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Electric Powered Aircraft

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Electric Powered Aircraft

Old 21st Jun 2019, 14:30
  #81 (permalink)  
 
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Originally Posted by Less Hair View Post
They teach them from scratch to fly their electric aircraft in their own school. Said to be one reason to take Cape Air for the first batch of production aircraft.
I was just being tongue in cheek.
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Old 21st Jun 2019, 14:40
  #82 (permalink)  
 
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Here is a status report on NASA's electrically-powered prototype aircraft: NASA's X-57

- Ed
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Old 21st Jun 2019, 14:55
  #83 (permalink)  
 
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This is all very well, but what will the turn round time be to recharge a 600 mile range battery to allow it to fly back?
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Old 21st Jun 2019, 15:02
  #84 (permalink)  
 
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I might just be confused, but it seems as though this 'electric' plane is powered by a gas turbine which drives the main pusher propeller and runs a generator that powers two wing tip electric motors; that's how they can achieve a 650 mile range - it's not running of batteries. How is this an 'electric' plane? What about the loss of efficiency every time there is a power conversion step? Am I missing something here?
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Old 21st Jun 2019, 15:20
  #85 (permalink)  
 
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Originally Posted by Winemaker View Post
I might just be confused, but it seems as though this 'electric' plane is powered by a gas turbine which drives the main pusher propeller and runs a generator that powers two wing tip electric motors; that's how they can achieve a 650 mile range - it's not running of batteries. How is this an 'electric' plane? What about the loss of efficiency every time there is a power conversion step? Am I missing something here?
What is your source for the above ?
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Old 21st Jun 2019, 15:46
  #86 (permalink)  
 
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The linked article's final paragraph mentions a different aircraft (or different optional hybrid power system) - EcoPulse. In passing, it should be noted that many large ships (E.G. RMS Queen Mary 2) now use "distributed power" - diesel or turbine-powered generators produce electric power to drive the actual electric motors attached to the props.

See: https://en.wikipedia.org/wiki/Integr...ric_propulsion

As to the change to a tailwheel - probably to protect the pusher-prop (as noted, it was a bit exposed to a prop-strike in the tricycle configuration).

But for those wondering about where the nose wheel would have fitted in the original: Pilots have been stepping over a hump between the cockpit seats since the DC-3 and B-17 - it's called a control pedestal. Check that original shiny-floor mockup and you'll see the nose-wheel would have retracted right between the pilots. And in an electric plane, the throttles are probably simple rheostats - the pedestal will be mostly empty space with minimal levers and such inside. Tuck the wheel right in there.
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Old 21st Jun 2019, 17:48
  #87 (permalink)  
 
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Thanks pattern, I did misread the article.
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Old 21st Jun 2019, 19:51
  #88 (permalink)  
 
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Originally Posted by DaveReidUK View Post
Can somebody convince me that it's a prototype and not just a mockup, please ?
For what it's worth, the narrator refers to the airplane as an "airworthy aircraft" in this video. But, he is with media...so...



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Old 21st Jun 2019, 22:34
  #89 (permalink)  
 
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Color me skeptical. Here are some VERY rough numbers; please feel free to correct any errors of bad assumptions.

I am comparing the weight of energy for a Cessna Grand Caravan and the electric plane, simply because they are about the same size and carry approximately the same number of passengers.

1) The energy density of kerosene is 39.5 kw-hr/gallon
2) The Caravan consumes in the range of 75 gallons (550#)/hour in cruise. For a 540 mile trip this is approximately 1650# or 8850 kw-hr of energy.
3) The energy density of a Lithium battery is maximally about 250 wh/kg, so let's give the electric a generous 400 wh/kg.
4) Let's give the electric machine another boost and call the efficiency of the turbo-prop 30% and the electric 100%.
5) With these assumption the electric will need 2655 kw-hr of stored energy and will arrive with a flat battery and no reserve.
6) At 0.4 kw-hr/kg the battery will weigh 6600 kg.

