress. The KC-135 and C-5 re-engine programs were dragged out over decades due to budget priorities from Congress and competition from other programs. The services would like nothing more than speeding up these lines—Congress and budget gets in the way.

I'm thinking more about aircraft like the F-15C, F-14A, and F-18E/F. There were improved engines available early on (within 5-10 years) in all three cases (PW1128 for the F-15C, EPE for the SH) Now the F-14 got new engines (14 years late) but they still didn't have the performance of the engine it was originally supposed to get, with the F110 having 1200 lbs less thrust, weighing 1000 lbs more, and having worse fuel consumption than the F401, and that is all on the Navy. Sure the F401 had some teething troubles but they were all solved by the late 70's and thrust had even risen another 2000 lbs to 30k in the F401-PW-29C from 1979.

747classic wrote:

This whole idea of adding winglets to an aircraft, with relative low utilisation at the very, very end of its career, is IMHO the result of non-technical skilled politicians and below par skilled decision making bras.

The same is valid for the KC-46A design requirements :
- no winglet from the start for obscure reasons, now winglets may be installed later ?
- no T/R's for weight / maintenance saving, resulting in expensive non standard PW4062 cowlings and less safety for the (expendable) flight crew.
- selecting PW4062 engines , while the GE CF6-80C2B6F/B7F is the engine of choice for all civil 767 operators for the last 5-10 years. Also the KC767's are GE powered, so the combination airframe /engine / warps was already certified. PW seems to have a lot of lobby power inside the DOD. and politicial decision makers..
- The constant change in requirements for the KC-46A or not properly described requirements.

In fairness, the KC-767's WARP's are no longer manufactured; Smiths Aerospace is no more and is a division of GE Aerospace. And they no longer compete in the aerial refueling market.

It feels like, to me, that the Air Force is both bowing to the realities that they are now facing with the "pivot to the pacific" and having slightly loser purse strings in congress to support it. Supporting any sort of military activity in the pacific will push the refueling assets to their limits and produce a massive drain on both fuel reserves and on the money to keep them full. This suddenly makes ANY investment in increasing the capabilities of their existing tankers an important and reasonable expenditure. For the tempo of operations any conflict will require, you are talking about tens of thousands of gallons of fuel saved by the presence of the winglets in any given month. That's a big deal. It was never as important in most past conflicts as the vast majority of missions involved only regional operations with lower flight times and the ability to keep tankers relatively near enemy airspace. In the pacific, missions will be considerably longer, with tankers flying farther to get on station.

Every little bit will help.

LightningZ71 wrote:

It feels like, to me, that the Air Force is both bowing to the realities that they are now facing with the "pivot to the pacific" and having slightly loser purse strings in congress to support it. Supporting any sort of military activity in the pacific will push the refueling assets to their limits and produce a massive drain on both fuel reserves and on the money to keep them full. This suddenly makes ANY investment in increasing the capabilities of their existing tankers an important and reasonable expenditure. For the tempo of operations any conflict will require, you are talking about tens of thousands of gallons of fuel saved by the presence of the winglets in any given month. That's a big deal. It was never as important in most past conflicts as the vast majority of missions involved only regional operations with lower flight times and the ability to keep tankers relatively near enemy airspace. In the pacific, missions will be considerably longer, with tankers flying farther to get on station.

Every little bit will help.

If you need more range, not retiring the KC10's until the next tanker arrives would be the perfect "pivot to the pacific" solution.

747classic wrote:

LightningZ71 wrote:

It feels like, to me, that the Air Force is both bowing to the realities that they are now facing with the "pivot to the pacific" and having slightly loser purse strings in congress to support it. Supporting any sort of military activity in the pacific will push the refueling assets to their limits and produce a massive drain on both fuel reserves and on the money to keep them full. This suddenly makes ANY investment in increasing the capabilities of their existing tankers an important and reasonable expenditure. For the tempo of operations any conflict will require, you are talking about tens of thousands of gallons of fuel saved by the presence of the winglets in any given month. That's a big deal. It was never as important in most past conflicts as the vast majority of missions involved only regional operations with lower flight times and the ability to keep tankers relatively near enemy airspace. In the pacific, missions will be considerably longer, with tankers flying farther to get on station.

Every little bit will help.

If you need more range, not retiring the KC10's until the next tanker arrives would be the perfect "pivot to the pacific" solution.

That certainly makes the most sense which seems to be why it’s not happening

Avatar2go wrote:

Max Q wrote:

747classic wrote:

If you need more range, not retiring the KC10's until the next tanker arrives would be the perfect "pivot to the pacific" solution.

That certainly makes the most sense which seems to be why it’s not happening

It makes the most sense if you restrict the evaluation criteria to range alone. But the reality is that the USAF cannot do that. They have to maintain the fleet in a state of readiness, which entails many forms of costs. When all of that is considered, alongside the alternative capabilities they have with the KC-46, it doesn't make sense.

The entire KC10 infrastructure (hangars, engineering, special tools, simulators, etc ) is at the moment still in place. Spare part availibilty is no issue (many FedEx MD10-30 recently stored at VCV)
Re-activation of KC10's (if needed) will be possible at moderate costs. Note : 59 aircraft is not a small fleet, aging aircraft cost of KC-10's are minimal, compared to the aging aircaft costs of the Boeing KC135 fleet.

However, in a few years time when all KC10's will be stored , the infrastructure and knowledge are gone forever.
Getting the stored KC-10's activated will then be very very expensive.(read : impossible)

The Pentagon only thinks in budget years, the POM, and four competing services. Unlimited wants and limited resources.