Why The B-21 Raider Stealth Bomber May Be the Stealthiest Plane Ever To Exist

The recently revealed Northrop Grumman photo of the sleek, stealthy airborne B-21 Raider bomber presents a new and significant view of the mysterious and largely “black” aircraft, a next-generation platform reported by Pentagon weapons developers containing paradigm-changing technologies in the realm stealth, sensing, computing and high-altitude, high-risk bombing attack.

Clearly many of its stealth properties and advanced technologies will not be available for public discussion given the secret nature of the program, yet the recent photo does offer an as-of-yet unprecedented side-view of the new aircraft. A quick look at the external configuration would seem to suggest that indeed the aircraft may contain massive “leaps-forward” in the realm of stealth technology.

A key element of the aircraft might jump out at observers, as its “inlets” are smoothly woven into the rounded fuselage-wing-body structure in a way that is flatter, more horizontal, less angular and more seamless than its B-2 predecessor. Simply put it is less vertical and flatter in its integration with the body of the aircraft, something of great significance because any kind of protruding or vertical structure, however rounded or “blended” into the fuselage of the aircraft, introduces the prospect of an increased radar signature. Vertical structures and sharp angles, in pure aerodynamic terms, create shapes, angles and contours electromagnetic radar “pings” are able to bounce off and generate a return rendering. A completely flat aircraft, by contrast, offers few if any protruding structures or angles off of which radar pings traveling at the speed of light can bounce off. Radar and air defense systems, of course, generate a picture or rendering of a threat object by virtue of bouncing electromagnetic signals off of a structure and analyze the return, thus creating a rendering or image of some kind of the size, shape or even speed of the object. This is why the F-35 and F-22, while quite stealthy and believed to be effective against many air defense systems, are ultimately less stealthy than a fully horizontal blended wing-body aircraft such as the B-2 or B-21.

This makes sense, as a B-21 is not designed to “dogfight” or vector in the air per se but instead actualize “broadband” stealth and “penetrate” defended enemy airspace without an enemy even know it is “there” at all. B-2 and B-21 bombers therefore, are said to present as a “bird” or small airborne animal to enemy radar, given the absence of detectable “shapes,” “structures,” and angles contained on the fuselage. Vertical structures, such as tails and fins for example, decrease stealth properties to some extent while simultaneously enabling maneuver, speed and air-to-air combat. At the same time, an ability to maneuver at high speeds and “vector” in the air are things which in and of themselves are stealth enhancing, radar signature reducing attributes, something capable of presenting challenges to ground-based radar seeking to establish a “target lock” or “track” on a threat object.

The intent of broadband stealth is to be entirely “stealth,” meaning the aircraft can elude both lower-frequency “surveillance” radar able to detect something is “there,” and higher frequency engagement radar able to establish a track and lock on the target and actually “engage” and destroy the aircraft.

Heat Signature

Also, looking at what can be seen in relation to the back of the airplane, there are no exhaust pipes or area. None? At least none that can be seen. This could be extremely significant, as thermal signature management is among the most important variables in the realm of stealth; the closer an aircraft is to its surrounding temperature and the less “heat” it emits, the less detectable it is to infrared or thermal sensors. It certainly could be true that an internally buried engine and certain unknown or yet-to-fully-exist technological systems have massively lessened or removed the aircraft’s heat emissions. There are known to be many advanced “cooling” technologies, yet it might indeed seem paradigm-changing if the B-21 were somehow able to operate with a new generation of thermal management technologies.

Several years ago, former Air Force Acquisition Executive Gen. Arnold Bunch (now the Commander of Air Force Material Command) told me that the B-21 would be able to hold “any target at risk in the world … at any time.” This was several years ago as some of the earlier subsystems of the aircraft were starting to take place, yet his remarks as an acquisition leader and expert made an impression. Since this time, the program is reportedly quite successful, so it may be that there is a clear, if yet unknown, technological basis for the measure of confidence senior Air Force weapons developers have in the B-21.

“Even the most sophisticated air-defense systems will struggle to detect a B-21 in the sky,” Austin said in December 2022 at the unveiling of the platform.

Sensing and Computing

Alongside whatever stealth technologies the aircraft contains, attributes which likely include radar absorbent materials, embedded antennae, and acoustic signature management, the B-21 is reported to contain unprecedented advantages in the area of weaponry, sensing, and computing. Very little is said about this, however at its formal unveiling in December of 2022, Defense Secretary Lloyd Austin did say the aircraft would function as a flying sensor “node” or command and control platform in the sky supporting a multi-domain network of platforms, weapons, drones and sensors.

