"Since the 1960s engineers around the world have been fiddling with a novel type of jet called a rotating detonation engine (RDE), but it has never got beyond the experimental stage," reports the Economist.

"That could be about to change."
GE Aerospace, one of the world's biggest producers of jet engines, recently announced it was developing a working version. Earlier this year America's Defence Advanced Research Projects Agency awarded a $29m contract to Raytheon, part of RTX, another big aerospace group, to develop an RDE called Gambit.

Both engines would be used to propel missiles, overcoming the range and speed limitations of current propulsion systems, including rockets and existing types of jet engines. However, if the companies are successful in getting them to work, RDEs might have a much broader role in aviation — including the possibility of helping revive supersonic air travel.

In a nutshell, an RDE "replaces fire with a controlled explosion", explains Kareem Ahmed, an expert in advanced aerospace engines at the University of Central Florida. In technical terms, this is because a jet engine relies on the combustion of oxygen and fuel, which is a subsonic reaction that scientists call deflagration. Detonation, by comparison, is a high-energy explosion that takes place at supersonic speeds. As a result it is a more powerful and potentially a more efficient way of producing thrust, the force that drives an aircraft forward...

By modifying an aircraft's fuselage and wings, engineers believe they can reduce the boom's impact on the ground below. Such work will help to determine whether or not future supersonic passenger planes will, like Concorde, be restricted to flying beyond the speed of sound only over oceans.

Thanks to long-time Slashdot reader SpzToid for sharing the article.