Commercial Aviation air refueling

[Clark Griswold]

I'm skeptical this will happen or if there is really a need but there is a good bit of research going into this...

https://www.bbc.com/future/story/20161220-the-aerial-tankers-that-helped-shrink-the-globe

https://www.google.com/patents/US20030136874

https://www.range-unlimited.com/

https://theconversation.com/in-flight-refuelling-for-airliners-will-see-non-stop-services-shrink-the-globe-39931

Reading this and thinking about my own time flying the mighty 135, the only way I could see this happening and being profitable/logistically sensible is if you could synchronize the tankers and receivers by a reciprocative schedule/flight plan or rendezvous .  

If the receiver was scheduled to a destination that allowed for a  convenient  AR for the tanker which was also flying another revenue producing mission (they have intersecting or parallel flight plans) then maybe but putting a tanker up just to extend the range of 2 or 3 airliners doesn't seem commercially viable with relatively cheap Jet A and transport category aircraft getting more fuel efficient.

Just guessing that a commercial tanker would cost about 15K per hour and would have logistical costs at it's MOB of about 2k per mission and WAGing an average 3 hour mission comes to 47k.  Round up to 50k for just under 10% in unforeseen costs and that is a considerable bill for airlines to foot.  

Also, didn't see anything in the articles about what happens when things go wrong (tanker breaks, receiver can't take gas, WX sucks in the track, air traffic congestion interference).  Not sure they are considering the entirety of the whole effort to pass gas in the sky. 

Still, an interesting idea, here's the linked sims flown by the RECREATE project to try this out in the Matrix before taking it live...

 

 

Edited December 24, 2016 by Clark Griswold
spell check bent

[Clark Griswold]

4 minutes ago, Kiloalpha said:

It would be the Germans...

I'm with you, don't see the viability when it comes to scale and cost.

Yup, AR is easy and great when everything works and everything happens as planned, and that happens almost never.  Not saying every AR mission was a life and death struggle but there was always some hiccup or change to deal with.  

If the AR gets slipped by 15 mins, that's (in my hypothetical 15K per hour comm tanker) another $3750 charged to the customer or absorbed by the tanker company, that could be the profit for the whole mission.  

Also, what happens when you delay/flex for one customer but have a contract to deliver to another and they now conflict with each other?

Lots of moving parts to deal with.  The military does AR because it has too, don't really see the Commercial Aviation enterprise needing to do this, but hey give it a try they might make it work.

Boeing or Airbus equipment would probably be too expensive for this but Ukraine with it's An-112KC could probably deliver this hypothetical commercial tanker:

https://image.slidesharecdn.com/an112kc-100710063555-phpapp02-100714232617-phpapp02/95/an112kc-100710063555phpapp02-9-728.jpg?cb=1279150020

They would likely be around 30% or more less expensive (not saying better but cheaper) and have a cargo mission capable aircraft to maximize potential revenue on each mission.

 

[hispeed7721]

If I had to throw out a possible customer, it would be Emirates or someone like that who could use the plane as a PR stunt for "the world's longest non-stop flight" or some nonsense. 

This is the only situation that will ever make this a reality. Current major fleets don't need them, and any smaller companies who would use it to move up in competition couldn't afford it because they're too small to pay for all new AR-capable tails.


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[JarheadBoom]

5 hours ago, Kiloalpha said:

A significant hurdle is the fact that none of the current commercial fleet is equipped for AR. Retrofitting isn't an option that I know of, so they'd need all new designs to hookup and take gas.

Boeing has UARRSIs flying on military versions of the 737, 747, 757, and 767, so the engineering is done for those airframes.  Retrofitting the hardware is definitely possible... it would just require each airframe being retrofitted to be taken out of service for a while for the install.  I'd have to dig into the FARs to be sure, but I don't believe fuel lines are allowed in passenger cabins of transport-category aircraft, so this might only be possible on non-US registered aircraft.    Having said all that, of the aircraft I listed, only the 737 is still in long-term production.  747, 757, and 767 are all either out of production or close to it, and in their golden years WRT passenger service. 

