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Commercial Aviation air refueling


Clark Griswold

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The vast majority of airline pilots have NEVER flown formation. Ever. And when I used to push off the gate in the 787 headed to Australia, we had over 200,000 pounds of fuel on board, or twenty hours of duration.

Commercial AR will never happen. 

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7 hours ago, daynightindicator said:

 


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.

 

3 pilots in a bone?  Do you guys have a jumpseat or something?

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17 hours ago, matmacwc said:

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

Fuel spray, staring at the boom, constant power corrections as the jet gets heavier, and a constantly shifting center of gravity as you fill the tanks makes it more challenging.

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20 hours ago, Tinker51 said:

From a benefit vs. risk comparison I just cannot come up with any metric that would make this a good idea.

The only thing I can think of that makes this (commercial AR) worth the effort would be for a UAV or manned platform like a BACN (a civilian version) or a SAR aircraft.  

A civilian platform (commercial or state aircraft) needing / wanting extreme endurance.  The application to passenger air travel seems / is unneeded but there is a sliver of requirement for a few possible operators if they wanted the capability (USCG, CBP, DoS,  Telecomm providers, etc...) to fly for 10+ hours.

Edited by Clark Griswold
grammar fix
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11 hours ago, Naviguesser said:

Just imagine the condition of the lavs for a small airliner after 18+ hours of flying.  *shudder*

Just imagine the condition of the lavs after 20-30 mins of AAR.  If you thought that last whale watching tour or deep-sea fishing trip was bad, just wait until 250 people start to get sick from the back end of receiver AAR.  I've heard the loads tell some terrible/hilarious stories of sick pax in the back of the C-5 after/during taking gas.  Can't imagine that it would be much better in any other jumbo jet.

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Another site on the RECREATE Cruiser - Feeder concept:

https://transport.weblog.tudelft.nl/2014/11/05/recreate-research-on-a-cruiser-enabled-air-transport-environment/

How they envision the AR event to be, an offset enroute reverse cowgirl AR...

Figure2.png

And rendezvous points, on the nat tracks, enroute points and close to departure...

Figure5.png

Just grist for the mill but interesting.  Me thinks AR close to their departures would be better if they ever actually deployed this system (doubtful).  

Benefits:  Check AR capability before the receiver (cruiser) is over BFE low on fuel and could more quickly cycle one tanker (feeder) for multiple customers.

Edited by Clark Griswold
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On 1/14/2017 at 10:29 AM, Naviguesser said:

Just imagine the condition of the lavs for a small airliner after 18+ hours of flying.  *shudder*

+1. No one wants to sit in coach longer than the current long-haul flights. The big twin jets can fly almost half around the world non-stop - there is little need to go further than that.

23 hours ago, Clark Griswold said:

Me thinks AR close to their departures would be better if they ever actually deployed this system (doubtful).  

I think this is the only viable advantage of this concept - it could help larger aircraft or enable longer flights from smaller airports. Rather than trying to extend range/endurance, you could load up with passengers (or cargo) at a smaller airfield and enough fuel to get to AR rendezvous near departure then top off to reach your destination. There are several cities around the world with large, distant hubs and smaller airfields near the city center. This could make those smaller airfields more accessible and enable non-stop long-haul flights. But passengers would certainly pay a premium.

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48 minutes ago, HerkPerfMan said:

I think this is the only viable advantage of this concept - it could help larger aircraft or enable longer flights from smaller airports. Rather than trying to extend range/endurance, you could load up with passengers (or cargo) at a smaller airfield and enough fuel to get to AR rendezvous near departure then top off to reach your destination. There are several cities around the world with large, distant hubs and smaller airfields near the city center. This could make those smaller airfields more accessible and enable non-stop long-haul flights. But passengers would certainly pay a premium.

This.  AR opens the door to high/hot/heavy, just like it does for us.  It could be a game changer for access to regional airports.

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1 hour ago, HerkPerfMan said:

But passengers would certainly pay a premium.

 

38 minutes ago, HU&W said:

This.  AR opens the door to high/hot/heavy, just like it does for us.  It could be a game changer for access to regional airports.

Most of the articles focus on a 230 PAX jet getting AR and saving 20% fuel for the trip via multiple AR events, doing bar napkin math...

Assume Commercial Tanker costs 15K per hour and flies a 2 hour mission for two customers on the same mission, 30k charged to two airlines, so it's 15k to each.

Both customer jets are at 200 PAX each and because they are departing less congested airfields at lower GW, the airport fees are lower, estimate those costs at $750 per jet.

So distribute $30k in tanker costs, $1500 in landing fees and we'll make up a new fee for Commercial AR that would likely be charged by ATC if this system were implemented, $500 per AR event, and that is another $1000....

30 + 1.5 + 1 = 32.5k over 400 PAX comes to $81.25 but then figure that the aircraft will burn 20% less fuel and assume these flights burn 80k over a 10 hour flight and that is 16k in fuel savings per flight so 32k total, about $20k less fuel costs so apply those savings to the PAX.

That's about $50 in savings per customer so that takes the $81.25 down to $31.25 per PAX to pay for the AR.

That does not figure in cost to acquire and start up the Commercial Tanker aircraft / service but a per PAX cost seems almost conceivable.  

Another WAG, the tanker would probably cost $40 mil a copy so to pay for it in 10 years figuring 500 AR events a year and adding 10% profit comes to $8,800 in profit per mission required, so the real operational cost of the tanker would need to be $6,200, just does not seem possible...

