Air Force Plans New Blended Wing Body Cargo/Tanker Aircraft by 2027 | Hacker News Reader

Air Force Plans New Blended Wing Body Cargo/Tanker Aircraft by 2027

airandspaceforces.com

107 pointsdangle1110 comments

A tanker is a good fit for a blended wing body. Fuel efficiency is important for that mission, fuel tanks can be easily adapted to the odd shape (compared to cargo), and fuel doesn't care about the bobbing up and down in turns that comes from the wide hull shape (compared to passengers who don't like about that).

Reconnaissance would work too.

  > fuel doesn't care about the bobbing up and down

Maybe the fuel doesn't care, but the flight crew certainly will care about a large oscillating mass constantly changing the aircraft's center of mass.

Baffles are typically used to control this, even in conventional aircraft fuel tanks. It's a non-issue.

I mean, baffles aren't free, since they add empty weight and reduce payload. The designers will be tempted to keep them to a minimum. There definitely will be at least some free surface effect and slosh.

Plastic bags to reduce slosh?

Plastic bags to vomit in.

Is it drastically different from conventional aircraft though? The KC-135 houses a great deal of it's own fuel in the wings as well. So does most commercial air liners AFAIK.

30% more efficient according to the article.

Wonder how much a computer can dampen/remove/counter these sloshing events by constantly adjusting the control surfaces. super interesting stuff.

What about an isolation platform aka a pilot cockpit and boom operator gimble?

I agree the computing tech should help a lot! Seeing what experiments were done with the ground effect RC project (what’s his name, cool YouTube vids) indicates the software exists or will soon for a large craft. Especially because this will be generation 3 of a flying wing!

> the flight crew certainly will care

How long will tankers be crewed?

The new Navy MQ-25 tanker is uncrewed. I expect this future Air Force tanker will be optionally manned. The main issue is that Air Force tankers use a boom system which requires an operator onboard to manually "fly" the boom into the receptacle. In theory that could be automated but it's a difficult technical problem. Navy tankers use a simpler drogue system which doesn't require a boom operator.

Surely the fuel will be separated in to multiple tanks with pumps between them, similar to conventional aircraft.

The KC-46 program has not gone swimmingly. I'm curious how they think they're going to get a demonstrator flying in 5 years when they can't get a tanker that's based on an existing production airframe flying on schedule.

https://en.m.wikipedia.org/wiki/Boeing_KC-46_Pegasus

Maybe working off an existing design is harder than greenfield?

If that were true why did we get the 737 MAX?

Actually, the 737 MAX as a new plane would have been fine. The MCAS software was used to try to give it the same flight characteristics as the 737 so that existing 737 pilots did not have to get additional certification for it.

Yeah, but they didn’t just build a new plane (pilots perhaps?) and instead always seem to try to modify existing designs, which would argue that is cheaper than greenfield.

a new plane would not have been eligible for the same type certification, thus forcing all pilots who flew it to obtain the new type rating. This training is very expensive for the airlines.

in other words, Boeing's thesis was, because we (heavily) modified the 737, it's the same basic plane. The FAA accepted this argument. The FAA would never have accepted the argument that a totally new design was "actually a 737 ".

Modifications to old certifications are subject to older certification rules. They can be flown by pilots with existing training. Thus saving money at the cost if safety and decades of improvements in technology and regulation. End of story ... And of lives.

It wasn't Boeing that was trying to save money themselves- it was Boeing trying to save airlines money. There are hundreds of thousands of people today who can fly a 737, and mechanics who can fix a 737, etc. The airlines wanted to get the better fuel efficiency from modern engines on a plane that everyone already knew how to fly and fix. Boeing actually started with a clean sheet design, tried to pitch it to airlines, the airlines didn't bite, so Boeing gave them what they wanted- the same plane but more fuel efficient. It was a huge fiasco, but it was about leveraging the advantage Boeing had in users, not saving on development costs.

“Give us a 737 but more crashy” is also not what their customers really wanted. There were surely more possibilities available than just the two extremes of “737 but crashes more” and “tiny Concorde.”

