Questions tagged [solar-impulse]

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55
votes
4answers
10k views

Why do solar planes have many small propellers instead of fewer large ones?

Many solar planes, like NASA's Helios (pictured above), NASA's Pathfinder, and to a lesser extent Facebook's Aquila employ the use of many small motor propeller sets instead of one or two engines like ...
18
votes
2answers
3k views

Why did the Solar Impulse flight take so long?

The Solar Impulse just made big news for flying from Japan to Hawaii on a solar-powered plane in five days. But five days seems really long. Let's do the math on that. The distance from Japan to ...
11
votes
1answer
657 views

Why wasn't Solar Impulse 2 cleared for takeoff?

I've recently been watching videos of the Solar Impulse 2 (HB-SIB) flights, and I noticed that on several occasions, instead of giving clearance for takeoff, the tower told the pilot that "departure ...
10
votes
4answers
494 views

How does lowering altitude conserve energy in Solar Impulse 2?

In this article the author explains that the aircraft flies at a lower altitude to conserve energy. During the day, it climbs to its maximum cruising altitude of 8,500 metres to capture the most ...
10
votes
2answers
626 views

What considerations drove the choice of the Solar Impulse engines configuration?

Solar Impulse makes me think of a motorglider due to its aspect ratio. The Upward cranked tips wing configuration along with the engines configuration particularly draw my attention: The 2 innermost ...
5
votes
1answer
195 views

What is the reason for different engine configurations seen on Solar Impulse?

In various images of the Solar Impulse aircraft, I see the engines mounted in different positions along the wing. Am I looking at SI 1 vs SI 2, or are the mount positions capable of reconfiguration ...
4
votes
1answer
1k views

What would be the stall speed of Solar Impulse?

In most of the tables, only the take off (22 mph) and cruise (43) speed of the Solar Impulse are listed. It is an experimental plane, slow, with very huge wing for solar batteries. The take off speed ...
4
votes
2answers
209 views

What happens if Solar Impulse II encounters un-expected head wind and runs out of battery power?

I noticed that battery charge level dropped to fair levels in some occasions in this article. It dropped to around 20% at the end of day 5 before morning of day 6. To what extent will a flight be ...
0
votes
1answer
141 views

Is there any benefit to science from the Swiss built solar plane flying across the globe? [closed]

Are there any innovations that were made during the development or flight of the Solar Impulse plane that would go into any type of regularly used airplanes in the near future?
0
votes
0answers
40 views

Can a large aspect ratio wing be actively controlled using distributed electric propulsion to avoid getting ripped apart in wind shear?

This question is related to the recent possibility of solar aircraft becoming flyable. Solar Impulse, the NASA Helios, and the Titan Aerospace/Ascenta Aerospace solar drones have all have issues with ...