Bye Aerospace Unveils 8-Seat All-Electric EFlyer 800 | Hacker News Reader

Bye Aerospace Unveils 8-Seat All-Electric EFlyer 800

byeaerospace.com

48 pointshindsightbias68 comments

I’m not particularly superstitious, but getting on a “Bye” airplane still seems a bit like asking for it.

More seriously though, the claimed cruise speed looks competitive, but a 500nm range is a serious deficiency in this class of aircraft. I’m sure battery tech will get there one day, but there’s still a ways to go. I applaud the companies that are pushing the envelope, but I’m bearish on their chance of commercial success at this point.

DC to Boston and London to Paris both fall well within 500nm.

Short flights are dominated by ground transport times (door-to-door).

Assume that you need an hour to get to a general aviation airport, and an hour from the other GA airport to your final destination. Assume that you are a qualified pilot and have a driver's license and access to cars anywhere you want to go. 280 knots puts you in the air for not quite two hours, so a full-length flight is 4 hours or so door to door, moving you 560 miles or so.

That's quite an improvement over a 10 hour car trip. But a 4 hour car trip will get you 220 miles, whereas the EFlyer still needs 2 hours 45 minutes to do that.

The EFlyer can't get you anywhere in less than 2 hours, so anything under 120-150 miles you definitely want to do by car.

If you have a bunch of cities that you want to visit often, which are more than 200 miles apart but less than 500 miles apart, all of which have general aviation strips convenient to your destinations, and most especially if you have 4-7 other people who all want to make the same trips... this could be a winner.

Or you could telecommute.

This range is also the sweet spot for high-speed rail which is far more efficient, in energy and travel time. France has even banned short-haul flights for this reason.

But why would they ban short hops for highly efficient electric aircraft?

They didn't. There are no commercial electric aircraft yet. They banned current commercial airliners due to carbon emissions.

An hour to get to a GA airport is really uncommon in the US, most people live within 20 min. If you're a pilot-owner, then sure, it adds to the time, however this aircraft will most likely be professionally flown.

I think most commercial flights with these sorts of planes are sub 500nm, no? Think routes like ANU-SBH, TOB-MVY or MLE-Hotel.

Where do you see frequent PC-12 ops requiring 500nm range?

Operational costs is the killer advantage here ("..one-fifth the operating costs of traditional twin turboprops...").

That feels like an extraordinary claim that calls for extraordinary detail and proof. Electric cars have lower operating and maintenance costs than ICE cars, but nothing huge like that...not even "half"...perhaps "3/4". I get that the spread would be larger for aircraft but "1/5" is a big claim. Maybe they are cherry picking the shortish time period before the aircraft needs its first major maintenance event?

Edit: It's not the lower cost I'm disputing. It's the 1/5th bit. That's a huge claim that should come with some detail. How much of that is fuel cost, maintenance...over what time period?

I think it's quite possible that the maintenance events for an electric airplane are further apart and simpler than for a traditional engine, and those maintenance costs are a very major component of total infrastructure costs.

Oh, me too. Just not to the degree that it would have 1/5th the operating costs. Especially considering the fuel doesn't get lighter as it's spent. One-fifth is a very strong claim.

Engines are complicated and the maintenance and certification requirements on such a complex system in the context of aviation is very expensive. Airplane engines must be rebuilt at set time intervals even if they’re working perfectly because of what is at stake if they fail.

Electric motors are vastly simpler devices with far less moving parts. Much less to go wrong, much less to inspect and replace.

These are savings even before you get to talk about energy efficiency.

These savings aren’t realized in the car market because if the motor of a car fails, it is just an inconvenience. All that extra work doesn’t exist.

These savings aren’t theoretical either —- there are smaller scale electric aircraft used for pilot training on the market already. An hour of time in a Cessna costs $150ish/hour, these new electric planes are boasting costs of around $30/hour.

"These savings aren’t theoretical either —- there are smaller scale electric aircraft used for pilot training on the market already. An hour of time in a Cessna costs $150ish/hour, these new electric planes are boasting costs of around $30/hour."

That would be somewhat compelling proof, but you seem to be mixing "price offered to the renting flyer" and "cost incurred by the owner".

This seems dubious. Even auxiliary costs of the average plane rental (hangar, insurance) can exceed that rate depending on utilization.

>These savings aren’t theoretical either —- there are smaller scale electric aircraft used for pilot training on the market already. An hour of time in a Cessna costs $150ish/hour, these new electric planes are boasting costs of around $30/hour.

I'm curious, do the training hours on electric planes count towards normal ICE planes? I would assume at they very least they have different operating procedures if not outright handle differently.

