5 ms·

Unless this has the capacity of a 737-700 / Max-7, there's no way six emergency exits are enough. They're also all up at the front, making egress difficult if a

Unless this has the capacity of a 737-700 / Max-7, there's no way six emergency exits are enough. They're also all up at the front, making egress difficult if an isle is blocked. Yes, it's a nitpick, but if that's a design flaw that jumps out to a complete amateur with moderate aviation knowledge and no industry experience, it doesn't inspire a great deal of confidence.

deleted 3y ago
[deleted]
rozab 3y ago
This is part of why Boeing shut down the idea back in the 90s iirc. But I think this company is not actually aiming to develop an airliner at all, it just makes for pretty pictures. Their demonstrator is being built for the USAF (along with Northrop Grumman and Scaled Composites), with a view to being used as a tanker and transport. I'm sceptical. Boeing, Lockheed Martin and Airbus have all investigated this exact concept over the last few decades, and none have gone forward with it.
- JumpCrisscross 3y ago
  > Boeing, Lockheed Martin and Airbus have all investigated this exact concept over the last few decades, and none have gone forward with it Low incentives for taking risks and massive improvements in CAD and computer testing. A new airframe should always bring scepticism. But as someone with aerospace engineering training, it’s somewhat funny to see the space side of the market seeing more competition and thus innovation than the aero.
  - tekla 3y ago
    I don't think its THAT particularly surprising. The old school rocket engines are still some of the most efficient engines ever created and most rockets never had a strong commercial market backing it so there was never pressure to try something else. The RS68 and RS25 are still amazing pieces of technology. SpaceX succeeded because they were able to take advantage of NASA literally creating a commercial market (and also making an amazing engine that is "good enough" for 99% of payloads)
    - JumpCrisscross 3y ago
      > old school rocket engines are still some of the most efficient engines ever created Sure. But there are other niches than maximal ISP. SpaceX and other launch providers have demonstrated it. In both cases—airlines and rocketry—there was latent demand once someone looked for it. And in both cases, I believe, public support is necessary.
      - notahacker 3y ago
        I think the person suggesting their more realistic short term goal is defense funding for future USAF tanker contracts might not be too far from the mark. Whether the fuel economy of an airliner-sized tanker is enough to convince doubting airline execs facing very different operational constraints is another question.
    - panick21_ 3y ago
      These engines were horrible bad in terms of thrust or isp per $. And turns out that actually matters. There had been a commercial market for a while, but US companies and their amazing engines didnt compete in it. Better to just feed of military contracts.
- mdasen 3y ago
  I'm skeptical too, but part I wouldn't necessarily write it off because a company like Boeing hasn't gone forward with it. Boeing won't even go forward with a redesign of the 737, preferring to go the cheaper route of continually modifying an existing design from the 1960s. I do think there are other concepts that are farther along and have more promise like the Aurora D8 "double bubble" (https://en.wikipedia.org/wiki/Aurora_D8 https://en.wikipedia.org/wiki/Aurora_D8). Its design isn't as much of a departure, but it would still reduce fuel burn and noise significantly. Likewise, Boeing's TTBW (transsonic truss braced wing) design is promising especially since they have a full-sized demonstrator at this point. But companies have been hesitant to invest in new types of aircraft. It's an industry that's essentially a duopoly where the big two have a decade worth of orders for their current aircraft. There isn't even a lot of competition between the two because neither has the capacity to produce more planes if they create something that airlines want. The A380 was probably the biggest risk that's been taken recently and that turned out to be a pretty big failure. I don't think either Boeing or Airbus wants to take risks when they have pretty guaranteed profits by staying the course. Boeing has even shelved its plans for the Boeing NMA (new midsize airplane) to replace the 737. I'd also add that these projects often end up learning important things about aeronautics even if they don't become things you fly on. For example, one of the big things with the Aurora D8 was figuring out how to deal with boundary layer ingestion inefficiencies. Even if the D8 never becomes something you'll fly on, the knowledge gained there might be used in other planes that you will fly on. You're right to be skeptical and I am too. It's really difficult to bring a new plane to market. However, I'm not sure I'd take Boeing and Airbus' reticence as evidence that it isn't worth exploring more. We've been talking about the bean counters taking over Boeing for