(AW) The Defiant JMR demonstrator would take the coaxial-rotor/pusher-propeller configuration to a new size category. Working with Boeing, Sikorsky is taking its coaxial rigid-rotor technology to the next level Scale is everything in rotorcraft: What works at one size might not at another, because of complex interactions between aerodynamics, propulsion, structures and control. That is why the U.S. Army plans to fly competing high-speed rotorcraft demonstrators before deciding which direction to take in replacing its utility and attack helicopters beginning in the mid-2030s.