Welcome to the website of icaré 2, the world recording breaking solar plane designed and built at the University of Stuttgart.

On this site you will be able to find information about the team behind the project, some of the partners, news, plus images of the aircraft and her pioneering pilot Klaus Ohlmann.



Fly with icaré 2

As airlines and conscientious passengers continue to struggle with ways to offset the carbon impact of flying, advances in technology are bringing environmentally friendly alternatives ever closer.

For many, the most logical, but perhaps most elusive, resource to turn to is the almost limitless energy of our nearest star: the sun.

With several solar aircraft currently in development, the race to harness the energy of the sun has become the new gold rush for aviators and academics.

icaré 2, the brainchild of Prof. Rudolf Voit-Nitschmann’s team at Stuttgart University, is among those setting new standards in design and efficiency. And as materials and technology begin to catch up with human imagination, records are starting to fall.

In September of 2010 German pilot Klaus Ohlmann set two records in one attempt, taking off and flying more than 370km using nothing but solar energy.

He added to his haul within the following weeks taking his total number of scalps for 2010 to four.

While he awaits formal ratification of his feats, Ohlmann is planning to build on this solid base with a significantly longer flight planned across Southern Europe next year in which he hopes to break his own records of 2010 and even establish a couple more.

Among the categories in his sights are the duration flight and the daunting altitude challenge.

With more than three-dozen World Airsports Federation (FAI) records to his name, there’s little reason to doubt him, especially in an aircraft as sophisticated as icaré 2.

While most like a traditional glider in appearance, icaré 2 also carries a vast array of wing-mounted solar panels and an electric motor, which provides the thrust for take off and is powered by batteries that are charged using the sun’s energy. If the pilot suddenly finds himself without enough lift to glide in un-powered flight, the engine can be flicked back into life for a much-needed boost.

Work on icaré 2 began in a successful attempt to win the 1996 Berblinger Prize in Germany, which offered DM100,000 (around €50,000) to the designers of the first aircraft to take off and stay aloft using only its solar panels for power.


Records Current record Date FAI Ref Remarks
Distance up to 3 turn points 367.8km 5.9.10 1.4.3c Way points with up to 3 turn points declared preflight
Free distance using up to 3 turn points 375.7km 5.9.10 1.4.3c Way points with up to 3 turn points claimed after flight
Out-and-Return Distance 1.4.3b Way points declared pre-flight
Straight distance pre-declared 1.4.3a Way points declared pre-flight
Straight distance free-flight 1.4.3a Way points claimed after flight
Out-and-Return Distance 384.4km 17.8.11 Way points declared pre-flight
Distance up to 3 turn points 439.3km 10.9.11 Way points with up to 3 turn points declared preflight

Flying any distance powered by nothing but the sun has not always been easy or graceful. Nor is it an endeavour for the faint-hearted.

When pioneer Albert Berblinger, the famous Tailor of Ulm, valiantly tried to fly his homemade hang glider across the Danube in 1811, he finished up in the drink. Despite having failed, his audacious attempt provoked technological innovations beyond even his imaginings.

Early solar aircraft were extremely light and fragile, with even slight gusts resulting in loss of control and even disintegration. But what seemed almost impossible mere decades ago is now becoming reality thanks to giant leaps in design, construction and thinking as the race for sustainability becomes the new gold rush.

Step forward icaré 2, Stuttgart University’s super lightweight glider. With its 25m wingspan it combines the latest composite materials and a huge array of solar panels to make flight possible.

The principle behind it is little different to that of the tailor’s early hang glider: the only things keeping it up are ingenuity, aerodynamics and the energy of the sun.

Since its conception, icaré 2 has stretched aircraft designers to the limits of what is possible in terms of minimum weight, maximum strength, optimum solar cell surface, best take off performance and superior drive efficiency.

It’s not the first solar powered aircraft – pilots and engineers have been developing the concept since the early 70s – but the Stuttgart team have consistently raised the standard of both performance and design. It took a network of seven departments at the Faculty of Aeronautics and Astronautics at the University of Stuttgart pulling together to create the seemingly impossible.