Cars don't require a complete rebuild every 2000 hours. Maybe that's the cost they are hoping to eliminate?

For an existing electric aircraft (Pipistrel Alpha), the fuel cost advantage is claimed to be 10x of equivalent ICE-powered model.

ICE Pipistrel: "Poweredby the Rotax 912 80 HP engine it burns only 2.5 US gal (9.5 litres) of ordinary mogas fuel per hour"[1]

$6/gallon would be way on the high side estimate for mogas, so say $15 total, so we're sure to be generous.

Electric Pipistrel: "The cost of electricity per hour of flight is roughly between $4 and $6," said Krzysztof Będkowski of Pipistrel Alpha Poland."[2]

I can't work out how $4-6/$15 is 1/10. Is is attractive, for sure. Again, I'm not disputing electric is cheaper, but the claim of 1/5th the cost is pretty extraordinary.

[1] https://www.pipistrel-aircraft.com/aircraft/flight-training/...

[2] https://www.businessinsider.com/electric-plane-charges-in-ho...

Probably referring to total cost savings, not just fuel savings. As mentioned other places in this thread, electric motors have less/simpler maintenance needs than ICE engines and the TOTAL labor/parts/fuel savings is probably where the 1/5 or 1/10 claims come in.

Possibly. I was responding to "the fuel cost advantage is claimed to be 10x" though.

With a PC-12 you'll burn around $300 per engine hour in fuel alone, hot section inspections will come up every 1750 hours or so and cost $50k each, the engine overhauls will come up every 3500 hours and cost $350k

I wouldn't be shocked if replacing the electric motor costs less than what a turboprop inspection would.

That probably doesn't account for replacing the batteries though. I know a flight school that bought one electric aircraft and had to replace the battery within a year or two.

> 500nm range is a serious deficiency in this class of aircraft

My thoughts exactly. What happens when you fly 400 miles and need to divert to another airport because you can’t land at your destination. Talk about range anxiety!

Batteries make sense for cars, but I doubt aircraft will ever be mostly electric. There are other ways of making them green that make more sense, like hydrogen.

You don't just go up in the air and wander around yelping various airports; air travel is meticulously planned. There's no "range anxiety", your destination is either within range or not and you figure that out on the ground.

Hah... you should talk to more GA folks, which are the people who will be flying this plane. Think: doctors, software engineers, and car dealership owners.

Gasoline powered engines also fail once the tanks are empty...

This is why you have the 45 minute fuel (battery) reserve, to deal with scenarios like this. It’s well covered in all pilot training.

> There are other ways of making them green that make more sense, like hydrogen.

Or just producing fuel in a carbon neutral way. Seems crazy to add the weight of batteries which are less energy dense when you can have higher energy density fuel that gets lighter as the flight goes on.

The 500nm is quoted, as with all aircraft ranges, with the legally-mandated 45 minute reserve.

So it's 500nm + 45 minutes at cruise speed (= ~200nm or so)

Sure, but it's still very short.

How are they even going to deliver this plane? That's not enough range for a ferry pilot to deliver it to Europe or Asia, even hopping at every available airport around the Arctic.

How is that any different from non-electric planes?

Generally, they don't just fill airliner tanks full for every flight. They fill them with enough to reach their destination, plus enough extra to reach their alternate if they get diverted, plus enough for 45 minutes more flying.

All aircraft have a range. Your flight plan (and contingencies) just has to fit in the envelope or you don't go.

It's "500 nm range with 45-minute IFR reserves".

Reserve time is built into the range number.

Wanting 1500 nm range if 500 is sufficient is the airborne version of unnecessary range anxiety.

This is targeting regional flights - a quick search tells me the average regional flight distance is exactly 495 miles.

There is another one called Boom. I am aware it is about sonic boom but still.

Never hold much faith in any proposed new GA aircraft this early in the development process. This announcement basically is a group of people saying "Wouldn't it be cool if we..."

Unveils = provides high-level spec for a proposed airplane?

Out of curiosity, how do batteries behave in the cold temperature you can experience in altitude (or by cold weather)? The plane will not have a combustion engine to heat everything up.

Batteries will self-heat, since they're constantly being drained.

Cold temps on the ground might be an issue.

I wonder how swapping the battery packs works. Or do you throw away the entire aircraft after 500 flights? If it's anything like model-scale aircraft, air travel is more taxing on battery packs than automotive, since you have to more deeply cycle the battery during each flight.

The lack of battery replicability in consumer EVs is something that needs to be fixed with regulation.

