4 ms·

I wonder if satellite-based system to use space-based solar power generation and convert to microwaves to beam power to aircraft would work? Store just enough o

I wonder if satellite-based system to use space-based solar power generation and convert to microwaves to beam power to aircraft would work? Store just enough on the plane for take off and emergency landing nearby plus a buffer for in-flight space power. For long flights the plane receives a beam of energy. Everyone would probably die from being cooked but it may work.

meindnoch 3y ago
Just to put that into perspective: a 747 uses 90 MW peak power during takeoff. And that's the useful power it needs as thrust, so the engines produce quite a bit more than that.
- angiosperm 3y ago
  Yeah, microwaves are right out. Lasers, maybe, but lasers that can focus so closely qualify as offensive weapons. Generally, less-focused lasers, picked up by nighttime solar farms that absorb sunlight directly in the daytime, are a much more likely medium for orbital power than microwaves. Monochromatic light can be converted to electrical power with much higher efficiency than can blackbody solar radiation. Lasers producing no greater intensity than sunlight worry people less than microwave radiation.
Ekaros 3y ago
What is the surface area of the top of a plane? How much power do you need? How much power per area do you need to deliver and with what efficiency?
- Someone 3y ago
  https://energycentral.com/c/ec/flying-without-fossil-fuels-need-high-energy-density https://energycentral.com/c/ec/flying-without-fossil-fuels-n...: “Mid-flight a Boeing 747 uses around 4 litres of jet fuel per second. Therefore given the energy density of jet fuel, approximately 35 MJ/litre, a Boeing 747 consumes energy at a rate of around 140 MW (million watts). We can then convert this rate of energy consumption into power density, that is the rate of energy consumption per square metre. Typically this is measured in watts per square metre (W/m2 ). A Boeing 747 is 70 by 65 metres. So the power density over this 70 by 65 metre square is approximately 30,000 W/², and of course the power density over the surface area of the plane will be a few times higher, over 100,000 W/m²” There may be gains there if electric motors are more efficient than jet engines (are they?), but overall, you’d need a lot more power than solar. I think that density is attainable, but wouldn’t bet on it being practical except, maybe, for military use, and probably not for planes but for ground use (beaming energy to a base in Iraq may be easier than transporting oil there via trucks driving through a war zone) For powering planes, I guess you’ll have to give up speed. That drastically decreases power need at level flight (the planes that flew around the world on solar energy were slow for a reason) You also will have to track the plane withyour energy beam as it moves.
- dghughes 3y ago
  I wasn't planning that far ahead I'll file my patent later. But a quick Google shows: A320 900 sq m for wings and top of fuselage and elevators. https://aviation.stackexchange.com/questions/54511/what-is-the-total-wing-surface-area-of-the-a320 https://aviation.stackexchange.com/questions/54511/what-is-t... A320 needs 150 G Joule / hour https://www.quora.com/How-many-joules-of-energy-does-it-take-to-fly-a-plane https://www.quora.com/How-many-joules-of-energy-does-it-take... edit: make it 1.5GJ not 150 To make it easy assume 1,000 sq m and 1.5GJ spread over that area 1.5MJ per sq m/hour. As for power transfer efficiency it may require a few thousand satellites per aircraft if this is any indication. https://www.esa.int/Applications/Technology_Transfer/More_efficient_solar_power_with_space_technology https://www.esa.int/Applications/Technology_Transfer/More_ef...

meindnoch 3y ago

Just to put that into perspective: a 747 uses 90 MW peak power during takeoff. And that's the useful power it needs as thrust, so the engines produce quite a bit more than that.

angiosperm 3y ago
Yeah, microwaves are right out. Lasers, maybe, but lasers that can focus so closely qualify as offensive weapons. Generally, less-focused lasers, picked up by nighttime solar farms that absorb sunlight directly in the daytime, are a much more likely medium for orbital power than microwaves. Monochromatic light can be converted to electrical power with much higher efficiency than can blackbody solar radiation. Lasers producing no greater intensity than sunlight worry people less than microwave radiation.

Ekaros 3y ago

What is the surface area of the top of a plane? How much power do you need? How much power per area do you need to deliver and with what efficiency?

Someone 3y ago
https://energycentral.com/c/ec/flying-without-fossil-fuels-need-high-energy-density https://energycentral.com/c/ec/flying-without-fossil-fuels-n...: “Mid-flight a Boeing 747 uses around 4 litres of jet fuel per second. Therefore given the energy density of jet fuel, approximately 35 MJ/litre, a Boeing 747 consumes energy at a rate of around 140 MW (million watts). We can then convert this rate of energy consumption into power density, that is the rate of energy consumption per square metre. Typically this is measured in watts per square metre (W/m2 ). A Boeing 747 is 70 by 65 metres. So the power density over this 70 by 65 metre square is approximately 30,000 W/², and of course the power density over the surface area of the plane will be a few times higher, over 100,000 W/m²” There may be gains there if electric motors are more efficient than jet engines (are they?), but overall, you’d need a lot more power than solar. I think that density is attainable, but wouldn’t bet on it being practical except, maybe, for military use, and probably not for planes but for ground use (beaming energy to a base in Iraq may be easier than transporting oil there via trucks driving through a war zone) For powering planes, I guess you’ll have to give up speed. That drastically decreases power need at level flight (the planes that flew around the world on solar energy were slow for a reason) You also will have to track the plane withyour energy beam as it moves.
dghughes 3y ago
I wasn't planning that far ahead I'll file my patent later. But a quick Google shows: A320 900 sq m for wings and top of fuselage and elevators. https://aviation.stackexchange.com/questions/54511/what-is-the-total-wing-surface-area-of-the-a320 https://aviation.stackexchange.com/questions/54511/what-is-t... A320 needs 150 G Joule / hour https://www.quora.com/How-many-joules-of-energy-does-it-take-to-fly-a-plane https://www.quora.com/How-many-joules-of-energy-does-it-take... edit: make it 1.5GJ not 150 To make it easy assume 1,000 sq m and 1.5GJ spread over that area 1.5MJ per sq m/hour. As for power transfer efficiency it may require a few thousand satellites per aircraft if this is any indication. https://www.esa.int/Applications/Technology_Transfer/More_efficient_solar_power_with_space_technology https://www.esa.int/Applications/Technology_Transfer/More_ef...