“You know, the B-21 looks imposing. But what’s under the frame and the space-age coatings is even more impressive,” Austin told the audience in December 2022.

“It can handle anything from gathering intel to battle management to integrating with our allies and partners. And it will work seamlessly across domains, and theaters, and across the joint force,” Austin said.

A very intelligent analytical essay in The War Zone by Tyler Rogoway mentions the presence of “sensors” on the aircraft visible in the newly released photograph.

“Air data sensors are now visible along the B-21’s lower and upper fuselage. These flush-mounted devices are absolutely critical to maintaining stable flight for the Raider, which relies entirely on fly-by-wire computers to keep airborne and flying in the right direction,” Rogoway writes.

Rogoway may be onto something here, as for years aviation experts have maintained that future military aircraft will fly with “smart skins,” meaning with advanced sensors woven into the fuselage of the aircraft itself.

Threat Sensing & Manned-Unmanned Teaming

Senior Air Force weapons developers have also been clear that the B-21 will operate with and likely control unmanned systems as “loyal wingmen” in position to advance forward sensing, reconnaissance and targeting.

When it comes to threat information, Austin also made this clear that the bomber will be “multifunctional,” meaning it will perform a wide range of missions beyond simply “attacking” or dropping bombs.

More than 100 B-21s?

Members of Congress, think tanks, and even some Air Force senior leaders have suggested in recent years the possibility that perhaps the planned fleet size for the B-21 should be much larger than the planned 100 planes and possibly double up to more than 225. Future budgets may adjust the service’s plans for t
he fleet, yet the expected program plan is to acquire as many as 100, the first several of which are already well along and in the air.

Ground-based air defense radar technologies have become increasingly sensitive and precise, longer-range, better networked through digital processing and capable of operating on a wider range of frequencies. These technologies, as exhibited by Russian S-400 and Chinese HQ-9 air defenses, have vastly increased the risk to stealth platforms in recent years and inspired a need for a new generation of low-observable technology.

Russian Air Defenses

Russian media claims its new S-400 and S-500 Surface-to-Air-Missiles are able to track and shoot down even “stealth” platforms, an ambitious claim which does not seem to have been verified or corroborated in any substantial way. What is known, however, is that new Russian-built air defenses are networked to one another with much faster computer processing, able to see or detect targets at much greater ranges and capable of operating on a wider range of frequencies.

However, this does not mean that these systems can actually succeed in “hitting” or engaging a stealth bomber, especially an advanced one like the B-21 is reported to be. A given radar or air defense system may succeed in determining that something is “there” or in a general area of operations using low-frequency surveillance radar, however that does not mean the system can actually establish a target track on a moving stealth bomber and actually “destroy” a stealthy platform. This requires a much greater level of precision, track loop fire control and image fidelity to accomplish, and it appears there are likely many “undisclosed” stealth properties built into the B-21.

B-21 Computing

It is also a reasonable assumption that the B-21 will incorporate a new generation of data processing, sensing, weapons employment and AI-empowered computing. Several years ago, former Air Force Acquisition Executive William Roper published some significant comments about the B-21’s progress regarding software and key elements of mission command, saying that developers completed an essential software-empowered process intended to bring greater levels of information processing, data management, and computerized autonomy.

Through virtualization and software-hardware synergy, it seems conceivable that B-21 sensors, computers, and electronics could better scale, deploy, and streamline procedural functions such as checking avionics specifics, measuring altitude and speed, and integrating otherwise disparate pools of sensor information. In effect, it means war-sensitive sensor, targeting, and navigational data will be managed and organized through increased computer automation. This will allow pilots to make faster and more informed combat decisions.

In previous statements, Roper has referred to the B-21’s inclusion of “Containerized Software,” something which refers to an ability to program computer operating systems to streamline and compartmentalize different functions simultaneously, yet without launching an entire machine for each app, according to “Kubernetes’” website. Roper cited Kubernetes, which is a computer system for “automating application deployment, scaling and management.” Much of this, as cited by Roper, is made possible through what’s called application containerization; it is defined as an operating system-level “virtualization method used to deploy and run distributed applications,” according to Techtarget.com. Containerization enables multiple “isolated applications or services to run on a single host and access the same operating system.” (See Warrior’s previous B-21 article citing Roper)