In 1996 icaré 2 snatched the Berblinger Prize – named after our hapless tailor – by becoming the first aircraft to take off and stay aloft using only its solar panels for power, without the need for a boost from its batteries. And in 2003 it flew uninterrupted for 350km.

Icaré 2 is a masterpiece of lightweight construction: The 25m glider weighs a mere 650 pounds (300kg) ready to fly. The structure includes a wing area of 25 square meters, engine, propeller, solar cells and a Lithium polymer battery pack. Then there’s the minor detail of the bells and whistles that hold the aircraft together under the pressures of take off, flight and landing.

Many sailplane pilots will do a double-take when they see icaré 2, since the fuselage is based on the familiar Schleicher ASW-15, the main differences coming from the selection of weight-optimized materials and equipment.

The batteries can be charged using solar prior to installation behind the pilot’s seat, and give a total of 2200 watt-hours. Once the batteries are topped up, it’s chocks away.

Icaré 2 can get airborne at around 55mph from an asphalt runway, climbing at around 2m/sec under power. The electric motor is deceptively silent on the outside, its vibrations thrumming through the carbon fibre hull and into the cockpit.

She’s hardly the fastest bird in the skies, but its 25m wingspan and elegant lines make it an impressive sight. Once airborne, level flight is possible without needing to drain the batteries, and even climb is achievable if sufficient lift can be found.

SEIKO is a world leader in energy efficient watchmaking, and its range of zero-battery solar watches makes it an environmentally sound choice to back the project. SEIKO is proud to sponsor icaré 2 and Klaus Ohlmann as part of its Clean Energy program.

SEIKO Solar is a quartz watch which takes its energy from light, and stores it in a self-recharging battery which never needs to be changed. By eliminating the need for battery change in a quartz watch, SEIKO Solar makes an obvious and important contribution to the cause of a healthier planet. SEIKO was an early pioneer in solar watch technology, with its first Solar watch being launched in 1977.



World Records for solar flight champ

September 12th, Gap, France: One of modern aviation’s most prolific record setters1 has chalked up another distance milestone in the final weekend of his European season. The record belongs in the category “Solar-powered Aeroplanes” as defined by the FAI (Fédération Aéronautique Internationale).


German pilot Klaus Ohlmann already had 46 records to his name. He added to this trove on Saturday [September 10] with a 439km “Distance using up to 3 turn points” flight in the Alpes Maritimes in Southern France, this time aboard Seiko-icaré 2. In August he set a record in the “Out-and-return distance” of 384.4km, more than doubling his own previous record.


In a frenetic weekend trying to outdo himself, Ohlmann raced against the weather clock and a date with a racing commitment stateside.


He said: “Obviously I wanted just one more go at it before the autumn, and this was the perfect ending.”


“When you put pressure on yourselves like this, you have to be careful not to take risks and to do everything right, but the weather was with us and that made the difference.”


Seiko-icaré 2 is a solar powered glider built by a team at the University of Stuttgart and sponsored by the Japanese manufacturer, whose solar-powered watches are particularly successful on the US market. The technological innovations by the Stuttgart team have shown that solar flight is an achievable goal for small aircraft, even in the near future.


Seiko-icaré 2 generates all its energy from photovoltaic cells, which provide enough thrust to take off without the help of a towing plane. The pilot can alternate between soaring and powered flight whilst aloft.


He said: “Gliders are already extraordinarily efficient machines, and this is a new and almost inevitable step, not only exploiting the air heated by the sun, but also transforming the sun’s rays into electric energy.


“It opens new possibilities and I am determined to add some records to my collection.”

Icaré 2 ready to fly again

SEIKO-Icaré 2 is flying again with Klaus Ohlmann in the Suthern Alps in France. The aim is to improve on the performances it established last September and to set some new world records for solar powered aircraft.

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