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The largest electric aircraft just flew [video]

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Re: The largest electric aircraft just flew [video]

#171
post #87

Earlier quoted context omitted.

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.

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.

[deleted]

Re: The largest electric aircraft just flew [video]

#172
post #34
post #21

Earlier quoted context omitted.

It may be too hard to do a good retrofit. If you basically have to tear the entire plane apart and rebuild and recertify it to put batteries in the right places, maybe the costs aren’t worth it for potential customers. I know many planes use their wings as fuel tanks but given the weight of batteries maybe that doesn’t work. I agree it’s interesting. Not a small undertaking.

Generally all the weight of the fusaage has to go through the wings anyway so it is structurally more efficient to put weight on the wings in the first place.

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Re: The largest electric aircraft just flew [video]

#173
I'm surprised by the struts supporting the wing; that saves weight (probably important here), but at the cost of drag. Wikipedia suggests a rule of thumb of 200mph being the break-even point for struts vs cantilever, and I would guess this plane is supposed to cruise faster than that. However, I didn't see the cruise speed listed anywhere; does someone know what they are targeting?

On another note, other than the struts, the design is reminiscent of the DHC Dash-7, a STOL airliner from the '60s that also used slower propellers (with gearing instead of an electric motor, of course) to reduce noise. That plane wasn't particularly fast either (240kts max speed).

Re: The largest electric aircraft just flew [video]

#174

The moment he talked about "remote pilots managing many planes," I closed the tab. Remote pilots sound great until something goes wrong, and things inevitably go wrong, not often, but they go wrong. I will never fly on any aircraft that does not have a minimum two-person crew on the flight deck. The ability to "feel" the plane is invaluable in an emergency situation. Frankly, just the fact that someone whose life is…

> I will never fly on any aircraft that does not have a minimum two-person crew on the flight deck.

You're missing out. Flying solo in a small plane is great.

Re: The largest electric aircraft just flew [video]

#175
post #143

Earlier quoted context omitted.

Batteries are rapidly improving (on many metrics, but the relevant one here is increasing in energy density). The range is apparently 125 miles electric, and 500 miles as a hybrid. That's not enough for Melbourne Sydney. Give it a couple doubling-times though (5 years total?) and it will be. Meanwhile aircraft take forever to develop and there should be enough of a market in shorter hall flights to occupy a scaling c…

Batteries aren't rapidly improving. Every single battery that has proposed higher energy density also has downsides in max discharge current. We may get at best like 10% improvement over what it is today.

That's max discharge current per cell though. You are going to have a lot of cells in a plane like this.

Re: The largest electric aircraft just flew [video]

#176
post #16

Interesting decision to build the whole aircraft instead of the propulsion system only. I wonder what the decision process was between retrofit of existing turboprop frame vs. build from the ground up? I would expect the level of effort and certification to be much higher building from scratch even though you get complete control.

Judging by the seats, perhaps making it as light as possible. Existing airframes are relatively light but let's be honest, they aren't trying to save 500g here and there when they have massive jet engines to get everything airborne.

[deleted]

Re: The largest electric aircraft just flew [video]

#177
post #87

Earlier quoted context omitted.

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.

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.

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.

Re: The largest electric aircraft just flew [video]

#178

'The first clean sheet airliner to be flown in any category. electric or not, in the US in the last 18 years' This is the statement that matters and why I think electric is a huge deal. We can't get new designs into the air. It costs too much and takes too long. Electric has the potential to bring the design cycle back to something reasonable. Electric engines, and the supporting systems around them, are just so much…

The 737-Max is only not a clean-sheet only because the selling point is pilots don't need to retrain, which is a competitive advantage when selling to airlines.

Re: The largest electric aircraft just flew [video]

#179
post #87

Earlier quoted context omitted.

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.

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.

Re: The largest electric aircraft just flew [video]

#180

I'm surprised by the struts supporting the wing; that saves weight (probably important here), but at the cost of drag. Wikipedia suggests a rule of thumb of 200mph being the break-even point for struts vs cantilever, and I would guess this plane is supposed to cruise faster than that. However, I didn't see the cruise speed listed anywhere; does someone know what they are targeting? On another note, other than the str…

That sounds like the breakeven if you're holding wing geometry constant and want to compare cantilever weight cost to bracing drag cost. The real advantage is in allowing for thinner and higher aspect ratio wings like in the Boeing X-66 which was designed to fly considerably faster than 200mph and make fuel savings.

I guess an additional advantage in this design is that the weight of the batteries is in the fuselage rather than the wing, so additional strengthening of some type may be necessary in either scenario.

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