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Bell’s new attack helicopter concept looks like a bull shark with a 20mm rotary cannon in its mouth, with a sleek organic fuselage that should allow it to fly at more than 180 knots in forward flight.
Unveiled Oct. 1 at the company’s Advanced Vertical Lift Center outside Washington, D.C., the so-called “360 Invictus” is Bell’s pitch for the U.S. Army’s Future Attack Reconnaissance Aircraft (FARA). Bell is one of five companies competing for FARA. The others are AVX Aircraft, Boeing, Karem Aircraft, and Sikorsky.
Focusing on affordability, Bell has mustered its extensive experience and history building reliable, utilitarian military aircraft to pitch a less-exotic option for the U.S. Army’s new attack helicopter. The 360 Invictus tag is in line with the company’s naming scheme of a significant number followed by a glorious-sounding adjective. It also developed the V-280 Valor advanced tiltrotor (its target speed was 280 knots), the V-247 Vigilant unmanned tiltrotor, and the 525 Relentless.
Invictus’s somewhat conventional design is a single-main-rotor helicopter with a tandem cockpit. It borrows the rotor system from the 525, which the company notes has been flown at speeds above 200 kts in test flights. Both the shrouded hub and rotor blades have been “ported over” from the 525 program, but will be scaled to fit the Invictus, according to Keith Flail, vice president of advanced vertical lift systems at Bell. Where the 525 has five blades, Invictus will have four and will not exceed the Army’s 40-foot size limitation.
Invictus also will use a version of the 525’s fly-by-wire flight control system and features a modular, open-systems avionics system provided by Collins Aerospace.
The aircraft will be powered by a single GE improved turbine engine mounted aft and to the left of the main rotor hub. On the opposite side will sit a “supplemental power unit” that “engages with the drive system to provide additional horsepower when required to give us that extra power and speed we need,” Flail said. He declined to say if the SPU is required to reach the program target speed of 180 knots.
“It adds significant increase in horsepower,” Flail said. “Today, we’re not going to reveal more about how it engages with the drive system. We have a patent pending related to that.”
Another interesting and also unexplained design feature is the engine intake is on the left side of the fuselage and the exhaust ports out horizontally on the opposite side.
The aircraft should have a combat radius of 135 nautical miles with more than 90 minutes of time on station and achieve 4k/95F hover out of ground effect (HOGE).
At cruising speed, two “lift-sharing” wings, which are 24 feet tip-to-tip, will offload half the burden from the fully-articulated main rotors. Horizontal stabilizers controlled by the fly-by-wire system will keep the aircraft trimmed in the lowest drag position at high speed. The ducted tail rotor is canted to reduce drag and provide additional lift, Flail said.