 

 

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But what about training costs and currency requirements?  Long haul flights have 3 or 4 pilots and how does that affect who is qualified and who is not to fly the trip.  Smaller airports might have lower landing fees but I doubt they have the passenger traffic to generate the requirement for a wide body jet.  And finally, the current generations of twin jets can fly half way around the world so instead of using a tanker to fly further, why not just go the other way around the planet?

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33 minutes ago, TreeA10 said:

But what about training costs and currency requirements?  Long haul flights have 3 or 4 pilots and how does that affect who is qualified and who is not to fly the trip.  Smaller airports might have lower landing fees but I doubt they have the passenger traffic to generate the requirement for a wide body jet.  And finally, the current generations of twin jets can fly half way around the world so instead of using a tanker to fly further, why not just go the other way around the planet?

For the Cruiser (receiver) pilots and crew, probably minimal.  

RECREATE designed / tested (simulators) on the receiver pilots pretty much doing nothing while a special autopilot mode, automatic boom and the receiver aircraft managed the AR event and fuel intake.  Their reverse cowgirl AR keeps the tanker on the bottom and could limit the number of pilots / crew required to have specialized AR skills to a minimum for training costs.

Agree on the smaller airport argument however unless some extra parallels are put in at some the largest airports, they are at capacity.  Even then, gate congestion is getting to be an issue.  An argument for this could be to clear gates/company ramps a bit faster but that is rather thin...

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One other way this might be profitable is with cargo, rather than pax.  If there are enough cargo flights that aren't utilizing their full ACL due to required fuel loads, they could increase their cargo loads to the max ACL/ZFW of the aircraft, potentially get off smaller runways at less than MGTOW (or use more derated takeoffs, and get more hours out of the engines), and still make a profit off the flights due to the increased cargo revenue.

I have no idea if there are cargo flights could benefit from this to make it profitable; I know there's a fair number of flights that cube out their cabins long before they hit their ACL/ZFW.  I would also imagine the cargo carriers would have a similar potential to pax carriers to incur losses on flights, due to the financial consequences of an AR canx.

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12 hours ago, JarheadBoom said:

One other way this might be profitable is with cargo, rather than pax.  If there are enough cargo flights that aren't utilizing their full ACL due to required fuel loads, they could increase their cargo loads to the max ACL/ZFW of the aircraft, potentially get off smaller runways at less than MGTOW (or use more derated takeoffs, and get more hours out of the engines), and still make a profit off the flights due to the increased cargo revenue.

I have no idea if there are cargo flights could benefit from this to make it profitable; I know there's a fair number of flights that cube out their cabins long before they hit their ACL/ZFW.  I would also imagine the cargo carriers would have a similar potential to pax carriers to incur losses on flights, due to the financial consequences of an AR canx.

Good idea.  

Trade fuel for revenue producing cargo and/or lower operational cost/wear & tear and get the gas you need in the air.

The problem I see from my overly simple calculations from above posts is the pay back rate from the direct profits to be made from the Feeder sorties, you would have to quantify the other savings you mentioned (derated takeoffs, longer times between major overhauls, etc..) for customers and have them bake that into their business model for Cruiser aircraft.

Question(s), considering a hypothetical 777 Freighter AR Cruiser capable aircraft, if you stopped filling the wings to capacity for fuel, would that impart greater structural stress due to the loss of load spreading?  If so, would that necessitate or incentivize a wing redesign?  Designing a new wing to optimize a Cruiser AR (for operations and structural reasons) would seem to negate or again make the payback time too long to generate interest in developing the capability.   

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12 hours ago, Clark Griswold said:

Question(s), considering a hypothetical 777 Freighter AR Cruiser capable aircraft, if you stopped filling the wings to capacity for fuel, would that impart greater structural stress due to the loss of load spreading?  If so, would that necessitate or incentivize a wing redesign?  Designing a new wing to optimize a Cruiser AR (for operations and structural reasons) would seem to negate or again make the payback time too long to generate interest in developing the capability.   

I don't know any details of the 777 freighter's fuel system, or any of it's loading "gotchas" WRT wing fuel qty. vs. cargo load/gross weight.  It might require some creative fuel scheduling, and possible software revision to the fuel management computer software.

I can't see a wing redesign, just to accommodate this niche market, being financially feasible. 

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45 minutes ago, JarheadBoom said:

I don't know any details of the 777 freighter's fuel system, or any of it's loading "gotchas" WRT wing fuel qty. vs. cargo load/gross weight.  It might require some creative fuel scheduling, and possible software revision to the fuel management computer software.

I can't see a wing redesign, just to accommodate this niche market, being financially feasible. 

Sorry for the distraction of mentioning the 777 freighter specifically, not really necessary as this idea of an optimized wing - thinner and structurally different for lower fuel loads - for a Cruiser Freighter could be applied to any existing or a future design.

Looking at what the RECREATE teams have proposed; the wings, stabilizers, etc.. are all unique designs mated to what look like conventional fuselage designs.  

Figure-4.png

Trying to keep it inexpensive by reusing current designs but trying to reap the full potential benefits doesn't seem to be possible from their proposals.  Interestingly, it looks like from their comparisons, the Cruiser concept aircraft could be powered by smaller, less expensive engines.  

That could be a large potential savings in acquisition, operation and maintenance.

 

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