As the "leader" in the aviation field, the United States' military engines have also always led the world. Recently, aerospace power giant General Electric (GE) announced that its XA100 engine can be adapted to F-35B vertical take-off and landing fighter jets, which also means that the entire F-35 series has better power options.
[XA100 for ground testing in Virginia ]
According to GE, after testing, the XA-100 engine has proved to have the ability to power F-35B. It has been previously proved that it can be adapted to conventional F-35A and carrier-based F-35C. GE's "Edison Factory" has completed the integration research of the XA100 engine and the F-35B fighter , and has evaluated the performance improvement data after the F-35B is replaced.
So who is this XA100? It can actually replace the F-135 turbofan engine currently used by the F-35?
XA100 is known as the world's first three-passage adaptive cycle engine and was first ignited in December 2020. The XA100 is said to be able to adapt to both F-35A and F-35C, and can be replaced without any structural modifications to the fuselage.
[GE uses CG to display XA100's three-duct adaptive technology]
XA100 On the surface, GE is the new generation of turbofan engine developed by the F-35 family, but it is actually the product of the "Next Generation Adaptive Propulsion Plan" (NGAP), and NGAP is actually serving the "Next Generation Air Advantage Plan" (NGAD). Simply put, NGAP is an adaptive engine project led by the US Air Force, and NGAD is the sixth-generation fighter project.
XA100 can be regarded as an engine developed by GE for the sixth-generation fighter, but it can also be used for the power upgrade of the F-35. However, the P-High F135 series engine equipped by the F-35 family is already the most powerful military high-thrust turbofan engine in service. Why should the XA100 engine be replaced?
[F135 is already a very advanced engine, but the US military is still not satisfied]
From the data, the maximum afterburner thrust of the F135-PW-100 equipped with the F-35A is 191kN, while the thrust of the XA100 can reach more than 200kN. If you roughly convert it, it will be about 20 tons of thrust. According to GE's expectations, the final thrust increase can reach more than 10%. In addition, the fuel consumption of XA100 is 25% lower, and the acceleration response is 20%-40%. Using lighter and more durable materials and advanced additive manufacturing methods improves the life limit, reliability and serviceability of the engine.
If estimated according to the thrust value, one XA100 is equivalent to two F414 medium-thrust turbofan engines, and the fuel consumption is even lower. For twin-engine fighters like the F/A-18, you can no longer need a dual-engine design, and one engine is enough. The F-35 only uses a single shot, achieving a take-off weight equivalent to the F/A-18E/F. It can be seen that the saying that as long as the thrust is strong enough, it is not groundless to fly into the sky even if you move bricks.
[In GE's publicity, the XA100 engine has achieved a comprehensive improvement compared to F135]
XA100 The most important reason for all these advantages is the use of adaptive variable cycle technology, which is also the core technology of the sixth generation engine recognized by the industry.
Compared with the conventional turbofan engine , the XA-100 variable cycle engine has three ducts. According to the engine's working scenario, the size and diameters of the three ducts can be adjusted through adaptive fans and the airflow direction can be controlled, thereby improving the fuel efficiency of or thrust.
In economic cruising state, the engine needs to improve fuel efficiency and save fuel. The fan of the XA100 engine can direct the airflow to the third bypass duct; during acceleration or transsonic speed, the engine needs to increase the thrust, and the fan can direct all the airflow to the core engine.
[ variable cycle engine working mode demonstration diagram]
According to GE, compared with the current small bypass ratio turbofan engine, XA100 can increase the battery life by up to 35% under the same internal oil state, and can provide stronger cooling capacity, providing the possibility for future use of directional energy weapon .
Aerospace Engineering is one of the areas in which the US aviation industry maintains its dominant position. The United States pays more attention to maintaining a leading position in this field and strives to lead other opponents at least one generation.
As early as 2007, the US Air Force and Navy had long dominated the "Adaptive Multi-Purpose Engine Technology Project" (ADVENT) to try to develop adaptive variable cycle engines, but due to the advanced concept, they soon encountered technical bottlenecks. However, the US military did not give up. The "Adaptive Engine Technology Demonstration Plan" (AETD) was released in 2012. This plan is determined to enter the actual testing stage, and GE occupies an important position in this plan.
[Schematic diagram of F-35A installing an adaptive variable cycle engine, pay attention to the ducted air flow of three colors]
GE used a three-stage adaptive fan and a ten-stage high-pressure compressor derived from the CFM LEAP engine to assemble a ground demonstration prototype. It began to enter the ground testing stage in 2015 and reached the highest combined working temperature of compressor and turbines in the history of the development of jet engine , laying the foundation for subsequent testing.
In 2016, the US military launched the "Adaptive Engine Transition Plan" (AETP), which clearly stated that it would develop power for the sixth-generation fighter jets. In the end, only GE and Pratt & Whitney were the ones who got the budget. The former took out the XA100, while the latter developed the XA101. However, due to unknown progress in the sixth-generation aircraft at that time, the AETP plan was finally revised in 2018 to mainly seek alternative power for the F-35.
In August 2022, the XA100 completed its last major contract test at the Arnold Engineering Development Complex of the US Air Force, which could theoretically be provided to the F-35A and F-35C in 2027.
[The XA101 engine developed by Pratt & Whitney has also entered the testing stage]
XA100 is a pioneer model among adaptive variable cycle engines. Although it has made a significant improvement compared to traditional small duct turbofan engines, the hard indicator improvement is not obvious. To some extent, it should be considered a "five-generation and a half" engine. However, adaptive variable cycle technology has definitely allowed the XA100 to surpass any military turbofan engine in service. The future sixth generation of the US military is most likely to be the descendants of the XA100 or XA101.
From 2007 to 2027, through the exploration and development of these models, the US military will spend 20 years to establish the technical generation difference for potential opponents.
