Why battery-powered aircraft will never have significant range

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Martin R.

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Mar 21, 2019
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....... Yep - agree on both counts. Although fuel cell technology, right now, is NOT light...
OK.

But - already 12 years ago - light enough to cross the English Channel in an ultralight ;-)
 

EzyBuildWing

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Sep 23, 2009
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Sydney NSW Australia
OK......so Pipistrel can taxi on 3kW and cruise at 75kts on 20kW, ......and similarly 2-seater Phoenix. Great numbers!
So use electric for quiet take-off and climb to "out-of-earshot" then crank up a simple light 4-stroke Paramotor (35HP) range-extender.
Paramotor engine could drive main propeller via belt-reduction and sprag-clutch......and if desired, it could even be left idling during taxi, take-off, and climb or even partially contribute during same.
Should satisfy the noise-protesters that live around airports.
 

John.Roo

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Oct 8, 2013
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Letohrad / Czech Republic
My first electric Phoenix had only 30 kW electric motor... So theoretically one Poliny Thor 303 would be enough :)
 

Bigshu

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Or, install a more effective muffler and save a few thousand dollars and lot of weight.
Sure, but whatever power loss you see from the muffler is there all the time, not just during noise sensitive operations. Electric in the pattern and smaller ICE for cruise could give an interesting solution, and possible safety advantage from redundancy.
 

Bigshu

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I was hoping, with 1700 hours on my engine, that 3X factor would have occurred a bit sooner, as I expect to have to rebuild the engine in 3 - 5 years, and was thinking I would go electric if the battery technology had gotten there. It won't in that time frame, so gasoline it will be for as long as I own the plane, as I don't expect to be around to rebuild it again in another 20 years :).
Unless we're in 3D printed robot bodies by then...
 

Marc Zeitlin

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Dec 11, 2015
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Tehachapi, CA
The fact that the car cruises at 30% power and the airplane at 75%?
So what? If I flew as slow as I drove (75 mph), I'd be flying at about 30% - 35% power, too. And if I tried to drive my car at the mentioned 192 mph, well, a Subaru Outback obviously wouldn't get there, and would have needed 100% power just to get to about 120 mph. The D x V equations still hold for both, and the faster you go, the more it matters.

We're talking about whether a battery powered aircraft can EVER have adequate range to be useful, and I've showed that a factor of 3X in battery capacity will get ME to that point in a cross-country cruising 4 seat aircraft. And that the energy required to go a particular distance is about the same in my old car and my current airplane.
 

Marc Zeitlin

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Dec 11, 2015
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Max range/endurance with a battery powered aircraft is always at about the slowest reasonable speed it can fly.
Maximum range for ANY propeller powered aircraft is always at about the slowest reasonable speed it can fly, which is the best L/D speed. Maximum endurance is generally even slower. Battery / electric aircraft are not going to be substantially different. You want to go fast? It costs.
 

BBerson

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Dec 16, 2007
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Port Townsend WA
Barnaby designed a 830 pound four seat car that got 102 mpg.
 

Urquiola

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Aug 23, 2013
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192
Location
Madrid, Spain
I'm not sure hybrid would offer much improvement in economy for aircraft. When cars cruise on flat and level road, they require just 15 - 20% of the maximum available engine power. Aircraft cruise at airspeeds that cause significantly more drag, which requires much more energy to overcome, hence 55 - 75% power requirement for cruise. And having both the combustion engine, AND an electric motor, AND fuel tanks, AND batteries would incur such significant weight penalty that any possible savings in energy consumption would likely be wiped out by the significant increase in weight.
My proposal was a low weight ICE, eg. a Wankel RCE, a Turbine, working alwaay at best SFC regime, power matching the cruise needs, as electric power generator, plus a very small battery, just for safety, for reserve, and for emergencies, for temporal high power needs, with electric engines for direct propulsion, which are lighter than an standard reciprocating, air cooled aircraft engine. This arrangement weight and costs can be calculated, I ignore calculations, and every plane has its owns features and performances, thus, sorry, I can't offer figures, no decent aviation without figures, you know.
The propulsion possibilities in this video
may be also worth considering. Thanks. Blessings +
 

Bigshu

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Will the 3D printed bodies be capable of sustained flight without a vehicle?
Depends on how fast the robot can move. Clip on wings could roll up or fold up, carry in a brief case or backpack. In the comics, Iron Man carried the arms and legs and helmet in a brief case, with only the torso piece on (to keep his damaged heart going). Or you could wear them like a cape, like Batman! Computing power being what it is, and auto land technology being available now, it should be no trouble to integrate into the national airspace.
 
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