4 ms·

Hybrid after the first 125 miles, total range 500 miles. Their problem is diversions - an incident at the destination airport may mean an passenger aircraft may

by luma 1mo ago

Hybrid after the first 125 miles, total range 500 miles. Their problem is diversions - an incident at the destination airport may mean an passenger aircraft may need to land at an airport which could be a couple hundred miles away. The hybrid powerplant throws the fuel efficiency numbers off so goal is not to run it unless needed, but they could not get certification without it.

misterderpie 1mo ago
For anyone looking for the reference, it's stated at 10:16 [0] [0] https://youtu.be/nM86DBOqgPM?si=BdoZzp1Dxa4S3C_9&t=616 https://youtu.be/nM86DBOqgPM?si=BdoZzp1Dxa4S3C_9&t=616
- coin 29d ago
  Yes it's super misleading. All the marketing and title is calling it "electric" where in reality it's a hybrid electric-gas airplane with a 125 mile electric range. Aviation uses nautical miles yet they advertise 125 statute miles so the number seems bigger (125 statute miles = 108.62 nautical miles). It would be like Toyota marketing the Prius as an electric vehicle, then buried in their presentation sneaking in the gas propulsion. Same with Chrysler Pacifica (32 mile electric range).
werdnapk 1mo ago
So what do regular aircraft do when they run out of fuel? They require a forced landing. Aircraft fly with a buffer of fuel though to avoid such situations, so why can't an electric aircraft fly with a similar buffer on it's range? ie. Always fly less than the current charged range of the aircraft.
- luma 1mo ago
  Simply put, batteries are heavy.
  - gblargg 1mo ago
    Something like 1/30 the energy density of liquid fuel. Plus unlike fuel, a discharged battery weighs virtually the same as a charged one.
- marcosdumay 1mo ago
  Regular aircraft fly with enough fuel to change into at least one other airport in an emergency (ideally two). That aircraft would need a very large battery to do that, and it's way more efficient to have some burnable fuel there that you'll never actually use.
- MobiusHorizons 1mo ago
  Regular aircraft are required to have enough fuel to be able to divert to the alternate airfield in their flight plan plus all the margins for taxiing and waiting for a landing clearance. If a plane is low on fuel they can declare an emergency and get priority over other traffic, but that obviously is disruptive and should not happen on well planned flights unless something pretty significant happens after takeoff.
  - phire 1mo ago
    > and should not happen on well planned flights You make it sound like it is acceptable for a badly planned flight to have a fuel emergency. It is not. If there is a fuel emergency (or the plane lands with less than 30min of fuel) there will be an incident investigation that treats the situation as serious as if the plane had crashed. If the investigation discovers it was nothing more than bad planning, (at minimum) the planning procedures will be changed to ensure it never happens again.
    - bluGill 1mo ago
      Badly planned flights should not happen. Pilots who don't carefully plan their flights end up dead quickly. Lack of fuel is one of the easier to handle things that can go wrong from bad flight planning.
      - throwaway2037 29d ago
        Can you give an example of a "badly planned flight"? And did local regulators agree with your opinion?
        bluGill 29d ago
        My dad dreamed of being a pilot and when I was a kid he subscribed to the flying magazine (or something like that I don't remember that name.) every single issue had the last story being "I learned about flying from that" and nearly every single one was a case of bad planning, usually a case of flying into bad weather because of the bad planning.
- jmward01 1mo ago
  Lots of down votes on this but it is a legitimate question. The goal is likely to have the majority of flight off of batteries. That being said, the total weight of the emergency fuel plus generators is likely far less than the weight of the extra batteries they would haul around for the safety margin they need. So they end up lighter and more capable AND don't need to burn fuel. That being said, I wouldn't be surprised if they didn't start the generators during critical phases so they may end up using some fuel for a flight, but not much. Total guess on that though.
  - phire 1mo ago
    > That being said, I wouldn't be surprised if they didn't start the generators during critical phases I somewhat doubt that. Part of the advantage of the design is that the generators don't need to be sized as big enough to power take off, climb and a potential go-around on landing. They only need to be sized as big enough for cruising. So powering them up during critical phases wouldn't help with safety. If anything, normal operating procedures might actually require shutting them down during critical phases. What this does mean is that the batteries need to be reasonably full when it comes into land, possibly as high as 50%. And most go arounds will require immediately powering up the generators, so it probably needs to be fuelled for all but the shortest flights.
  - labcomputer 1mo ago