months now and complaining about Boeing continually modifying the 737 rather than creating a new plane. Is it likely we'll be flying on these things? No. Even if it's a good and viable design, there's so much beyond that to get done. Actually manufacturing something as complex as a plane is very hard - there's a reason Airbus and Boeing have a decade long backlog of orders. But there's also a reason why places like NASA want to fund experimental projects like this - because there aren't really incentives for companies like Boeing to take risks on new designs. I mean, you're right: this probably won't happen. At the same time, I think it's important to keep trying because sometimes these things do work and even when they don't work we often learn important things that can be applied in the future.
- api 3y ago
  People made the same arguments about reusable rockets. If there’s one thing that saga taught us it’s that traditional aerospace is incredibly conservative and risk averse. “If it hasn’t already flown it can’t fly.” Not saying this design is the answer but it’s quite clear that the opinions of the big players about novel ideas are to be taken with a certain amount of salt. I’m not sure where this mentality came from. My guess would be many boom bust cycles and shifting political winds causing project cancellation. That probably burned people too many times on new projects. Combine that with a safety at any cost mentality and a lack of incentives to innovate.
  - WalterBright 3y ago
    Developing a new airframe is enormously expensive. This incentivizes reducing the risk of it as much as one can. For example, when I worked on the 757 stab trim gearbox, my lead engineer suggested I do a design study on using a planetary gearbox rather than a differential gearbox. The former was significantly lighter. The study went up a few levels of management, and was nixed because the differential box was a proven and well-understood design on other aircraft (747).
  - Alpha3031 3y ago
    > People made the same arguments about reusable rockets. NASA could have totally gone forward with developing the DC-3 if Nixon didn't cut their funding. The lower cross-range and payload were dealbreakers for the USAF but perfectly acceptable for civil spaceflight purposes.
  - sofixa 3y ago
    > If there’s one thing that saga taught us it’s that traditional aerospace is incredibly conservative and risk averse Was that ever in doubt? > I’m not sure where this mentality came from. My guess would be many boom bust cycles and shifting political winds causing project cancellation. That probably burned people too many times on new projects. Combine that with a safety at any cost mentality and a lack of incentives to innovate. Look into the history of aviation. How many aircraft manufacturers disappeared or barely survived, usually no longer making civilian jets, because they made a wrong bet at the wrong time? How many disappeared because their planes got a bad reputation for being unsafe? Just a small selection off the top of my head: BAC, de Havilland, Bombardier, Lockheed, Dassault, Convair, McDonnel Douglas, Sud Aviation, Dornier. A new jet design is extremely expensive, needs to add concrete benefits to the potential customers (airlines) and needs to be convincing for both airlines and passengers alike. And for the record, Airbus are working on a bunch of radical design moonshots: https://www.airbus.com/en/innovation/low-carbon-aviation/hydrogen/zeroe https://www.airbus.com/en/innovation/low-carbon-aviation/hyd... , and so are Embraer https://embraercommercialaviationsustainability.com/concepts/ https://embraercommercialaviationsustainability.com/concepts... .
- sofixa 3y ago
  > I'm sceptical. Boeing, Lockheed Martin and Airbus have all investigated this exact concept over the last few decades, and none have gone forward with it. Airbus has the ZEROe program to look at the future of aviation that is ramping up and should have tech demonstrators flying in the 2030s, exploring all sorts of options like open fan engines, hydrogen(-electric) propulsion, radical designs, etc. One of the concepts is the "Blended-Wing Body".
interestica 3y ago
Those skylights? Just pop em out to exit in a hurry.
- hermitcrab 3y ago
  Only if it is inverted.
  - toss1 3y ago
    Or, if engineers include an escape device such as a fold-out ladder in the mechanical kit that makes the skylights pop-out. Yes, that won't work for many disabilities without assistance, but it could still save many lives, and get them out of the way so those needing walk-off egress can get to the doors.
fakedang 3y ago
This is a valid point, but as a hobbyist pilot, damn that aircraft is beautiful. It may not replace the Boeing, but it would certainly replace a Gulfstream or Pilatus.
dzhiurgis 3y ago
Does FAA mandate this particular safety feature or is it up to plane manufacturer? Part of me wants to hire cargo plane, put bunch of bunk beds, call it 'cargo flight experience' and shuffle people between continents for 1/4th the price...
- daemonologist 3y ago
