Build a hovercraft, make CAD designs for each of the parts. Use the group collaboration process to designt eh parts so nobody has to do it all.

Use the Kelvin hovercraft kits and instructions. HoverCraftProcess

Here are some basic questions to help you get started on information on hovercrafts:

How does a hovercraft work?

What are the common parts of hovercrafts?

how do you design for weight distribution?

How do you make the hovercraft float?

How do you make the hovercraft move in a direction?

How can you steer the hovercraft?

What surfaces are best for hovercraft operation?

Products:

individual CAD designs of the parts of the hovercraft

Assemblies of the CAD designs

Functioning prototype model of the hovercraft

Redesign the hovercraft for ideal design qualities

Additional prototypes demonstrating the new design(s)

Text explaining how the hovercraft works

Text explaining what you did and how you did it.

Photos showing your designs

HoverCraftRaceDay

Here are a few links to get more info on Hovercrafts

http://flickr.com/photos/connors934/sets/72157600322768590/

http://hovercraftmodels.com/How_a_Hovercraft_works.htm

http://kids.pbs.org/dragonflytv/parentsteachers/tguide_hovercraft.html

http://www.olshove.com/HoverHome/hoverfaq.html

http://www.olshove.com/HoverHome/hovcalc.html

http://www.eng.uab.edu/me/faculty/amcclain/hovercrafts.html