Hydrogen is so often considered as the fuel of the future for our cars but may have other, ulterior, applications, as long-held research into hydrogen-fuelled internal combustion engines in cars pays off and Ford has received its first order – for an unmanned spy plane.

Boeing has finally revealed it is using Ford’s 4-cylinder, supercharged 2.3 litre hydrogen engine in its High Altitude Long Endurance (HALE) aircraft project. The I4 engine burns hydrogen with almost no emissions except water vapour and tiny amounts of oxides of nitrogen.

The HALE aircraft are designed to stay in the air for 7 days, carrying up to 2,000lb and maintaining communication links, or surveillance over specific areas. Boeing successfully tested the unit last month with a multi-stage turbocharger running continuously over 4 days, including simulated conditions at 65,000 feet.

George Muellner, Boeing’s advanced systems president, commented, “This test could help convince potential customers that hydrogen-powered aircraft are viable in the near term.”

Ford already sells its V10 hydrogen-burning engine in minibuses to public authorities in Florida and Canada.