Karem Aircraft has unveiled its Future Attack Reconnaissance Aircraft (FARA) design, as it pursues a development deal with the US Army.
The company is pitching a rigid main rotor helicopter with a rotating wing and a pivoting tail rotor, called the AR40. The design also has a three-blade main rotor that uses Karem’s Optimum Speed Rotor technology, which was initially developed using US Army research funds to create optimal efficiency for tiltrotors in vertical or horizontal flight.
On the AR40 helicopter, the system would be used to control each individual blade as it rotates, instead of forcing the blades to move in unison as is the case with a traditional swashplate system, says Thomas Berger, director of the FARA programme at Karem.
“You're able to shape the trajectory of the blade path around the azimuth,” he says. “Being able to shape the trajectory gives you the possibility to get better performance, better acoustics, better reliability, automatic tracking.”
The AR40 aircraft has a 12.2m (40ft) wingspan – wider than the helicopter’s 11m main rotor diameter. The wing can provide the majority of the aircraft’s lift and tilts upwards during the helicopter’s descent or ascent in order to make its vertical flight more aerodynamic.
The AR40 also has a swiveling tail rotor, which in forward flight is angled backwards to be used as a pusher propeller. The company says in forward flight the aircraft’s vertical stabiliser compensates for torque from the main rotor blades. The swiveling tail rotor should allow for the aircraft “to manoeuvre aggressively at low speeds,” says Karem.
Karem believes the AR40 should be able to exceed the US Army’s 180kt (333km/h) maximum speed requirement by 40kt.
The aircraft is single engined and designed around the US Army’s Improved Turbine Engine Programme selection, the GE Aviation T901.
The AR40’s cockpit has room for two pilots sitting side-by-side. It also has a small cabin directly behind the cockpit with room for four passengers, such as special operations troops. Behind the cabin is the rotorcraft’s internal weapons bay.
Karem is partnering with Northrop Grumman and Raytheon on the AR40. Karem is contributing its rotor and drive technologies, and is leading the design and prototyping process. Northrop is providing production and product support, as well as avionics expertise. Raytheon is the mission systems integrator and modular open systems architect.