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Educational Material

The Solar Impulse Pedagogical Program is the project’s communication platform for young people, the ‘mouthpiece’ of its symbolic and philosophical values.

 

It highlights the adventure, technology and scientific research elements of the project in order to develop young people’s curiosity, their taste for exploration and discovery and their pioneering spirit.

 

It seeks to interest them in the perspectives of future technology and to sensitize them to the important and continuing role of science in solving energy and environmental problems.

 

Join us in becoming messengers and ambassadors of the project by talking about it with your friends and family.

Datasheets

Datasheet 1 : THE ORIGIN, THE SPIRIT
Datasheet 2 : THE CHALLENGES
Datasheet 3 : FROM DRAWING BOARD TO REALITY
Datasheet 4 : BUILDING THE HB-SIA
Datasheet 5 : VIBRATION AND LOAD TESTS
Datasheet 6 : ON-BOARD ELECTRONICS
Datasheet 7 : VIRTUAL FLIGHTS
Datasheet 8 : FIRST TAKE-OFF
Datasheet 9 : MAIDEN FLIGHT, 87 MINUTES
Datasheet 10 : TEST FLIGHTS
Datasheet 11 : DAY-AND-NIGHT FLIGHT
Datasheet 12 : SECOND AIRCRAFT

 

Schede in italiano / Fiches en italien

Bertrand’s message inspires 1600 young pioneers

During this year’s “Climate Pioneers” event, 1’600 presented the projects they’ve developed for a cleaner and more sustainable planet. The event took place in Zürich’s new Umwelt Arena (Environment Arena), an exhibition space dedicated to topics ...

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During this year’s “Climate Pioneers” event, 1’600 presented the projects they’ve developed for a cleaner and more sustainable planet. The event took place in Zürich’s new Umwelt Arena (Environment Arena), an exhibition space dedicated to topics related to sustainability, renewable energy, mobility, nature and living. André and Bertrand are both patrons of the Climate Pioneers program, using Solar Impulse as an inspiration. 

Launched in 2010 by Swisscom in partnership with Solar Impulse and myclimate, Climate Pioneers is an initiative designed to engage students from preschool to High School in today’s environmental issues while raising awareness about the potential risks of climate change. There are currently 6’330 young climate pioneers in Switzerland who have initiated 276 projects so far.

This year it was Bertrand that met with all the young pioneers between the ages of 7-16 encouraging them to strive to achieve the impossible – an objective he had set for himself at the tender age of 11. It was a moving and encouraging experience to see today’s youth concerned about our future. The excitement was high and, after an inspirational presentation, hundreds of little hands were raised eager to have their questions answered.

“I always asked myself what it felt like to be a rock star. Now I know! 1’600 students were gathered by Swisscom to hear discussions about the environment during the Climate Pioneers event. They absorbed Solar Impulse’s message with the same passion as if it were a rock concert! The way they welcomed me onstage could do nothing more than give me shivers of joy, but it especially offered me hope for the future…” Bertrand didn’t miss the chance to share his enthusiasm: when the first rhythmic beats resounded throughout the hall, Solar Impulse’s visionary and founder let loose into a few carefree dance moves surrounded by the swarm of little pioneers.

Perpetually inhuman: HB-SIA’s flight cycle

Since I started working at Solar Impulse two months ago, a lot of people have asked me “but how does it fly at night?” It might seem like a miracle, but it’s actually a simple game of physics and energy maximization.

When HB-SIA is on the runway ready for take-off, the batteries are typically charged ...

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Since I started working at Solar Impulse two months ago, a lot of people have asked me “but how does it fly at night?” It might seem like a miracle, but it’s actually a simple game of physics and energy maximization.

When HB-SIA is on the runway ready for take-off, the batteries are typically charged with solar power to minimum 50% for pilot safety. Aside from take-offs and landings where the aircraft speed is increased to 30 knots (approximately 55km/h) for maneuverability, the solar aircraft is always flown at 25 knots (approximately 45km/h), its design point for minimum energy consumption. The entire flight cycle revolves around energy savings and optimization. The aircraft essentially makes use of electric and potential energy. Electric energy or – to be physically correct, chemical energy is collected in the batteries. Potential energy is stored in the aircraft height. For example, a football on a hill has latent potential energy. As soon as it gets a slight push, it will roll down converting its potential energy in kinetic energy (speed) and eventually comes to stop because in real life, every motion is accompanied by losses.

