F-47 First Flight and NGAP Engine Schedule Discrepancy
The U.S. Air Force’s next-generation air superiority fighter, the F-47, is under development with a target for its first flight in 2028. In contrast, the Next Generation Adaptive Propulsion (NGAP) engine, a next-generation propulsion system, is expected to reach the aircraft integration stage around 2030, making it likely that the initial test aircraft will use a different engine.
However, it is difficult to immediately conclude that this indicates inferior engine performance. The U.S. Air Force has not disclosed the engine model used in the initial F-47 test aircraft, nor the timing of the NGAP (Next Generation Adaptive Propulsion) implementation. Furthermore, a phased testing approach utilizing existing engines has not been officially confirmed.
What is the current progress of the F-47 development schedule?
On March 21, 2025, the U.S. Air Force selected Boeing as the prime contractor for the F-47 design and development program, initiating the engineering and manufacturing development phase. The F-47 is a manned fighter aircraft designed to replace the F-22 Raptor and operate in conjunction with other combat aircraft.
U.S. Air Force officials stated that they are maintaining the goal of a first flight in 2028, even in 2026. Initial aircraft construction and test preparations are underway. During the development phase, a limited number of test aircraft will be used to evaluate flight control, structure, software, and mission system integration.
The first flight does not mean that the combat mission capabilities have been completed. The development test aircraft can gradually integrate sensors, weapons, engines, and mission software after confirming safety and basic design within a limited flight area.
NGAP engine: Target for integration by approximately 2030
According to a report by Breaking Defense, John Snieden, the U.S. Air Force’s propulsion systems director, stated that the NGAP program aims to prepare for potential aircraft integration activities around 2030. He explained that the NGAP engine could be applied to the F-47, but that a final decision has not been made.
In the NGAP program, the GE Aerospace XA102 and the Pratt & Whitney XA103 are competing. Both engines aim to incorporate adaptive engine technology, which adjusts the balance between thrust, fuel efficiency, and cooling capacity based on flight conditions.
Pratt & Whitney announced that it will complete the assembly readiness review for the XA103 in May 2026 and will proceed with the procurement and manufacturing of components for the service engines. Ground testing is planned for the late 2020s, which creates a gap between that schedule and the planned first flight of the F-47 in 2028.
According to an analysis of the U.S. Air Force budget data by the Air & Space Forces Magazine, the NGAP engine research and development budget for fiscal year 2027 is approximately $514,000,000, and is projected to increase to approximately $906,000,000 for fiscal year 2028. This suggests that the development and testing of the engine will likely be concentrated during that period.
Early engines are not necessarily inferior engines
If the F-47 uses engines other than those provided by NGAP during its first flight, the test aircraft’s range, thermal management capabilities, power output, and some high-speed performance may not reach the final target specifications. However, if the purpose of the initial flight is to verify the airframe’s safety and flight control, it is not necessary to implement all final performance characteristics from the beginning.
Conversely, if the airframe, intake, and cooling system are designed specifically for a particular Next-Generation Adaptive Propulsion (NGAP) engine, subsequent engine replacement could increase the burden of integrated testing and design modifications. The size and weight of the engine, as well as its airflow, vibration, and exhaust characteristics, also affect the aircraft’s stealth performance and center of gravity.
Therefore, the key issue is not the superiority of the initial engines, but rather how efficiently the differences between the test engines and the final propulsion system are managed. The choice of which engine the U.S. Air Force uses for initial testing, and from which production stage the NGAP engine will be implemented, will likely determine the future schedule and costs.
Lessons from the F-22 development case
During the development of the F-22’s predecessor, the YF-22, aircraft and engine competitions were conducted simultaneously. According to materials from the U.S. Air Force National Museum, the YF-22 and YF-23 prototypes were equipped with either the Pratt & Whitney YF119 or the General Electric YF120 engines for flight testing.
The U.S. Air Force selected the YF-22 airframe and the YF119 engine in 1991. Subsequently, an improved version of the F119 engine was used in the production F-22 aircraft. This is an example of how the engine configuration in the early development phase may differ from the final production model, but it does not necessarily mean that the prototype engine was inferior.
F-47 Engine Selection Will Determine Development Success or Failure
Based on the currently available schedule, there is a significant possibility that the NGAP engine will not be used in the F-47’s first flight in 2028. However, details regarding the type and performance of the initial engine, as well as the timing of the NGAP implementation, are classified and have not been disclosed.
A key aspect of the F-47 development, more significant than the first flight itself, is the integration of the propulsion system, which is planned for around 2030. To achieve the thrust, fuel efficiency, and thermal management capabilities that the NGAP engine aims for, and to ensure it is integrated according to the aircraft’s schedule, is crucial for realizing the F-47’s long-range operational capabilities and its ability to operate next-generation sensors.
Frequently Asked Questions (FAQ)
When will the F-47 have its first flight?
The current goal, as revealed by the U.S. Air Force, is 2028. Boeing is currently conducting development, prototype aircraft production, and engineering and manufacturing development work.
Does the F-47’s first flight use the NGAP engine?
The details have not been finalized. Because the NGAP program aims to complete aircraft integration preparations around 2030, it is possible that a different test engine or an existing engine model will be used for the first flight in 2028.
Do the initial engines of the F-47 have lower performance than the final engines?
While there is a possibility that some performance aspects may not reach the final target, the official specifications have not been released. Initial tests primarily focus on structural integrity and flight control verification, so engine differences do not necessarily indicate a general performance deficiency of the entire aircraft.
What are the candidate engines for the NGAP?
GE Aerospace’s XA102 and Pratt & Whitney’s XA103 are competing. Both candidates are under development with the goals of adaptive engine technology and improved thermal management capabilities.
Did the F-22 use different engines in the prototype and production versions?
During the YF-22 prototype phase, the YF119 and YF120 engines competed. The U.S. Air Force ultimately selected the YF119. Subsequently, the production F-22 aircraft were equipped with the F119 engine, which was a further development of the YF119.