Had the software worked as intended, no one would have noticed.

That's the problem - it's not clear to me that it could have worked as intended. But you can easily get that impression in high level meetings I imagine.

I think it could have, but perhaps without the safety factors needed, because of insufficient redundancy in the AOA sensors.

American Airlines ordered 130 330neos and 100 "re-engined 737s" while Boeing was still pitching their "smaller 787" design. Note that this was the first time AA had ever ordered a non-Boeing plane.

Everything stems from Boeing taking this deal. Within the constraints of the 737 type certification: more efficient engines are larger, larger engines must move forward, forward engines change flight characteristics, flight characteristics must be augmented to maintain certification.

So you are correct that Boeing had choices other than "crashy 737", but that choice was between throwing billions away to Airbus and the crashy 737.

Not sure if you're being sarcastic or not, but I'll bite:

The 747 MAX that killed 346 people in two separate accidents and was grounded for nearly two years and cost Boeing 10's of billions of dollars in fines, cancelled orders, etc.?

It is perhaps not the best example of modifications to an existing design.

All because they didn't want to completely redesign the landing gear, to give it a higher ride height, which would allow the engines to be put at a normal position under the wing, thereby permitting a normal center of thrust axis. Just to keep the existing faa certification.

Don't you mean 737 MAX or is that some other plane?

I did - thanks for picking that up, but I am no longer able to edit my post.

Aren’t you answering your own question?

The 737 was harder than a new design - that’s why it went wrong.

IIRC part of the problem with the Max was that since it was based on the 737 it bypassed a lot of processes that a brand new design would've had to go through. Both on the regulatory and pilot training side (eg a pilot who was already qualified on other 737 variants would get a fast tracked and probably inadequate training)

I am ready to consider that proposition as soon as I see quantitative evidence.

It seem it is possible to write specifications that cannot easily be met by incremental change, and that might be one reason why the British aircraft industry ended up creating technically competent aircraft with little sales potential.

> Maybe working off an existing design is harder than greenfield?

Except that Boeing has already one it:

* https://en.wikipedia.org/wiki/Boeing_KC-767

And Airbus (who originally won) didn't seem to have a problem:

* https://en.wikipedia.org/wiki/Airbus_A330_MRTT

Maybe NGAD rapid development cycles can be applied.

That's what I thought as well. Then you read this[1] and all the NGAD "record breaking" starts to look like smoke and mirrors.

Who knows? Maybe a tanker could happen that fast since it won't integrate a bunch of weapons. They're only promising a full scale test by 2027.

[1] https://www.thedrive.com/the-war-zone/next-gen-air-dominance...

Pretty much. Roper's Digital Century pitch for iterative 6G fighter(s) seemed like powerpoint bullshit. But a relatively clean sheet tanker much less complex integration demands seems feasible, more comparable to how B21's development is going, apparently on time and under budget.

P8 went pretty well. Blended wing isn’t sci-fi, B2 and plenty of ucav are full flying wing.

https://en.wikipedia.org/wiki/Boeing_P-8_Poseidon

Boeing was a very very different company then. I’m bullish on blended wing body, but I would have much more confidence if it were Lockheed or someone emulating the SpaceX, rapid development cycles working on this.

As someone in industry, I can assure you Boeing is still a disaster. I know a fuckload of good people who have turned down working there because the culture is shit and management is braindead even by defense contractor standards.

I worked at Boeing on both the p8 and the kc46, and it's unreal how poorly leadership let things run. Handing thumb drives with excel sheets around, waiting years to provision vms. Etc.

I'm working with Boeing people on a project, having their email system randomly fail to deliver incoming messages doesn't help.

I am up the road from Lockheed and know quite a few employees there and I'm pleased to hear a better reputation - I've heard the issues with Boeing leadership for years now as well. There's nothing like watching their airstrip for some really cool machines coming and going.

P8 to KC46 introductions was 6 years. I think it’s more likely different parts of a large corp get run differently. MQ25 and 28 seem to be proceeding fine.

> P8 went pretty well.

Did it really?

