Free Flash Tutorials	Home • Food • Mates • Members • Tutorials • Forum • Buy Templates • Contact Us

Homemade Hovercraft

801 Miscellaneous

Written by: David Williamson  from:   Link to his site

Editor: Phil Schulz

Length: 900 words

Assumed Knowledge: None

Difficulty: Easy

Free Tutorial

How to make a Hover Craft at home. Here is my friend David making a Hover craft with the kids:

Take the blade off the flymo. Use polythene dust sheet 15 ft square folded in from the corners, join with parcel tape. Details of toy hovercraft built on same principal follow.

The skirt must assume a doughnut shape or friction is too great. If making a toy, use a flimsy swing-bin liner or cling film, thicker polythene doesn't form an effective seal because it doesn't conform to the inequalities in the surface it's running over.



Understanding skirts opens the door to ceiling robots (travel on ceiling by sucking not blowing).

They can also go on walls but this is trickier because of the uphill problem.

This is a diagram of how to make a hand-over-hand wall climbing robot. They are easier than the wheeled variety. You have to make a push-pull mechanism using fishing line which winds/unwinds round a motorised shaft. One end of the dowel is rigidly attached to one of the plates (it is held by a drinking straw); the other end passes through a drinking straw which acts as a slider. By switching the fans on and off alternately and working the slider the robot can be made to climb a wall.

It is surprisingly tricky getting the wind/unwind idea to work.

For better grip on smooth walls add a bead of rubber band immediately under the plate rims. Attach to the polythene with double-sided tape.
Not too good on ceilings because of the leverage effect of the dowel. Don't switch the 'off' fan off completely, just enough for it to let go a bit.
The centrifugal fan is easy to make and is perhaps the most important component of a wheeled ceiling robot, there is a much better fan design at the bottom of the page.

Try just holding the fan above a styrofoam plate with a half-inch hole in the middle on a smooth work surface. Even without the polythene skirt the grip is quite surprising, even when the fan is running on 3 volts.

This is a wheeled ceiling robot. The problem with these is that you have to create a seal which can slide easily. The partial vacuum must provide enough down force to give the wheels traction and yet not create too much friction in the seal. This apparent paradox can be reconciled by making a skirt out of bubble-wrap.

Bubble wrap is stiff enough not to tuck up under the box and yet flexible enough to create a continuous seal; also the vacuum can to some extent spread between the bubbles. For this reason the edge of the bubble wrap must have an additional skirt (the petticoat) made of very flimsy polythene to seal the outer edge. This should extend for about 2cm under the edge of the bubble wrap because an inner seal is constrained in such a way that it remains smooth. The polythene is only taped to the bubble wrap along the edge of the bubble wrap. The inner edge of the bubble wrap is taped to the styrofoam box.

The skirts/box should be taped together on a flat work surface. Do this first. Tape the corners of the polythene to keep everything flat. When you've finished, remove from work surface, cut inner hole in polythene and trim inner edge of bubble wrap to conform to the edge of the box. If you've got it right, even at this stage it should show an amazing tendency to cling to smooth surfaces and the seal should be quite reluctant to break.

The ground clearance of the wheels is quite critical, I find about 3mm works best. Start with a very small ground clearance then super glue more and more rubber bands to the wheels: this increases the ground clearance incrementally and improves the grip of the wheels.

link to 500 kilobyte movie of wall/ceiling robot


This is a simple bubble machine which uses the same centrifugal fan, in this case it blows rather than sucks. Use 1.5 volts. Dip toilet roll in washing up liquid solution with fan off, remove and switch fan on.

You can just see the string trying to close the bubble.

This shows the fan inside the machine.

This is a greatly improved fan design.

It is much easier to make and is almost twice as efficient. You can measure the efficiency of a suction fan with a mono-meter.

It is made of a flat bit of card with a drinking straw through it; the fan should suck the liquid up a vertical height of about 2.5 cm when running off 2 AA batteries. Use a dark liquid like wine or fruit juice.

The fans are made from 50mm cardboard discs, I bought mine but you can make them. A plastic bush is pushed into the central hole.

The blades are made of bits of plastic cup.

It's easier to mark out if you cut the cup into quarters but I found they are a slightly too big and had to cut a bit off. Quite small changes make a big difference to efficiency, that's why it's a good idea to test it with a mono-meter.
When you get fed up trying to make a fan make one of these instead.

Here is some other stuff: Bubble Blower and a Simple Robot

Go to David's Main Site

Link to interesting site

my email is davidvwilliamson@hotmail.com