    > That being said, I wouldn't be surprised if they didn't start the generators during critical phases so they may end up using some fuel for a flight, but not much. I would guess the opposite. Many parts in a turbine engine are "lifetime limited" by number of engine starts. That is, you are required to tear down the engine and replace certain parts after a certain number of engine cycles. That makes the economics of the turbine hybrid radically different if you need to start it every time you land vs. only the rare cases where you need to dip into fuel reserves. For example, the PT6A (a common 500-1000hp turboprop) requires the turbine and compressor disks to be replaced every 16,000 cycles. That's about 5 years of commercial service at 4x round trips per day. But if you only start the engine once in every 10 flights, now those components (theoretically) last for 50 years of flying.
- Toutouxc 1mo ago
  > Aircraft fly with a buffer of fuel though to avoid such situations, so why can't an electric aircraft fly with a similar buffer on it's range? Because the required buffer is HUGE and we’re at a point where electric planes barely have enough energy for the actual route. So they’re doing the sensible thing here, flying the actual route electrically and falling back to combustion if the plane needs to divert.
  - deleted 1mo ago
    [deleted]
  - tonyarkles 1mo ago
    To that point, the battery capacity they’ve got, rough envelope math, is maybe 10 minutes beyond reserve. They’d likely need at least double, probably triple battery capacity to fly useful routes all-electric with enough reserve stored in batteries. The turbines are a great move.
    - labcomputer 1mo ago
      > They’d likely need at least double, probably triple battery capacity to fly useful routes all-electric with enough reserve stored in batteries. Yup. And to bring this point home: "Only" doubling the battery capacity likely eats well over half of the payload capacity, in terms of mass. So your 38 seat plane is now a 19 seat (or fewer) plane.
dyauspitr 1mo ago
Unless they have a whole new airport and flying experience, I don’t think a lot of people are going to fly just 125 miles. That’s less than two hours of driving. It would be 2 hours of just airport shenanigans much less the flight itself.
- deleted 1mo ago
  [deleted]
- tomjessessky 1mo ago
  There are a fair number of connecting flights that this is a good fit for. For example, I fly out of Madison, WI regularly and almost always connect through Chicago, which I believe is right around the 125 mile mark.
  - zxexz 1mo ago
    Used to regularly take the shortish flight from Boston to Chicago, and then a bus >3x as long to Madison to see family, because the puddlejumper was too expensive or not even running.
- Toutouxc 1mo ago
  > 125 miles … That’s less than two hours of driving. I don’t know where you live or what you drive, but I just punched in a destination 200 km away as the crow flies, the Alps are in the way and I’m looking at five hours of driving. Also, water.
  - Thlom 1mo ago
    Rookie numbers. As the crow flies it's 250km between me and my old town. Used to drive back and forth a lot back in the days and it takes everything from 8 hours to 10 hours depending on the route you take and whether you hit the ferries on schedule or not. Plus 30 minutes for resting and eating. Flying takes 50 minutes in a propeller airplane + travel to and from airports and airport shenanigans (not too bad at these small airports). If you take the morning flight you'll be in town by the time people start showing up for work. If you drive you'll be in town by the time people start leaving work.
giancarlostoro 1mo ago
Honestly, I'd feel better knowing it has a reserve system in case there's any issues, even if the batteries have more than enough power, beats having it and never using it, than needing it and suffering as a result.
- IrishTechie 1mo ago
  Do current aircraft have a backup in-case their fuel tanks run dry?
  - ben-schaaf 1mo ago
    There's reserve tanks or more generally reserve fuel for emergencies. Other than that there's no propulsion backup for when the fuel runs out, instead redundancy comes from multiple independent fuel tanks.
    - SideburnsOfDoom 1mo ago
      > redundancy comes from multiple independent fuel tanks. And in larger aircraft, multiple independent engines. See for instance ETOPS https://en.wikipedia.org/wiki/ETOPS https://en.wikipedia.org/wiki/ETOPS From the pictures, I see that this new aircraft has 4 engines. So it should be adequately resilient to single engine failure.
  - dmitrygr 1mo ago
    Current aircraft have * MULTIPLE HOURS* of fuel tanks. Compared to dozens of minutes of battery that this thing has.
    - tonyarkles 1mo ago
      Typical reserve requirement is 30 min for a turbine aircraft (45 for piston). Given the 125 mile battery-only range and the probability that it flies at at least 200 kts (230 mph), it’s pretty unlikely to hit even a 30 min reserve on only batteries. I like the design, I think they get the problem and have a decent solution for it
seanmcdirmid 1mo ago
I remember reading about making ground effects electric planes for this reason. You need a reserve, but if your plane could double as a boat and was flying over water, that would satisfy the requirement.
- nradov 1mo ago
  As long as water conditions allow for a safe landing. In much of the world that severely limits when you can operate due to storms or ice. In practice routine use of ground effect vehicles will be mostly limited to lakes and inland seas with fairly benign weather. Like I don't think we're going to have regular passenger service from San Francisco to Los Angeles or Detroit to Cleveland.
  - deleted 1mo ago
    [deleted]
  - seanmcdirmid 1mo ago
    Ground effect planes are already pretty limited to calm water situations. Like between Seattle and Victoria, or maybe Seattle and Vancouver. I would say the Alaskan marine highway would be a good fit, but that is mostly for freight and cars.
deleted 1mo ago
[deleted]