Doesn't look doable to me

Last edited by Winemaker; 22nd Jun 2019 at 23:42.
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Old 22nd Jun 2019, 01:21
  #90 (permalink)  
 
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These folk think they are achieving something.

https://www.ampaire.com/
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Old 22nd Jun 2019, 01:55
  #91 (permalink)  
 
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Originally Posted by Lantern10 View Post
These folk think they are achieving something.

https://www.ampaire.com/
The company said this is a "parallel hybrid," meaning the internal combustion engine and electric motor work to optimize power output as the plane flies.

https://www.dw.com/en/ampaire-test-f...ane/a-49098126


Looks like they put an electric unit in the rear, while keeping the recip in the front- and STILL needed a pod to house the batteries.

Hardly ground-breaking.

It's all vapour-ware until battery technology makes another quantum leap. It will happen, but not as soon as the plethora of "paper aeroplane" companies suggest.
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Old 22nd Jun 2019, 08:02
  #92 (permalink)  
 
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Batteries as we know them are certainly not weight efficient enough for aviation use and won't be for tens of years to come. Hydrogen has volume and storage issues. It looks like the only high capacity electrical power source for aircraft might be nuclear fuel from a pure technical standpoint. I'd stick to Kerosene.
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Old 22nd Jun 2019, 08:43
  #93 (permalink)  
 
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Originally Posted by Wizofoz View Post
The company said this is a "parallel hybrid," meaning the internal combustion engine and electric motor work to optimize power output as the plane flies.

https://www.dw.com/en/ampaire-test-f...ane/a-49098126


Looks like they put an electric unit in the rear, while keeping the recip in the front- and STILL needed a pod to house the batteries.
I suppose one way you could try to make a parallel hybrid work would be to have an ICE running at a constant power output, set to be just a little above cruise power. Surplus power would be electrified and stored in the battery or capacitor, to be used for times of high power need, like take off and climb. It's the principle called a "mild hybrid" in cars.

In land transport, with weight not being a critical factor and constant variation of speed to charge the battery, I can see this might be a win, with a smaller ICE running more of the time in its most efficient regime. I would be very sceptical about an aviation application, but I know nothing, and it would presumably take some fairly serious analysis to see if the added complexity was worth the gains. Does anyone have information?
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Old 22nd Jun 2019, 14:05
  #94 (permalink)  
 
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UTC is betting on an electric future and is building a flying demonstrator. They are not playing with small airframes but are converting a Dash 8.
The hybrid electric is a good start to an electric future. There will be much experience gained and a potentially viable hybrid aircraft to boot.

Besides building a flying demonstrator, they are also building a lab to support future development. Construction has already started.
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Old 24th Jul 2019, 06:34
  #95 (permalink)  
 
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The "Alice" has been ordered in double-digit numbers by Cape Air, a US airline that flies small planes on short routes.
https://www.capeair.com/#/availability

Apparently, they are now flying to Australia...."Billings to Sydney" (dry humour)...
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Old 24th Jul 2019, 20:04
  #96 (permalink)  
 
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As an all-electric car owner, I'm happy after a full charge from the mains electricity gives me 70 miles range ... at c. 30 mph.

The basic physics of batteries have a long way to go, IMO.

There's a lot of fantasy in these expositions.
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Old 25th Jul 2019, 09:29
  #97 (permalink)  
 
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Perhaps the all-electric aircraft will be the airship of the mid 21st century.
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Old 25th Jul 2019, 11:22
  #98 (permalink)  
 
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Originally Posted by Lantern10 View Post
These folk think they are achieving something.

https://www.ampaire.com/
read the fine print. Itís another hybrid design.
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Old 25th Jul 2019, 18:53
  #99 (permalink)  
 
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Originally Posted by FlightlessParrot View Post
Perhaps the all-electric aircraft will be the airship of the mid 21st century.
I suspect most of these companies are the Pyramid Schemes of the mid 21st century.
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Old 25th Jul 2019, 20:50
  #100 (permalink)  
 
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Another one bites the dust:

https://www.seattletimes.com/busines...s-out-of-cash/

Zunum, the Bothell-based startup developing a small hybrid-electric airplane, has run out of cash, and much of the operation has collapsed.The company promised to develop a family of small jets to serve lucrative short-hop routes with on-demand air-taxi services. A graphic produced by the company showed three different electric aircraft flying over Seattle: a 10-seat plane; a 50-seat plane; and a 100-seat airliner.The credibility of the company’s Silicon Valley-style pitch for a technology shift that would transform aviation was boosted by investments from Boeing and JetBlue. But unless new investors step forward, that fanciful dream is dead.
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