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Air Force Plans New Blended Wing Body Cargo/Tanker Aircraft by 2027
- d_silin 4y agoBlended-wing body makes a lot of sense for cargo/tanker aircraft. No issues with emergency evacuation procedure for passengers.
- colordrops 4y agoHas 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.
- chrisseaton 4y agoDo 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?
- colordrops 4y agoThat'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?
- lmm 4y agoAll 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).
- chmod775 4y ago> 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.
- colordrops 4y agoThat'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.
- chmod775 4y agoAll 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 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.
- ars 4y agoNot 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.
- DocTomoe 4y agoThe 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.
- Merad 4y agoAircraft 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 https://www.smithsonianchannel.com/shows/air-disasters
- rascul 4y agoCould it make sense for a fighter?
- Vecr 4y agoPossibly, 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.
- walrus01 4y agoAlso 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.
- DocTomoe 4y agoSo 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 https://www.youtube.com/watch?v=VdDzaNlGSmk
- sorenjan 4y agoI 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.
- maxcan 4y agoI 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.
- maxcan 4y agoI 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.
- robotnikman 4y agoThe design in the photo reminds me a lot of the Lockheed CL-1201 design
- skybrian 4y agoThey 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?
- chrisseaton 4y ago> where would the weight have to be placed? In the body?
- skybrian 4y agoI meant that there might be balance issues. You wouldn't want something heavy placed far out towards the wing.
- socialismisok 4y agoYou know airliners carry fuel in their wings today?
- topspin 4y ago> Why isn't this design used commercially? Commercial airports. Planforms that don't fit the existing leased gate regime are non-starters.
- bombcar 4y agoIt 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.
- mauvehaus 4y agoThe 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 https://en.m.wikipedia.org/wiki/Boeing_KC-46_Pegasus
- chrisseaton 4y agoMaybe working off an existing design is harder than greenfield?
- bombcar 4y agoIf that were true why did we get the 737 MAX?
- RcouF1uZ4gsC 4y agoActually, 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.
- bombcar 4y agoYeah, 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.
- ledauphin 4y agoa 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 ".
- MR4D 4y agoAn 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.
- nomel 4y agoWhat about a flying wing makes the approach slow? Is there some ground effect that comes into play?
- unionemployee 4y agoCargo 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.
- walrus01 4y agoOn 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.
- walrus01 4y agoI 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.
- topspin 4y ago> 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!
- DocTomoe 4y ago> 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.
- Gravityloss 4y agoA 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.
- dotancohen 4y ago> 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.
- pinko 4y agoBaffles are typically used to control this, even in conventional aircraft fuel tanks. It's a non-issue.
- sbierwagen 4y agoI 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.
- actionfromafar 4y agoPlastic bags to reduce slosh?
- liotier 4y agoPlastic bags to vomit in.
- somerandomqaguy 4y agoIs 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.
- kart23 4y agoI 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.
- MBCook 4y agoBut 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.
- kart23 4y agotrue. 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.
- nradov 4y agoModern 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.
- swagasaurus-rex 4y agoDon't some fuels like gasoline evaporate more quickly under lower pressure?
- ompaLompa 4y agoTransported fuel will be in sealed containers.
- deleted 4y ago[deleted]
- galaxyLogic 4y ago" lack of highly radar-reflective vertical stabilizers." Then how do they stabilize it?
- topspin 4y agoAutomatic so-called "split rudders" induce drag to control yaw as per the B-2.
- 6stringmerc 4y agoPersonally, 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.
- adastra22 4y ago> 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.
- yabones 4y agoMost 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.
- 6stringmerc 4y agoI 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."
- raydiatian 4y agoMan… does anybody believe we’ll actually make it to 2027, let alone “want” to be there?
- belter 4y agoThe 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.
- pooper 4y agoI 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...
- belter 4y agoMake it in the USA, get a profit percentage to Airbus, opening for them a market they could never win. Both would profit.
- nradov 4y agoWhy? The A380 isn't cost effective and doesn't fit the mission requirements. Let it die.
- Merad 4y agoA380s 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-2638cc62527bd387b0a387130b6503fa https://qph.cf2.quoracdn.net/main-qimg-2638cc62527bd387b0a38...
- dghughes 4y agoThe pilot for the weight and balance calculations of a wide body aircraft must need a PhD in physics.
- jbverschoor 4y agoLol it looks like one of my first 3dsmax models. I should still have it somewhere