I don't believe Airbus has flown a receptacle on any of their commercial airframes, so there's a bunch of engineering, development, and testing money that would need to be spent (and eventually recovered) for that capability.

Probe and drogue is far too limiting, WRT offload rate and airspeed limitations of the drogue.

I just can't see this being profitable commercially, at any scale.  As already stated, maybe a niche capability from one of the Asian/Middle Eastern airlines, solely for bragging rights.

[SurelySerious]

I just can't see this being profitable commercially, at any scale.  As already stated, maybe a niche capability from one of the Asian/Middle Eastern airlines, solely for bragging rights.

Yep. Most airliners already have ranges in the realm of 7.5k nm, or 8.5knm for your 777-200LR. There are very few routes that would need this; for those that could use it, the cost to implement alone would probably kill the slim profit margins, let alone any hiccups like rendezvous timing etc.

[Clark Griswold]

They (advocates for this) seemed to be looking for a problem to solve, the closest I read in their proposals to a legitimate problem/reason was to have large long range aircraft operate out of shorter, less congested airfields having lower GW via low fuel loads to allow operation out of these fields and picking up their gas for their long range flights after departure. 

Still just seems easier to just land or get a bigger jet / better wing & motors.

For long range, speed and short(er) field capability, the 757, IMO fills the bill, plus it was/is just beautiful.

Too bad Boeing didn't think there was a case for making a MAX version of it.

Sexy beast...

 

Edited December 24, 2016 by Clark Griswold

[Clark Griswold]

More on this idea...

RECREATE was originally investigating nuclear powered continuously flying aircraft taking on modules in flight, gave up on it after realizing no one would ever let an operating nuclear reactor fly over their country, started looking at doing AR as it is done now, tanker on top receiver on the bottom, sts just to cover that.

But decided a tanker on the bottom pushing fuel up to the receiver was logistically easier and safer, less receiver training requirements and safety was enhanced, put sexual innuendo comment here: __________________.

Proposed routes with AR orbits for long range commercial aircraft:

https://www.mirror.co.uk/news/technology-science/technology/nuclear-powered-planes-could-see-passengers-5474910

https://airnation.net/hangar/threads/aviation-week-air-to-air-refueling-for-commercial-air-travel.18228/

Receiver on top AR CGI...

 

From the last article linked:

But as a near-term option, aerial refueling showed promise. Here the “cruisers” are 250-seat aircraft designed for 2,500-3,000-nm range. Optimizing the aircraft for a 5,000-nm flight with one refueling, by resizing the wing, reduced fuel weight just over 20%. Two refuels and the savings approached 25%.

The “feeders” are purpose-designed tankers with refueling booms, able to offload 35,000 lb. of fuel over three contacts per 4-hr. mission. “Three refuels per tanker looks sensible, based on aircraft size and the load on their bases,” says Tomas Martensson, senior scientist at Swedish defense research agency FOI.

3 contacts to offload 35K total?  Again, doesn't seem financially / logistically worth it...

 

 

Edited December 26, 2016 by Clark Griswold

[Majestik Møøse]

AR for commercial air travel only looks viable for hucksters soliciting startup capital and uninformed BBC hacks. Reasons:

- If you're filling up a big jet with a big tanker, you're flying two planes instead of one to do what airlines can already do; fly from somewhere like DFW to Sydney nonstop over 17 hrs. No one wants to fly further than this.

- If you're filling up small jets with a big tanker, you're putting all your eggs in one tanker basket. If you like diverting half the fleet to Rekyavik once a week, this may be the option for you. 

- The one scenario where this is viable: AR for SSTs at halfway points. The super rich will pay a premium to get places fast, and AR can just be rolled into the cost. Now all we need is for someone to build an SST. 

[Hacker]

This is a solution looking for a problem.

[JarheadBoom]

22 hours ago, Clark Griswold said:

But decided a tanker on the bottom pushing fuel up to the receiver was logistically easier and safer, less receiver training requirements and safety was enhanced, put sexual innuendo comment here: __Reverse Cowgirl... with airplanes!__.

< snip >

 

Receiver on top AR CGI...

