The B-21 Raider, developed by Northrop Grumman for the United States Air Force, is a cutting-edge stealth bomber designed to replace the aging B-1 Lancer and B-2 Spirit bombers. One of its critical features is midair refueling, which extends its range and allows for long-duration missions.
However, this capability comes with several challenges. The USAF has options to solve these issues, but naturally, none of them are cheap.
The B-21 Raider’s advanced stealth features make it less detectable by enemy radar, crucial for penetrating heavily defended airspace. Midair refueling, which involves receiving fuel from aerial tankers while in flight, significantly extends the bomber’s range and mission duration.
The B-21 is expected to use the boom refueling method, where a rigid, telescoping tube is extended from the tanker to the receiving aircraft. This method allows for a higher fuel transfer rate compared to the probe-and-drogue method used by smaller aircraft.
The B-21 Has a Refueling Problem
Despite its advantages, midair refueling for the B-21 presents several challenges. One issues that many are concerned about is the lack of refuelers necessary to maintain the future fleet on B-21s.
With an order currently ongoing for a fleet of 100 or more new bombers, the USAF does not currently operate enough refuelers to meet this need. Air Force Gen. Randall Reed, head of U.S. Transportation Command (TRANSCOM), stated before congress that the B-21 has a “bit higher requirement, specifically in the fuel transfer.”
Whether he is referring to the specific rate at which tankers dispense fuel, total fuel capacity available for transfer, or both, is unclear.
The main concern in regard to the B-21 is maintaining the bomber’s stealth profile during refueling operations. The process of connecting with a tanker and the presence of the refueling boom can potentially compromise the B-21’s low observability. Ensuring that the refueling operation does not expose the B-21 to enemy radar is a critical challenge.
Refueling any Aircraft is a Stressful Process
The exact weight and fuel capacity of the B-21 are still unknown. However, according to a report by Aviation Week, “The B-21’s weight and fuel capacity are not known, but the bomber’s size is generally considered around two-thirds the mass of a B-2A,” The report continues, “a single B-2A can carry up to 167,000 lb. of fuel. Assuming a 1,200 gal. per minute transfer rate, it could take about 17 min. for a KC-46 to completely refill 80% of the fuel capacity of a B-2A.”
Additionally, midair refueling requires precise coordination between the bomber and the tanker aircraft, including maintaining the correct speed, altitude, and positioning. Any deviation can result in a failed refueling attempt or even damage to the aircraft.
During the refueling process, both the B-21 and the tanker aircraft are vulnerable to enemy attacks, requiring additional protective measures such as escort fighters.
Does the Air Force Need Stealth Tankers?
To address these challenges and enhance refueling capabilities, the Air Force is investing in Next-Generation Air-Refueling Systems (NGAS). Expected to enter service by 2040, one key advancement is autonomous refueling, which uses advanced sensors and artificial intelligence to automate the process, reducing the need for manual intervention. This can improve precision and reduce the risk of human error.
Thes tankers, designed with low observability features, can operate in contested environments without being easily detected by enemy radar. Stealth tankers would enhance the survivability of both the tanker and the receiving aircraft during refueling operations. Improvements in boom technology are also being pursued, including developing booms with greater flexibility and precision, allowing for more efficient fuel transfer and reducing the time required for refueling.
Advanced booms may also incorporate stealth features to minimize their radar signature.
Effective communication between the tanker and the receiving aircraft is crucial for successful refueling operations. The NGAS expected to incorporate advanced communication technologies that provide secure, real-time data exchange, improving coordination and reducing the risk of errors.
The Air Force is also exploring the development of multi-role tankers that can perform various missions in addition to refueling. These tankers could be equipped with sensors and weapons systems, allowing them to provide reconnaissance, electronic warfare, and even defensive capabilities during refueling operations.
The NGAS project is still firmly in the conceptual phase and is far from being a reality.
B-21 Raider bomber.
Can the Airforce Solve its Fuel Issue?
The B-21 Raider’s midair refueling capabilities are essential for extending its operational range and enhancing its mission flexibility. However, maintaining the bomber’s stealth profile, integrating advanced technologies, and ensuring operational coordination present significant challenges.
To address these issues, the Air Force is actively developing next-generation air refueling systems that incorporate autonomous refueling, stealth tankers, advanced boom technology, enhanced communication systems, and multi-role capabilities.
These advancements aim to improve the efficiency, safety, and stealth of midair refueling operations, ensuring that the B-21 and other aircraft in the fleet can effectively carry out their missions in contested environments.
The ongoing efforts to enhance air refueling capabilities reflect the Air Force’s commitment to maintaining air superiority and operational readiness in an increasingly complex and contested global security environment.
By investing in cutting-edge technologies and innovative solutions, the Air Force could overcome the challenges associated with midair refueling and ensure the continued effectiveness of its strategic bomber fleet.
About the Author: Isaac Seitz
Isaac Seitz, a 19FortyFive Defense Columnist, graduated from Patrick Henry College’s Strategic Intelligence and National Security program. He has also studied Russian at Middlebury Language Schools and has worked as an intelligence Analyst in the private sector.
