The two industry teams the U.S. Army selected to build advanced rotorcraft designs under its joint multi-role technology demonstration (JMR-TD) revealed details of their proposals during the Association of the U.S. Army (AUSA) annual meeting this week in Washington, D.C. Bell Helicopter displayed a full-scale mockup of its V-280 Valor tiltrotor.

Bell announced its choice of GE Aviation T64-GE-419 turboshaft engines to power the V-280 and plans to use a version developed for the Army’s Future Affordable Turbine Engine technology effort. It also named new members of the “Team Valor” industry team it has assembled to build a flying demonstrator by 2017. Israel Aerospace Industries will supply the nacelle structures of the aircraft, which will have fixed engine nacelles at its wingtips with tilting proprotors. TRU Simulation + Training, a sister company of Bell’s under the Textron corporate umbrella, will provide a high-fidelity flight training device and interactive multimedia virtual maintenance trainer. They join Lockheed Martin, AGC AeroComposites, Astronics, Eaton, GKN Aerospace, Lord, Meggitt, Moog and Spirit AeroSystems on the Bell team.

Boeing and Sikorsky Aircraft held a joint briefing at the AUSA event at which they described attributes of the SB-1 Defiant, a compound helicopter with coaxial main rotors and a rear pusher propeller. The Defiant is based on the configuration of Sikorsky’s X2 technology demonstrator, and with the larger S-97 Raider the company is developing will help the JMR team validate design tools for the configuration in three different weight classes. “Now we have 6000-, 11,000- and roughly 30,000-pound aircraft. We have a toolset that can scale with Army requirements,” said Doug Shidler, Sikorsky’s JMR program director. Pat Donnelly, Boeing’s JMR program director, added, “Our coaxial is different from what the Russians have flown for the last 20 or 30 years.” With rigid main rotor blades “there’s no flap hinge, there’s no lead lag hinge…which allows us to move those rotors very close together, [providing] an opportunity to reduce drag and to improve our speed.” The pusher propeller can serve as a brake, reverse the aircraft’s direction or power a hover at 20 degrees nose up or nose down, he said.

Earlier this year, the Boeing-Sikorsky team selected the Honeywell T55-GA-714A turboshaft that powers the Boeing CH-47 Chinook as the Defiant’s engine. The T55 is not fuel efficient enough to meet the Army’s future range specification, but the aircraft will accommodate the engine technology expected at that time, the executives said. “When we selected an engine, we wanted an engine that had adequate power; it had to be off the shelf and it also had to have a digital engine control system because we’re going to be modifying the speed of our rotor and we’re going to do that right now through the engine,” said Donnelly. The GE T700 engine that powers UH-60 Black Hawk and AH-64 Apache helicopters “is slightly underpowered so we’ve gone to the other extreme. We have more power than we need on this demonstrator, more power than we’ll use, but it will work for us.”

The JMR effort is part of the Pentagon’s Future Vertical Lift (FVL) program to develop a series of advanced rotorcraft that would begin replacing the Army’s helicopter fleet by 2030. JMR TD Phase 1 addresses the technical risk of developing an FVL medium-class air vehicle that would replace the UH-60 Black Hawk. The Army wants companies to demonstrate a 30,000-pound gross weight or lighter aircraft capable of cruising at 230 knots, with the ability to hover with a full combat load in “hot and high” conditions of 6,000 feet msl and 95 degrees F.