Has there ever been a trial/project/design, in which solar panels were incorporated in the design of a commerical airliner (e.g. on the wings), with the aim to reduce fuel consumption by lowering the generator workload?
If no, why not?
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Sign up to join this communityHas there ever been a trial/project/design, in which solar panels were incorporated in the design of a commerical airliner (e.g. on the wings), with the aim to reduce fuel consumption by lowering the generator workload?
If no, why not?
If no, why not?
While I can't say categorically that it's not happened, I'm pretty sure.
Solar radiance is approx. 1kW/m^2. A 737 has approximately 100m^2 wing area. Solar cells are approximately 20% effective.
If you covered the entire wings in solar panels, that would work out to 20kW of electrical power at best. At night, it would be close to zero extra power.
Jet fuel contains ~43MJ/kg of energy. 20kW is 20kJ/s. For a 2 hour flight, the total energy produced would be 144MJ, or comparable to energy in 3-4 kilograms of jet fuel.
Turbines is not 100% efficient, so let's say that with all losses in engine, 25% of the power in the fuel is available as electricity. That means you'd need 12kg of fuel to provide the same amount of electricity as the solar panels.
12kg of fuel. That's probably far less than the solar cells will weigh, probably by a factor of at least ten. In addition, the you don't have to carry around already burnt fuel, unlike solar cells, which you will have to carry around.
Edit: I found another answer on this site, that claims extra fuel use is on the order of 0.125kg/kWh. I don't know if that's correct or not, nor do I really care. It doesn't change the conclusion, it only makes jet fuel even more favorable.
In short the amount of power provided by solar cells is tiny compared to the energy contained in jet fuel. And that doesn't even touch on the mechanical requirements of a wing...
No, there are several reasons:
So it's a lot of weight and cost for a technology that isn't going to generate power for much of the time the airplane is in use.
Not purely on topic but there is a solar airplane. Solar supported airliner isn't out of the realm of possibilities, just solar tech isn't there yet. Also it would have to be economically feasible to even be considered.
Here's an article from 2016 about a solar airplane that traveled the globe.
I once worked for a company that made electronics for commercial aircraft (flight deck printers, Ethernet switches, digital chart recorders).
In addition to what others have mentioned on this thread, you also have to account for the fact that if a product is manufactured for aircraft in the US, it must comply AS9100 and FAR, and whatever standard the EU is using nowadays. This includes rigorous testing to ensure that, not only is the device safe, but also that the device will not interfere with any of the critical systems of the aircraft.
One consideration that makes solar aircraft less feasible is that the figure of 1kw/m2 is for sunlight striking the solar panel square on - i.e. perpendicular to the panel. Unless you're flying in the tropics at noon, an aircraft's wings won't meet that. Their insolation (the amount of power from sunlight) drops with the cosine of the angle from vertical incidence.
Regarding doubling 747 wingspan for two seats - how many passengers will settle for a 45 MPH / 39 knot / 72 kph flight speed (i.e. New York to London in 77 hours if no headwind)?