This project's funding goal was not reached on November 11, 2012.
About this project
The SUNSEEKER DUO is our third and most ambitious solar powered airplane to date. Built in co-operation with companies all over the World, this beyond State of the Art motor glider will certainly surpass all other electrically propelled aircraft flying so far! Based on the well known Stemme S-10, our goal has been to build one for half the weight, including everything, solar cells batteries, and a well equipped instrument panel, for the pilots.
Why you should fund this project:
Because it will be the coolest plane ever! Because it is a high visibility way to promote solar power. Because if you really believe in saving the planet, it's not good enough to just talk about it, you need to support those who are actually doing something about it. Because if you want your own solar powered sport plane, there has to be a first one. Make this a success and you know there will be more!
To meet our goals, we have been using the very best materials. All carbon fiber composites, with cores of Nomex honeycomb, and Rohacell foam.
A few words about some of our supporters,The fuselage was molded in the Stemme factory, Allstar Gliders in Poland, and the wing molds were provided by the University of Stuttgart, left over from their solar powered airplane, ICARE. Solar cells of 22.8% efficiency were provided by SunPower.
We need additional funds for the all important electronics. Motor controller, battery management system, solar peak power trackers, and the cockpit displays. Also an extensive test flight program is planned before carrying any passengers, so we need some time and money for that stage of the project, when we find out how well it really performs in the real World.
We are finishing most of the structural work in Europe, but planning to bring the plane back to the USA for test flights and Registration, as a US Experimental aircraft. After it has been fully tested, we plan to make a long series of flights, all over the World, to bring attention to what is possible with the latest technology. First would be a circumnavigation of the Americas, following the sun south to Tierra de Fuego. We plan to stop in as many places as possible, gradually following the sun south for the winter, and then back north again. A TV crew will follow along, and make a documentary film, and we plan to publish a book with many photos from the adventure.
Risks and challenges
Our biggest challenge has been finding good electronics engineering support for the custom electronics, such as solar peak power trackers, and motor controller.
We can fly with some existing hardware, but they are not really optimized solutions for this aircraft. For high efficiency, the airplane is wired for 300 volts, and special parts are needed to work best with 300 volt DC systems. Any companies or individuals are invited to participate in the completion of our airplane, so please contact us if you think that you have something to contribute.
To fold the propeller blades back, we need to stop the motor with electrical braking, otherwise it windmills. Then the wind blows the blades back. They are geared togeather, so they fold and unfold at the same time. It is important when starting the motor that both blades come out symetricaly.
Both planes have batteries that give a good strong take off and climb, for at least 20 minutes. If I can get over the clouds in that time, then I am in bright sunshine, so I can continue to fly for hours. Otherwise I come slowly gliding back down. I always land as a glider anyway.
Could you go in a little more detail on the electronic heart of the glider and the engine/battery management system in the cockpit?
The power system of the SUNSEEKER DUO is 300 volts, DC. That is 72 Lithium Polymer batteries in series. They store the solar power, which can be delivered to the motor at up to 25 kW, or 33 HP. A DC to DC converter provides 12 volts for the cockpit electronics, landing gear system, and eventualy landing lights for night flying. No high voltage enters the cockpit, for the safety of the crew.
Flying under power the airspeed will only be about 45 - 50 mph, but with the motor turned off it will be much faster, able to fly a little over 100 mph in a slight dive. (gliding)
It sounds strange, but it is true. That is my experince with the SUNSEEKER II. Usually I climb for a while at full power, then turn the motor off and glide, while the batteries re-charge from the solar cells.
- (30 days)