The US Air Force (USAF) has released a new rendering of the Northrop Grumman B-21 Raider stealth bomber, showing an unusual window layout.

The “artist rendering graphic” is only the third image of the highly secretive, in-development flying wing to be released.

B-21 rendering at Edwards AFB c USAF

Source: US Air Force

The B-21 is one of the USAF’s top priorities

“As with past renderings, this rendering is an artist’s interpretation of the B-21 design,” the USAF said on 6 July. The shape and configuration of the B-21 is highly sensitive as it influences the aircraft’s radar cross section.

This most-recent artist rendering differs from the second rendering, released in early 2020, in that the B-21’s cockpit windows are shown to be divided into multiple pieces: a triangle-shaped forward window and a diagonal parallelogram side window. The rendering only shows one side of the aircraft, but presumably the layout is the same on the opposite side, meaning the cockpit is made of four window pieces.

The USAF gave no explanation for the window layout. However, cockpit canopies can reflect radar waves increasing the radar cross section of an aircraft. Smaller windows might make the aircraft stealthier.

The B-21 is in the engineering and manufacturing development phase. The USAF says it is “focused on scaling the manufacturing infrastructure and capacity across the industrial supply base to prepare for low-rate initial production” of the aircraft.

The 420th Flight Test Squadron based at Edwards AFB in California is tasked with planning for testing, analysing and reporting on all flight and ground testing of the B-21 Raider, says the service. The stealth bomber is being built at Northrop Grumman’s facilities at nearby US Air Force Plant 42 in Palmdale.


Source: US Air Force

The final configuration of the B-21 remains open to speculation as renderings released by the USAF differ. For example, the windows on this 2020 image are different from the most-recent image

The service says the next-generation stealth bomber is designed to perform long-range conventional and nuclear missions. It should be able to “operate in tomorrow’s high-end threat environment”.

The USAF wants to buy a minimum of 100 examples of the B-21. The average unit procurement cost of the stealth bomber is estimated to be $639 million (in 2019 dollars).

The aircraft is to be part of the USA’s nuclear triad, a strategy that aims to have three options for nuclear strike: aircraft-carried bombs and missiles, ground-based ballistic missiles or submarine-based ballistic missiles.

“Nuclear modernisation is a top priority for the Department of Defense and the air force, and B-21 is key to that plan,” says Randall Walden, air force rapid capabilities office director. “The built-in feature of open systems architecture on the B-21 makes the bomber effective as the threat environment evolves.”

The USAF plans to gradually replace its fleet of Boeing B-1B Lancer and the Northrop B-2 Spirit bombers with the B-21. It aims to have a two-type bomber fleet made of the B-21 and modernised Boeing B-52s, which would receive more efficient engines and electronics upgrades.

The USAF wants the B-21 to be operational starting in the mid-2020s. Service officials have said they anticipate the aircraft will first fly in early 2022.

The article was updated on 7 July with information about US Air Force Plant 42

B-21 rendering

Source: US Air Force

The shape and configuration of the B-21 is highly sensitive as it influences the aircraft’s radar cross section