 

Yep... definitely reverse cowgirl.

[Clark Griswold]

Found the RECREATE website:
https://www.cruiser-feeder.eu

Enjoy

About 99.69% sure this is not necessary but interesting to see how someone else would approach doing AR


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[Don Frank]

I read an interesting AIAA paper on this concept. While in theory it could save on fuel burn and operating costs, there's still the aforementioned issue of scheduling/ATC, plus figuring out civilian refueling training and extra tanker hub infrastructure needed. Considering the size of the global airline fleet and frequency of flights, that could take a huge amount of time and money to build up to the point where fuel savings might not be worth it. 

[Clark Griswold]

43 minutes ago, Don Frank said:

I read an interesting AIAA paper on this concept. While in theory it could save on fuel burn and operating costs, there's still the aforementioned issue of scheduling/ATC, plus figuring out civilian refueling training and extra tanker hub infrastructure needed. Considering the size of the global airline fleet and frequency of flights, that could take a huge amount of time and money to build up to the point where fuel savings might not be worth it. 

It does seem not worth the while (Civil AR with a large aircraft as a tanker) but what if instead of another transport category manned aircraft to act as the feeder (tanker) you used a UAV to deliver the fuel at one or more AR points, continuing on to your destination...

Instead of this MQ-25 getting gas, it could be pumping gas up to receiver to extend flight, enable very high speed cruise, etc... of course it would need be a way bigger RPA but that is just a matter of scaling it up.

Could be a multi-benefit project for some countries developing aerospace capabilities:

RPA delivered AR, new AR systems readily adaptable to existing transport category civilian aircraft, operational/logistical experience with long range RPA ops, etc... 

That is a bit of problem to solve finding there but for China, India, even Russia this could be a capability to develop to garner respect, demonstrate capabilities and potentially win new customers for civil/military aviation systems...

 

Edited December 27, 2016 by Clark Griswold

[Don Frank]

13 minutes ago, Clark Griswold said:

It does seem not worth the while (Civil AR with a large aircraft as a tanker) but what if instead of another transport category manned aircraft to act as the feeder (tanker) you used a UAV to deliver the fuel at one or more AR points, continuing on to your destination...

Instead of this MQ-25 getting gas, it could be pumping gas up to receiver to extend flight, enable very high speed cruise, etc... of course it would need be a way bigger RPA but that is just a matter of scaling it up.

Could be a multi-benefit project for some countries developing aerospace capabilities:

RPA delivered AR, new AR systems readily adaptable to existing transport category civilian aircraft, operational/logistical experience with long range RPA ops, etc... 

That is a bit of problem to solve finding there but for China, India, even Russia this could be a capability to develop to garner respect, demonstrate capabilities and potentially win new customers for civil/military aviation systems...

 

RPA AR is definitely probable; Gen Everhart from AMC even talked about the eventual KC-Z possibly being unmanned. At any rate, this still seems very far off considering we're only just defining rules for UAV use in the airspace. Changes in ATC and airspace regulations would be needed before this could work. For the time being, I can see the airline industry simply investing in more efficient propulsion systems.

[Clark Griswold]

33 minutes ago, Don Frank said:

RPA AR is definitely probable; Gen Everhart from AMC even talked about the eventual KC-Z possibly being unmanned. At any rate, this still seems very far off considering we're only just defining rules for UAV use in the airspace. Changes in ATC and airspace regulations would be needed before this could work. For the time being, I can see the airline industry simply investing in more efficient propulsion systems.

Ditto - just buy a 777-200LR and fly to wherever the hell you want.  

Geared turbofans, better wings/winglets, composite materials, etc.. probably make this a moot point but it is interesting and could be another military technology that makes it's way to the civilian world.

[HerkPerfMan]

On 12/24/2016 at 11:10 AM, JarheadBoom said:

I don't believe Airbus has flown a receptacle on any of their commercial airframes, so there's a bunch of engineering, development, and testing money that would need to be spent (and eventually recovered) for that capability.

Airbus A330 MRTT has UARRSI installed as well.

