There is no doubt that the new B-21 looks stealthier and possibly much more advanced than its B-2 predecessor. Yet the Air Force's newly unveiled “rendering” or image of the new B-21 stealth bomber seems to introduce some interesting questions about how new paradigms of the low-radar signature may have been achieved. 

Little or nothing is known about the technological composition of the new bomber, apart from a visible external configuration and consistent comments about computing, sensing, open architecture, weapons applications, and overall upgradeability. However, there does seem to have been a consistent belief that the B-21 bomber may in fact break through new levels of previously nonexistent stealth characteristics and technologies.  While avoiding specifics, senior Air Force leaders have for many years now said the B-21 will be able to hold any target at risk, anywhere in the world — anytime. That is quite a measure of confidence given the many well-known advances in air-defense technology, something which may indicate that new innovations have changed the detectability specifics related to stealth to a surprising degree. 

If true, how is this achieved?  Well, a few questions do seem to jump out to the naked eye.  Where are the engine inlets? The image is only a side rendering, so they may simply be less visible. However, fuselage embedded inlets on top of the fuselage just alongside the main cockpit body have been visible in most if not all other renderings and photos of the aircraft. 

This may simply be because they cannot be seen due to the angle of the image. Or perhaps they are even smaller, smoother, and even more blended into the body of the aircraft so as to be less visible to enemy radar.  Clearly, the incoming air to be compressed and ignited with gasoline in an engine needs to come from somewhere, so surely the aircraft does has inlets, yet there may be something entirely new about how they are blended into the body of the fuselage in a smooth, conformal way in order to avoid giving off any kind of electromagnetic “ping” return signal. 

On the B-2, by contrast, the engine inlets protrude up from the top of the fuselage on either side. While still rounded into a horizontal body shape, the inlets on the B-2 clearly protrude a bit, something which seems to have been avoided with the B-21. The inlets may be smaller, more conformal and more closely built into the main structure of the fuselage to be less “findable” by enemy radar. 

Then there is the issue of the exhaust or potential heat signature question. There appears to be a not-so-surprising internally buried engine, something characteristic of many stealth bombers, yet has the Air Force found new infrared suppressors or thermal management technology sufficient to manage, dissipate or even eliminate the exhaust and heat fundamental to propulsion and aircraft take off? 

There are no visible exhaust structures, something which raises the interesting question as to whether newer kinds of stealth innovations have been found and applied.  

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.

Image: Reuters