Why battery-powered aircraft will never have significant range

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Sraight'nlevel

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To get wing loadings down, you need bigger wings, which means longer wings, which means much stronger spars and fuselage carrythroughs and so on. None of it is weightless.

Everything in airplanes involves compromises, and going too far in any direction results in a poor airplane.

Lifting body/blended body may be answer here ?_111193375_maveric-03.jpg
 

Sraight'nlevel

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If lifting body was the answer for an electric airplane, it would be the answer for all airplanes. But it's not. Been tried many times. Aspect ratio is a big deal in flight efficiency.

MAVERIC does not seem to have extreme aspect ratio:


pm_38_533_533224-iv98us7mpj.jpg

To me looks as if the fuselage is as wide as one wing panel.

airbus-maveric-blended-wing-aircraft-hydrogen-power.jpg
 
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Rhino

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MAVERIC does not seem to have extreme aspect ratio:
It's also not in production. It's only an RC model. There are tons of research and development/proof of concept aircraft that have never made it to production. Lifting body technology will likely advance as time goes on, but Dan Thomas is right. It isn't the answer right now.
 

tspear

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If lifting body was the answer for an electric airplane, it would be the answer for all airplanes. But it's not. Been tried many times. Aspect ratio is a big deal in flight efficiency.
A lifting wing has the potential for less drag and also has a greater volume. These are the reasons engineers keep coming back to it.
For the less drag aspect; there is no fuselage intersections, and less wetted area due to the fact multiple airfoils are not required, come counter acting each other in most configurations.

Note: the config has many balance issues and thrust attenuation problems, which from a practical standpoint have largely prevented anyone but the military doing it.

Tim
 

AeroER

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A blended wing body is the worst case configuration for wetted area. Everything about the configuration has to buy its way onto the airplane.
 

tspear

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A blended wing body is the worst case configuration for wetted area. Everything about the configuration has to buy its way onto the airplane.
Hmmm. then maybe I have the wrong name. What is the type of drag which represents constant pressure change? It is why you have swept wings, fuselage bulges around wings, indents around the engine pylons for business jets....

Anyway, this is way outside my knowledge area, but I have read from multiple aerodynamic engineers that lifting airfoil body's is the most efficient from an academic point of view (just like a one bladed prop), however they tend to fail from a practical standpoint.

Tim
 

AeroER

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Hmmm. then maybe I have the wrong name. What is the type of drag which represents constant pressure change? It is why you have swept wings, fuselage bulges around wings, indents around the engine pylons for business jets....

Anyway, this is way outside my knowledge area, but I have read from multiple aerodynamic engineers that lifting airfoil body's is the most efficient from an academic point of view (just like a one bladed prop), however they tend to fail from a practical standpoint.

Tim
You're thinking of area ruling to reduce wave drag in supersonic flow.
 

Sraight'nlevel

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A blended wing body is the worst case configuration for wetted area. Everything about the configuration has to buy its way onto the airplane.

Wetted area may be increased, but if the weight is half, I'll buy it. Seems to be missing the heavy flap systems etc.
 

AeroER

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Can we define "significant range" for a homebuilt Part 103 or equivalent aircraft ?

Is it 200-300 km with present systems?

Let's consider the possibilities of a Part 103 cruising at the 63 mph maximum speed -

186 miles requires 3 hours. The fuel consumption required to make that range with 5 gallons of fuel on board is 2.7 gallons per hour.

Does the engine chosen satisfy those requirements, power to cruise at 63 mph at 2.7 gallons per hour?

What about 124 miles? 2 hours at 2.5 gallons per hour?

What range is possible at 4 gallons per hour from a 50 hp class two stroke engine?

Throttling back will extend endurance and range in still air; hopefully the sight seeing is excellent.
 

Sraight'nlevel

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Okay let's say that significant range inside Part 103 is 250 km/150 miles.

What does electrified e-Lazair land today range wise ?
 

Rhino

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It's not just range. It's the ability to continue once that range has been reached. With an ICE aircraft you simply refuel. Electric aircraft have to be recharged. What's the turnaround time for that? If you only ever take short, one-leg trips this won't matter. But if you ever anticipate taking multi-leg journeys, this is important. And most pilots would like to have that capability even if they don't use it much, or never do. They want to have the option. Other than a battery recharge, someone mentioned battery swap stations, where you would simply swap your discharged batteries for charged ones, for a small fee. That idea has merit to me, though the logistics and infrastructure involved would be complex and time consuming to create.
 

tspear

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It's not just range. It's the ability to continue once that range has been reached. With an ICE aircraft you simply refuel. Electric aircraft have to be recharged. What's the turnaround time for that? If you only ever take short, one-leg trips this won't matter. But if you ever anticipate taking multi-leg journeys, this is important. And most pilots would like to have that capability even if they don't use it much, or never do. They want to have the option. Other than a battery recharge, someone mentioned battery swap stations, where you would simply swap your discharged batteries for charged ones, for a small fee. That idea has merit to me, though the logistics and infrastructure involved would be complex and time consuming to create.
Nah, if I could have an electric plane which could fly 800 miles no reserve with 600 miles normal reserve and kept that range for a decade or more; even if the recharge time was 36 hours it would put it in serious contention for me. That is a simple limitation to deal with, and I would plan my trips around it. In all my flying, I can think of only one trip where such a limitation would have had a material impact on the trip, and that was returning from Utah to Boston this past May, however I could have easily planned around around it.

Tim
 

blane.c

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What does electrified e-Lazair land today range wise ?
[/QUOTE]

The electric Lazair is a self launchable amphibious glider that "happens to be" an ultralight. Since it is a glider its range is not strictly limited by its power source but instead it is enhanced by it.
 

Sraight'nlevel

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The electric Lazair is a self launchable amphibious glider that "happens to be" an ultralight. Since it is a glider its range is not strictly limited by its power source but instead it is enhanced by it.

I understand that, but what is the best range in calm conditions ?


Elazair.jpg

Closely related to Demoiselle:

 
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Sraight'nlevel

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It's not just range. It's the ability to continue once that range has been reached. With an ICE aircraft you simply refuel. Electric aircraft have to be recharged. What's the turnaround time for that? If you only ever take short, one-leg trips this won't matter. But if you ever anticipate taking multi-leg journeys, this is important. And most pilots would like to have that capability even if they don't use it much, or never do. They want to have the option. Other than a battery recharge, someone mentioned battery swap stations, where you would simply swap your discharged batteries for charged ones, for a small fee. That idea has merit to me, though the logistics and infrastructure involved would be complex and time consuming to create.

Yes but if you have your own wind turbine or solar cell system, you fly almost free.
 
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