According to this fairly recent GAO report[1], the Poseidon's mission capable rates have missed their minimum 80% target since 2015, trending downwards (Table 1); only the first 2 out of 7 years were satisfactory (Figure 7), and yet those years' metrics were based on Increment 1 low-rate initial production lot that were "not effective for the intelligence, surveillance and reconnaissance mission" and "not effective for wide area anti-submarine search" that they were originally intended for[2].

Even in early years when maintenance staff was stacked balls deep at well over 100% (Figure 5), persistent supply issues plagued the platform, trending upwards (Table 5). To be sure, this outcome was entirely predictable; e.g. picking on Northrop Grumman's Electronic Support Measures system[3] that the Bloomberg article calls out as just one example: if you knew how the sausage was made, then this 2006 GAO report[4] which highlights certain risks "of particular concern" surrounding ALQ-218 development is all of sudden prescient in that it took so long to get the underlying system to acceptable maturity on the Growler that it became a very real commercial obsolescence sustainment risk by the time the Poseidon's full-rate production decision was made!

[1] https://www.gao.gov/products/gao-22-104533

[2] https://archive.ph/356bG

[3] https://news.northropgrumman.com/news/releases/northrop-grum...

[4] https://www.gao.gov/products/gao-06-446

No one is expected to really believe that schedule. It's just an imaginary number so that they can get Congress to allocate enough money to start the development program. Just the way the game is played.

And I don't even blame the Air Force for deliberately underestimating. They have a legitimate need for this aircraft and the existing fleet has been worked to death.

Corrected the title for you: "Air Force Plans New Blended Wing Body Cargo/Tanker Aircraft by 3027"

Wow, what's a TL;DR of the problems? The KC-767 seems to be working fine, one has been flying over my house at least once a week since I was a teenager

The KC-46 uses a different refueling boom control system than the KC-767 which is overly complex and makes to hard for operators to see what they're doing.

https://www.thedrive.com/the-war-zone/40821/kc-46as-long-tro...

With the ACCA being designed in 5 months and flown in 20 months from the go-ahead, I would say 5 years is definitely possible.

I wouldn't be surprised if its got a heavy use of composites as well, in order to reduce he number of total parts. For the ACCA, they had 300 structural parts vs 3,000 metallic and 4,000 mechanical fasteners vs 40,000 otherwise.

https://www.lockheedmartin.com/en-us/news/features/history/a...

To be fair, there’s a pretty massive difference in scope between a 50 mil Afrl tech demonstration program and what this would be. If/when this materializes, it’s likely to be a capital A Airforce program worth at least a billion dollars with a goal to produce at least one demonstrator that can be directly followed by LRIP and then IOC probably only a couple years after the demonstrator first flies.

For that level of effort, five years probably isn’t impossible, but it’s definitely unlikely.

> The KC-46 program has not gone swimmingly

That's what happens when protectionism gets involved. The Boeing design (based on an existing plane, but with some new systems and a combination of components from different generations of 767s) was chosen over the proven, already in production A330 MRTT. Delays and cost overruns are to be expected.

Same thing with ships, in the end US Navy had to accept it's not that special and it ended up ordering an RFP based on existing off the shelf designs (with the Franco-Italian FREMM winning).

I think that a blended wing body design extremely similar to this was one of the more radical proposals on the table, when they were developing the budget and concept for the 787.

Ultimately ended up with a carbon fiber bodied more conventional aircraft of course.

Reading the URL, I think that anything about the Air Force caring about a climate action plan, or environmental sensitivity, is window dressing to say that it's also a operational benefit to have a tanker aircraft with greater loiter time, and greater distance possible from base with full fuel load, loiter time, and return distance.

> I think that anything about the Air Force caring about a climate action plan

Indeed. The Military Industrial Complex has figured out that anything with a lot of zeros must be Climate-Washed.

Looking forward to our climate friendly hypersonic anti-ship missile program!

> concept for the 787

Such designs come up every once in a while in civil aviation - but then disappear, mostly because they would require new (expensive) airport infrastructure.

