Slicing through the sky faster than 230 knots, sleeking beneath the radar clutter, maneuvering just above buildings and mountainous terrain to deliver infantry into hostile fire for a massive, coordinated attack, are all mission sets planned for the Army’s now fast-emerging Future Long Range Assault Aircraft (FLRAA).
Future Long Range Assault Aircraft (FLRAA)
The FLRAA program is intended to fly alongside, complement and greatly expand upon the Army’s Black Hawk helicopter, with first fielding in the 2030s and fly well into the second half of the 21st century.
It is part of the Future Vertical Lift program intended to improve, reshape and actually change paradigms for air attack and assault helicopter missions moving into future decades.
The Army is now working with two competing vendors, Bell Helicopter and Lockheed Martin Sikorsky-Boeing, in a developmental phase for the FLRAA aircraft wherein designers and builders are submitting their formal configuration proposals.
While both are being closely examined by the Army as possible options for a new generation of attack and utility helicopters, the designs are quite different.
Bell Helicopter’s V-280 Valor is a Tiltrotor aircraft intended to advance beyond the capacities of today’s V-22 Osprey, while the Lockheed Martin Sikorsky-Boeing DEFIANT X much more closely mirrors the size, shapes and forms of existing Black Hawks.
At the same time, while some of the length, height and width specifics of the DEFIANT X are comparable to a Black Hawk for both logistical and operational purposes, the new Lockheed Martin Sikorsky-Boeing offering introduces an entirely new, far more advanced helicopter.
Lockheed Martin Sikorsky-Boeing DEFIANT X
The DEFIANT X, which can travel at speeds equal to or greater than 230 knots and fly twice as far as a Black Hawk without needing to refuel, also brings an entirely new suite of mission systems, targeting technology, command and control and of course weapons applications.
“Whether it’s air assault operations with troops, artillery raid with howitzers, MEDEVAC or CASEVAC, DEFIANT X will be able to do all that and it’ll be able to do it more effectively and more efficiently because of the speed and range at which we can do it. It’ll be able to do the same amount of work in half the time or twice as much work in the same amount of time,” retired U.S. Army Lt. Gen. Kevin Mangum, said in a video statement.
DEFIANT X: X2 Technology
The DEFIANT X achieves its breakthrough speed, range and maneuverability through a series of helicopter innovations called X2 Technology to include more power and efficient torque management and distribution, coaxial counter rotating rotor blades and a smoother, less jagged and therefore stealthier configuration with fewer protruding external structures likely to generate a return radar signal.
The DEFIANT X can load up with litters for MEDEVAC missions, missiles and guns or transport large numbers of armed infantry for coordinated assault.
DEFIANT X: Maneuver and Propulsion
Two of the largest breakthroughs with the DEFIANT pertain to maneuver and propulsion. Unlike a Black Hawk which, having a single rotor blade, has to lower its front section to create the airflow angles sufficient for faster speeds, the DEFIANT X can double the speed while staying parallel to the ground and fly in a straight ahead, more linear fashion.
The airflow is balanced by counter-rotating blades, therefore enabling massive maneuverability without pulling the front of the aircraft up to slow down or lowering the nose to increase speed.
This stabilizing, dual-rotor configuration allows the DEFIANT X to fly straight without needing a side-mounted, small rear rotor to maintain alignment like that which is on the Black Hawk, a scenario which opens up the chance to place a vertical rotor perpendicular to the rear of the aircraft to both maintain flight trajectory alignment and adding massive new amounts of “thrust” or propulsion to achieve breakthrough speeds.
Unlike a fighter jet engine propulsion system which sucks in air, compresses the air, combines it with fuel to generate a controlled explosion pushing force out of the back for thrust and speed. The DEFIANT X takes air in through its ducts or inlet, certainly compresses and ignites the air with fuel, yet instead of generating something like an “explosive” thrust out the rear, the DEFIANT X’s engine helps send a massive amount of “twisting force” or “torque” down to rear rotor or up to the main rotor.
Torque distribution can be optimized, Lockheed Martin-Sikorsky developers tell The National Interest, by managing the amount of torque which goes to the rear and main rotor blades to achieve the ideal balance between speed and maneuver depending upon the mission.
