5 ms·

> I can endure buggy software but I don’t want to deal with buggy planes A plane built for resilience against defective engine components would be very differe

by rbanffy 4mo ago

> I can endure buggy software but I don’t want to deal with buggy planes A plane built for resilience against defective engine components would be very different from the airliners we fly today. I would assume more engines for redundancy, better protection against catastrophic failure, different designs to allow engines to function even if parts flew out, and so on. It’s an interesting design exercise to build from radically different expectations from the fundamental parts. Alternatively, a far less radical redesign would be turbines running at a much more forgiving regime feeding electric motors.

mrmlz 4mo ago
Lol. Do you think todays aircraft are not designed with the idea that the engine can fail? And if you have unreliable components do you think redundancy is going to save you? And lets be real - there already exist a aerospace arena where you have a higher number of CAT-events - it's called the military. And they deal with it by having a parachute for each passenger.. No - in effect building jet-engines (that are commercially viable i.e. fuel and efficeny) is not a easy to disrupt business. And the cost of entering it would be - high. And the benefit, well less obvious.
- rbanffy 4mo ago
  > Do you think todays aircraft are not designed with the idea that the engine can fail? Of course they are - but the engines are also designed to be extremely reliable, and that's why you get away with two engines on long flights over water, something previously only available for planes with four engines. > No - in effect building jet-engines (that are commercially viable i.e. fuel and efficeny) is not a easy to disrupt business. That's true. My point being that building a better jet engine might be the hardest way to disrupt the business - making a better propulsion system, which might or not include a jet engine, is a less difficult approach. If you have an electric plane with two motors, a big APU-like turbine charging a battery and powering the motors, you might get away with a cheaper turbine, running in less extreme regimes, and still have a more fuel efficient plane requiring less maintenance than a pure turboprop would. You don't win a stacked game by playing it by the rules. You win by changing the game to another one you can actually win. China did that with cars already.
  - londons_explore 4mo ago
    > If you have an electric plane with two motors, a big APU-like turbine charging a battery and powering the motors, you might get away with a cheaper turbine, running in less extreme regimes, and still have a more fuel efficient plane r This works for hybrid cars because the power demand when driving varies widely, as does the output speed. The 'hybrid' bit gets huge gains by always running the engine at optimal rpm+throttle, and using the battery to cover peaks and absorb troughs (regen). A plane cruises for many hours at a fairly constant speed and throttle, which is designed to hit peak efficiency of all components. The 'hybrid' design therefore falls far behind on weight, efficiency and cost.
    - rbanffy 4mo ago
      > A plane cruises for many hours This is why short-haul flight will be the first to adopt hybrid propulsion.
      - londons_explore 4mo ago
        There are already some trials with very short flights - ie. Sub 25 miles. Used for getting between islands for example
  - coderenegade 4mo ago
    Aerospace as a discipline has tried just about every propulsion system under the sun. What you're proposing has already been flight tested on an unmanned vehicle, albeit with many smaller props for a larger effective prop disk than the two you're proposing. This is actually better, because electric motors want to use rpm control, so you need to keep the moment of inertia of the propellers low. The efficiency penalty of smaller props is overcome by having many of them arranged closely together to create a large effective prop disk. For a hybrid system to be worth it, you need to claw back more efficiency than you lose in going from mechanical energy to electrical energy, and then back again. For cars, this is generally the case, because they're always accelerating and decelerating. Their wide operating band means that the engine will always be a game of compromises, which is why sticking a motor and battery in the loop and decoupling the engine from the wheels is beneficial. But planes aren't like that; they go from setpoint to setpoint, and they stay in a given configuration for long periods of time. They have very narrow, highly optimized operating bands, so hybridization just isn't as effective.
coderenegade 4mo ago
The philosophy in aerospace is more to build a better engine rather than to have more engines, and this extends to every aspect of aircraft design. Engines are already built to contain catastrophic failure, and the planes themselves remain functional for all but the most extreme situations. We're at the point where essentially every lost aircraft is a compound failure, with significant human factors contributing to the event. It's likely that we're on the pareto front of what engineering can reasonably accomplish, and the only gains in safety either barely nudge the needle of what we would notice (better materials, say), or difficult for the market to accept (removing pilots altogether). Aerospace RND has been looking into hybrid propulsion systems for a long time. If there's one thing they aren't shy about pushing, it's the ability to go higher, faster, more efficiently. Such systems aren't used because they aren't yet good enough.
- nradov 4mo ago
  There's no reason think that removing pilots altogether would enhance safety. Military experience has shown that mishap rates for unmanned aircraft are significantly higher than similar crewed aircraft. Routine flight operations can be automated pretty well now but where human pilots really earn their pay is with handling emergencies and other unexpected situations. The variety of potential emergencies is effectively infinite so it's simply impossible to write and test code to handle them in advance. Instead pilots have to improvise in real time based on intuition and first principles logic. Current AI technology still isn't capable of that.
  - coderenegade 4mo ago
    When I last looked into it (admittedly a number of years ago now) this was true for remotely piloted aircraft, but there wasn't enough data on systems that pilot themselves with humans doing the navigating. I'm not convinced that humans are particularly effective in emergency situations, especially when they're expected to go from monitoring systems that work 99.99% of the time, to suddenly aviating with alarms going off everywhere. I guess there's not really much of an alternative as it currently stands, but seeing how effective agentic AI is at chewing through data and analyzing systems makes me think that eventually, such systems will be used if they ever get to the necessary level of reliability.

