•New

The challenge for the seven students on the Trencalòs Team of ETSEIAT-UPC is to turn a scale commercial glider into the Solar Endeavour prototype, a plane propelled exclusively by solar photovoltaic energy. Ultimately, the aim of the project is to achieve the longest possible cruise flight.

In February 2010, the students bought a scale commercial plane and started making the technical modifications necessary to transform it into a solar plane propelled exclusively by the sun's energy. The modifications involved are complex and must take into account the interaction between aerodynamics, electronic systems, and the electricity generated by the solar photovoltaic system.

The two main technical challenges facing the team are the incorporation of solar cells on the wings and the design of the Energy Management System (EMS), which must ensure the autonomy of the aircraft. The optimal solar cells that need to be used are very fragile: they have to be lightweight, flexible, and conform perfectly to the curvature of the wings.

The technology required to incorporate solar cells on a plane’s wings already exists and has been implemented in other projects carried out around the world, including the Solar Impulse, a solar plane constructed by Swiss aviator Bertrand Piccard, whose ultimate goal is to achieve a round-the-world flight, and the Zephyr-6, a British prototype that holds the world endurance record for a flight by an unmanned aircraft. It has also been applied in the solar plane being developed by the Technological Institute for Renewable Energies (ITER) in Tenerife. The researchers involved in these projects have not made their technology public, so the students at ETSEIAT-UPC must conduct research and create their own technology to achieve the same objective.

The Energy Management System (EMS) will also need to be based on technology developed by the students. The EMS is the heart of the plane. Its function is to distribute energy stored in lithium batteries, and it comprises electronic components that must interact precisely to ensure that the plane's motor works properly in any atmospheric condition, even when the sun is not shining.

The Solar Endeavour will also be equipped with a complex telemetry and remote control system so the plane can be reliably kept on course.

Demonstrating the effectiveness of solar energy in aeronautics
Solar flight technologies are a perfect way to increase the capabilities of unmanned aircraft. As the use of unmanned aerial vehicles (UAV) has exploded in recent years, it has become clear that their capabilities are constrained by their limited autonomy. UAVs equipped with solar flight technologies could fly nonstop over a particular zone for days – a key capability in applications such as forest fire prevention, traffic control, telecommunication repeaters in isolated areas, and scientific missions involving earth observation.

In some countries UAVs have also been used to obtain measurements for precision agriculture. Detailed information is collected about the irrigation level in specific zones to maximise field production while minimising water consumption.

According to the students involved in the Solar Endeavour project, “if we can achieve our goal of developing a solar plane that can stay aloft for many hours, we’ll demonstrate our technological capability as UPC students and show that solar energy can be effectively applied in aeronautics.”The members of the Trencalòs Team expect the Solar Endeavour to be ready to make its first flight in August of this year. The aircraft has already made its first experimental flights without a motor to validate its flight mechanics, landing gear, servo control mechanisms, and the aerodynamic modifications required to transform a glider into a solar plane.

The students are receiving support from a number of companies to help them achieve their dream. GTD Sistemas de Información S.A., the main initiator and sponsor of the project, has designated an engineer to act as a tutor and liaison between the company and the university.

The electric motor being designed exclusively for Solar Endeavour is courtesy of the Mexican manufacturer KOFORD LLT Engineering. High-performance photovoltaic cells are being provided by the company Heliene S.L. Finally, the firm CAT UAV is providing the telemetry and remote control system, which makes it possible to pilot a plane of this type just as if it were manned. Some of the students on the team building the Solar Endeavour have tackled this kind of challenge before. The Solar Endeavour project is being carried out by the Trencalòs Team, which was set up in 2006 to build a plane, including everything from the structure to the propulsion system. The Trencalòs prototype, which gave the association its name, flew with a load equivalent to six times its own weight. In 2007 and 2009, the prototype participated in a number of international university competitions and achieved very good results.

The student members of the Trencalòs Team involved in the Solar Endeavour project are Joaquim Creus, Carles Felip, Josep Fernández, Marta Marimon, Ignacio Pedrosa, Arnau Pons and Xavier Serena.

The students working on the Solar Endeavour want to provide regular reports on how the project is evolving. Information on all new developments up to the first flight – including photographs, text and videos – will be shared at the Arcitec blog, which focuses on research carried out by the UPC’s youngest investigators (http://arcitec.blog.upc.edu/).

The team has launched a Facebook page (http://tinyurl.com/fbsolen) and a Twitter feed (http://twitter.com/#!/SolarEndeavour) to provide updates on the project.