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.
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
The most common flight on my island is to the island about 50 miles away from us.
We pay about $120 for the privilege, which takes 20 minutes of flying.
So I think even in this case the reserve capacity is "needed" (for the reserve requierement), but I can see them realistically being able to fly between the islands purely on electric power.
Unless we ignore the additional maintenance cost of having to completely different proportion systems to maintain (and it is worse than a twin engine plane, because the propulsion systems are different, so you have to stock up on more different kinds of parts and possibly have different kinds of mechanics on staff to understand them)
Something that wasn’t super clear to me was whether the turbines are actually used for propulsion or if they’re used solely as generators to recharge the batteries/power the electric motors. I could honestly see it going either way.
Having the turbine, electric motor, gearbox, and potentially clutches to isolate the turbine or electric motor from the transmission seems pretty viable though. This would waste a little bit of power keeping the turbine spinning (unless there are clutches) but would also ensure that the turbine’s been spun recently, the oil pumps are primed and the bearings are lubed and ready to go.
Not that I’m saying a turboprop turbine like a PT6A is a simple device, but compared to a high-bypass turbofan like you’d see on a 737 or A320, they are considerably simpler.
Edit: looking quick, the time-before-overhaul (TBO) on modern PT6As can be up to 6000 hours, with a ~2000hr Hot Section Inspection. I’m not sure how “spinning but not burning fuel” counts on TBO, but it should at least mean the HSI is simple.
But... given that turbine APUs already exist for ground power and are already engineered to be as light as practical, my naive guess would be that it's easier, simpler and faster to just use a COTS APU as a series hybrid rather than trying directly couple a turbine to the propeller.
On inspections and overhauls: I'd expect that not needing to start the turbine at all on a given flight massively helps the economics of the airplane. Turbines often have parts that must be replaced after a given number of (startup) cycles, and that's going to be especially important for a turbine that is only expected to run for a short time (if at all) at the end of a flight.
If you only start the turbine on, say, 5% of flights, that means you get 20x as many flights before overhaul/inspection. I could see that being incredibly attractive to airlines.
> Typical reserve requirement is 30 min for a turbine aircraft (45 for piston).
For private, yes. For airlines, the requirement boils down to basically enough fuel to "fly to the intended destination as scheduled, then loiter for XX minutes, then fly at normal speeds to a pre-designated alternate, land".
For short flights, that means the fuel loaded at departure can be more than twice what is actually needed to get from A to B...
Which is why the hybrid approach is fairly clever: You can use it for ~125 mile flights, and remain 100% electric on ~95% of flights. Whereas, without the reserve turbine the practical limit would be ~60 miles. On the ~5% of flights requiring more range, you're still mostly operating on electricity.
Yes the are strict regulations requiring them to carry extra fuel; despite its weight having a real cost.
Carrying extra battery would be too heavy even compared to having a whole extra engine.
The savings in CO2 emissions for the likes of rapeseed, sunflower etc per MJ of energy is only around 50% compared to diesel. You have to release a lot of CO2 to grow these crops intensively. And that’s before you even consider where the land for these crops come from, potentially chopping down CO2 absorbing rainforests in many sorts of the world.
Biofuel from Used Cooking Oil is worthy considering for sure, but the quantities possible are tiny compared to the petrol/diesel we use.
> The DSA wants to abolish the existing US democratic process.
That reads as though you’re saying they want to abolish the democratic process, but as somebody living in a country with many of the democratic processes they’re proposing, looking in on what seems like a very dysfunctional democratic process in the US, it seems to be that they want to replace it with a much better version of itself.
While many people find the Leftist route of saving the country, the right route makes more sense to me. Reduce taxes to near zero - eliminate minimum wage - it's a recipe for starting companies. The left's answer is to destroy all companies. People think a company will exist in a leftist controlled world, but they're dead wrong.
I don't think so. I'm not an expert and I'm not an American. I did read their web site, I listen to what their candidates are saying and doing. I could very well be wrong. But when they say "socialism" there are two or three options. The first is they don't understand what that word means. The second is they do understand what that word means. The third is they've redefined this word. We already had a word for what people want, it's social-democratic, not socialism. So if they called themselves social-democrats and not socialists I would support them and we wouldn't be having this discussion.
"We want a democracy powered by everyday people. The capitalist class tells us we are powerless, but together we can take back control."
What are they not saying? They are not saying things like we should raise taxes to fund social programs so we can be more like Europe. Europe is capitalist. Europe has free markets. DSA opposes capitalism. DSA wants to, in their words: "We want to collectively own the key economic drivers that dominate our lives, such as energy production and transportation.".
What am I not understanding? Barrack Obama wanted accessible healthcare for all, he was not DSA. That's an awesome idea for the US that Democrats rallied behind and partly failed. Show me in DSA's words, material and action, how they are really social-democrats who just want more vacation, healthcare, worker protection while still maintaining capitalist free markets - like Europe. I mean they want all that but not in that way.
