Solar Impulse Co-Pilot André Borschberg shares his views on the Si2 test flights and technology

Q&A: The Solar Impulse CEO and Co-pilot talks test flights, solar cells, physical training and the virtual co-pilot system

As the Solar Impulse team takes a short mid-summer break from its test flight schedule, I took the opportunity to ask André Borschberg about the progress his team is making with the new aircraft technology…

In terms of performance, what were you specifically testing for during the first five test flights this summer?

André Borschberg (AB): It’s not really about performance. It’s more about testing the aircraft itself. To verify if it flies as expected in terms of controllability, stability. We check all the systems like the motors, the batteries and the solar generator. The engineers are also testing the different systems they developed to assist the pilot i.e. the autopilot, the oxygen system, etc. It’s a delicate phase because it’s new technology and it is quiet complex to make an airplane fly day and night with a high level of security.

What technology do you use to monitor the plane’s performance during the test flights?

AB: We have a telemetry system to monitor live the performance of the aircraft and collect all the data of the aircraft. We pay special attention to the consumption and production of energy of the airplane. Indeed the key for success is to have an aircraft consuming the lowest amount of energy.

What kind of challenges does the SI ground staff face on test flight days?

AB: The main challenge is to be ready all the time to cope with the unexpected. We absolutely have to bear in mind that the behavior of the airplane is not fully explored yet.

How does the ‘virtual co-pilot’ system work?

AB: The autopilot, the Stability Augmentation System (its official name) is an electronic device totally independent of the rest of the instruments. It measures through independent sensors what the airplane is doing in flight. Its role is to maintain the flight attitude (horizontal, longitudinal and lateral axis) and the directional heading. The autopilot is coupled with a Monitoring Alert System that will immediately inform the pilot if one of the parameters differ with what has been set.

What is unique about the solar cell technology that is integrated into the plane’s structure and how does it differ from the technology typically found in commercial solar installations?

AB: The solar cells we have on the airplane are provided by our official supplier SunPower. They are at the forefront of the development in their category and available on the market. They are extremely thin (135 microns) and flexible. They don’t have the best efficiency rate of the market (23%) but they represent the best compromise between lightness, flexibility and efficiency and that’s exactly what we needed for Solar Impulse 2 (Si2).

What kind of fitness regime are you and Bertrand currently taking to prepare yourselves physically and psychologically for the round-the-world solar flight next March?

AB: Our approach is more on the long term basis. We are looking at improving our healthy lifestyle. Personally, I have a healthy and well-balanced diet and I’ve practiced yoga for many years. In preparation of the round-the-world flight I am developing a special program for pre, during and post flight.

Is there an aspect of the Si2 technology that you are particularly proud of that hasn’t been featured much in the media?

AB: Solar Impulse 2 is not about one revolutionary technology. It’s the mix of many solutions, the sum of all the efforts of our engineers supported by our partners that enable us to achieve the impossible! In fact, I am very proud of the team. Year after year they have built such a high level of bonding spirit and collaboration that will definitely be a key factor in the success of the mission.

Related blog post:

Google hangout: MIT students quiz Solar Impulse 2 pilot André Borschberg 

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Gregory Hollings

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