U.S. Air Force Tests “Pathfinder” Subscale Model of Blended-Wing Body Jet

JetZero is working on the subscale BWB aircraft demonstrator, named “Pathfinder,” while Northrop Grumman’s Scaled Composites division is fabricating the full-size airplane and has already produced test articles of components.

The U.S. Air Force is collecting data from flight tests of a subscale version of its BWB (Blended-Wing Body) demonstrator to inform the full-scale aircraft’s control software and final configuration, recently reported Air and Space Forces Magazine. A USAF spokesperson revealed several updates about the project, confirming that it remains on track for a first flight in 2027.

The BWB project saw the Department of the Air Force select aerospace startup JetZero on Aug. 16, 2023. The company subsequently revealed a 12.5% scale version of the future full-size aircraft in Apr. 2024. The subscale aircraft has a 23 feet wingspan.

Among the details, the spokesperson mentioned that the demonstrator, nicknamed “Pathfinder”, confirmed that the concept being developed by JetZero has similar flight dynamics to the last such BWB subscale project, the Boeing Phantom Works’ X-48.

BWB aircraft, a sort of a mix between a “flying wing” like the B-2 Spirit and conventional fuselage-and-wing configurations, have more space in the middle for payload and reduce drag by providing greater lift, allowing to cut fuel use by 30%. The reduced cost and easier logistics have cascading benefits for both military and civilian passenger, cargo aviation, which is also why the project is led by the Air Force Assistant Secretary for energy, installations and environment.

Under a cost-sharing agreement for the BWB program, the Air Force will front  $230 million, with private investors having pledged roughly $300 million, according to industry officials. The FAA (Federal Aviation Administration) granted the airworthiness certification in Mar. 2024 for the 1:8 scale aircraft to begin flight tests.

The test flights were originally planned to begin in 2023, but were pushed back due to supply chain issues. While 2026 will see fabrication of the full-scale aircraft, ground testing will start in Apr. 2027 and the first flight is expected by Sept. 2027.

Subscale model informing full-scale design

As per the spokesperson, the subscale aircraft initially flown at Crow’s Landing in California “has similar flight dynamics to previous BWB subscale aircraft, namely X-48.” The NASA-Boeing program concluded the test flying of the remotely piloted X-48B and X-48C Hybrid/Blended Wing Body research aircraft after what has been defined as a highly successful and productive flight test campaign at the Dryden Flight Research Center by early-2013.

The current project sees JetZero working on the subscale BWB aircraft while Northrop Grumman’s Scaled Composites division is fabricating the full-size airplane. Scaled Composites “has begun manufacturing full-scale parts for testing purposes,” said the spokesperson.

To that effect, the company built “a wing test article” that will be used to “refine and validate structural models for the full-scale aircraft.” JetZero also made “significant progress in its integrated test facility…which enables systems integration testing to begin well before initial manufacturing of the full-scale aircraft.”

Tests of the Pathfinder subscale demonstrator is also enabling “refinement of flight control laws applicable to the full-scale demonstration aircraft,” added the spokesperson. “Further flight testing will serve to validate [Computational Fluid Dynamics] models and performance characteristics of the outer mold line,” she said.

As Tom O’Leary, co-founder and CEO of JetZero, told CNN, the main technical challenge is the “pressurization of a non-cylindrical fuselage.” A tube-shaped plane can better handle the “constant expansion and contraction cycles that come with each flight.”

“If you think about a ‘tube and wing,’ it separates the loads — you have the pressurization load on the tube, and the bending loads on the wings. But a blended wing essentially blends those together. Only now can we do that with composite materials that are both light and strong,” O’Leary said in the report.

JetZero  also announced, on Nov. 4, 2024, its partners for the flight control systems of the full-scale BWB aircraft. BAE Systems, Moog, Thales, and Woodward would supply the Active Control Sidesticks, Flight Control Actuators, Pilot Controls and Flight Control Computers respectively.