Solar Plane

Introduction:
This instructable will show you how to create a solar powered plane. This project was done at Newman Smith High School (Carrollton-Farmers Branch Independent School District [CFBISD]) in Carrollton, Texas and was sponsored by the Texas A&M University Society of Flight Test Engineers. We received most of the needed parts from Texas A&M University and built the plane for the High School Solar Plane Competition on May 25, 2013. The project is not for the beginner as it gets a bit complicated. Skills that you will need include soldering skills, plane building skills, monokoting skills, and general R/C plane knowledge. Our team ended up with the Most Creative award and 2nd place in Endurance.

Special Thanks to Texas A&M University, Newman Smith High School Teachers and Principal & the DIY Drones Community (http://diydrones.com/forum/topics/solar-powered-plane).

Below are some pictures of the completed project. The next step will be the list of materials needed.
Also included below is the link for build basics and aircraft aerodynamics- there are two PowerPoints included by Texas A&M University. If you are going to do the project, printing out these two PowerPoints will help you immensely. However, please take note that all the cells must be in series, not in parallel as one of the PowerPoint presentations describes.
https://drive.google.com/folderview?id=0B_bYmGJ0v1Ncb283TF8tWXF6ZWc&usp=sharing

Want to see more photos? PM me and I'll give you a link.

UPDATE: 03/31/2014: Research Paper now included.

Step 1: Materials

Materials Needed: 
Glider (we used the Gentle Lady) 
Monokote (We ended up using about 3 rolls- two for the 8 foot wing [bottom] & body of the plane and another clear roll for the panels)
3x6 Solar Panels
Tabbing Wire
Bus Wire
Normal Wire
Micro Servos 
Push Rods 
Nylon Control Horns 
Propeller 
Li-Po Battery
ESC (Electronic Speed Controller) 
Charger 
Connectors (for Wires) 
Receiver 
Propeller 
Electric Motor 
CA Glue 
Heat Shrink Tubing 
Sewing String 
Pairing Connector (depends on your transmitter/receiver) 
Nuts (for balancing wing) 
Balsa Wood Sheets (optional- depends on how big your wing is) 

Tools: 
Soldering Iron
Flux
Solder 
Hobby Knife and extra blades 
Heat Gun 
Sealing Iron 
Large Table 
Sand Paper 
Drill
Wire Cutter 
Digital Multi-Meter
First Aid Kit 

Step 2: Building the Wing

To begin the project, start by building the wing. The wing is where the panels will go on. Depending on what glider/plane kit you use, you may want to do it differently. We extended our two meter wing span to make it 8 feet to fit 22 panels in-between the ribs. The other teams that we competed with did not do so this way. They put the panels directly on the wings and did not extend the wing span. By extending the wing span and putting the panels in between, we used less ribs and made the wing more fragile, but it paid off and did not break because we did a pretty good job of reinforcing it. 

To extend our wing, we cut out extra ribs from some balsas wood and duplicated the middle of the wing to extend it. 

Follow the plans provided with your kit and build the wing. Extend the wing from the center if necessary. 

Step 3: Solar Panels

Solar Panels: something that is a pain in the butt to install. 
These solar panels were about as fragile as anything we had ever handled before. Rigid and inflexible, we broke about half of them. 
Handling them with the uttermost care is very important to avoid damage to them. Some cracks are okay, it just depends on where they are located and how they broke. Searching up how solar panels work, how to cut them, and how to tab them really helps. 

Some background information: The shiny blue side of the panel is negative. The bottom grey side is positive. To connect in series, connect the top tabbing wire to the bottom tabbing wire. There is more information in the PowerPoint. 

After tabbing the cells, CA glue them onto the wing in-between the ribs. After doing so, then connect them in series carefully with the soldering iron, making sure to not hurt yourself. 

The bus wires go at the end of the panels and are connected to a wire that leads to the middle of the wing from either side. 

Step 4: Fuselage, Monokote & Electronics

Building the fuselage
The construction of the fuselage is not very difficult. Follow the instructions on the airplane plan provided. Wiring on the other hand may be more difficult. If you extend the wing, the CG on the plane may shift and you might have to do some minor modifications on servo placement. Heat shrink all electrical components to avoid any short circuits.


Monokote

Monokoting is not hard either. Use youtube videos to learn how to do it. Make sure when you are monokoting the wing, do the bottom first and then the top and make sure you curve the monotkote over to maintain a good airfoil and reduce any drag. You want to have as much laminar flow as possible. Make sure to use clear monokote for the top of the wing so the solar panels can charge. Cut and Iron the monokote on the wing, then blow it with the heat gun so it contracts and creates a tight wrap around the skeleton of the wing. 

Wiring & Electronics
Follow the PowerPoints provided and you should be fine. Put the Nylon control horns where they belong and wrap them in tape so they don't fall off in flight. 

Step 5: Testing Electronic Parts

To test the solar panels, plug them all into the charger where they belong and bring it outside to test on a sunny day. Plug the DMM into the output and measure the voltage. The charger that we used only started charging when the voltage was greater than 12 volts. 

To test the other parts, pair the receiver and the transmitter together. Depending on which brand on transmitter you use, you may need a pairing plug. 

Step 6: Test Flying

Bring the plane to an airfield and find an experienced pilot to fly the plane. That person will give you further instruction on how to modify the plane to give it better flight. For us, we needed to reinforce the elevator and rudder. We accomplished that with duct tape. 

Step 7: Conclusion

The Solar Plane project is an amazing starting point to getting into green energy, R/C, planes, electronics, aerospace, or just about anything else. As for our team, we had an amazing four person group plus our amazing teacher. If you're in a team, make some team shirts, it boosts morale and on competition day, everyone knows who you are. 

We ended up with 2nd in endurance because the charger wouldn't charge below 12 volts and competition day was an overcast day. But having the cells between the ribs gave us creativity points and using duct tape gave the judges a bit of a kick. We ended up with the most creative award and we're proud. From doing this project, you will learn so much about planes, solar energy, teamwork. It is a great way to spend a couple of weeks on a cool project. 

Make sure that if you're interested in green technology and solar planes in general, check out the Swiss project Solar Impulse. Our team got to chat with them when they came to Dallas because of our involvement in a similar project. : http://www.solarimpulse.com/

This dude in Finland is also worth checking out. Here's his Facebook link: https://www.facebook.com/SolarDrone 

Steps from here: To move beyond what we've created for now, we can add an auto-pilot system, cameras, and other equipment to make it a semi-autonomous drone. Light sensors can be added on either side of the wing and the plane can circle up the sky  with maximum sun exposure on the panels; then at night, it can loiter around, slowly circling back down to Earth. This plan however, would require a new plane, a new design, and a lot of effort, but that is what we intend on doing next year. Heck, we could even connect  the plane to a cell tower as one commenter below suggested. The GPS system would then tell people in the vicinity of the plane that the plane is there and the plane could fly over on top, giving the people a live bird's eye view of themselves. Awesome plan, right? The only part getting the technology down is acquiring FAA approval to do such a project.