The new B-21 bomber was unveiled to keep many of its innovations under wraps, but more than 34 years of technological advances since the B-2’s 1988 rollout were visible.

The majority of what makes the B-21 a “sixth-generation” combat aircraft is “on the inside.” Still, several external features hint at its evolution from the technology of the B-2, which is also a stealthy flying wing.

The Intakes

First off, the intakes. The B-21’s slender, air-eating air inlets are among its most attention-grabbing aspects. The B-21’s wing roots are almost intimately connected to the intakes, unlike the B-2, where the scalloped intakes are higher and more prominent. Radar likes abrupt angles and big cavities, but the B-21’s intakes look too small to draw in air for the plane’s engines adequately.

However, according to other analysts, “as long as you have enough inlet area to accept the required mass flow of air, your engines will work fine.”

The real challenge, however, “is designing an inlet that can handle the distortions and gradients caused by the fact that the air is moving over significant surface area of the inlet before being ingested. That’s more a matter of tailoring the channel shape in the inlet.”