I want to experiment with airplane design for high efficiency and solar power. I want to try putting counter rotating propellers at the wingtips. I think this can be very efficient. Building an airplane out of balsa wood seems like way to much work for experimenting. The idea I have come up with is to use a Maslow CNC to cut foam frames and then use a wing covering film, like UltraCote. Here is my first attempt There are two chains that pull the router around and a motor on the router to adjust the height. It is a cheap way to be able to automatically cut very large things. We are using 1.5 inch thick Foamular 250. This is pink insulation foam rated for 25 psi. We have been having trouble going from our CAD tools to our Maslow. However, we can use easel.com to project flat things to a fixed depth and load that onto Maslow. So we had the Maslow hollow out the body of the wing and made some templates to use with a hot wire cutter. We covered the templates with a
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Solar panels produce the most watts when operated at some ideal voltage called Vmppt. Normally people use special hardware called an MPPT controller to draw power from the solar at that voltage and then convert it to the right voltage for a battery. We have worked out a program for iNav so that this extra hardware and weight won't be needed. The idea is to adjust the throttle higher if the voltage is higher than ideal and to lower it if the voltage is lower than idea. Since we already have a computer onboard that knows the battery voltage and controls the motors, we can get things operating at the ideal voltage just using some software. This will help keep weight down on solar airplanes we make. We also save any conversion losses or power limitations of the MPPT hardware. You can see this in the video and the picture after that. Here is a shot of the program: A shot of the supercapacitor, flight controller, volt meter: The solar out the window: The power mete
We got our solar panels from solarealdrone.com ! They were very well packed and all seem fine. The cost was $1.90/watt. They are so small and light that express shipping from Taiwan to the USA was very reasonable. They also included 2 MPPT boards and some wire good for solar panels for free. The solar panels are about 15 inches by 5.5 inches. We got 18 solar panels and the total weight for all 18 was about 528 grams or 29.3 grams per panel. The side view showing how thick a stack of 18 solar panels is: The back of one panel showing wiring: These panels are their F2X5S panels. The MPPT voltage for these is 5.72V and at that voltage it produces 2.04 amps for a total of 11.66 watts. Next to get them on a plane and into the air. These seem like a very good product for solar RC airplanes. Very happy with them so far. We will probably put 4 on an Opterra (46.4 watts) and then 8 on a custom airplane (93.3 watts).