No, Bell's Invictus Armed Scout Helicopter Isn't Stealth But It Aims To Be Fast And Cheap

Bell is pushing traditional helicopter design to its limits in an effort to offer the Army a capable, but low-risk and low-cost armed scout solution.

Bell Helicopter

Bell has unveiled its much-anticipated offering for the Army's Future Attack Reconnaissance Aircraft (FARA) tender, an initiative that seeks to replace some of the Army's AH-64 Apache attack helicopters as well as better fulfill the mission left somewhat underserved by the early retirement of the OH-58D Kiowa Warrior. Bell has branded this new design the "360 Invictus." The storied helicopter manufacturer made somewhat of an unconventional move by going with a conventional helicopter configuration, one based its 525 Relentless next-generation medium-twin engine model, instead of pursuing a more exotic concept in order to meet the program's threshold speed of 180 knots, among other requirements. Bell said it could meet FARA's demands and do so at a lower cost and with lower risk than its more complex and unorthodox competitors, such as a design based on Sikorsky's S-97 Raider and AVX and L3's design, by sticking with a classic helicopter layout. Now we know just how they intend to do this and what such a flying machine will look like.

First off, I know what you are thinking—is this a stealth helicopter? In other words, was low observability a primary driver in its design? Many are comparing it to the RAH-66 Comanche looks-wise, but even though it may look similar, sources close to the program have assured us that the design came to be primarily to reduce drag and increase top-speed, not to hide from enemy radars. Signature control is a significant part of most combat aircraft designs these days, but in this case, it came secondary to performance. This wasn't just Bell making a design choice, low-observability is not part of the FARA requirements, and it's not like Bell doesn't have the know-how when it comes to infusing stealth aspects even into its existing designs. In fact, certain aspects of foreign designs look somewhat similar to Bell's Invictus, such as China's Z-10, which is not a "stealth" helicopter, either. 

Sikorsky

RAH-66 Comanche during flight testing.

The 360 Invictus is definitely a modern take on the classic attack helicopter configuration, with its tandem, stepped cockpits, single rotor, and fenestron. But it seems that Bell poured a ton of pointed optimization into this design and a lot of new technology that could fit within the somewhat classical attack helicopter mold. The biggest being its propulsion system. It uses a single General Electric turbine in the 3,000hp class, that is mounted offset to one side. The air intake is also only on one side and the exhaust is on the other. 

The primary engine is geared with some sort of supplemental power unit that provides extra power when needed to give the helicopter the dash capability demanded under the FARA requirements. It will be interesting to learn more about what exactly this secondary propulsion unit is and what difference in performance it makes when it is engaged and when it isn't. Also, questions like how long it can run, what does it do to the aircraft's range and fuel consumption, and even its infrared signature, are also important. At this time, Bell is sharing very little about it beyond the fact that it exists as part of the 360's configuration.

The 360 Invictus has a lift-sharing clean wing that reduces the load on the main rotor in forward flight and helps with the helicopter's high maneuverability. The main rotor has an aerodynamic shroud and is articulated with 'high flapping' capability that helps with high-speed flight, as well. It shares a lot of commonality with the rotor on the 525 Relentless, but it has four blades instead of five. To counter torque, the Invictus has a fenestron that is slightly tilted to reduce drag and increase thrust. Continuing with the airframe efficiency focus, the design has retractable landing gear, as well.  

Its flight control system also builds off of the 525's very advanced fly-by-wire system, which has the potential to cut down pilot workload dramatically and can be leveraged for autonomous, unmanned operations in the future. The avionics all run on Collins Aerospace's open architecture concept (Modular Open Systems Approach (MOSA) enabled by a Digital Backbone) so upgrades and enhancements will be very easy to realize, both in terms of adding new software and hardware, to the airframe.  

Bell

When it comes to sensors, Bell just says that the helicopter is "provisioned for enhanced situational awareness and sensor technologies." You can use your imagination here, but suffice it to say that sensors will be among the most important elements of any FARA entrant. The concept art shows a multi-role FLIR sensor on the helicopter's nose and missile approach warning sensors (MAWS) and/or distributed aperture system (DAS) apertures scattered around its fuselage. Survivability will largely be gained through speed, situational awareness, advanced electronic warfare capabilities and countermeasures, and new weapons when it comes to the Army's future armed scout helo. 

As far as those weapons, the aircraft is seen with a 20mm cannon, similar to what arms the mature AH-1 Cobra family of helicopters. In fact, the Army has contracted General Dynamics to supply its XM915 20mm cannon that is derived from the one once intended for the Comanche for all FARA participants. Beyond that, its weapons will be carried internally in its primary configuration on launchers that can both fire missiles and drop unpowered glide and gravity weapons. Bell describes this as an "integrated munitions launcher with ability to integrate air-launched effects, and future weapons, as well as current inventory of munitions." The helicopter's stub wings are also able to carry weapons, as well.

