Steam Balloon

Steam is an excellent lifting gas that provides about 60% of the lift of helium but is much cheaper. It is also a much better lifting gas than hot air at the same temperature. Steam is a very inexpensive, non-flammable, non-toxic, readily available buoyant gas. This is the basis for the concept of the steam balloon, i.e. lighter than air steam technology.

Uses / Product Ecology

 * transport materials over great distances for minimal cost
 * use steam engine for propulsion. This concept was extensively discussed at Flying Kettle (link below)

Links

 * http://flyingkettle.com/
 * http://www.festo.com/cms/en_corp/9820.htm