I think most of us want a moderate Democrat. I hope populism dies with Trump/MAGA in the coming years. We don’t need to match them with our own distasteful populism.
CHAZ was an idealistic symptom of applying John Lennon's Imagine to a neighborhood of Seattle, and it wasn't the only city tempted by this endeavor (if only it didn't finish with an arms dealer taking leadership of the locality);
"Defund the police" was a campaign slogan at last election.
I'm looking from Europe and I'm often impressed how extreme american leftists are. If it's not socialism, it sure shares the same conclusions. And yet "The most extreme left in the US is the most extreme right wing for Europe" is a common belief.
>I'm looking from Europe and I'm often impressed how extreme american leftists are.
I am often impressed how abusive and violent US policemen are. And they have budgets rivaling the defense spending of whole countries and are armed to the teeth with military grade equipment.
The world has moved forward. There was slavery in many places.
I had a similar discussion in real life. Where we concluded it that Roe vs. Wade being overturned was the biggest step backwards. Most of the other stuff is noise but this one is a biggy that's hard to fix. It sucks for Americans (which I'm not but I was debating an American).
Nobody is saying we can't let workers decide. Most of us are workers. Most of us vote. We are deciding. The US has also made progress on workers' rights at the state level to my understanding. At the end of the day we still have to lean on the democratic process, we need to debate policies and we need to get people to think critically and think things through. This is very hard to do today given the public discourse and tribalism.
The localisation of it struck me when I read an Irish EPA report on traffic-related air pollution a few years ago that recommended carrying your child if you were walking regularly near heavy traffic. The air at 0.8m (their breathing height) has 5-15% more NOx in it than the air at 2m (the height they would breath at being carried by you).
I remember reading something similar about walking on the part of the pavement furthest from the road, because being an extra meter or so away makes a big difference
I moved into a house with an obscene number of GU10 LED downlighters. The bulbs were all mid market (I think) brands like Energizer etc. I’d guess they’re coming up to 7-8 years old and I have now had to replace most of them, probably 30-40 bulbs from a couple of manufacturers that all just started to fail over about 12 months.
I also have quite a few Philips Hue bulbs, I’ve had 1 fail out of 20-30 and I think that was not the LED itself but some control board. Some are going on 10 years old.
I know there are some criticisms of Capital in the 21st Century and Picketty himself, but the book changed how I see the world profoundly, I cannot recommend it highly enough to anybody interested in these topics. The audiobook is a good way to digest it for the average person.
Same here. I can't stand the new Reddit. It spins up fans on my $3500 laptop, freezes and loads very slow. Once the old one stops working, I will have to stop using it.
I drink milk because a) I prefer flat whites to espressos and b) to make my cornflakes wet. In both cases I prefer oat milk and in neither cases do I care about nutrition. I’m guessing that’s the reason.
Makes sense. For me it was less about the health aspects of nutrition than the fact that I just feel a lot less sated when I drink protein-devoid plant milks. Corn flakes with oat milk is basically a big bowl of sugar with a little bit of oil and some vitamins sprayed on - it's not like it's a ton better with cow's milk but I'm not craving a "second breakfast" an hour later like I do if I have a breakfast that's primarily only carbs.
Soy milk actually has as much protein as dairy and less sugar. It has even more protein if you get the traditional kind. You can often find soymilk with a single ingredient at an Asian grocery store.
We have more issues with FileVault than we do with BitLocker, the latter being a fleet 5 times larger than the former. I find both “fine” for enterprise.
Also found it fascinating, although on the discussion about brakes I thought about how regen braking turns off in my EV when the battery is full, because there is no where to put the power. So you either keep some of the battery always available to soak up braking energy (and hope people never charge to full at the top of a mountain and exhaust the buffer) or you include a set of normal brakes for when regen is not possible, both options negating the weight savings. Right?
i wonder how much heat you'd have to dump if you just used a resistive load and heatsinks. aluminum isn't very heavy. Look at the size of a rotor and brake shoe on modern cars, it can't be that much larger surface area as a heat sink to dump the charge. Although someone would have to test it. Since EV are so smart, wouldn't they know that all routes generally are downhill, and thus stop the charge at 80% or something? Further, the absorption phase means you have to dump excess current somewhere anyway if you're over 80% charged.
Interesting, it seems like keeping the battery at some level below 100% (e.g. 80%) would make sense then because I don't think regen would ever top it off that much right?
My understanding is that after 80% the rate of charge a lithium ion battery can accept diminishes.
Could the 80% Li-on battery accept the charge from the brake regen fast enough? Or would it still have to be drained somewhere else if the battery could not accept it?
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