[daynightindicator]

The money and effort being put into this would be better spent looking at improving fuel efficiency or developing new fuel/energy sources for aircraft.

Agree it's a solution looking for a problem.


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[jango220]

17 hours ago, HerkPerfMan said:

Airbus A330 MRTT has UARRSI installed as well.

Airbus has definitely gone all-in on the MRTT as of late. They are currently flight testing an automatic version of their boom, as well as an avionics and aerodynamics upgrade. While the KC-46 may be the "next-gen" tanker, the 330 MRTT is definitely going to make up a large chunk of tankers worldwide. Just off the top of my noggin: Australia and England have been flying theirs (with the UK looking to add a boom as well) for a while,the European consortium is doing a bulk buy, several middle east countries are flying/have bought, India finally paid for theirs, the South Koreans and Singaporeans are buying, etc etc.

Oddly enough, they have one big LIMFAC: landing gear configuration. They are twin-tandem just like the -135 but weigh about a hundred K more. They are gross-weight limited at a huge number of military airfields worldwide as a result.

[JarheadBoom]

19 hours ago, HerkPerfMan said:

Airbus A330 MRTT has UARRSI installed as well.

Damn, forgot about that...

[Vito]

 As an airline guy, how do you plan on keeping AR pilots current? In the AF I had to get a plug every calendar month...in the Airlines, especially for long-haul widebody flights, it's difficult for pilots to get landing currency.  Also, seniority rules in the Airlines, so your young hot shot sticks won't be refueling, it'll be the old fat guys, who may may have the seniority but not the skills....the whole idea is untennable for a passenger airline...maybe cargo, but as a UPS pilot, you'd have to pay me a big premium for any AR mission!$$$$$$$$$$$

[matmacwc]

There is a currency for fighter dudes but it doesn't mean much, I hadn't tanked in 5 years and my first time back I was in a single seater with an IP on the wing.  They can make it easy.  

[Clark Griswold]

4 hours ago, Vito said:

 As an airline guy, how do you plan on keeping AR pilots current? In the AF I had to get a plug every calendar month...in the Airlines, especially for long-haul widebody flights, it's difficult for pilots to get landing currency.  Also, seniority rules in the Airlines, so your young hot shot sticks won't be refueling, it'll be the old fat guys, who may may have the seniority but not the skills....the whole idea is untennable for a passenger airline...maybe cargo, but as a UPS pilot, you'd have to pay me a big premium for any AR mission!$$$$$$$$$$$

 

4 hours ago, matmacwc said:

There is a currency for fighter dudes but it doesn't mean much, I hadn't tanked in 5 years and my first time back I was in a single seater with an IP on the wing.  They can make it easy.  

As JarheadBoom said, it is reverse cowgirl with the receiver on top probably still on autopilot with the tanker (feeder in their terms) pumping fuel up to the receiver aircraft.

The boom is automatic or drouge if they went that route and the skills would be required by the "feeder" aircraft.

Agreed it looks like a solution to a nonexistent problem but it was/is interesting how much research they have done, simulator time and serious engineering work is not cheap so someone thought spending a million or whatever researching this was worth it.  

This would have so many moving parts, places to go wrong, expensive (possibly dangerous) risks, that I don't see how the airlines that would do this could break even considering the whole endeavor and doing it only for the longest flights in the world that are just not the revenue makers for the airlines.

Edited January 10, 2017 by Clark Griswold
minor

[Hacker]

Time for whales humping!

[daynightindicator]

There is a currency for fighter dudes but it doesn't mean much, I hadn't tanked in 5 years and my first time back I was in a single seater with an IP on the wing.  They can make it easy.  

Bomber (at least in the Bone) AR currency is a pretty big deal for maintaining CMR. Self re-hacks not allowed and it wreaks havoc with scheduling when IPs go dead. We end up generating a lot of 3-pilot proficiency sorties to get everyone current which detracts from training.

Probably also has to do with the fact that it's a somewhat difficult skill to master since the receptacle is in the nose like the Hog and taking 100K+ means hanging on for 15 minutes or more.


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[matmacwc]

I think the nose AR would be easier than not seeing the receptacle 10 feet behind you.