Is this EV or Hybrid?
The founder seems to sneak in the word "hybrid", around 1m30 mark in the video below.
https://youtu.be/nM86DBOqgPM?si=5unXLmPxk6M_kmuN&t=86
Note: not being negative, I just want to ensure I understand correctly since the title might imply something else.
Update: confirmed, it does use aviation fuel.
> "The airplane will also include a reserve-hybrid configuration, consisting of two turbo generators powered by sustainable aviation fuel. The reserve-hybrid system is installed to secure reserve energy requirements without cannibalizing battery range, and it can also be used during cruise on longer flights to complement the electrical power provided by the batteries."
https://www.heartaerospace.com/newsroom/heart-aerospace-unve...
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.
For anyone looking for the reference, it's stated at 10:16 [0]
[0] https://youtu.be/nM86DBOqgPM?si=BdoZzp1Dxa4S3C_9&t=616
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.
Do current aircraft have a backup in-case their fuel tanks run dry?
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.
Current aircraft have * MULTIPLE HOURS* of fuel tanks. Compared to dozens of minutes of battery that this thing has.
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.
Depending on the cost, and availability, 125 miles gets you within easy public transit range of NYC from Boston.
Now, of course, most of the hassle of getting to NYC from Boston is transit to and from the airport. And of course, transit from JFK, Laguardia, etc into the city.
There are at least 5 capable airports/airstrips closer to me than Logan or T.F. Green. Only one of them, Worcester, offers NYC flights. Worcester is almost an hour from me on average, and a bit more expensive. It’s an hour from takeoff to landing (I’ve arrived 10 minutes before takeoff, at the PARKING LOT many times without it being an issue).
If they can get this in and out of even smaller airports, like in Stow, MA, which is beyond capable, it will be a gamechanger.
Could be useful for hub and spoke type systems, where you fly from a smaller city to the main hub, and catch a connection from there.
Even then there are lots of flights in Europe that are between cities less than 1 hour apart.
This idea generally makes more sense in Europe than the US, I think.
Without noise, over time, travel will change.
> 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.
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.
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.
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.
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.
> 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.
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.
> 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.
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.
> 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.
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.
Simply put, batteries are heavy.
The X1, which is what flew, is all electric. The ES-30, their proposed product, is hybrid.
With limited information form their web site, both. Being able to run pure electric while switching to fossil fuel. [0]
The way modern hybrids can charge from an outlet, I classify them as EV-Hybrid, and only use gas if need be vs older ones that only charge through the gas engine, Hybrid.
[0] https://www.heartaerospace.com/es-30
Surprised they are not using linear opposed piston crankshaftless generators to make an extended range EV aircraft.
Smaller, lighter, simpler, cheaper, and more flexible about fuel.
https://www.youtube.com/watch?v=NeG4zLlFkak
Linear engine starts around 11:19
Turbines are extremely reliable and well-understood in aviation propulsion
This! Anything unproven makes the flight certification process longer. They already have to get their electric side certified, might as well make the backup generator as easily certified as possible.
Good point. Only have one new tech at a time.
Generation II then.
My father, a mechanical engineer, was a tireless advocate of the hypocycloid crankshaft mechanism. In the 90s, hybrid vehicles with a hypocycloid-based generator feeding the batteries that make the electric motors go was the application he was going for, especially since hypocycloids function best at constant RPM.
I say this with all sincerity, I love this sentence:
"My father, a mechanical engineer, was a tireless advocate of the hypocycloid crankshaft mechanism."
For some reason just reading that brought a smile to my face.
From mechanical engineers I’ve met it almost seems a requirement that they have something they tireless advocate for.
Yeah. I bet he was.
It uses aviation fuel only after the electric battery is empty. And uses the fuel to run generators, the motors are all electric.
Its hard to call that the largest electric aircraft IMO. It's electric until it can't, then its not.
Well, technically, it's always electric. Sometimes the source of that electricity is from the battery system, and sometimes it's from an onboard generator.