  The FAA mandates that exits be distributed "as uniformly as practical" and requires certain numbers and types of exit according to the number of passengers [0] Also, at max capacity all passengers and crew must be able to evacuate in 90 seconds [1]. So, your cargo experience might have regulatory trouble. The "as uniformly as possible" might allow for a blended wing design though, provided you could get everyone out fast enough. There might be some other relevant regulations that I've missed as well. [0] - https://www.law.cornell.edu/cfr/text/14/25.807 https://www.law.cornell.edu/cfr/text/14/25.807 [1] - https://www.law.cornell.edu/cfr/text/14/25.803 https://www.law.cornell.edu/cfr/text/14/25.803
  - sofixa 3y ago
    > Also, at max capacity all passengers and crew must be able to evacuate in 90 seconds [1]. With half of all emergency exits (assuming that something like a fire could be blocking the rest, which has already happened).
SkyMarshal 3y ago
Looks like there are other use cases besides passenger jet - freighter and tanker won't need the extra exits. Also one of the other mockup pictures seems to show multiple possible exits per side. Maybe there are only two regular-use exits at the front, with extra emergency exits on both sides a little further back, but which are not opened during normal operations: https://www.jetzero.aero/hubfs/Z5-0029-cloud-hero-GENX-JetZero-livery.jpg https://www.jetzero.aero/hubfs/Z5-0029-cloud-hero-GENX-JetZe...
hn_throwaway_99 3y ago
Where did you see it say there were only six emergency exits?
chipsa 3y ago
https://aviationweek.com/aerospace/emerging-technologies/jetzero-unveils-midmarket-airliner-air-force-tanker-bwb-plan https://aviationweek.com/aerospace/emerging-technologies/jet... Looks more like Max10 sized. It looks like there is a small door behind the wing, which matches the location of the back end of the cabin. There’s no window in them, but they are probably depicting the aft emergency exits, given regulatory requirements that exits be on both ends of the cabin. Based on the cut away, I think the large door aft of the main door, that has no window is likely the cargo hold door. It doesn’t look like there’s a hold under the cabin. The main door appears to be extra wide, which improves the exit capacity of the door, and reduces the actual number of exits required. There’s also the option for a ventral exit, but those are pretty rare on passenger airliners.
AtlasBarfed 3y ago
... I mean, emergency exits are largely a theater of safety, aren't they? Like oxygen masks and the flotation seat cushion? Also, I'm curious, is CFD (Computational Fluid Dynamics) modeling still so poor that conceptual designs are still very uncertain when converting to a model or scaled down example?
- panick21_ 3y ago
  No they arent. Wtf are you even talking about. We literally just had a crash on an A350 where everybody escaped threw the exit doors before the plane burned down. Inost crashes most people escape threw the emergency doors. There is a question how fast is fast enough. But fast escape are incredibly important.
Asraelite 3y ago
How many lives would that really save? We've improved airline safety to the point that there's only a single major disaster every few years. Consider how few lives extra emergency exits have actually saved in the past decade. I would guess less than 10. If that is the price we pay for a huge range of other improvements then I think it's worth it.
- fransje26 3y ago
  What an absolute rubbish idea. That's not how it works, at all. There are so few lives lost thanks to the stringent requirements put in place, like the mandatory 90 second evacuation rule. Remove these requirements, and it's a guarantee that the numbers will go up, sooner rather than later. Like most of those rules, the evacuation rules were established after a very thorough analysis of previous accidents, painstakingly determining who died where, and from which cause. It is not some number pulled out of thin air that is suddenly irrelevant thanks to "technology". The MAX saga is a very good reminder of what happens when you start playing loose with those rules. People die. Quickly, and in mass. And, as "luck" would have it, we are not even 3 months into 2024, and we have already been served the perfect, actual, counter example to this proposal: the JAL flight, where 379 lives where saved thanks to rapid evacuation. I'll leave a nice little article link from January here. It just happens to have the perfect headline: https://apnews.com/article/japan-plane-fire-safety-jal-tokyo-haneda-b1c9e220788868be8c297d35b03c0fb8 https://apnews.com/article/japan-plane-fire-safety-jal-tokyo...
  - Asraelite 3y ago
    Well since you're against me anyway, let me double down: current airline regulations are way, way too strict in every way and are based entirely on an irrational overreaction people have to aircraft incidents because flying feels unnatural. Increasing airline deaths to even over 1000 per year for marginally increased comfort would be worth it. If anyone actually cared about saving lives then all focus would be on motoring, not planes. Planes should not be as safe as they are.
    - sofixa 3y ago

