Electric planes

[daniel]

If aviation authorities will allow parcel delivery drones (U.S. will probably be first), why not beef-up the rotors and airlift passengers? Electric rotor technology is constantly evolving, so are lightweighting and battery technology. If we expect cars to ‘2D-maneuver’ autonomously through dense city traffic... then it should be less of a problem to have rotor-equipped vehicles auto-pilot themselves through the air, where there’s lots of 3D space to maneuver. Expect authorities to designate air corridors (running parallel to freeways?).

First of all, navigating through a 3D space is more complicated than navigating through a 2D space, not easier. Second, cars can stop very quickly to allow other cars to cross their path. Aircraft, even those that can hover, cannot stop nearly as quickly because they don't have the ground to push against. Third, if you have designated airports, then people have to drive to them, losing the convenience: You drive to the airport, wait for an air taxi, fly to another airport, then drive to your location. What people want is to be able to fly from origin to destination, but then you have hundreds of thousands of aircraft ascending and descending through multiple layers of air corridors.

The practical issues are far from trivial and will take many years to iron out, after the technology becomes available, and we still don't have the technology to put this within reach of the ordinary citizen.

 

[voyager]

It says designated air corridors, NOT designated airports. Nonsense what you state about auto-piloting 2D easier than 3D, particularly since it will never get as busy up in the air as down on the ground in and around town.

 

[RubberToe]

Just read a good article about electric planes in the 4/17-30 Aviation Week magazine. Here is a link to the article, but you have to be a subscriber to read the entire article:

Boeing, JetBlue Back Hybrid-Electric Regional Startup

One of the companies discussed is Zunum, and here is a link to their website;

http://zunum.aero/

I'm surprised they are so far along, though I haven't been following electric jet development that closely. The short version is that they believe they can cut the operating cost 40-80% for short haul flights by using electricity versus jet fuel. The planes will serve short haul markets mostly ignored by the larger jets. First plane will be a 19 seater optimized for a 700 mile range. Viable aircraft with a 300 watt hours per kilogram battery, which they say is available. As battery energy density increases, so does the planes range, and eventually no backup engine would be required.

Filling the role that HSR provides in European short haul markets. The initial planes will be hybrid, but only fire up the engine when the battery needs to recharged for a longer flight. They believe they can get certified by 2020.

Boeing is backing Zunum, but Airbus is also pursuing electric flight technology.

RT

 

[daniel]

It says designated air corridors, NOT designated airports. Nonsense what you state about auto-piloting 2D easier than 3D, particularly since it will never get as busy up in the air as down on the ground in and around town.

The claim was made earlier in the thread that electric air taxis would be cheaper than car taxis. If this happened, nobody would want to use car taxis and the skies over cities would be massively crowded unless regulations limited the number of aircraft allowed. And that alone would drive the price up.

Elsewhere in the thread it was suggested that the chaos of aircraft ascending from and descending to potentially anywhere in the city would be alleviated by having designated air terminals (airports, taxiports?) rather than allowing flights from anywhere to anywhere.

Note again, as I've said before, I think electric VTOL air taxis are possible and will probably come fairly soon. Just not at a price that ordinary folks will be able to afford.

... First plane will be a 19 seater optimized for a 700 mile range. Viable aircraft with a 300 watt hours per kilogram battery, which they say is available. ...

I don't believe a 19-seat 700-mile range electric plane is possible with today's batteries, certainly not at a price competitive with today's turboprop planes flying the same routes. Too much of the loaded weight of the plane would be batteries. Weight that today can be used for paid cargo

 

[RubberToe]

The claim was made earlier in the thread that electric air taxis would be cheaper than car taxis. If this happened, nobody would want to use car taxis and the skies over cities would be massively crowded unless regulations limited the number of aircraft allowed. And that alone would drive the price up.

Elsewhere in the thread it was suggested that the chaos of aircraft ascending from and descending to potentially anywhere in the city would be alleviated by having designated air terminals (airports, taxiports?) rather than allowing flights from anywhere to anywhere.

Note again, as I've said before, I think electric VTOL air taxis are possible and will probably come fairly soon. Just not at a price that ordinary folks will be able to afford.



I don't believe a 19-seat 700-mile range electric plane is possible with today's batteries, certainly not at a price competitive with today's turboprop planes flying the same routes. Too much of the loaded weight of the plane would be batteries. Weight that today can be used for paid cargo

A small jet engine would be used to charge the batteries in flight. Probably during takeoff and as required if circling or diverting. I haven't studied the website in detail yet, the Cubs are on for goodness sake!