by luma 1mo ago

misterderpie 1mo ago

For anyone looking for the reference, it's stated at 10:16 [0] [0] https://youtu.be/nM86DBOqgPM?si=BdoZzp1Dxa4S3C_9&t=616 https://youtu.be/nM86DBOqgPM?si=BdoZzp1Dxa4S3C_9&t=616

coin 29d ago
Yes it's super misleading. All the marketing and title is calling it "electric" where in reality it's a hybrid electric-gas airplane with a 125 mile electric range. Aviation uses nautical miles yet they advertise 125 statute miles so the number seems bigger (125 statute miles = 108.62 nautical miles). It would be like Toyota marketing the Prius as an electric vehicle, then buried in their presentation sneaking in the gas propulsion. Same with Chrysler Pacifica (32 mile electric range).

werdnapk 1mo ago

So what do regular aircraft do when they run out of fuel? They require a forced landing. Aircraft fly with a buffer of fuel though to avoid such situations, so why can't an electric aircraft fly with a similar buffer on it's range? ie. Always fly less than the current charged range of the aircraft.

luma 1mo ago
Simply put, batteries are heavy.
- gblargg 1mo ago
  Something like 1/30 the energy density of liquid fuel. Plus unlike fuel, a discharged battery weighs virtually the same as a charged one.
marcosdumay 1mo ago
Regular aircraft fly with enough fuel to change into at least one other airport in an emergency (ideally two). That aircraft would need a very large battery to do that, and it's way more efficient to have some burnable fuel there that you'll never actually use.
MobiusHorizons 1mo ago
Regular aircraft are required to have enough fuel to be able to divert to the alternate airfield in their flight plan plus all the margins for taxiing and waiting for a landing clearance. If a plane is low on fuel they can declare an emergency and get priority over other traffic, but that obviously is disruptive and should not happen on well planned flights unless something pretty significant happens after takeoff.
- phire 1mo ago
  > and should not happen on well planned flights You make it sound like it is acceptable for a badly planned flight to have a fuel emergency. It is not. If there is a fuel emergency (or the plane lands with less than 30min of fuel) there will be an incident investigation that treats the situation as serious as if the plane had crashed. If the investigation discovers it was nothing more than bad planning, (at minimum) the planning procedures will be changed to ensure it never happens again.
  - bluGill 1mo ago
    Badly planned flights should not happen. Pilots who don't carefully plan their flights end up dead quickly. Lack of fuel is one of the easier to handle things that can go wrong from bad flight planning.
    - throwaway2037 29d ago
      Can you give an example of a "badly planned flight"? And did local regulators agree with your opinion?
      - bluGill 29d ago
        My dad dreamed of being a pilot and when I was a kid he subscribed to the flying magazine (or something like that I don't remember that name.) every single issue had the last story being "I learned about flying from that" and nearly every single one was a case of bad planning, usually a case of flying into bad weather because of the bad planning.
jmward01 1mo ago
Lots of down votes on this but it is a legitimate question. The goal is likely to have the majority of flight off of batteries. That being said, the total weight of the emergency fuel plus generators is likely far less than the weight of the extra batteries they would haul around for the safety margin they need. So they end up lighter and more capable AND don't need to burn fuel. That being said, I wouldn't be surprised if they didn't start the generators during critical phases so they may end up using some fuel for a flight, but not much. Total guess on that though.
- phire 1mo ago
  > That being said, I wouldn't be surprised if they didn't start the generators during critical phases I somewhat doubt that. Part of the advantage of the design is that the generators don't need to be sized as big enough to power take off, climb and a potential go-around on landing. They only need to be sized as big enough for cruising. So powering them up during critical phases wouldn't help with safety. If anything, normal operating procedures might actually require shutting them down during critical phases. What this does mean is that the batteries need to be reasonably full when it comes into land, possibly as high as 50%. And most go arounds will require immediately powering up the generators, so it probably needs to be fuelled for all but the shortest flights.
- labcomputer 1mo ago
  > That being said, I wouldn't be surprised if they didn't start the generators during critical phases so they may end up using some fuel for a flight, but not much. I would guess the opposite. Many parts in a turbine engine are "lifetime limited" by number of engine starts. That is, you are required to tear down the engine and replace certain parts after a certain number of engine cycles. That makes the economics of the turbine hybrid radically different if you need to start it every time you land vs. only the rare cases where you need to dip into fuel reserves. For example, the PT6A (a common 500-1000hp turboprop) requires the turbine and compressor disks to be replaced every 16,000 cycles. That's about 5 years of commercial service at 4x round trips per day. But if you only start the engine once in every 10 flights, now those components (theoretically) last for 50 years of flying.
Toutouxc 1mo ago
> Aircraft fly with a buffer of fuel though to avoid such situations, so why can't an electric aircraft fly with a similar buffer on it's range? Because the required buffer is HUGE and we’re at a point where electric planes barely have enough energy for the actual route. So they’re doing the sensible thing here, flying the actual route electrically and falling back to combustion if the plane needs to divert.
- deleted 1mo ago
  [deleted]
- tonyarkles 1mo ago
  To that point, the battery capacity they’ve got, rough envelope math, is maybe 10 minutes beyond reserve. They’d likely need at least double, probably triple battery capacity to fly useful routes all-electric with enough reserve stored in batteries. The turbines are a great move.
  - labcomputer 1mo ago
    > They’d likely need at least double, probably triple battery capacity to fly useful routes all-electric with enough reserve stored in batteries. Yup. And to bring this point home: "Only" doubling the battery capacity likely eats well over half of the payload capacity, in terms of mass. So your 38 seat plane is now a 19 seat (or fewer) plane.

