Bell Helicopter has added the first international partner to its V-280 Valor program to build an advanced medium-utility rotorcraft for the U.S. Army’s Joint Multi Role (JMR) technology demonstration.

Israel Aerospace Industries will supply the nacelle structures for the 280 kt.-cruise tiltrotor. Unlike the Bell Boeing V-22 Osprey, the V-280 has fixed wingtip-mounted engine nacelles with only the proprotors tilting.

Bell has also selected Textron sister company TRU Simulation & Training to build a high-fidelity marketing simulator and desktop maintenance trainer with which to give Army pilots and maintainers exposure to operating the tiltrotor ahead of its first flight in 2017.

"The Army does not have tiltrotors, so when the simulator is complete next spring we can start to get more pilots in and help them understand how to fly a tiltrotor," says Keith Flail, Bell’s Future Vertical Lift (FVL) program director.

Bell has to show the Army that a high-speed, long-range tiltrotor has the hover performance and low-speed agility needed to replace the Sikorsky UH-60 Black Hawk medium utility helicopter beginning around 2035.

The V-22 has proved a tiltotor is fast, and can decelerate and accelerate quickly to increase survivability into and out of the landing zone. But the Osprey has a higher disk loading and lower hover efficiency than a helicopter.

Compared to the V-22, the 280-kt V-280 Valor JMR will be simpler and lighter, with lower disk loading and longer wing for greater hover and cruise efficiency. But Bell does not have a prototype to showcase before the V-280 flies.

Sikorsky and teammate Boeing have to show the Army that the unique flying characteristics of their 230-kt SB.1 Defiant JMR demonstrator justify the additional complexity of its rigid coaxial-rotor compound helicopter configuration.

But Sikorsky plans to fly its first prototype S-97 Raider armed scout helicopter by year’s end, and will have a second aircraft it plans to use to conduct customer demonstrations to show the military utility of its high-speed configuration.

Bell plans to use the marketing simulator to give Army pilots early experience of the tiltrotor’s acceleration and deceleration characteristics and the V-280’s low-speed agility, Flail says.

The desktop maintenance instruction device, meanwhile, will let Army maintainers accustomed to working on overhead-mounted dynamic systems see how the V-280’s engines, gearboxes and proprotors would be serviced.

"The wingtip nacelle is different to what they are used to, but V-280 is designed so they can get at components without removing the nacelle. They can take the [rotor] mast off and pull the proprotor gearbox off a spline shaft," he says.

Bell and Sikorsky/Boeing have been selected by the Army to fly competing JMR high-speed rotorcraft demonstrators as a precursor to an FVL Medium program, beginning around 2020, to develop a replacement for the Black Hawk.

Essentially full-scale, Flail says, the V-280 demonstrator is to be powered by two 5,000-shp General Electric T64-419 turboshafts. The engines, previously used in the Sikorsky CH-53E, will be overhauled and modified for the demo.

The T64s will enable demonstration of the tiltrotor’s speed, range and hot-and-high hover capability, but GE says Bell plans to use a version of the Army’s Future Affordable Turbine Engine demonstrator in a production V-280.