Hovecraft

The goal of a fully autonomous hovecraft has not been achieved. After my return from studies in Amsterdam (an exhausting experience), I decided to take real holidays for the rest of the summer. I had one dream not fulfilled yet - to find out how difficult it is to build and control an autonomous hovercraft.

After few weeks I had a working hovecraft:

Construction

The picture below reveals, how the body of the hovecraft is constructed. It is based on two polystyrene boards with a gap between them. I used the plastic material from garbage bags for the skirt and the fingers from house-cleaning gloves as the fingers of the skirt. The hovecraft would not work without these fingers. The hovecraft is propelled by two Speed 480 class electromotors (lift & thrust), powered by two lead accumulators. The accumulators were chosen because of the current needed for the motors (>10A). Both accumulators together weight slightly more than a kilogram, which can be carried on a flat surface, but not elsewhere.

The software is meant to run on a PDA, communicate with the ATMega8-board (ATMega8 based control board with a universal control software) and drive the motors by regular hobby model regulators (up to 20A). The hovecraft has not been equipped (and very likely will never be) by sensors necessary for the autonomous operation.

Advantages and drawbacks

One of the reasons for choosing a hovecraft were its similarities and differences with helicopters. The controlling software needs to be essentially the same - taking inputs from accelerometers and dealing with a big momentum. The basic advantage of a hovercraft is, that it cannot fall on someone's head and kill him.

There are some drawbacks I have not realized before, though. One of them is, that a small crack in the road bellow (or waste-water channel cover with holes) causes large loss of pressure, effectively killing the machine. The other one is, that already on a slightly non-horizontal surface, a hovercraft starts to drift, which is impossible to handle with my construction.

Summary

It is extremely easy to built a remote controlled hovercraft from spare parts. It may be even more difficult to control, than it is to control a helicopter (because of the drift on a non-horizontal surface, which is because of the water drain almost on every road).