All EVs on the market can have their packs replaced. For old Nissan Leafs, the price of a refurbished pack has gone down to the point where it even makes sense to extend their lives with a pack refurbishment.

Spec in SI units:

- 518 km/h cruise speed

- 593 km/h max speed

- 946 km max range

- 10.67 km max altitude

The performance figures are pretty optimistic, but hats off if they actually pull this off. Whoever gets a competitive e-plane to this market first is going to drown in money.

Electric drivetrains have the unique ability to recover energy, often used in braking for EV cars. Is there any corollary for recovering potential energy for electric planes?

The reason energy recovery in cars makes sense is that you're constantly stopping and starting. In a plane you definitely don't want the engine to stop running while you're in the air.

Isn't altitude ultimately a function of energy? If you're decreasing altitude wouldn't that be a decent amount of recovery?

Gas turbines need to keep running to sustain combustion but electric motors can start and stop instantly with current flow; it seems possible to use this as part of the dynamic control of the aircraft.

You don’t change altitude frequently enough and even if you could recover 80% of the energy you spent on reaching cruising altitude when you perform your landing approach it won’t be much, and probably won’t be worth the extra complexity and weight of an energy recovery system.

Unless we’re talking about very short flights the majority of your energy would be expanded at cruising altitude especially since electric engines have a fairly flat efficiency curve.

Actually, why don't planes cycle climbing to a height, switch off the engines, glide for X miles, restart engines to climb, etc ...

Pretty sure I used to do that when I used to fly in my Microprose F-15 and was short on fuel.

Generally, you don't want to stop an engine that's running fine. It might just not restart...

Because it’s not a very efficient or pleasant flight experience, and it’s probably too much of a risk.

Kindof. Currently used for emergency recovery: https://en.wikipedia.org/wiki/Ram_air_turbine

Potentially on descent, but I think it's a much smaller potential benefit in an airplane, and perhaps tricky because you don't want to extract so much energy that you lose speed and stall.

Planes don’t brake (except for a brief moment while landing), so no.

There is at least one commercial EV aircraft that can do it, but frankly it won't be as big a deal as it is with cars. Cars are speeding up and slowing down all the time. Aircraft generally speed up, stay fast, and then slow down at the very end of the flight. And for most aircraft, the entire flight is powered from takeoff to landing. It could be useful in emergency situations where the pilot is at risk of overshooting the runway.

For aerobatic aircraft it could be a big deal. High power motors and the desire to be as light as possible will probably drive power recovery and even crazier stunts at airshows.

Electric planes don't really need much breaking, except when coming in for a landing.

At that point, your flight is over and you don't need any extra range.

>500 nm range

The choice of abbreviation for nautical miles made me do a double take... Thats 575.39 miles, and 926 kilometers for anyone wondering.

Thank you, me too.

"and a full airplane parachute"

... is that a thing?

Edit: today I learned!

yes, it's a thing for small aircraft. Cirrus has it standard on some of their planes, and you can buy third-party addons for some other types.

Absolutely!

https://en.wikipedia.org/wiki/Cirrus_Airframe_Parachute_Syst...

I could imagine two ways this could work:

Slow down (if possible/necessary), stop the e-motors, feather the props, get the parachute out while attached to the back, sail down to the ground at a sufficiently low speed of impact to maybe just injure the passengers but not necessarily kill them.

Slow down (if possible/necessary), somehow jettison the wings from the fuselage (maybe explosive bolts like with Solid Rocket Boosters?), parachute out while attached to the top or back, sail down to the ground at a sufficiently low speed of impact to maybe just injure the passengers but not necessarily kill them.

Given its 500 nautical mile range & specs, what ballpark battery capacity will this thing be carrying?

As a wild guess: 2 hrs (500 nm at 250 kts)

500 kW (2x250 kW motors)

So 500 kW for 2 hours, or 1 MWh. Perhaps battery density is 250 Wh/kg, so around 4000 kg for batteries alone.

Perhaps serial hybrid would makes more sense?

How long does recharging take? And what infrastructure is required at the airport?

Li-ion batteries are typically limited to a minimum of about 40min for a complete charge. If you don't need the full 500 nm range, you can get away with a lot less. Maybe 20min.

Infrastructure for this plane would be an oversized electric car supercharger.

Larger planes (Wright Electric is working on a 186 seat electric plane) will require a much larger charger. The charger might actually need batteries itself so it can charge off the grid while the plane is not connected and then dump it all into the plane much faster than the electrical grid would allow.

so would that be the <sassy voice> BYE-E!! </sassy voice>

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