Solar Powered Hovercraft

there are lots of little toy hovercraft tutorials on the web, i encourage you to look at those for ideas and and better understanding of how to create these. this instructable will focus on using solar panels and capacitors to power the hovercraft. once created the hovercraft can be used indefinitely without need to worry about charging or replacing batteries, perfect for younger kids. the body is made out of a foam plate thus easy to replace if damaged.

the materials and design of this hovercraft are selected to minimize weight while maximizing power. to achieve a high power to weight ratio several of chosen items have higher than average costs. it might be possible to build a solar power hovercraft with less expensive parts but it will be more challenging. the cost of making a two panel craft without capacitors cost about $24 USD not including the plate, glue and solder and a two panel with capacitors cost about $33 USD not including the plate, glue and solder.

the items used were also paired together to match each others input/output and minimum/maximum tolerances. be careful about the power output from solar panels so as to not burn out the motor or overcharge the capacitors, similarly make sure the capacitors don't also burn out the motor.

you will need foam plates, solar panels, fans and optionally capacitors if you wish to use the hovercrafts without the sun. i ordered all of my parts from digikey but there are lots of places to order from. i ordered more items than you would need to just make a couple of hovercrafts but you do get a price break for bulk rates thus if you plan to make 3 or more [or if you are like me and worried you will make some mistakes] then the numbers in the invoice should match your needs.

• foam plates

the best plates are the larger versions [aka dinner plates normally 10+ inches], the more expensive plates [ie name brands] will make for a stronger hovercraft and have a better chance of being flat. the cheaper plates tend to be a little warped. you might also use foam trays or similar options. although foam plates are the worst option environmentally speaking, it will be harder to make paper or plastic plates work because they are substantially heavier.

• solar panels MPT6-75

the panels used are made by powerfilm MPT6-75 these panels have the highest power to weight ratio available. to save weight this version does not have the UV protection or the weather proof options. the downside to film based solar panels is the large surface area they require compared to other panels, however, increased area is helpful for making hovercrafts.

• fans CFM-4010-13-10

there are lots of fans options and normally a computer fan is not the best choice for making a hovercraft. computer fans are not designed for high volume output. this means they will have a hard time lifting a heavy hovercraft. nor are they typically made for high power to weight ratios. this fan was chosen because it does have a higher power to weight ratio than most computer fans. if you use a different fan compare the CFM to weight. this fan has 10 CFM at only 14.2 grams.

• capacitors TPLC-3R8/25MR8X20

capacitors are optional, but thankfully the best capacitors for the project are also more affordable, however these hybrid lithium capacitors require more care than the average capacitor.

for best results the parts should be soldered together, you can attempt to skip the soldering process but these hovercrafts will be bouncing around so a loose connection is very likely without soldering. here are a couple of links to help you with soldering: text and video

to solder onto the solar panels check out this video

you might be able to only use tape to hold everything together but for best results use a combination of superglue and hot glue gun

take a foam plate trace fan on the center of the plate, mark a smaller square inside of traced square. the goal is to provide enough of a seat for the fan without blocking the air flow. attach fan, hot glue works best, superglue tends to melt foam and tape may not be strong enough

layout solar panels, remove film and solder wire on. [see the links in the tools and skills section above]. then solder fan to panels [note don't exactly follow the images and DON'T attach solar panels to plate before you solder all the wires since the heat might melt the plate]. attach solar panels to plate, note these are two 6 volt panels and need to be wired in series to produce 12 volts. in the last image the solar panels are temporarily taped in place to make sure it was working before being glued into place. if your fan is on top [might be needed with a small plate] space out the solar panels so as to not have the fan cast a shadow.

again you can skip the soldering but it will be hard to maintain a good connection

note this is like the simple design with the fan under the plate and the panels angled, capacitors have also been added. an on-off switch should also be added to the circuit to control the fan. the solar panels can be wired directly capacitors but you will want to control when the fan is on. i used a switch from a broken solar lawn light but you can get some for about $0.25. while it is not very important for this project if you have the capacitors wired directly to the solar panels can, they can drain the capacitors over a few hours to a few days. to avoid this you can add a switch or a directional diode [which you can also salvage from simple electronics [like broken solar light]]

this one uses four solar panels and they make the body of the hovercraft instead of using a foam plate. the skirt is made from 1/8 inch flexible foam [mine was laminate floor padding scrap]. the skirt needs to be even or else the air will not flow out from under evenly and the craft will not hover. the solar panels in this design are set in parallel/serial => four 6 volt panels made into two 12 volt units.

Solar panels are 94mm by 73mm, 6Vdc [8Voc], 300mW and 2.3g. Solar panels are wired in series/parallel for 12Vdc at 600mW. Voc is 16Vdc while the series wired four capacitors max is only 15.2, fortunately, under load the solar panels top voltage will be lower than the Voc. The capacitors also have a surge max of 4.2 each or 16.8 in series so there should be no overloading issues, however for safety it would be best to charge the capacitors by placing not facing directly towards the sun. Max motor voltage is 13.8 but again under-load the panels and capacitors should not be able to reach their open circuit max voltages plus the capacitor’s voltage drops quickly during use. Thus the motor might experience brief periods where its maximum voltage is exceeded, which could reduce the lifespan of the fan, however, operating the hovercrafts will not be 24/7 operation so the fans should be fine for several years of heavy use.

the capacitors rated output is 0.13A and the motor's rated input is also 0.13A thus they are ideally suited for working together.