Let's talk about performance. Details remain pretty thin, but Bell says the 360 Invictus will be able to reach speeds in excess 185 knots and it will be able to hover in ground effect (low over the ground) at 4,000 feet elevation in 95-degree Fahrenheit heat. As far as projected range, a 135 nautical mile combat radius with better than 90 minutes on station once at its target area is what Bell is positing for the design. 

Bell

Textron's official announcement reads in part: 

Textron Inc. (NYSE: TXT) company, has announced a new rotorcraft, Bell 360 Invictus, as the company’s entrant for the U.S. Army’s Future Attack Reconnaissance Aircraft (FARA) Competitive Prototype program. Bell’s innovative approach to designing the Bell 360 Invictus combines proven low-risk technologies with advanced processes to deliver soldiers an affordable, agile and lethal solution to win on the modern battlefield. The Bell 360 Invictus meets or exceeds all requirements as laid out under the FARA contract.


“The Bell 360 will deliver advanced battlefield situational awareness, as well as lethal options, in support of the maneuver force at an affordable cost” said Vince Tobin, executive vice president of Military Business at Bell. “The multi-domain fight will be complex, and our team is delivering a highly capable, low-risk solution to confidently meet operational requirements with a sustainable fleet.”


The Bell 360 Invictus’ design emphasizes exceptional performance using proven technologies to fulfill the Army’s FARA requirements at an affordable cost and on schedule. One example is the Invictus’ rotor system. This design is based on Bell’s 525 Relentless rotor system which has been tested and proven at speeds in excess of 200 Knots True Air Speed (KTAS). By incorporating proven designs and the best available technologies from commercial and military programs, Bell delivers a low-risk path to a FARA program of record.

...

"Bell is committed to providing the U.S. Army with the most affordable, most sustainable, least complex, and lowest risk solution among the potential FARA configurations, while meeting all requirements," said Keith Flail, vice president of Advanced Vertical Lift Systems at Bell. “360 Invictus is an exciting opportunity for us to continue our support of Army modernization. This is the next solution to ensure soldiers have the best equipment available for the multi-domain fight.”


Bell has decades of experience providing attack and reconnaissance aircraft to the warfighter, such as the Kiowa Warrior which delivered high reliability and availability through more than 850,000 flight hours. The Bell 360 Invictus design builds from that legacy, Bell’s commercial innovations, and from the success in the development and manufacturing capabilities required for Future Vertical Lift (FVL) as part of the Joint Multi-Role Technology Demonstration (JMR TD) over the past six years.

It is pretty amazing what Bell is looking to pull off here. Just as our original analysis stated, it is abundantly clear that Bell's FARA team believes that offering the Army a relatively low-cost, low-risk solution to a fairly complex set of requirements is the winning ticket. Where other competitors, such as Sikorsky, will likely provide capabilities far in excess of FARA's base requirements, those technologies could very well come at an additional cost, both in terms of the purchase price and operating costs. They also come with uncertainty. Traditionally, armed scout helicopters are reliable, simpler airframes than their heavy-hitting attack helicopter brethren. Currently, when you look at the other offerings, FARA presents the possibility that this tradition will be flipped on its head, at least for a period of time, until—and if—the Army procures an attack helicopter based on the Future Vertical Lift (FVL) initiative

Bell/Boeing

The Invictus design is also reminicent of Bell and Boeing's Light Helicopter Experimental (LHX) concepts from the 1980s.

Bell/Boeing

The big question is what will the Army actually be willing to spend on an individual capability-set it largely abandoned when it retired the Kiowa Warrior and rolled it into the AH-64 Apache's repertoire? With so many other major priorities—Future Vertical Lift being a huge one of them—is the Army really going to invest in hundreds of 'exquisite' scout helicopters? Even the survivability of any of these less than stealthy helicopters over a modern battlefield is being questioned by some, rightfully so. Do an extra 50 knots or so of speed really buy survivability? Will other technologies provide robust enough defenses for these helicopters to make them truly employable in contested airspace? We will give you our take on these questions and more soon, but the fact that they exist does make Bell's approach to the FARA tender more relevant. If Bell can deliver a low-risk design at a substantially lower price than their counterparts, will the Army be willing to spend far more money on what may not even be a realistically employable concept in higher threat environments to begin with?

There is also the looming defense budget question. What happens if—or as I believe, when—the defense budget retracts after growing substantially over the past few years? What will be sacrificed? Bell may find itself in a unique and very favorable position to offer a baseline capability at low enough cost to mean the difference between program cancellation and acquisition.

Beyond these uncertainties, one thing is for sure, the fight for FARA is officially heating up. In all, Bell, Sikorsky, Boeing, AVX and L3, and a consortium of Karem, Northrop Grumman, and Raytheon, will be competing for the FARA prize. 

Contact the author: Tyler@thedrive.com