For the past four years, a team of engineers has been working on an aircraft that is powered only by solar energy. After countless hours of measuring, calculating and building, their aircraft was finally ready to be unveiled to the world.
The Solar Impulse HB-SIA made its debut on the 26th of June at an airfield just outside of Zurich. At the time more than 800 people were present, including the CEO of International Air Transportation Association. The ceremony was also broadcast over the internet where thousands of journalists and flight enthusiasts were able to participate.
The masterminds behind the HB-SIA are Bertrand Piccard (Chairmen) and Andre Borschberg (CEO). Both men are accomplished pilots and shared a passion for flight that eventually led the idea of the Solar Impulse project.
The aircraft itself is nothing short of a masterpiece. It has a wingspan of 208 feet, the equivalent of a Boeing-747, but weights in at only 3500lbs. Power for HB-SIA is provided by a quartet of small electric motors, each producing between 8 and 10 horsepower. Together, they can move the aircraft along at about 45mph. This relatively slow speed is the reason such a large wingspan was required. The massive wings also allow a takeoff speed of 22mph.
To keep the Solar Impulse in the air, an array of 11,628 solar cells cover the wings and horizontal stabilizer. The energy is fed into stacks of Lithium Polymer batteries, one stack per motor and then used to turn the props. In the course of 24 hours, the motors on the HB-SIA average about 8 horsepower output, slightly less than the Wright Brothers had during their first powered flight back in 1903.
The mission of the Solar Impulse HB-SIA is to verify the feasibility of an aircraft powered only by solar energy. The team has many tests planned for their plane, many to test the ability of the batteries to sustain flight overnight. The finale of the tests will be a flight that will circumnavigate the globe, with the team following its progress the entire way. The trip will be broken into 5 stages, each lasting about 4 days.
The first test flights, including several night flights, will be taking place next year, while the world tour is slated for 2012. Once the limits of the batteries have been established, even more weight could be dropped and allow for an additional pilot. If this happens, a non-stop flight around the world would be within reach.
The team plans on building another aircraft, called the BH-SIB, as soon as the initial testing of the prototype is complete.
Solar Impulse , GizMag