Swiss ex-military and commercial pilot Yves Rossy developed and built a winged pack with rigid aeroplane-type carbon-fiber wings spanning about and four small kerosene-burning Jetcat P400 jet engines underneath; these engines are large versions of a type designed for model aeroplanes. He wears a heat-resistant suit similar to that of a firefighter or racing driver to protect him from the hot jet exhaust. Similarly, to further protect the wearer, the engines are modified by adding a carbon fiber heat shield extending the jet nozzle around the exhaust tail.