RT

 

[daniel]

A small jet engine would be used to charge the batteries in flight. Probably during takeoff and as required if circling or diverting. I haven't studied the website in detail yet, the Cubs are on for goodness sake!

RT

That makes no sense at all. If you're going to carry a jet engine it makes more sense to leave the batteries out and just drive the electric motors directly from the jet engine, since batteries weigh about a thousand times as much as jet fuel.

 

[jbcarioca]

Just read a good article about electric planes in the 4/17-30 Aviation Week magazine. Here is a link to the article, but you have to be a subscriber to read the entire article:

Boeing, JetBlue Back Hybrid-Electric Regional Startup

One of the companies discussed is Zunum, and here is a link to their website;

http://zunum.aero/

I'm surprised they are so far along, though I haven't been following electric jet development that closely. The short version is that they believe they can cut the operating cost 40-80% for short haul flights by using electricity versus jet fuel. The planes will serve short haul markets mostly ignored by the larger jets. First plane will be a 19 seater optimized for a 700 mile range. Viable aircraft with a 300 watt hours per kilogram battery, which they say is available. As battery energy density increases, so does the planes range, and eventually no backup engine would be required.

Filling the role that HSR provides in European short haul markets. The initial planes will be hybrid, but only fire up the engine when the battery needs to recharged for a longer flight. They believe they can get certified by 2020.

Boeing is backing Zunum, but Airbus is also pursuing electric flight technology.

RT

The chief difference between Boeing and Airbus approaches is that Airbus is doing much development directly while Boeing is backing other players. Both could work, but 2020'commercialization is ridiculous because there is no existing regulatory basis for certification. Just the B787 took much longer than that, mostly to 'more electric' and higher use of omposites in high stress locations. 'More electric' had it's basis in DOD contract bids so the B787 approach had had years to mature. Still, the new technology has very serious 'growing pains'.

Airbus has had flying tests and partners closely with others, but they are doing lots of original work.
E-Fan electric aircraft
Either way commercial deployment, even of hybrids, is at least a decade away.

 

[davecolene0606]

One quick observation...
If ChargePoint has anything to do with it (1) most the flights will be grounded for lack of a working charger and (2) any flights that do occur will be delayed due to slow charging

Yuuuup

 

[swaltner]

I received the following today in an e-mail from IAC (International Aerobatic Club). This aircraft was mentioned earlier in this thread and is now on the list of things that I will definitely check out at Oshkosh this summer. I REALLY hope they fly it during one of the daily air shows or flight exhibitions.

===

Siemens, Extra Aircraft to Bring World-Record Electric Airplane to AirVenture

Walter Extra announced that he and Siemens are planning to bring the Extra 330LE electric-powered aircraft to EAA AirVenture Oshkosh 2017. It will be parked in front of the IAC Aerobatics Pavilion during its stay. Details are being worked out, including the possibility of a flying demo.

The aircraft, being used by Siemens AG as an electric motor test platform, has established numerous world records and firsts in its class.

 

[Graffi]

Since so much energy is spent on takeoff why not use something like a Mag-Lev sled that the plane sits on for takeoff so as the plane glides down the runway you slowly increase the prop speed to 80% just before liftoff then reduce further when at cruse altitude. Should get a lot more range like that. JMHO, an uneducated opinion at that....

 

[Etna]

Relative to climb and cruise energy, very little is spent on takeoff.

Takeoff lasts only about 30 seconds and represents 3 percent of the climb energy or 1 percent of climb+cruise, looking at a medium altitude short range aircraft for which I have precise data on my computer and just working on now. So you'd get only 1 percent more range, likely more than offset by the additional structural weight needed to take the sled loads.

 

[JRP3]

Since so much energy is spent on takeoff why not use something like a Mag-Lev sled that the plane sits on for takeoff so as the plane glides down the runway you slowly increase the prop speed to 80% just before liftoff then reduce further when at cruse altitude. Should get a lot more range like that. JMHO, an uneducated opinion at that....

 

[voyager]

Has Wright been covered yet?