deleted 3y ago

[deleted]

rozab 3y ago

This is part of why Boeing shut down the idea back in the 90s iirc. But I think this company is not actually aiming to develop an airliner at all, it just makes for pretty pictures. Their demonstrator is being built for the USAF (along with Northrop Grumman and Scaled Composites), with a view to being used as a tanker and transport. I'm sceptical. Boeing, Lockheed Martin and Airbus have all investigated this exact concept over the last few decades, and none have gone forward with it.

JumpCrisscross 3y ago
> Boeing, Lockheed Martin and Airbus have all investigated this exact concept over the last few decades, and none have gone forward with it Low incentives for taking risks and massive improvements in CAD and computer testing. A new airframe should always bring scepticism. But as someone with aerospace engineering training, it’s somewhat funny to see the space side of the market seeing more competition and thus innovation than the aero.
- tekla 3y ago
  I don't think its THAT particularly surprising. The old school rocket engines are still some of the most efficient engines ever created and most rockets never had a strong commercial market backing it so there was never pressure to try something else. The RS68 and RS25 are still amazing pieces of technology. SpaceX succeeded because they were able to take advantage of NASA literally creating a commercial market (and also making an amazing engine that is "good enough" for 99% of payloads)
  - JumpCrisscross 3y ago
    > old school rocket engines are still some of the most efficient engines ever created Sure. But there are other niches than maximal ISP. SpaceX and other launch providers have demonstrated it. In both cases—airlines and rocketry—there was latent demand once someone looked for it. And in both cases, I believe, public support is necessary.
    - notahacker 3y ago
      I think the person suggesting their more realistic short term goal is defense funding for future USAF tanker contracts might not be too far from the mark. Whether the fuel economy of an airliner-sized tanker is enough to convince doubting airline execs facing very different operational constraints is another question.
  - panick21_ 3y ago
    These engines were horrible bad in terms of thrust or isp per $. And turns out that actually matters. There had been a commercial market for a while, but US companies and their amazing engines didnt compete in it. Better to just feed of military contracts.
mdasen 3y ago
I'm skeptical too, but part I wouldn't necessarily write it off because a company like Boeing hasn't gone forward with it. Boeing won't even go forward with a redesign of the 737, preferring to go the cheaper route of continually modifying an existing design from the 1960s. I do think there are other concepts that are farther along and have more promise like the Aurora D8 "double bubble" (https://en.wikipedia.org/wiki/Aurora_D8 https://en.wikipedia.org/wiki/Aurora_D8). Its design isn't as much of a departure, but it would still reduce fuel burn and noise significantly. Likewise, Boeing's TTBW (transsonic truss braced wing) design is promising especially since they have a full-sized demonstrator at this point. But companies have been hesitant to invest in new types of aircraft. It's an industry that's essentially a duopoly where the big two have a decade worth of orders for their current aircraft. There isn't even a lot of competition between the two because neither has the capacity to produce more planes if they create something that airlines want. The A380 was probably the biggest risk that's been taken recently and that turned out to be a pretty big failure. I don't think either Boeing or Airbus wants to take risks when they have pretty guaranteed profits by staying the course. Boeing has even shelved its plans for the Boeing NMA (new midsize airplane) to replace the 737. I'd also add that these projects often end up learning important things about aeronautics even if they don't become things you fly on. For example, one of the big things with the Aurora D8 was figuring out how to deal with boundary layer ingestion inefficiencies. Even if the D8 never becomes something you'll fly on, the knowledge gained there might be used in other planes that you will fly on. You're right to be skeptical and I am too. It's really difficult to bring a new plane to market. However, I'm not sure I'd take Boeing and Airbus' reticence as evidence that it isn't worth exploring more. We've been talking about the bean counters taking over Boeing for months now and complaining about Boeing continually modifying the 737 rather than creating a new plane. Is it likely we'll be flying on these things? No. Even if it's a good and viable design, there's so much beyond that to get done. Actually manufacturing something as complex as a plane is very hard - there's a reason Airbus and Boeing have a decade long backlog of orders. But there's also a reason why places like NASA want to fund experimental projects like this - because there aren't really incentives for companies like Boeing to take risks on new designs. I mean, you're right: this probably won't happen. At the same time, I think it's important to keep trying because sometimes these things do work and even when they don't work we often learn important things that can be applied in the future.
api 3y ago
People made the same arguments about reusable rockets. If there’s one thing that saga taught us it’s that traditional aerospace is incredibly conservative and risk averse. “If it hasn’t already flown it can’t fly.” Not saying this design is the answer but it’s quite clear that the opinions of the big players about novel ideas are to be taken with a certain amount of salt. I’m not sure where this mentality came from. My guess would be many boom bust cycles and shifting political winds causing project cancellation. That probably burned people too many times on new projects. Combine that with a safety at any cost mentality and a lack of incentives to innovate.
- WalterBright 3y ago
  Developing a new airframe is enormously expensive. This incentivizes reducing the risk of it as much as one can. For example, when I worked on the 757 stab trim gearbox, my lead engineer suggested I do a design study on using a planetary gearbox rather than a differential gearbox. The former was significantly lighter. The study went up a few levels of management, and was nixed because the differential box was a proven and well-understood design on other aircraft (747).
- Alpha3031 3y ago
  > People made the same arguments about reusable rockets. NASA could have totally gone forward with developing the DC-3 if Nixon didn't cut their funding. The lower cross-range and payload were dealbreakers for the USAF but perfectly acceptable for civil spaceflight purposes.
- sofixa 3y ago
  > If there’s one thing that saga taught us it’s that traditional aerospace is incredibly conservative and risk averse Was that ever in doubt? > I’m not sure where this mentality came from. My guess would be many boom bust cycles and shifting political winds causing project cancellation. That probably burned people too many times on new projects. Combine that with a safety at any cost mentality and a lack of incentives to innovate. Look into the history of aviation. How many aircraft manufacturers disappeared or barely survived, usually no longer making civilian jets, because they made a wrong bet at the wrong time? How many disappeared because their planes got a bad reputation for being unsafe? Just a small selection off the top of my head: BAC, de Havilland, Bombardier, Lockheed, Dassault, Convair, McDonnel Douglas, Sud Aviation, Dornier. A new jet design is extremely expensive, needs to add concrete benefits to the potential customers (airlines) and needs to be convincing for both airlines and passengers alike. And for the record, Airbus are working on a bunch of radical design moonshots: https://www.airbus.com/en/innovation/low-carbon-aviation/hydrogen/zeroe https://www.airbus.com/en/innovation/low-carbon-aviation/hyd... , and so are Embraer https://embraercommercialaviationsustainability.com/concepts/ https://embraercommercialaviationsustainability.com/concepts... .
sofixa 3y ago
> I'm sceptical. Boeing, Lockheed Martin and Airbus have all investigated this exact concept over the last few decades, and none have gone forward with it. Airbus has the ZEROe program to look at the future of aviation that is ramping up and should have tech demonstrators flying in the 2030s, exploring all sorts of options like open fan engines, hydrogen(-electric) propulsion, radical designs, etc. One of the concepts is the "Blended-Wing Body".

