Single rotor radio-controlled hovercraft designed to fit a 5inch propeller. Despite only having a single propeller it's quite fast ;-)

Video of the hovercraft in action can be found at the following link: https://www.youtube.com/watch?v=orePqapvzG8

Required build volume
All parts are designed to fit on a 18x18x18cm build plate, as I was able to print everything on my Prusa Mini. If you have a larger print bed you can join several parts (of the hull for example) and print them at once.

Required hardware
Nuts & bolts

• 20 x M3x5mm (Secure top of skirt)
• 17 x M3x16mm + nuts (Secure bottom of skirt)
• 4 x M4x10/12mm + nuts (Mount duct and hull)
• 6 x M4x20mm (Mount top skin to hull)
• 2 x M3x6mm (Mount motor to duct)
• 1 x small screw (Screw servo onto hull)

Electronics (parts I used)

• Brushless motor (2204 2300kV mounting pattern = 16x19mm)
• Brushless esc (25A, 4S compatible)
• Lipo Battery(4S 800mAh)
• Receiver (FrSky X4R)
• Servo (+-12g, width of about 12mm, length of about 23mm)
• 5inch propeller

Miscellaneous

• Piano wire +-1mm (Mount rudders + servo pushrods)

The electronics can be chosen slightly differently, as long as the brushless motor has a similar mounting pattern.

Build process
3D printed parts
Most of the parts snap together without any glue. The duct has to be mounted using 2 bolts and the same goes for the bottom parts of the hull (2 bolts to secure the front parts to the back parts). Don't overtighten these bolts as this will lead to fracture of the plastic parts that hold the nuts. Both the motor and servo wires fit in slot just below the duct, don't forget to route these wires before tightening the bolts on the duct. The top skin requires 6 bolts in total for mounting, which should be inserted before mounting the skirt. Some glue might be needed in between these parts to keep them together nicely. Then the rudders can be installed. A piece of pianowire has to be pushed through the top holes of the duct, through the rudders themselves and then all the way through the holes in the skin plate. As a last step the skirt can be mounted. On top using the 20 M3x5mm bolts and top brace, on the bottom using the 17 longer M3 bolts + nuts, together with the bottom brace and the air outlet brace.

Skirt
Skirt segments must be sewn together along the right and left edge. Every segment has an extra border of 10mm all around, which can be used as a margin for sewing. The layout for the skirt parts can be found in one of the attached pictures.

Alternatively a simpler, one piece skirt can be made using a garbage bag for example. Many tutorial video's can be found online that explain how to do this.

Once the skirt segments are sewn together and the rest of the hovercraft is assembled, the skirt can be secured to the hull. Layout the skirt over the hovercraft and use the mounting brackets to align where the holes have to be punched through the skirt. Afterwards use the bolts to secure the skirt to the hovercraft.

The build process is of intermediate difficulty I think, as some parts can be finicky to assemble (mainly mounting of the skirt).