Just remember that when the A380 came out, every major airport that was a viable A380 destination started increasing their landing strip length, assuring the taxiways could handle the extra weight, worked on their baggage handling and check-in capacity and created gates that had more boarding bridges.

Now imagine what basically triangular aircraft would mean for that infrastructure.

Blended-wing body makes a lot of sense for cargo/tanker aircraft. No issues with emergency evacuation procedure for passengers.

Has it been evaluated whether any real-life evacuations were time sensitive enough to where a wide bodied plane would have resulted in more deaths? Doesn't seem like a real problem intuitively, but I don't really have any data to back that up.

Do they do all those evacuation tests with able-bodied volunteers? How would they evacuate for example five wheelchair users within the 90 seconds or whatever is required for the test?

That's what I'm getting at though. There are imagined criteria for these tests, but what has the real life situation been in actual emergencies? Have there been enough real life evacuations where getting everyone out within 90 seconds vs 3 minutes was the difference in saving many lives?

All airliner safety features are objectively pretty pointless given that cars remain legal and routine with like 100x the lethality. But yes, there have been at least a handful of cases where some but not all of the passengers were able to get out of a plane in time, particularly when the plane caught fire on landing (e.g. Air Canada 797).

> 90 seconds vs 3 minutes

That's a huge difference in case of a fire. Ninety seconds of smoke filled, oxygen deprived, or hot air, and many people will make it out alive. Three minutes and most will have passed out.

There's quite a few instances of burning planes being evacuated where not everybody, but a sizeable portion, made it out. Seconds matter*.

* Almost always there was some idiots slowing everything down by grabbing their luggage.

That's obvious. But I just made those numbers up - they aren't important to my point, which is that I'm asking if there is any real world data on evacuation timing.

All those instances where not everybody - but some - made it out of a plane that caught fire but where the passenger cabin was otherwise intact, physically allowing the evacuation of conscious passengers.

Here's a good example because it has a clear cutoff point: "Less than 90 seconds after touchdown, the interior of the plane flashed over and ignited, killing the remaining 23 passengers on board, who died from smoke inhalation and burns from the flash fire."

https://en.wikipedia.org/wiki/Air_Canada_Flight_797

It seems obvious that a faster evacuation would have saved more people and a slower one less, roughly proportional to speed of evacuation.

Not only is the test with able bodied people, they also are permitted to practice first to make the time.

But - the test handles this by only giving them 90 seconds. In the real world it would take far longer, but rather than testing a longer, more realistic test, they do a really fast one instead.

The test is about whether such an evacuation is theoretically possible, not if it is realistic under any conceivable circumstance (half the plane gone, blocked exits, plane resting at an incline, smoke and/or fire and/or water in the cabin...).

If the happy-path evacuation isn't possible to begin with, e.g. for design reasons, the more complicated realistic ones will be negatively affected as well.

Aircraft fires can escalate extremely quickly, and in an enclosed space like an aircraft there's nowhere for smoke to go. Accidents also often result in less than optimal evacuation conditions. Fire may block exits, doors can jam, slides can fail to deploy, all of which slow down the evacuation. I've spent way too much time watching the Air Disasters show [0] and off the top of my head remember at least half a dozen or so accidents portrayed in the show where a plane was evacuated in minutes but some passengers were killed by fire or smoke because they couldn't get off in time. I'm not saying that wide body planes couldn't be evacuated quickly or safely (haven't really looked into them at all) but I don't think it's a situation where you can just say, wide bodies are more slow to evacuate and that's no big deal.

[0]: https://www.smithsonianchannel.com/shows/air-disasters

Could it make sense for a fighter?

Possibly, depending if you think it needs to dogfight or not. The F35 actually can dogfight pretty much fine, due to the semi lifting body (after they fixed the software, old articles, pre 2016 really, are outdated), but blended wing is not the same thing. If you see the stuff the US is doing with NGAD concepts that pretty much only do beyond visual range and don't have guns it could be fine. Some of them are more fighter/stand off weapon delivery "bombers" like the B52 are becoming now.

Also no issues with passengers caring that they don't have a window seat, or aren't even anywhere near in the view of a window.