So in order to fly with the utmost efficiency, the Solar Impulse airplane needs to juggle the energy storage between height and battery to find the best equilibrium.

But what really happens during the flight? You have already seen how the energy production cycle works in the previous article (From Sunlight to Flight), now I will show you what happens to HB-SIA day and night, also illustrated in the image.

During the day, the pilot slowly ascends to a higher altitude in thinner atmosphere to avoid turbulence and cloud formations. Interestingly, the solar generators also convert more energy at altitude. Sun radiation is partly absorbed by Earth´s atmosphere before reaching the ground. The higher Solar Impulse is climbing, the more sun power is available and can be stored in the batteries. In fact, for the highest possible solar power generation, HB-SIA should be in outer space; but that’s a little too far for the time being.

As the sun begins to set on the horizon, solar power obviously decreases. Once the available solar power is not sufficient to support level flight anymore, the pilot reduces the motors and initiates a gentle descent (about 0,4 m/s) to a low night loitering altitude of 1000-1500m meters. Out of its maximum altitude of 28000ft (8000m), the prototype can glide for 4-5 hours consuming almost no electric energy. When the lowest altitude is reached, usually long after sunset, the motors, now powered by the batteries, are used to maintain a level flight at 25 knots until the morning. As the breathtaking tones of the sun on the horizon start filling the sky with warmth, the aircraft can once again begin its ascent, and the cycle begins.

What is most incredible is that this revolutionary aircraft could practically fly perpetually into infinity if it weren’t for the human side of the pilots. So how do we make humankind perpetual? Well, I think that’s another story. 

From sunlight to flight

Some of you must be wondering how the HB-SIA actually flies with nothing but the power of the sun. Well, today is your lucky day because I’ll be giving a little explanation on how sunlight is converted into energy allowing this unique airplane to glide through the skies.

The upper part of the ...

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Some of you must be wondering how the HB-SIA actually flies with nothing but the power of the sun. Well, today is your lucky day because I’ll be giving a little explanation on how sunlight is converted into energy allowing this unique airplane to glide through the skies.

The upper part of the solar airplane’s wings is covered by solar panels. These are solar generators, meaning that they convert sunrays directly into electricity. The panels together are constituted of a total of 12’000 solar cells which, in turn, are all grouped into “strings” of 300 cells. At the extremities of each string, just like in a battery, there is the positive (+) and negative (-) pole. Each string has what’s called a Maximum Power Point Tracker (MPPT) which is responsible for extracting the maximum amount of power from the panels at any given solar intensity.

The energy is then either stored in the batteries (there are 4 total) or immediately converted into mechanical energy, triggering the propellers to move. There are 4 motors on the HB-SIA.

Wondering how the energy is channeled? Well, when the motors are not running, the energy that is processed is directly stored in the batteries. However, if the airplane is in flight, sunlight is used to fuel the motors. When the energy produced is more than what is needed to fly, the remainder flows into the batteries. The Battery Management System (BMS) controls this process automatically reducing the electric current into the battery according to its charging status. The BMS also monitors the battery temperature during flights, ensuring they are not too cold (lowering their productivity) or overheating (which can be dangerous).

In simple words, the entire process is run through a chain of conversion. The cells convert sunlight into electricity; this electricity is channeled through the MPPT to get the maximum power output. The electricity can either be stored in the batteries or transmitted to the motors. The motors take the electricity and transform it into mechanical power, enabling the propellers to move and consequently the aircraft to fly. In flight, the pilot determines how much energy he needs depending on the speed of flight and how fast he wants to reach the desired altitude. Depending on the time of day, energy used is:

  • Only energy directly from the sun (day)
  • Some sun and some stored energy from the batteries (morning/evening)
  • Only energy from the batteries (night)

What is incredible in this process is that, while in flight, the HB-SIA can use direct sunlight to power the motors while simultaneously charging the batteries! It’s as if you left your home in the morning with a half-empty tank of gas and came back in the evening with a full one! Wouldn’t that be nice? Who knows, maybe one day it could become reality…


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