interestica 3y ago

Those skylights? Just pop em out to exit in a hurry.

hermitcrab 3y ago
Only if it is inverted.
- toss1 3y ago
  Or, if engineers include an escape device such as a fold-out ladder in the mechanical kit that makes the skylights pop-out. Yes, that won't work for many disabilities without assistance, but it could still save many lives, and get them out of the way so those needing walk-off egress can get to the doors.

fakedang 3y ago

This is a valid point, but as a hobbyist pilot, damn that aircraft is beautiful. It may not replace the Boeing, but it would certainly replace a Gulfstream or Pilatus.

dzhiurgis 3y ago

Does FAA mandate this particular safety feature or is it up to plane manufacturer? Part of me wants to hire cargo plane, put bunch of bunk beds, call it 'cargo flight experience' and shuffle people between continents for 1/4th the price...

daemonologist 3y ago
The FAA mandates that exits be distributed "as uniformly as practical" and requires certain numbers and types of exit according to the number of passengers [0] Also, at max capacity all passengers and crew must be able to evacuate in 90 seconds [1]. So, your cargo experience might have regulatory trouble. The "as uniformly as possible" might allow for a blended wing design though, provided you could get everyone out fast enough. There might be some other relevant regulations that I've missed as well. [0] - https://www.law.cornell.edu/cfr/text/14/25.807 https://www.law.cornell.edu/cfr/text/14/25.807 [1] - https://www.law.cornell.edu/cfr/text/14/25.803 https://www.law.cornell.edu/cfr/text/14/25.803
- sofixa 3y ago
  > Also, at max capacity all passengers and crew must be able to evacuate in 90 seconds [1]. With half of all emergency exits (assuming that something like a fire could be blocking the rest, which has already happened).

