Earlier quoted context omitted.
I thought they might make sense for trainer aircraft that flight schools would use.
Also saw this: https://harbourair.com/going-electric/?tab=Specification
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Why do transit agencies keep falling for the hydrogen bus myth?
41–50 of 503 posts
Re: Why do transit agencies keep falling for the hydrogen bus myth?
#42The electric airplane is another myth. There is no known battery technology, or one on the horizon, that can provide a large enough power/weight to make them practical. The investors are getting bilked.
They're great for trainers. Short hops with immediate control, low maintenance and operating cost, and you can save the magneto/ignition/etc workload for a different lesson series.
I can see that. Although managing the engine is a major part of learning to fly.
Re: Why do transit agencies keep falling for the hydrogen bus myth?
#43Earlier quoted context omitted.
> The ideal drivetrain was invented over 20 years ago by Toyota and apparently nobody but me and Honda noticed it! The problem is hybrid drivetrains are complex . You don't save anything on the complexity of a combustion engine and exhaust train (over 1000 individual parts that have to be machined at extremely low tolerances), but add a more complex transmission (it needs to be able to work with two distinct inputs)…
As a simple driver of cars, I've never understood why no one has mass produced an EV with a built-in generator. That would avoid the complexity of the hybrid drive train, allow easy plugin and short range electric-only travel, and could even be offered as an optional attachment. So what am I missing? Is the efficiency gained by the generator offset by losses through the EV system?
This was the GM Volt, predecessor to the Bolt: https://en.wikipedia.org/wiki/Chevrolet_Volt GM ceased production in 2019. The answer to your question can probably be found there, but IIRC [from GM's perspective] the consumer market preferred ICE + battery over electric + generator, especially after the all-electric options came to market and siphoned demand from the latter.
Re: Why do transit agencies keep falling for the hydrogen bus myth?
#44Earlier quoted context omitted.
> The ideal drivetrain was invented over 20 years ago by Toyota and apparently nobody but me and Honda noticed it! The problem is hybrid drivetrains are complex . You don't save anything on the complexity of a combustion engine and exhaust train (over 1000 individual parts that have to be machined at extremely low tolerances), but add a more complex transmission (it needs to be able to work with two distinct inputs)…
As a simple driver of cars, I've never understood why no one has mass produced an EV with a built-in generator. That would avoid the complexity of the hybrid drive train, allow easy plugin and short range electric-only travel, and could even be offered as an optional attachment. So what am I missing? Is the efficiency gained by the generator offset by losses through the EV system?
BMW i3 and Chevrolet Volt both had that option: https://en.wikipedia.org/wiki/Range_extender
And of course, there are plug-in hybrids: https://en.wikipedia.org/wiki/Plug-in_hybrid
Re: Why do transit agencies keep falling for the hydrogen bus myth?
#45Earlier quoted context omitted.
> The ideal drivetrain was invented over 20 years ago by Toyota and apparently nobody but me and Honda noticed it! The problem is hybrid drivetrains are complex . You don't save anything on the complexity of a combustion engine and exhaust train (over 1000 individual parts that have to be machined at extremely low tolerances), but add a more complex transmission (it needs to be able to work with two distinct inputs)…
Some hybrid drivetrains have fewer moving parts than a traditional ICE and are more reliable.
That undersells it. The data on hybrid drivetrains is pretty clear--it's definitely more reliable. Even mechanics will tell you that; certainly mine did, and he's not a masochist. Start+stop is hell on mechanical drivetrains. It's a no-brainer when purchasing a new car except that there's still a premium for hybrid, so the RoI might not be there given baseline reliability and depending on your preferences. Though the premium gap is closing, at least for non-plugin hybrids. Plugin hybrids are the new premium option in model lineups, so traditional hybrids are moving down market.
Re: Why do transit agencies keep falling for the hydrogen bus myth?
#46Earlier quoted context omitted.
The risk assessments are a teeny bit different. Edit: although maybe there's a good idea: catapult or winch launch for electric aircraft would massively reduce the power and energy storage requirements to be carried onboard.
Look at all the effort that goes into launching an airplane with a catapult on an aircraft carrier. There are other issues - like you cannot abort a catapult in progress.
Being constrained to a ship makes things harder though. If it was simply very long (runway length), I reckon an abort would be fine. There are probably a lot of different ways to do it.
But yeah, much harder than a regular runway. Probably not economical.
Re: Why do transit agencies keep falling for the hydrogen bus myth?
#47Huh. I kind of thought that batteries had comprehensively won in this market, tbh. I still can't quite get used to the electric buses. A 20 tonne double-decker bus should sound like it might explode at any moment; it is unnatural for them to move around more or less silently.
Batteries have won this so hard (if you ignore CNG busses, which have existed forever and are "almost as good as hydrogen could be") - because even when they hadn't won it, you just needed more busses. Is it nice if the bus can do a driver's entire shift without a recharge? Sure! But if it can't, you just design the route so that the driver can switch busses and buy another bus. That means the technology problem is n…
Many bus routes have a 5-10ish min break at some point (usually the main station) in the route. If you can utilize those ten minutes to do a top-up, you can go a lot further on the same sized battery.
Re: Why do transit agencies keep falling for the hydrogen bus myth?
#48The electric airplane is another myth. There is no known battery technology, or one on the horizon, that can provide a large enough power/weight to make them practical. The investors are getting bilked.
The plane, of course, flies anyway becuase planes don't care what humans think is impossible
/j
Re: Why do transit agencies keep falling for the hydrogen bus myth?
#49Earlier quoted context omitted.
> But if it can't, you just design the route so that the driver can switch busses and buy another bus Oof, that's a huge 'just' in many cases. That said, current electric buses have sufficient range that this mostly isn't an issue. The unnervingly silent double-deckers I mention have a claimed range of 320km, which, at least here, is sufficient. The big problem with Dublin's electric buses, ridiculously, was that the…
This depends a lot on local climate and topography. Seattle has kind of been a bust with them because the hills really reduce the amount of charge, and on top of that the existing bus depots are already full, so switching to electric only would mean having to find and locate space for more bus depots, which is quite difficult.
Hills should never reduce the range, because the energy lost during climbing up is recovered when going downhill.
This is one of the great advantages of electric vehicles with batteries, when properly designed.
Electric buses with batteries are even more suitable for cities with hills than for cities without hills, because they provide greater energy savings over buses with ICEs.
While I have never used buses with batteries, I have lived in cities with electric trolley buses. Even with the primitive technology of many decades ago, they were doing great in cities with hills, recovering most of the energy when going downhill, unlike the buses with ICEs, which had excessive fuel consumption because of the hills.
Re: Why do transit agencies keep falling for the hydrogen bus myth?
#50Earlier quoted context omitted.
> The ideal drivetrain was invented over 20 years ago by Toyota and apparently nobody but me and Honda noticed it! The problem is hybrid drivetrains are complex . You don't save anything on the complexity of a combustion engine and exhaust train (over 1000 individual parts that have to be machined at extremely low tolerances), but add a more complex transmission (it needs to be able to work with two distinct inputs)…
Some hybrid drivetrains have fewer moving parts than a traditional ICE and are more reliable.
Sounds counterintuitive.
Any references?