by rbanffy 4mo ago

mrmlz 4mo ago

Lol. Do you think todays aircraft are not designed with the idea that the engine can fail? And if you have unreliable components do you think redundancy is going to save you? And lets be real - there already exist a aerospace arena where you have a higher number of CAT-events - it's called the military. And they deal with it by having a parachute for each passenger.. No - in effect building jet-engines (that are commercially viable i.e. fuel and efficeny) is not a easy to disrupt business. And the cost of entering it would be - high. And the benefit, well less obvious.

rbanffy 4mo ago
> Do you think todays aircraft are not designed with the idea that the engine can fail? Of course they are - but the engines are also designed to be extremely reliable, and that's why you get away with two engines on long flights over water, something previously only available for planes with four engines. > No - in effect building jet-engines (that are commercially viable i.e. fuel and efficeny) is not a easy to disrupt business. That's true. My point being that building a better jet engine might be the hardest way to disrupt the business - making a better propulsion system, which might or not include a jet engine, is a less difficult approach. If you have an electric plane with two motors, a big APU-like turbine charging a battery and powering the motors, you might get away with a cheaper turbine, running in less extreme regimes, and still have a more fuel efficient plane requiring less maintenance than a pure turboprop would. You don't win a stacked game by playing it by the rules. You win by changing the game to another one you can actually win. China did that with cars already.
- londons_explore 4mo ago
  > If you have an electric plane with two motors, a big APU-like turbine charging a battery and powering the motors, you might get away with a cheaper turbine, running in less extreme regimes, and still have a more fuel efficient plane r This works for hybrid cars because the power demand when driving varies widely, as does the output speed. The 'hybrid' bit gets huge gains by always running the engine at optimal rpm+throttle, and using the battery to cover peaks and absorb troughs (regen). A plane cruises for many hours at a fairly constant speed and throttle, which is designed to hit peak efficiency of all components. The 'hybrid' design therefore falls far behind on weight, efficiency and cost.
  - rbanffy 4mo ago
    > A plane cruises for many hours This is why short-haul flight will be the first to adopt hybrid propulsion.
    - londons_explore 4mo ago
      There are already some trials with very short flights - ie. Sub 25 miles. Used for getting between islands for example
- coderenegade 4mo ago
  Aerospace as a discipline has tried just about every propulsion system under the sun. What you're proposing has already been flight tested on an unmanned vehicle, albeit with many smaller props for a larger effective prop disk than the two you're proposing. This is actually better, because electric motors want to use rpm control, so you need to keep the moment of inertia of the propellers low. The efficiency penalty of smaller props is overcome by having many of them arranged closely together to create a large effective prop disk. For a hybrid system to be worth it, you need to claw back more efficiency than you lose in going from mechanical energy to electrical energy, and then back again. For cars, this is generally the case, because they're always accelerating and decelerating. Their wide operating band means that the engine will always be a game of compromises, which is why sticking a motor and battery in the loop and decoupling the engine from the wheels is beneficial. But planes aren't like that; they go from setpoint to setpoint, and they stay in a given configuration for long periods of time. They have very narrow, highly optimized operating bands, so hybridization just isn't as effective.

coderenegade 4mo ago

The philosophy in aerospace is more to build a better engine rather than to have more engines, and this extends to every aspect of aircraft design. Engines are already built to contain catastrophic failure, and the planes themselves remain functional for all but the most extreme situations. We're at the point where essentially every lost aircraft is a compound failure, with significant human factors contributing to the event. It's likely that we're on the pareto front of what engineering can reasonably accomplish, and the only gains in safety either barely nudge the needle of what we would notice (better materials, say), or difficult for the market to accept (removing pilots altogether). Aerospace RND has been looking into hybrid propulsion systems for a long time. If there's one thing they aren't shy about pushing, it's the ability to go higher, faster, more efficiently. Such systems aren't used because they aren't yet good enough.

nradov 4mo ago
There's no reason think that removing pilots altogether would enhance safety. Military experience has shown that mishap rates for unmanned aircraft are significantly higher than similar crewed aircraft. Routine flight operations can be automated pretty well now but where human pilots really earn their pay is with handling emergencies and other unexpected situations. The variety of potential emergencies is effectively infinite so it's simply impossible to write and test code to handle them in advance. Instead pilots have to improvise in real time based on intuition and first principles logic. Current AI technology still isn't capable of that.
- coderenegade 4mo ago
  When I last looked into it (admittedly a number of years ago now) this was true for remotely piloted aircraft, but there wasn't enough data on systems that pilot themselves with humans doing the navigating. I'm not convinced that humans are particularly effective in emergency situations, especially when they're expected to go from monitoring systems that work 99.99% of the time, to suddenly aviating with alarms going off everywhere. I guess there's not really much of an alternative as it currently stands, but seeing how effective agentic AI is at chewing through data and analyzing systems makes me think that eventually, such systems will be used if they ever get to the necessary level of reliability.