For instance, should the DEFIANT X be traveling at higher altitudes from one point to another, more torque is likely to go back to the rear rotor blade to maximize thrust. However, should there be a need to hover and maneuver carefully lower to the ground, then naturally more torque will likely travel to the main rotor blades. This combination is what developers had in mind when initially developing the concept for FVL, meaning the intent for many years has been to engineer a future aircraft able to both achieve air-plane-like speeds and also hover and maneuver closer to ground like a helicopter.
DEFIANT X Additional Lift
The added “torque” and resulting increase in thrust and maneuverability also brings the advantage of additional lift. The DEFIANT X recently succeeded in air lifting 5,300 pounds, an ability sufficient to slingload an M777 towed Army Howitzer artillery weapon, with the crew and ammunition. A key combat system which currently must be carried by a very large and more vulnerable Chinook cargo helicopter.
Black Hawk & DEFIANT X
The overall concept is to build upon the success and combat performance of the Black Hawk, while bringing innovations and a new generation of technology to an entirely redefined threshold.
This is quite significant, given that the latest U.S. Army Black Hawk M helicopter is engineered with an upgraded, high-powered and fuel efficient engine, composite rotor blades and vastly enhanced digital cockpit displays and targeting systems. The Black Hawk has also in recent years had great success across a wide sphere of missions to include MEDEVAC, air assault, troop, cargo and ammo delivery, close air support to advancing ground forces and of course large-scale infantry attacks.
“Black Hawk pilots love the Black Hawk. The thing about DEFIANT X is it’ll go twice as far, twice as fast, will be twice as maneuverable, twice as survivable and have approximately half of the noise acoustic signature of a Black Hawk. So it’ll do everything the Black Hawk did - better,” Mangum said.
The DEFIANT X operates with more volume, stealthier external configuration, yet it is by design closely aligned with the size and shape of the Black Hawk. The width and height of the Black Hawk and DEFIANT X are marginally different. Designers of the DEFIANT X chose this deliberately to improve affordability so that the Army doesn’t have to rebuild global hangars and maintenance facilities for the new helicopters.
“Wherever you can put a Black Hawk, you can put a DEFIANT X. If you can put three or four Black Hawks in a hangar, you can put three or four DEFIANT X’s in the hangar. You don’t need to spend more time, more money and more energy building additional infrastructure to support what you already have today throughout the globe,” said Ed Fortunato, Vice President, Army Aviation Programs, Lockheed Martin Sikorsky.
Of equal or even greater value, Sikorsky engineers chose a Black Hawk like form factor for tactical reasons as well, as smaller aircraft can more effectively fly in larger numbers in formations to ensure large scale attacks in close proximity.
Should a “hot” or contested LZ (Landing Zone) require a large amount of soldiers to descend and attack for a “forcible entry” operation, larger numbers of troops would need to arrive and dismount in rapid succession and in close proximity. A larger Tiltrotor formation would need to operate and approach at much farther distances due to an aerodynamic phenomenon known as “rotor downwash”
The larger an aircraft is, naturally, the greater the amount of disruptive, turbulence-generation “rotor downwash” there is, something which can destabilize or even fully destroy flight trajectory or lift for aircraft. Caused by horizontally rotating blades, rotor downwash is the largest when a helicopter is in hover, the kind of position it will need to be in for troop delivery for air assault.
An interesting 2007 U.S. Army paper called “The Fundamentals of Flight” further explains the “downwash” phenomenon, an aerodynamic circumstance that can generate unstable, turbulent air components in the surrounding vicinity of an aircraft when rotor blades generate a “downward flow of air.”
“As blade pitch angle is increased, the rotor system induces a downward flow of air through the rotor blades creating a downward component of air that is added to the rotational relative wind. Because the blades are moving horizontally, some of the air is displaced downward. The blades travel along the same path and pass a given point in rapid succession. Rotor blade action changes the still air to a column of descending air. This downward flow of air is called induced flow (downwash). It is most pronounced at a hover under no-wind conditions,” the paper writes.
Kris Osborn is the defense editor for the National Interest. Osborn previously served at the Pentagon as a Highly Qualified Expert with the Office of the Assistant Secretary of the Army—Acquisition, Logistics & Technology. Osborn has also worked as an anchor and on-air military specialist at national TV networks. He has appeared as a guest military expert on Fox News, MSNBC, The Military Channel, and The History Channel. He also has a Master's Degree in Comparative Literature from Columbia University.