March 21, 2017. Gas is the biggest cost for airlines. The easiest way to reduce these costs? Don’t use gas at all. That was the pitch from Wright Electric, a startup building a commercial passenger plane that runs on batteries and can handle flights under 300 miles. These short-haul trips make up 30 percent of all flights and is a $26 billion market. Today Wright Electric gave its first preview to the world at Y Combinator’s Demo Day, where Silicon Valley’s most prestigious startup accelerator puts its new companies in front of investors. Wright Electric announced it’s building a 150-seat plane to disrupt the 737 market. It’s struck a partnership with budget British airline EasyJet, which could put its design in the air. And it even showed off its own electric plane in the parking lot.
Wright Electric unveils its commercial electric plane business

 

[voyager]

 

[voyager]

I'm not sure how we got on "flying cars" - Lilium doesn't make that claim, and this isn't a road-going vehicle.

There are some eyebrow-raising claims on their site, like "energy efficiency will be better than or comparable to an electric car," "90% less energy than drone-style aircraft," and "in flight, the Jet's power consumption per km will be comparable to an electric car."

Really? At 300 km/hr? I guess the laws of physics don't apply in Lilium-land. At those speeds, your S would draw 9x the power than at 100km/hr.

Maybe they're comparing consumption per km to a 300km/hr electric car.

This Funky ‘Jet’ Could Make Our Dreams of Flying Cars Come True
I agree with Prof. Anderson in the article. Lilium cannot and will never work! The Lilium guys seem to be well-funded... Which is crazy, since any aviation engineer can tell you that disk loading or DL is the figure to look for in any vehicle that takes off (and lands) vertically. The lower the DL, the more efficient the design and the lower the downwash. The popular Robinson helicopters R22 and R44 have a DL between 2 and 3 lb/ft2. Now, the Lilium people are secretive about the specs and how to compensate for the unprecedented high DL (of what seems to me well over 100 lb/ft2) which means that Lilium is incredibly INefficient, up to the point that it will never ever be able to score a decent range, because it will suck up battery power like there's no tomorrow.

 

[ggr]

This Funky ‘Jet’ Could Make Our Dreams of Flying Cars Come True
I agree with Prof. Anderson in the article. Lilium cannot and will never work! The Lilium guys seem to be well-funded... Which is crazy, since any aviation engineer can tell you that disk loading or DL is the figure to look for in any vehicle that takes off (and lands) vertically. The lower the DL, the more efficient the design and the lower the downwash. The popular Robinson helicopters R22 and R44 have a DL between 2 and 3 lb/ft2. Now, the Lilium people are secretive about the specs and how to compensate for the unprecedented high DL (of what seems to me well over 100 lb/ft2) which means that Lilium is incredibly INefficient, up to the point that it will never ever be able to score a decent range, because it will suck up battery power like there's no tomorrow.

But it's only inefficient for a few seconds at take-off and landing... the rest of the time it's flying like an airplane.

 

[voyager]

But it's only inefficient for a few seconds at take-off and landing... the rest of the time it's flying like an airplane.

You're right about that. Problem is dat VTOL costs a lot of energy! Might be the reason that so far, despite having been busy for a number of years and spending millions of euro, you only see clips with Lilium taking off the ground empty. Max takeoff weight is supposed to be 600 kg. So, you leave out a weight of approx. 160 kg.

 

[Etna]

Actually a helicopter is not that bad as VTOL in terms of efficiency, you can hover a R22 for a long time.

The Lilium will also be inefficient in cruise because for good efficiency you need a large wing span and/or a big propeller (by writing "or" I am referring to a helicopter).

With essentially no wing to speak off and a couple hundred little computer power supply fans taped together, the efficiency of that thing will be non survivable compared to what Vahana et al are doing.

 

[voyager]

Actually a helicopter is not that bad as VTOL in terms of efficiency, you can hover a R22 for a long time.
The Lilium will also be inefficient in cruise because for good efficiency you need a large wing span and/or a big propeller (by writing "or" I am referring to a helicopter).
With essentially no wing to speak off and a couple hundred little computer power supply fans taped together, the efficiency of that thing will be non survivable compared to what Vahana et al are doing.

You're right that opening up the wings to let the small diameter ducted fans do their thing will disturb the airflow.
The cabin is unusually wide though, which suggests that most of the lift will be generated by the fuselage.

 

[miimura]

A new all-electric aircraft with a range up to 600 miles unveiled at Paris Air Show

Eviation's recent prototype debut seems relevant to this thread. Does the hybrid battery approach make sense to people here? Hybrid meaning a conventional high power rechargeable lithium ion pack combined with an Aluminum Air battery.