So I flew Emirates First the other day. They now have virtual windows in some suites, which are linked to cameras outside of the plane. That worked surprisingly well, and after a few moments I forgot about having booked an aisle seat.

I would expect this to eventually be rolled out more widely and later replacing real windows, which are structural weak points of the hull and heavy. Also, for our Ryanair no-frills flyers: they are screens where you can show ads.

For the Emirates experience, see https://www.youtube.com/watch?v=VdDzaNlGSmk

I thought that the main disadvantage with flying wings for passenger traffic was that any kind of roll is made much worse the further you get from the main roll axis, so turbulence etc becomes more uncomfortable in the wing part.

I believe that is somewhat offset by having larger rotational inertia as more mass is further from the center. That does however, necessitate larger control surfaces achieve the same roll performance.\

Also, anecdotally from my flying (I'm a private pilot, small, single engine planes) turbulence tends to create much more vertical translation and pitching movement than it does roll movement.

I wonder if the design of blended wing body aircraft means that airlines will be more weight constrained by volume constrained. If that is the case, it would be economical for them to have much wider aisles (faster boarding) and exit rows which could offset the negative impact that having more than 2 aisles would have on evacuation time.

I thought the issue was that it was hard to pressurize a blended wing design. All pressurized planes are pretty much a tube shape, which are easier to design to endure metal fatigue and lots of pressurization cycles. The skin of an airliner is 2-4mm thick, I think you would need a substantially thicker skin for this shape.

But do you need to pressurize it? Only the crew space needs that which could be a small/short tube in the middle right behind (and including) the cockpit.

The fuel tanks don’t care. They’re not pressurized on a normal design. The cargo may not need it either.

true. I thought cargo planes are often used for troop transport and this would be the same, but if they're solely using it for cargo/fuel it should be fine.

Modern tankers are actually multirole aircraft which can carry small amounts of cargo and/or personnel when necessary. This makes operations more flexible. With something like a KC-46 the entire fuselage including the cargo area is pressurized.

Don't some fuels like gasoline evaporate more quickly under lower pressure?

Transported fuel will be in sealed containers.

The Air Force should have forced some kind of transatlantic agreement, and make the A380 the new tanker, instead of letting the airplane go out of production.

I totally agree but who will force them? I thought the US Senators (and politicians in general) are just as keen to keep "jobs" going to American companies?

Now, if Airbus just gives away everything we need to manufacture and support the A380 free of cost so Boeing / Lockheed / whoever can manufacture them in the US and keep all the monies, I am sure the pencil pushers and penny pinchers at these companies would jump at the opportunity but I suspect that would also run into problems in Europe...

Make it in the USA, get a profit percentage to Airbus, opening for them a market they could never win. Both would profit.

Why? The A380 isn't cost effective and doesn't fit the mission requirements. Let it die.

A380s are probably too big TBH. IIRC their size and weight limits where they can operate because not all runways can support them. Also fuel is fairly heavy and dense, so tankers are more limited by weight than volume. The classic KC-135 tanker for example can carry around 175,000 lbs of fuel, but the main part of the fuselage is basically empty: https://qph.cf2.quoracdn.net/main-qimg-2638cc62527bd387b0a38...

Personally, I think it looks beautiful. I hope it works. Generation 3 of the flying wing. A worthy tradition and a genuine problem to solve. Also, for the record, I think military operations get a different category on emissions. Yes they pollute but just hope they aren’t dropping ordinance. That stuff really pollutes.

I live by a major cargo hub airport with occasional military traffic. The occasional C-5 Galaxy doing a few touch and go practices, a pair of F-18s or trainers. The airshow is this month and I’m lucky to be at a waypoint for the aerobatic demonstration team. Last year Super Hornets at 500 feet for 3 days. Heaven!

Can you imagine how gorgeous the photo would be of this refueling a B2? Or dust off the last up to it Sr71 and buzz Ukraine and Crimea for an afternoon. Yes it is all ridiculous but most military might is proverbial dick waving in the first place, so might as well add some confetti and glitter to the mix.

> Yes they pollute but just hope they aren’t dropping ordinance. That stuff really pollutes.