dyauspitr 1mo ago

Unless they have a whole new airport and flying experience, I don’t think a lot of people are going to fly just 125 miles. That’s less than two hours of driving. It would be 2 hours of just airport shenanigans much less the flight itself.

deleted 1mo ago
[deleted]
tomjessessky 1mo ago
There are a fair number of connecting flights that this is a good fit for. For example, I fly out of Madison, WI regularly and almost always connect through Chicago, which I believe is right around the 125 mile mark.
- zxexz 1mo ago
  Used to regularly take the shortish flight from Boston to Chicago, and then a bus >3x as long to Madison to see family, because the puddlejumper was too expensive or not even running.
Toutouxc 1mo ago
> 125 miles … That’s less than two hours of driving. I don’t know where you live or what you drive, but I just punched in a destination 200 km away as the crow flies, the Alps are in the way and I’m looking at five hours of driving. Also, water.
- Thlom 1mo ago
  Rookie numbers. As the crow flies it's 250km between me and my old town. Used to drive back and forth a lot back in the days and it takes everything from 8 hours to 10 hours depending on the route you take and whether you hit the ferries on schedule or not. Plus 30 minutes for resting and eating. Flying takes 50 minutes in a propeller airplane + travel to and from airports and airport shenanigans (not too bad at these small airports). If you take the morning flight you'll be in town by the time people start showing up for work. If you drive you'll be in town by the time people start leaving work.

giancarlostoro 1mo ago

Honestly, I'd feel better knowing it has a reserve system in case there's any issues, even if the batteries have more than enough power, beats having it and never using it, than needing it and suffering as a result.

IrishTechie 1mo ago
Do current aircraft have a backup in-case their fuel tanks run dry?
- ben-schaaf 1mo ago
  There's reserve tanks or more generally reserve fuel for emergencies. Other than that there's no propulsion backup for when the fuel runs out, instead redundancy comes from multiple independent fuel tanks.
  - SideburnsOfDoom 1mo ago
    > redundancy comes from multiple independent fuel tanks. And in larger aircraft, multiple independent engines. See for instance ETOPS https://en.wikipedia.org/wiki/ETOPS https://en.wikipedia.org/wiki/ETOPS From the pictures, I see that this new aircraft has 4 engines. So it should be adequately resilient to single engine failure.
- dmitrygr 1mo ago
  Current aircraft have * MULTIPLE HOURS* of fuel tanks. Compared to dozens of minutes of battery that this thing has.
  - tonyarkles 1mo ago
    Typical reserve requirement is 30 min for a turbine aircraft (45 for piston). Given the 125 mile battery-only range and the probability that it flies at at least 200 kts (230 mph), it’s pretty unlikely to hit even a 30 min reserve on only batteries. I like the design, I think they get the problem and have a decent solution for it

seanmcdirmid 1mo ago

I remember reading about making ground effects electric planes for this reason. You need a reserve, but if your plane could double as a boat and was flying over water, that would satisfy the requirement.

nradov 1mo ago
As long as water conditions allow for a safe landing. In much of the world that severely limits when you can operate due to storms or ice. In practice routine use of ground effect vehicles will be mostly limited to lakes and inland seas with fairly benign weather. Like I don't think we're going to have regular passenger service from San Francisco to Los Angeles or Detroit to Cleveland.
- deleted 1mo ago
  [deleted]
- seanmcdirmid 1mo ago
  Ground effect planes are already pretty limited to calm water situations. Like between Seattle and Victoria, or maybe Seattle and Vancouver. I would say the Alaskan marine highway would be a good fit, but that is mostly for freight and cars.

deleted 1mo ago

[deleted]