SkyMarshal 3y ago

Looks like there are other use cases besides passenger jet - freighter and tanker won't need the extra exits. Also one of the other mockup pictures seems to show multiple possible exits per side. Maybe there are only two regular-use exits at the front, with extra emergency exits on both sides a little further back, but which are not opened during normal operations: https://www.jetzero.aero/hubfs/Z5-0029-cloud-hero-GENX-JetZero-livery.jpg https://www.jetzero.aero/hubfs/Z5-0029-cloud-hero-GENX-JetZe...

hn_throwaway_99 3y ago

Where did you see it say there were only six emergency exits?

chipsa 3y ago

https://aviationweek.com/aerospace/emerging-technologies/jetzero-unveils-midmarket-airliner-air-force-tanker-bwb-plan https://aviationweek.com/aerospace/emerging-technologies/jet... Looks more like Max10 sized. It looks like there is a small door behind the wing, which matches the location of the back end of the cabin. There’s no window in them, but they are probably depicting the aft emergency exits, given regulatory requirements that exits be on both ends of the cabin. Based on the cut away, I think the large door aft of the main door, that has no window is likely the cargo hold door. It doesn’t look like there’s a hold under the cabin. The main door appears to be extra wide, which improves the exit capacity of the door, and reduces the actual number of exits required. There’s also the option for a ventral exit, but those are pretty rare on passenger airliners.

AtlasBarfed 3y ago

... I mean, emergency exits are largely a theater of safety, aren't they? Like oxygen masks and the flotation seat cushion? Also, I'm curious, is CFD (Computational Fluid Dynamics) modeling still so poor that conceptual designs are still very uncertain when converting to a model or scaled down example?

panick21_ 3y ago
No they arent. Wtf are you even talking about. We literally just had a crash on an A350 where everybody escaped threw the exit doors before the plane burned down. Inost crashes most people escape threw the emergency doors. There is a question how fast is fast enough. But fast escape are incredibly important.

Asraelite 3y ago

How many lives would that really save? We've improved airline safety to the point that there's only a single major disaster every few years. Consider how few lives extra emergency exits have actually saved in the past decade. I would guess less than 10. If that is the price we pay for a huge range of other improvements then I think it's worth it.

fransje26 3y ago
What an absolute rubbish idea. That's not how it works, at all. There are so few lives lost thanks to the stringent requirements put in place, like the mandatory 90 second evacuation rule. Remove these requirements, and it's a guarantee that the numbers will go up, sooner rather than later. Like most of those rules, the evacuation rules were established after a very thorough analysis of previous accidents, painstakingly determining who died where, and from which cause. It is not some number pulled out of thin air that is suddenly irrelevant thanks to "technology". The MAX saga is a very good reminder of what happens when you start playing loose with those rules. People die. Quickly, and in mass. And, as "luck" would have it, we are not even 3 months into 2024, and we have already been served the perfect, actual, counter example to this proposal: the JAL flight, where 379 lives where saved thanks to rapid evacuation. I'll leave a nice little article link from January here. It just happens to have the perfect headline: https://apnews.com/article/japan-plane-fire-safety-jal-tokyo-haneda-b1c9e220788868be8c297d35b03c0fb8 https://apnews.com/article/japan-plane-fire-safety-jal-tokyo...
- Asraelite 3y ago
  Well since you're against me anyway, let me double down: current airline regulations are way, way too strict in every way and are based entirely on an irrational overreaction people have to aircraft incidents because flying feels unnatural. Increasing airline deaths to even over 1000 per year for marginally increased comfort would be worth it. If anyone actually cared about saving lives then all focus would be on motoring, not planes. Planes should not be as safe as they are.
  - sofixa 3y ago