How so? Usually it’s just nitrate fertilizer. You can actually measure the greening effect that certain large 20th century ears (WW2, Korea, Vietnam) have had on global bio mass.

I tend to think about the unexploded stuff as having a long-term negative pollution effect - agreed that the chemicals themselves aren't really a culprit. In my view though, after watching tons of combat videos especially during WWII (and even with Syria and Ukraine examples) it's not the ordinance it's what they hit with it. Damaging infrastructure and chemicals and whatnot can have lasting effects by way of the ordinance dropping. Otherwise planes flying over taking recon photos are a different story.

Also I was just considering scale of military flights versus civilian. Yes they burn a lot of gas and haul ass, but there are way many more passenger and cargo flights day in and day out. I do love the idea of improving cargo shipping by sky in my lifetime. As my Uncle pointed out once, having dealt with Passengers and Cargo, "Cargo doesn't complain."

Most munitions have a toxic concentration of heavy metals. I really wouldn't want to eat anything grown in a field that was heavily shelled or bombed.

An updated B2 design without stealth would probably be highly achievable in this timeframe.

The problem being a cargo plane usually wants a fast approach and takeoff to eliminate threats near the runway. I don’t know if a B2 (or flying wing in general) would be good at that.

What about a flying wing makes the approach slow? Is there some ground effect that comes into play?

Cargo planes like the C-17 can make a steep “tactical approach” by creating lots of drag, with spoilers, reverse thrust, etc. It’s difficult to get very aerodynamic aircraft to ‘go down and slow down’. That’s not to say that the flying wing design couldn’t have drag devices, but it’d take more to reach similar performance.

The approach isn’t “slow” in terms of aircraft speed but rather its duration. Shallower equals more time in reach of adversary weapons.

On the other hand, a tanker aircraft typically flies from a much more prepared base, something with a longer, guaranteed to be well paved runway, in non-contested airspace, with minimal or no risk of MANPADS in the area.

The design requirements for a C-17 to operate from a rough field, such as that which was built at camp bastion in Helmand province, are considerably different than for an aerial refueling tanker.

The rough field tactical tanker role is as far as I know presently served by a variant of c130 modified for special forces missions.

The design in the photo reminds me a lot of the Lockheed CL-1201 design

They say there's a lot more volume, but would it carry more weight, and where would the weight have to be placed?

Why isn't this design used commercially?

> where would the weight have to be placed?

In the body?

I meant that there might be balance issues. You wouldn't want something heavy placed far out towards the wing.

You know airliners carry fuel in their wings today?

> Why isn't this design used commercially?

Commercial airports. Planforms that don't fit the existing leased gate regime are non-starters.

It would only work for cargo and would have other issues.

Almost all commercial planes are for both cargo and passengers, and you’d have to bank really slowly if that was full of passengers.

... full of paying passengers. Soldiers can just be strapped down in the dark and you can hose the decks down after landing.

Soldiers would still need it to be pressurised which might be hard to do. Easier to transport cargo that doesn't mind a drop in air pressure.

While presumably military transport does involve moving very dense things, Some of the things the air force is called upon to transport have high volume but low weight. Like helicopters, for example.

I don't think they're getting rid of the C-17. This will be an additional aircraft.

Wouldn’t the massive increase in wing area make more lift/load possible? Or do things not scale this way?

>Why isn't this design used commercially?

In a commercial plane, passengers will rise/drop during turns relative to the center line, but it's minimal due to distance from center line.

The further out passengers are from the center line, the more they will drop/rise during turns.

Imagine being seated towards the outer edge of this fuselage. You might rise/drop 20-30ft off the centerline during a turn.

The pilot for the weight and balance calculations of a wide body aircraft must need a PhD in physics.

Lol it looks like one of my first 3dsmax models. I should still have it somewhere

" lack of highly radar-reflective vertical stabilizers."

Then how do they stabilize it?

Automatic so-called "split rudders" induce drag to control yaw as per the B-2.

Man… does anybody believe we’ll actually make it to 2027, let alone “want” to be there?

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